web dynpro abap for practitioners

Web Dynpro ABAP for Practitioners

Ulrich Gellert l Ana Daniela Cristea

Web Dynpro ABAPfor Practitioners

Ulrich Gellertc/o S P LION AGRobert-Bosch-Str. 968542 [email protected]

Ana Daniela Cristeac/o S + P LION AGRobert-Bosch-Str. 968542 [email protected]

ISBN 978-3-642-11384-0 e-ISBN 978-3-642-11385-7DOI 10.1007/978-3-642-11385-7Springer Heidelberg Dordrecht London New York

Library of Congress Control Number: 2010929263

# Springer-Verlag Berlin Heidelberg 2010This work is subject to copyright. All rights are reserved, whether the whole or part of the material isconcerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting,reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publicationor parts thereof is permitted only under the provisions of the German Copyright Law of September 9,1965, in its current version, and permission for use must always be obtained from Springer. Violationsare liable to prosecution under the German Copyright Law.The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply,even in the absence of a specific statement, that such names are exempt from the relevant protective lawsand regulations and therefore free for general use.All printed screens, SAP, the SAP Logo, my SAP, SAP R/3, ABAP, NetWeaver Portal are subject tocopyright or are trademarks of SAP AG, Dietmar-Hopp-Allee 16, 69190 Walldorf, Germany

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Printed on acid-free paper

Springer is part of Springer Science+Business Media (www.springer.com)

Foreword

Taking Albert Einsteins quote as a motto Example isnt another way to teach, itis the only way to teach, our target was to create a book for explaining step-by-step the Web Dynpro ABAP to the reader. Assisted by practical examples, you will

learn more and more about Web Dynpro ABAP, from chapter to chapter. Moreover,

the connections with other areas are also pointed out by practical examples.

In Chap. 1, we explain what means the Web Dynpro integrated in a SAPNetWeaver platform.

Chapter 2 is about the Easy Access to a SAP System.In Chap. 3, we describe the modality to creating a Web Dynpro Component.

We explain all the elements of a view through examples, and we show you how to

use the ABAP Debugger to diagnose the Application.Chapter 4 gives attention to the ABAP Dictionary, where all the Development

Objects are created. These ones are the basis for all our examples. With thisknowledge, you will be able to easily create Web Dynpro applications.

In Chap. 5, we present the Context Nodes and Attributes and explain theirimportance for the Web Dynpro. We consider the possibilities to create, use, fill in

with data, and read the contents.

In Chap. 6, we go into details with Data Binding, Context Mapping andInterface Methods. For this purpose, we present the Data Binding through simpleexamples. We change these examples step-by-step, to show you a clear picture of

the context mapping (as well as in an internal and external way Direct Mappingand Reverse Mapping).

Chapter 7 covers the View Controller Methods, beginning with some exam-ples of Hook Methods and ending with User Defined Methods and Event Han-dler Methods. Each method is explained by an example.

Chapter 8 illustrates the layout of the UI Elements.In our largest chapter (Chap. 9), we describe in details the User Interfaces (UI).

Each UI element is presented through an example. Moreover, we show the dynamic

programming of these UI elements and give additional information.

v

Chapter 10 includes Messages and Exceptions. We start with the creation of thenecessary classes (Message Class, Exceptions Class andAssistance Class) and weshow you how to use them to create solid applications that catch exceptions and

inform the user through messages.

Chapter 11 is about creating Multilingual Applications on the levels of inter-faces and master data. We also present how to use these data in the Web Dynpro

components.

In Chap. 12, we present several Web Dynpro Models. We show you not onlyhow to use an Assistance Class, a Web Service or a BAPI, but also how to createMulti Component Applications.

Chapter 13 covers the ABAP list viewer (ALV) and the Select options (SO).We start again with simple examples and build them up to an ALV output configu-

ration in combination with SOs.

In Chap. 14, its described the integration of Web Dynpro Applications in theSAP NetWeaver Portal. We present the connection with the back-end ABAPSystem, ending with WD applications that send and react to a portal event.

The next Chapter (Chap. 15) is about Web Dynpro and Authorizations. Weshortly present the Role Based Access Control (RBAC) model and describe theSAP NetWeaver authorization concept.

In our last Chapter (Chap. 16), we would like to show how the Mind Map canhelp you to learn Web Dynpro ABAP easier and faster. We create a Mind Map that

includes all the necessary Web Dynpro Elements.

The examples in our book have been developed on a SAP System with SAP

NetWeaver 7.0 and Support Package 17. From SDN (http://www.sdn.sap.com), youcan download a free of charge SAP NetWeaver Trial Version with ABAP and SAP

GUI, for testing. With this Trial Version, you can create most of our exercises.

Youll also find most of the configuration steps at SDN. To use the SAP interactive

forms by ADOBE, you need both NetWeaver Trial Versions (ABAP and Java),

because ADS is an integral part of the SAP NetWeaver Java version. Additionally,

you need the ADOBE Live Cycle Designer from the SAP Service marketplace. The

configuration steps required in this case are shown in the SAP PRESS book SAP

Interactive Forms by Adobe (Hauser et al.). To be able to work with the portal, you

need the SAP NetWeaver Java Trial Version. In the SAP PRESS book Devel-

opers Guide to SAP NetWeaver Portal Applications (Banner et al.), you will find

all the software and hardware requirements, along with the configuration steps.

The creation of a book takes time. Many discussions with students and devel-

opers made us think about writing a practical book on the Web Dynpro ABAP

subject. The most important issue was to guide the reader step-by-step, with

practical examples. Many weekends, holidays and evenings were invested in this

book, and the positive feedback of our colleagues always gave us new energy.

vi Foreword

http://www.sdn.sap.com

Acknowledgements

We would like to thank our proofreaders Dieter Schmitt and Heinz-Jurgen

Gebhardt. Their advices and comments helped us a lot.

Ulrich Gellert would like to thank all his colleagues of S+P LION AG for theuseful input during the project. I also would like to thank my father, Gerhard

Gellert, who unfortunately died too early. He introduced me into the world of IT

in 1983 and, without him, our company could never become what it is. Special

thanks go to my mother, Gabriele Gellert. She has been supporting me until today,

and she is the heart of our company. Especially, I would like to thank my lovely

wife Carmen and my children Alexa and Marc, for their support during the project.

Ana Daniela Cristea gives special thanks to NWCON Technology Consulting,especially to Thomas Muschalik and S+P LION AG, for their great support. Taking

this opportunity, Id like to thank to the special persons who have been guiding me

through my dissertation: Octavian Prostean and Mircea Vladutiu. Not to forget the

people who encouraged me to publish my first books and articles: Aron Poanta and

Caius Panoiu, thanking them for the useful advices. Last but not least, I would like

to thank my family and friends. Especially to my mother, Sabina Cristea, and to

Susanne and Edgar Hammes, who supported me with all their powers. They gave

me the time I needed to be one of those who wrote this book for you.

vii

Contents

1 What is Web Dynpro? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2 SAP Easy Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52.1 Changing the SAP Easy Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2.2 Favorites List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2.3 Setting a Transaction as Start Transaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.4 Creating a Shortcut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3 Designing a Web Dynpro Component . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113.1 View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

3.1.1 View Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

3.1.2 Context View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3.1.3 Actions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

3.1.4 Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

3.1.5 Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

3.1.6 Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

3.2 Componentcontroller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

3.3 Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

3.4 Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

3.5 ABAP Debugger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

3.6 Web Dynpro Logon Page Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

4 ABAP Dictionary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 334.1 Data Element . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

4.2 Domain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

4.3 Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

4.4 Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

4.5 Search Help . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

4.6 Database View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

4.7 Table Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

4.8 Lock Object . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

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5 Context Nodes and Attributes at Design Time . . . . . . . . . . . . . . . . . . . . . . . . 555.1 Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

5.2 Nodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

5.2.1 Creating a Node that Uses an ABAP Dictionary

Repository Object . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

5.2.2 Working with Child Nodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

6 Data Binding, Context Mapping and Interface Methods . . . . . . . . . . . . . 676.1 Data Binding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

6.2 Context Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

6.2.1 Internal Context Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

6.2.2 External Context Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

6.3 Interface Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

7 View Controller Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 877.1 Hook Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

7.1.1 wdDoInit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

7.1.2 wdDoExit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

7.1.3 wdDoModifyView . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

7.1.4 wdDoBeforeAction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

7.1.5 wdDoOnContextMenu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

7.2 Supply Function Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

7.3 User-Defined Instance Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

7.4 Fire Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

7.5 Event Handler Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

8 Layout UI Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1138.1 FlowLayout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

8.2 GridLayout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

8.3 MatrixLayout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

8.4 RowLayout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

9 User Interface Elements (UI elements), Static and DynamicProgramming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1239.1 Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

9.1.1 Timed Trigger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

9.1.2 ButtonChoice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

9.2 Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

9.2.1 DropDownByKey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

9.2.2 DropDownByIndex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

9.2.3 RadioButtonGroupByIndex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

9.3 Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

9.3.1 ViewContainerUIElement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

9.3.2 TabStrip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146

9.3.3 PageHeader . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149

9.3.4 ContextualPanel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

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9.3.5 Tray UI Element . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155

9.3.6 MessageArea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

9.4 Complex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

9.4.1 Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

9.4.2 RoadMap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171

9.4.3 PhaseIndicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180

9.4.4 Tree Sequential Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . 186

9.4.5 DateNavigator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191

9.5 Graphic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197

9.5.1 Image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

9.5.2 BusinessGraphics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201

9.6 Integration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206

9.6.1 The InteractiveForm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206

9.6.2 FileUpload . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215

10 Messages, Exceptions and Web Dynpro ABAP . . . . . . . . . . . . . . . . . . . . . . 22110.1 Message Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222

10.1.1 Dynamic Texts Stored in the Text Pool

of the Assistance Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222

10.1.2 Text from Database Table T100 . . . . . . . . . . . . . . . . . . . . . . . . . . 225

10.2 Exception Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227

10.2.1 Exception Class with OTR Text . . . . . . . . . . . . . . . . . . . . . . . . . . 228

10.2.2 Exception Class with Text from a Message Class . . . . . . . . 233

11 Writing Multilanguage Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23711.1 Creating Multilanguage User Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . 238

11.1.1 Internationalization of Data Elements Defined

in ABAP Dictionary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240

11.1.2 Internationalization of Domains Defined

in ABAP Dictionary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241

11.1.3 Internationalization of Text from OTR . . . . . . . . . . . . . . . . . . . 242

11.1.4 Internationalization of Text from Assistance Class . . . . . . . 244

11.1.5 Internationalization of Messages . . . . . . . . . . . . . . . . . . . . . . . . . . 245

11.2 Multilanguage Records in the Database . . . . . . . . . . . . . . . . . . . . . . . . . . 247

11.2.1 Study an Example Created in the System . . . . . . . . . . . . . . . . . 248

11.2.2 Creating Table Structures and Internationalization

of the Records . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250

11.2.3 Using the Internationalized Records in WebDynpro . . . . . 255

12 Web Dynpro Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25912.1 Assistance Class as a Model for a Multicomponent

Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260

12.2 BAPI as a Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274

12.2.1 Creating a BAPI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274

12.2.2 Using the Created BAPI as a Model . . . . . . . . . . . . . . . . . . . . . . 279

12.3 Web Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283

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12.3.1 Creating the Web Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284

12.3.2 Web Service Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287

12.3.3 Testing the Web Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288

12.3.4 Consuming the Web Service in Web Dynpro . . . . . . . . . . . . 289

13 ALV and Select Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29513.1 SAP List Viewer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295

13.1.1 Simple ALV Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296

13.1.2 ALV Configuration Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299

13.2 Select Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306

13.3 ALV and Select Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313

14 Integrating a Web Dynpro Application into the SAPNetWeaver Portal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31514.1 Creating a Folder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 316

14.2 Connecting to the Back-End ABAP System . . . . . . . . . . . . . . . . . . . . . . 317

14.3 Creating an iView . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 321

14.4 Creating a Role and Role Assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324

14.5 Running the Application into the Portal . . . . . . . . . . . . . . . . . . . . . . . . . . 327

14.6 Triggering a Portal Event . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 327

14.7 Reacting to a Portal Event . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329

14.8 Creating a Page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 331

14.9 Running the Application that Processes Portal Events . . . . . . . . . . . 333

15 Web Dynpro and Authorization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33515.1 Role Based Access Control Pattern RBAC . . . . . . . . . . . . . . . . . . . . . 337

15.2 Authorization Object Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338

15.3 Authorization Object . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338

15.4 Authorization Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 340

15.5 Creating a Single Role and Changing its Authorization Data . . . . 343

15.6 Creating the Web Dynpro Component . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346

15.6.1 Checking the Authorization of the Current User . . . . . . . . . 346

15.6.2 Assigning the User-Role and Running

the Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349

16 Web Dynpro Mind Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35116.1 Creating a Mind Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 351

16.2 Web Dynpro ABAP Mind Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 352

Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 357

xii Contents

Chapter 1

What is Web Dynpro?

Logic will get you from A to B. Imagination will take you everywhere.

Albert Einstein

Abstract In this chapter, we present the place and role of the Web Dynpro withinthe SAP NetWeaver platform. So, we start with the layers of the SAP NetWeaver

platform, we continue with the importance of the Application Platform layer, and

we conclude with the place and role of Web Dynpro (ABAP and Java) within the

Application Server ABAP and, respective, Application Server Java.

To answer this question we have to look at the SAP NetWeaver technology

platform (Fig. 1.1).

As we can see, four layers are distinguished in this context: Application Plat-

form, Process Integration, Information Integration and People Integration.

The Application Platform represents the technical basis of almost all the other

SAP products. This is the reason why the Application Platform plays a central role

in the SAP NetWeaver.

The Application Platform essentially offers two programming interfaces: ABAP

and Java (J2EE). ABAP is the programming interface for Application Server (AS)

ABAP and Java is the programming interface for AS Java.

To create ABAP and Java applications, we have two independent development

environments: ABAP Workbench for ABAP and SAP NetWeaver Developer

Studio for Java.

Both development environments offer the possibility to create web based appli-

cations built by using declarative programming techniques based on the Model

View Controller (MVC) paradigm.

SAP NetWeaver Developer Studio is the SAPs own development environment

used to develop Java-based multilayer business applications. This development

environment is based on Eclipse and offers a Web Dynpro Perspective to createWeb Dynpro Java applications (Fig. 1.2).

All the tools we need to create Web Dynpro Java applications are found within

the SAP NetWeaver Developer Studio.

U. Gellert and A.D. Cristea, Web Dynpro ABAP for Practitioners,DOI 10.1007/978-3-642-11385-7_1, # Springer-Verlag Berlin Heidelberg 2010

1

ABAP Workbench is the SAPs own development environment used to develop

ABAP-based multilayer business applications. This development environment

offers Web Dynpro Explorer to create Web Dynpro ABAP components (Fig. 1.3).

Fig. 1.2 SAP NetWeaver Developer Studio Web Dynpro perspective

Fig. 1.1 SAP NetWeaver components (SAP)

2 1 What is Web Dynpro?

The Application Server ABAP has the structure presented in Fig. 1.4.

Fig. 1.3 ABAP Workbench Web Dynpro Explorer

Fig. 1.4 AS ABAP (SAP)

1 What is Web Dynpro? 3

As we can see, most of the AS ABAP components can be divided into three

layers:

l Presentation layer.l Business layer.l Persistence layer.

Web Dynpro ABAP is part of the presentation layer and its the SAP standard UI

technology used for developing web business applications without knowing HTML

or JavaScript.

Web Dynpro ABAP offers many advantages, as follows:

l Strict separation between the layout and business data.l Re-use and better maintainability through reusability.l Automatic input checks.l Automatic data transport, using data binding.l WYSIWYG (What You See Is What You Get) view editor.

Web Dynpro ABAP andWeb Dynpro Java mostly offer the same functionalities.

But, of course, there are some differences between them, for example:

l Web Dynpro Java, unlike the Web Dynpro ABAP, disposes of a ViewSet that

allows us to integrate in a Screen more Views, by using certain pre-defined

layouts. In this respect, their common part is the View Container UI Element.l Web Dynpro Java offers graphical tools that ease the programming work, as:

Navigation Manager and Diagram View, unlike the Web Dynpro ABAP where

we dispose only of a tool used to visualize and to define the window structure.

The Web Dynpro ABAP is what the current book is about. More information

about Web Dynpro Java can be found in the Book Inside Web Dynpro for Java byChris Whealy.

4 1 What is Web Dynpro?

Chapter 2

SAP Easy Access

The way to get started is to quit talking and begin doing

Walt Disney

Abstract This chapter presents the SAP Easy Access, highlighting some aspectsfound in our everyday work. So, we show how to change the standard settings, how

to add in the Favorites list the frequently used transactions, and how to create a

Shortcut on the Desktop.

SAP easy access starts automatically after logging-in into the SAP system. In the

left side, we can see the user menu. Here are the functions the user needs to perform

his tasks (Fig. 2.1).

SAP Easy User Menu

Fig. 2.1 SAP easy access


5

2.1 Changing the SAP Easy Access

We can change the SAP easy access settings through the menu Extras ! Settings,by specifying settings as follows:

l The place of the Favoritesl The presents of the menul The easy access picture in the right side of the screen to be present or notl Displays or not the technical names (Fig. 2.2).

2.2 Favorites List

The user menu is mostly defined by the administrator, but we can define our own

Favorites list. Here, we can create our own list of favorites containing items as

transaction, files, web addresses or other objects.

To add new transactions in the Favorite list, we can choose from the menu

Favorites ! Insert Transactions (Fig. 2.3).

As a result, the new item appears in our Favorites list (Fig. 2.4).

We can find the list of the SAP transaction codes in the transparent table TSTC.

Besides the transactions predefined in the system, we can create our own transac-

tions (e.g. with transaction SE93) which are going to be inserted in this table.

Fig. 2.2 Settings

Fig. 2.3 Inserting transaction onto the Favorites list

Fig. 2.4 Favorites list

6 2 SAP Easy Access

Every time we use a transaction, the system verifies in this table whether the

transaction exists and if we have the proper authorization to use it.

As support for our daily tasks, we add here some of the transactions we use in

this book (Fig. 2.5).

To add other objects, we can choose them from the menu Favorites ! AddOther Objects (Fig. 2.6).

Fig. 2.5 Transactions used

Fig. 2.6 Adding new objects in Favorites list

2.2 Favorites List 7

We add the web address to open the SDN page (Fig. 2.7).

We can use Favorites ! Download to PC to save on our computer a list with allthe objects we have in the Favorites folder. To upload in a Favorites folder objects

from a list saved on our computer, we can use Favorites ! Upload from PC.

2.3 Setting a Transaction as Start Transaction

We have the possibility to set a transaction as start transaction: Extras ! Set starttransaction (Fig. 2.8). In this way, the desired transaction is automatically startedafter logging-in into the system (in our case the SE80 transaction), and we dont see

the SAP easy access anymore.

2.4 Creating a Shortcut

After installing the SAP GUI, a SAP logon icon appears on our desktop. By using

this logon, we can login into the system. Additionally, we can create a SAP logon

shortcut to be used to perform the same logon, but we dont need to fill all the

entries in the logon form. A SAP shortcut allows us not only to perform a logon into

the system, but to execute other commands, too. So, we can start a SAP transaction,

run a report or perform a system command.

To create a SAP Shortcut on our desktop to start the transaction SE80, we can

use the Wizard available in the layout menu, by clicking on the respective icon

located in the system function bar (Fig. 2.9).

Fig. 2.7 Inserting a web address

Fig. 2.8 Setting the start transaction dialog box

8 2 SAP Easy Access

Another possibility to create a SAP shortcut on our desktop is to select a

transaction or another object from the Favorites list, and to use the menu Edit !Create Shortcut on the Desktop.

Fig. 2.9 Creating a SAP Shortcut on our Desktop

2.4 Creating a Shortcut 9

Chapter 3

Designing a Web Dynpro Component

Experience is something you dont get until just after you need it

Steven Wright

Abstract The present chapter is dedicated to the constitutive elements of a WebDynpro ABAP component. Moreover, we show how to use the ABAP Debugger to

execute, by line or by section, a Web Dynpro application, and how to use the new

tool offered by ABAP Debugger to reach the context attributes values.

In order to develop a Web Dynpro ABAP component, we have to open the ABAP

Workbench of the Application Server ABAP. To work with ABAP Workbench, we

need an authorization as a developer or a developer key, and for the SAP NetWea-

ver ABAP trial version we can use BCUSER, automatically registered as a devel-

oper. Web Dynpro is available with release SAP NetWeaver 2004s and later.

After logging into AS ABAP, we can use the transaction SE80 to call the objectnavigator (Fig. 3.1).

Fig. 3.1 Object navigator


11

All the repository objects we develop with the ABAP Workbench tool we build

by using the Object Navigator. Here, we develop not only Web Dynpro applications,

but also other development objects (e.g. reports, database tables, data elements,

classes, function modules, etc).

The development objects we create as customer have the first letter y

or z. Therefore, we created a Web Dynpro component with the name

y_wd_component.

We have to assign all the development objects created with ABAP Workbench

to a package. We can use the default package $TMP to create test programs

without transporting, or we can create our own packages. We choose to create our

own package, named Y_WEBDYNPRO (Fig. 3.2).

We have chosen the package type Not a Main Package, because this package

holds development object and not other packages.

After creating the package, we create a Web Dynpro component, as follows:

right-click on the package name and, from the context menu, we select Create !Web Dynpro ! Web Dynpro component. We have to enter the componentname, a short description, the type we want to create, the view name and the

window name (Fig. 3.3).

Fig. 3.2 Creating the package Y_WEBDYNPRO

Fig. 3.3 Creating a Web Dynpro component

12 3 Designing a Web Dynpro Component

After saving our component, we have to assign it to our package (Fig. 3.4).

As a result, in Object Navigator we can see the Package Y_WEBDYNPRO and

our first created Web Dynpro Component (Fig. 3.5).

The name of the development objects marked in blue are not active. After

creating the Web Dynpro component, we have to activate it (Fig. 3.6).

Fig. 3.4 Assigning the component to a package

Fig. 3.5 The content of our package

3 Designing a Web Dynpro Component 13

3.1 View

Each Web Dynpro application has at least one view. Each View has a view Layout,

where we can add different UI (User Interface) elements that can be nested one in

the other one, to create the screen. The positioning of the UI elements in a view is

realized by using the layout and data layout.

Each View has a view controller that is automatically created for this view and

each View has several tabs (Properties, Layout, Outbound Plug, Inbound Plug,

Attributes, Context, Actions and Methods). This indicates that a View consist of

many parts.

3.1.1 View Layout

The screen content of a view is designed in the Layout tab. The View Layout isdivided in three areas:

l UI element libraryl View designerl Context menus, UI elements properties and UI element hierarchy (Fig. 3.7).

Tip

In case an error occurs and in the View Layout we cant see UI Element Library and View

Designer, we have to map the IP address to the host name, because the Web Dynpro ABAP

uses a fully qualified domain name FQDN; in conclusion, the URLs that contain the IP

addresses are not supported

To realize this mapping, we use the HOSTS file (C:/Windows/system32/drivers/etc) where we

enter the IP address and the host name, separated by (at least) one space

In case an error occurs: URL http://hostname:port/sap/bc/wdvd call was terminated because the

corresponding service is not available we have to activate the respective service by using the

SICF transaction

Fig. 3.6 WD component activation


http://hostname:port/sap/bc/wdvd

The UI Elements are grouped in a library to be accessed via the View Layout.

We have several ways to add an UI element into the view layout. For example:

l By right-clicking on the ROOTUIELEMENTCONTAINER (Fig. 3.8)

l By dragging & dropping (Fig. 3.9).

All the UI Elements we enter into a screen are children of the node ROOTUI-

ELEMENTCONTAINER and are represented as a hierarchy where ROOTUIELE-

MENTCONTAINER is the top of this hierarchy. With Swap Root Element we

have the possibility to transform ROOTUIELEMENETCONTAINER from a

Transparent Container into another UI element (Table, FlashIsland, Group, etc.).

In this way, we can use, for example, the FlashIsland UI element to integrate Adobe

Flex into our web Dynpro component. This transformation is possible only if the

ROOTUIELEMENTCONTAINER doesnt have any child UI elements.

Fig. 3.8 Adding UI elements into the view

View Designer

UI element Library

UI elements properties

UI elements hierarchy

Context Menus

Fig. 3.7 View Layout

3.1 View 15

In our ROOTUIELEMENTCONTAINER, we insert one Group UI element, one

InputField UI element, one Label UI element, one TextView UI element and one

Button UI element (Fig. 3.10).

If we select individual UI elements in the layout of a view, their properties are

displayed in the Properties area. In this way, we can change the properties of eachelement. For example, we have changed the property design of the button UI

element and the property state of the InputField UI element (Fig. 3.11).

As a result of changing the property state of the InputField UI element from the

Normal item to the required one, the label associated to this UI element becomes a

red star and the end user knows that this value is mandatory.

For a property, we can create fixed character strings, we can choose from a list,

or we can bind properties to context nodes or attributes by using the Binding button.

For the text property of an UI element Button, we have created a fixed character

string Save. For the design property, we have chosen from the list one of the

supported designs.

Group

Label

Button

TextView

InputField

Fig. 3.10 View layout

Drag & Drop

Fig. 3.9 Adding UI elements into the view


We need to bind the value property of the InputField UI element and the text

property of the TextView UI element. To be able to do this, we will create two

context attributes.

By using Context Menus we have the possibility to create, for an application,

our own context menus displayed in the Browser when the user presses right click

on an UI element. In standard mode, the web Dynpro Framework offers the default

context menus with certain functionalities, e.g. hiding an UI element displayed into

the Browser. After running the application, we can test this standard mode by right-

clicking on the inputField UI element.

3.1.2 Context View

The data are stored in the context and the UI Elements are the only objects the user

interacts with.

Every View has a Context View where we can create context nodes and

attributes. Via data binding, the context of a view controller provides a view with

all the required data. For our application, we create two context attributes named

NAME and GREETING, of STRING type (Fig. 3.12).

To put the data on the screen and to read data from user, we connect the proper

UI Elements properties with attributes or nodes.

In our case, we connect the property value of the InputField UI element with the

NAME attribute. To create a greeting for the user and to show it after the user presses

the Save button, we connect the property text of the TextView UI element with the

GREETING attribute. These connections are known as data binding (Fig. 3.13).

Fig. 3.11 UI element properties

3.1 View 17

The effect of the binding is that, at runtime, any data changes are transported

in both directions and these changes affect all the properties bound to this

element.

Fig. 3.13 Data binding

Fig. 3.12 Creating an attribute in context view


3.1.3 Actions

Some of the UI Elements have special events that are linked with the user actions.

The UI element Button is one of these UI elements and thats why we have to create

an action that reacts to the user interaction. To do this, we use the Action tab

(Fig. 3.14).

As we can see, each action has a corresponding event handler method, automati-

cally generated by the Framework. An event handler method is a special method of

a view controller that has the ONACTION prefix followed by the action name. For

the SAVE action, the Framework generates the ONACTION event handler.

After creating an action, we can assign it to an UI element that has attached an

event (Fig. 3.15).

After generation, this method is empty, but we can fill it with source code by

using the Methods tab.

3.1.4 Methods

In the Methods tab of a View, we can find some types of methods (e.g. event handler

methods, Hook methods, user-defined instance methods).

Fig. 3.15 Assigning an actionto an UI element

Fig. 3.14 Creating an action

3.1 View 19

In our case, in the Methods tab we can find the Hook methods, automatically

generated by the Framework, and our event handler method ONACTIONSAVE

(Fig. 3.16).

With double-click on the method name, we open the ABAP editor (Fig. 3.17). In

this way, we can insert the source code.

The user enters his name that we use to show a greeting message with the help of

textView UI element. To create a greeting for the end user, we concatenate his

name with the string WELCOME and we pass this string value in the GREET-

ING attribute. After this, we reset the inputField UI element. To do this, we pass an

empty string into the NAME attribute bound to the corresponding UI element

(Listing 3.1).

Fig. 3.16 Methods tab

Fig. 3.17 ABAP editor


For more details about Methods, please see Chap. 7.

3.1.5 Properties

In the Properties tab, we can create a description text for our view, we have

information about the view and about the person who created and changed this

view. In this tab, we can set the view lifetime:

l Framework controlled controlled by Frameworkl When visible lifetime limited to its visibility. A view controller is always

deleted as soon as the corresponding view is no longer displayed on the user

interface. It is used when a view is displayed only once and not repeatedly.

Additionally, Property tab offers the possibility to define the usages (Fig. 3.18).

METHOD onactionsave . DATA: lv_name TYPE string, lv_greeting TYPE string. wd_context->get_attribute( EXPORTING name = `NAME` IMPORTING value = lv_name ). CONCATENATE Welcome lv_name INTO lv_greeting SEPARATED BY space. wd_context->set_attribute( name = 'GREETING' value = lv_greeting ). CLEAR lv_name. wd_context->set_attribute( name = 'NAME' value = lv_name ).ENDMETHOD.

Listing 3.1 On action saveevent handler method

Create Controller Usage

Fig. 3.18 Properties view

3.1 View 21

We can define a usage to be able to access the methods of another internal

controller or of an interface controller, if the usage has been defined for an external

component. To create a new usage in the Used Controller/Components table, we

have to choose the Button Create Controller Usage. The table Used Controller/

Components includes a list with all the global controllers of our own component

and, in case we define usages, this list includes the external component and its

interface controller.

In our case, we dont use any external components. In the list we have only the

global controller COMPONENTCONTROLLER. We have to specify that, for each

view controller, the usage of the corresponding component controller is automati-

cally created.

3.1.6 Attributes

Each View controller contains some attributes automatically generated by the

Framework (Fig. 3.19).

The attribute WD_COMP_CONTROLLER is a reference variable of IG_

COMPONENTCONTROLLER type that we can use to access all the publicly

accessible methods of the component global generated interface of thecorresponding component controller.

The attribute WD_THIS is a self-reference to local controller interface. This

self-reference works similarly with the self-reference me found in the ABAPObjects. We can use it, for example, to call a user-defined method.

The attribute WD_CONTEXT is a reference to the controller context. The

IF_WD_CONTEXT_NODE interface provides several methods that enable us to

obtain read and write access to a context node.

Additionally, we can create our own attributes. These attributes are used to store

application data that are not relevant for the UI elements and we dont store in the

context. To access these attributes, we use the self-reference:

wd_this ! attribute_name

Fig. 3.19 Attributes tab


3.2 Componentcontroller

By default, every Web Dynpro component has a component controller that acts

as the central controller instance within the entire component (Fig. 3.20).

Data required across different views can be stored in his context. Besides the

Context tab, each COMPONENTCONTROLLER disposes of tabs: Properties,

Attributes, Events and Methods. Hereunder, in our examples, we will see how we

can cross-component access the methods and the attributes defined here.

3.3 Window

A Window is an entity into which we embed all the views that will be used to

construct the screen for the end user. When the user interacts with a view, their

interaction will cause a request to the server. In response, one or more views that

build the current screen will require to be replaced with other views. This is possible

through navigation links among the various views in the window.

Each Web Dynpro component can have several Windows. We have created only

one Window, named W_default.

A view or several Views are generally embedded in a Window. The first view

created at the WD component creation is directly embedded into the Window. To

embed other views in a Window, we can use dragging & dropping or right-clicking

on the window name to choose between embedding an empty view or the View we

have created. The Empty View is a special type of View, presented in the View-

ContainerUIElement example (Fig. 3.21).

In every window, at least one view is marked as default. A default view is the

first view displayed when the window is called. The first embedded view is marked

as default, but we can change it. To mark as default, after right-clicking on the view

we choose Set as default from the contextual menu.

Fig. 3.20 Component controller

3.3 Window 23

By using Inbound plugs and Outbound plugs, we define the navigation between

views or windows. For a Window, these plugs can be of Standard, Startup orResume type. As we can see, the Framework generates for each window an inboundplug of Startup type and an event handler method (Fig. 3.22). By using this eventhandler method, we can read, for example, the URL parameters from aWeb Dynpro

application.

For a View, we dont have the possibility to define a specific plug type.

3.4 Application

After developing a Web Dynpro component, we need to provide the users with

access to its functionality. To do this, we have to create a Web Dynpro Application

(Fig. 3.23).

Fig. 3.21 Embed View

Fig. 3.22 Default inbound plug for a window


For each application, the Framework generates an URL. We find this URL in the

Properties tab (Fig. 3.24).

In the same time, we can specify here how the Messages are handled:

l Show Message Component on demand the Message Component is displayed

only when we have a message.l Always Display Message Component the Message Component is always

displayed on the screen, even when we dont have any messages.

Fig. 3.23 Creating an application

Fig. 3.24 Application URL

3.4 Application 25

By using the Parameters tab, we can define our own parameters for the applica-tion or we can choose from the parameters offered by the Web Dynpro Framework

(Fig. 3.25).

To run the application, we can use the Execute button or we can copy and

past the URL into the browser (Fig. 3.26).

When the user interacts with the screen, specific adapter techniques are used to

convert data and events, as part of the request response cycle, into the browser

format as HTML, JavaScript or XML. In Fig. 3.27, we can see the generated source

code for our WD component.

Fig. 3.25 Application parameters list

Standard ContextMenus

Fig. 3.26 Running the application


3.5 ABAP Debugger

If any errors occur in our Web Dynpro components, we can use the ABAP

Debugger to execute our WD component, by line or by section.

To work with the debugger, we can create Breakpoints at the point where the

program should pause (Fig. 3.28).

Fig. 3.27 Generated source file

Click

Fig. 3.28 Setting a Breakpoint

3.5 ABAP Debugger 27

We run the application and, in the moment when the program flow reached the

defined breakpoint, the ABAP Debugger is open (Fig. 3.29).

As we can see in the Process Information, the main component of the ABAP

Debugger, we debug an HTTP application. The Exclusive represents the fact that

the application we debug occupies a work process of the application server.

By using the Buttons from the Control Area, we can control the program

flow. For example, we can choose to execute the program line by line Single

step, or to execute the program up to the next Breakpoint Continue.

We can use the ABAP Debugger tools to have information about the variable

(Fig. 3.30).

By using the New Tool button , we can open a selection window that offers

the possibility to access additional functionalities. In the Special Tools section, we

can find the created tool, to be used for a better debugging of the Web Dynpro

components (Fig. 3.31).

Fig. 3.29 ABAP Debugger

Fig. 3.30 Tool Component of the ABAP Debugger


As we can see in Fig. 3.32, we are offered the possibility to have access to all the

individual elements of the Web Dynpro component; we can see the view attributes,

the view layout, the UI elements and data binding, the context structure and its

attributes, etc.

Fig. 3.31 ABAP Debugger New tool selection window

Fig. 3.32 The ABAP debugger web Dynpro ABAP tool

3.5 ABAP Debugger 29

We are able to see not only the context structure, but also to display the runtime

object, by choosing from the contextual menu Display Runtime Object

(Fig. 3.33).

These are only some of the ABAP Debugger capabilities that can be used along

with other performance tools (for example, the transactions WD_TRACE_TOOLS,

S_MEMORY_INSPECTOR), to help us to develop Web Dynpro applications.

3.6 Web Dynpro Logon Page Configuration

As we have seen, a logon page appears when running our application, where we

have to provide some values, as follows: Logon Language, Client, User Password,etc. (Fig. 3.34).

Fig. 3.33 Displaying the runtime object

Fig. 3.34 Example of a webDynpro application logon

page


We can change the modality this logon page looks like and the modality we

realize the user authentication, by using the SICF transaction (HTTP ServiceHierarchy Maintenance). In the webdynpro ! sap hierarchy, each Web Dynproapplication disposes of one corresponding entry.

By using this transaction, we search for all the entries that begin with Y_WD_*

and are created by our test user Gellert (Fig. 3.35).

We find the entry that corresponds to our created Web Dynpro component

(Fig. 3.36).

With double-click, we are allowed to view or/and to change this service. In the

lower part of the Error Page tab, we can find the Configuration button for the system

logon. Here, we can define our own settings by choosing from the lists, or we can

use the global settings (Fig. 3.37).

Fig. 3.35 Searching for a service with the SICF transaction

Fig. 3.36 Entry corresponding to our Web Dynpro component

3.6 Web Dynpro Logon Page Configuration 31

As a result of our changes, in the logon page we have to provide only the Userand the Password, through a popup window, and we are able to change our logonpassword (Fig. 3.38).

Fig. 3.37 System logon configuration

Fig. 3.38 Logon page


Chapter 4

ABAP Dictionary

Mystery creates wonder and wonder is the basis of mans desire to understand

Neil Armstrong

Abstract The following section details and describes the ABAP Dictionary. Themain purpose of this chapter is to show how to realize all the development objects to

be used in the future Web Dynpro applications. Therefore, we present not only the

modality to create the various development objects in the ABAP Dictionary, but

also the modality to use them in realizing Web Dynpro applications.

We can create development objects in ABAP Dictionary, by using the transactionSE11 (ABAP Dictionary Maintenance) or the Object Navigator (Fig. 4.1).

ABAP programming language has a number of ten elementary data types that we

can use in our programs. When we want to create global data types by using the

ABAP Dictionary, we have to use dictionary built-in types. These predefined types

are different from the elementary data types. We need them for reasons of compati-

bility with the external data types.

Fig. 4.1 Development object with transaction SE11


33

In Fig. 4.2, we presented some of the ABAP Dictionary Built-In types and a few

corresponding examples ofDictionary built-in data types andABAPelementary types.

4.1 Data Element

A data element defines an elementary data type and has certain properties. We

create a data element YDATEOFBIRTH (Fig. 4.3).

Dictionary ABAP typeExample

CHAR c DATS d INT4 i

NUMC n STRING string

TIMS t RAW - x

RAWSTRING- xstring FLTP - f DEC - p

Fig. 4.2 Some of ABAP Dictionary Built-In types and corresponding ABAP elementary types

Fig. 4.3 Definition of a data element

34 4 ABAP Dictionary

In the Data Type tab we can choose between the elementary type and reference

type. The elementary type can be a domain and a build-in type. In this case, we

have chosen the build-in type DATS that has a predefined format (YYYYMMDD)

and a predefined length 8.

In the tab Field Label, we can set a field label that is automatically shown

in the label, or caption of an UI Element that is bound to an attribute of this

type.

For a data element, we can create documentation F1 Help with Goto ! Docu-mentation ! Change. This documentation is not seen on screen if the WebDynpro application attribute WDHIDEMOREFIELDHELPASDEFAULT was set

as ABAP_TRUE. We create a text that describes the content of our data element

(Fig. 4.4).

4.2 Domain

A domain defines a value range. To be able to use it in a Web Dynpro application, in

other repository object, as parameter in GUI programming, etc. we have to assign it

to a data element (Fig. 4.5).

Fig. 4.4 Creating a F1 help for a data element

4.2 Domain 35

We create a domain named Y_COUNTRY_DOMAIN that holds all the names

of EU member states, with the proper abbreviation. In Definition tab we have to

specify properties as data type, number of characters or length of output (Fig. 4.6).

In Value Range we have three possibilities:

l Single valuesl Intervalsl Value table

Fig. 4.5 Data elements and domains

Fig. 4.6 Definition of a domain tab Definition


We begin with the first possibility, Single values. We define the domain fixed

values all the abbreviations of the EU countries, and a short text the

corresponding country names (Fig. 4.7).

As we have specified, to be able to use a domain we have to assign it to a data

element. To do this, we create a new data element and we choose the elementary

type domain (Fig. 4.8).

When we use this data element in our Web Dynpro application, for example to

define a parameter or a context attribute, the user is allowed to choose only the

values that range among values we have defined in Domain.To explain the next possibility (Intervals), we take an example where we need

to store, in a table column, the ages between 18 and 45. In this case, we can use an

interval to limit the values that the user may enter (Fig. 4.9).

Fig. 4.7 Definition of a domain tab Value Range

Fig. 4.8 Assigning a domain to a data element

4.2 Domain 37

We use this interval in the database table YPERSON, defined hereinafter. For

this, we assign it to a data element Y_DEINTERVAL.

To explain the last possibility (Value Table), we use a domain that is defined

in the system: WAERS (Fig. 4.10).

It is recommendable to use the value table when we have many fixed values. In

our case, we have used the system table TCURC. This table holds all the system

currency.

We use this value table in the database table YEU_COUNTRIES, defined

hereunder. For this, we assign it to a data element Y_CURRENCY.

4.3 Structure

Structures consist of any combination of other data types of the ABAP Dictionary.

In Fig. 4.11, we present a structure with three components: FIRSTNAME, LAST-

NAME and DATEOFBIRTH.

Fig. 4.9 Definition of a domain interval

Fig. 4.10 Domain WAERS value table


For each component it is defined a component type, as follows: a data element,

other structure, table type, etc.

As a component type for a structure, we can choose a type that is already defined

in the ABAP Dictionary, or we can create a new type. For example, the component

DATEOFBIRTH has YDATEOFBIRTH data type. This data type has been alreadydefined.

If we want to create a new type for a component, we have to enter its name (for

example, YFIRSTNAME) and then, with double-click, we can choose the new type

(Fig. 4.12).

After we create a structure, we have to maintain the enhancement category:

Extras ! Enhancement Category, from the menu. In case we dont want to furtherextend the component structure, we choose Cannot be Enhanced (Fig. 4.13).

Fig. 4.11 Definition of a structure

Fig. 4.12 Creating a newcomponent type

Fig. 4.13 Maintaining enhancement category

4.3 Structure 39

We can use the structures defined in ABAP Dictionary to create the context node

structure for a Web Dynpro application.

4.4 Table

We create two transparent tables, YPERSON and YEU_COUNTRIES. We will use

this table later, for our Web Dynpro example.

In the YPERSON table, we want to store the competition candidates. All thecandidates should be 1845 years old and live in an EU country. After creating the

table, we have to enter a short description along with the delivery and maintenance

(Fig. 4.14).

We set Data Browser/Table View Main ! Display/Maintenance Allowed, tobe able to populate our table with values, using Create Entries, from the menu.

Then, we will define our table structure. To do this, we select the tab Fields and

enter the table columns (Fig. 4.15). For the fields MANDT and ID_PERSON, we

have marked the option Key, meaning they are the table keys. The field MANDT

is the SAP client field, a three-character client ID. The field ID_PERSON repre-

sents the candidates ID, required to uniquely identify each competition candidate.

Fig. 4.14 Table maintenance

Fig. 4.15 Table structure


As can be seen, we have used the data elements created hereinbefore: YFIRST-

NAME, YLASTNAME, Y_DEINTERVAL, Y_DEFORDOMAIN. When we want

to create a new data element, we write its name and, with double-click, we activate

the forward navigation. If this data element doesnt exist, we are asked if we want to

create the new data element (Fig. 4.16).

Before being able to activate this table, we have to maintain the technical

settings (Fig. 4.17).

We choose a size category 0, because we dont require many data records.

We have to maintain the enhancement category: Extras ! EnhancementCategory, from the Menu. We choose the same Cannot be Enhanced, becausewe shouldnt further extend the table structure.

After this, we can activate our table and create the second table YEU_COUN-

TRIES. We hold here all the EU Member states information, as follows: country

Fig. 4.16 Creating a dataelement

Fig. 4.17 How to maintain the technical settings for the table YPERSON

4.4 Table 41

name, year of EU entry, political system, capital city, currency and the flag image

name. The structure of this table is presented in Fig. 4.18.

After this, we have to define a foreign key for the field CHECK_CUR. For this

purpose, we use the button Foreign Keys. We are asked if we want to use the

value table TCURC as check table (Fig. 4.19).

We need TCUC as a check table, because we want to use its table contents,

respectively the Currency Codes (Fig. 4.20).

Fig. 4.18 Table structure

Fig. 4.19 How to create foreign key


After we maintain the Technical settings and enhancement category, we can

activate the same as for the table YPERSON.

The candidates can live only in an EU country. Therefore, we create a 1 to CN

relationship between the tables.

From the table YPERSON field ID_COUNTRY, we create a foreign key,

(Fig. 4.21).

Fig. 4.20 Currency codes

Fig. 4.21 How to create a foreign key

4.4 Table 43

The system can generate the graphical representation of the relationships we

have defined between tables. To show this graph, we use the Button Graph

(Fig. 4.22).

We can see our tables YEU_COUNTRIES, YPERSON and the 1:CN relation-

ship. The table TCUC is the check table for the table YEU_COUNTRIES. To see

this relationship also, we have to select the name of YEU_COUNTRIES table and

to press the Button Check Table (Fig. 4.23).

We can create contents with Utilities ! Table content ! Create Entriesfrom Menu (Fig. 4.24).

Fig. 4.22 Foreign key relationship

Fig. 4.23 Foreign key relationship


To display the content: Utilities ! Table content ! Display from Menu(Fig. 4.25).

Tip

With Utilities ! Database Object ! Database Utility or through the transaction SE14, wecan use the Database Utility to activate and adjust a database table, in case we have changed its

structure and an activation error is shown. We can use the Database Utility not only to activate

and adjust a database, but also for other basic functions, as to create or delete a database table

We can use the transparent tables defined in the ABAP Dictionary to create the

context node structure for a Web Dynpro application.

4.5 Search Help

ABAP Dictionary offers the possibility to create simple search help and collective

search help.

To create a search help, we can use the context menu of our package (Fig. 4.26).

Fig. 4.24 Insert table YEU_COUNTRIES

Fig. 4.25 Select table YEU_COUNTRIES

4.5 Search Help 45

We create a simple search help YSH_ID_PERSON for the column ID_PERSON

of the table YPERSON (Fig. 4.27).

As can be seen at Data collection ! Selection method, we have used the tablename YPERSON. This means that all the data required come from our table

YPERSON. A search help can have the following parameters: import parameters,

export parameters or no import and no export. We have used ID_PERSON as

export parameter, because we want its value to be returned to the input template.

LPos represents the parameter position in the hit list: FIRSTNAME has the position

Fig. 4.26 Creating a development object in the ABAP Dictionary by using the Object Navigator

Fig. 4.27 Creating a simple search help


1 and it is firstly displayed in the hit list, and LASTNAME has the position 2, being

displayed after the FIRSTNAME.

We can test a search help (Fig. 4.28).

Afterwards, we want to use this search help in a Web Dynpro application.

We create a search option for a competitor. The user has to enter the competitors

ID into a search mask. The list of IDs is limited to the number of competitors. When

the user doesnt know the competitors ID, he uses the search help and can choose

the competitors name. The content of the ID_PERSON parameter is returned to the

search mask as soon as the user has selected a line of the hit list in the input help.

In this way, we facilitate the input.

We can use this search help if we link it with the ID_PERSON column of the

YPERSON table. To do this, we select the column ID_PERSON and press the

button Srch Help (Fig. 4.29).

Fig. 4.28 Testing a search help

Fig. 4.29 Search Help for the field ID_PERSON

4.5 Search Help 47

After we enter the search help name, we have to create the search help attach-

ment, and to save and activate the table (Fig. 4.30).

In this way, we have created a simple search help for the column ID_PERSON of

the table YPERSON. When we use this column in Web Dynpro, the Framework

creates a special icon to be used at the runtime to call the input help. Moreover, we

can use the keyboard key F4 to call an input help.

To be able to access a search help from a WD component, the proper Input Help

Mode context attribute property has to be set (Automatic or Dictionary Search

Help).

4.6 Database View

By using a view, we can combine the data distributed in several tables. For a better

understanding, we create a view on the tables YPERSON and YEU_COUNTRIES.

When we create a view, we can choose one of the four view types (Fig. 4.31).

Fig. 4.30 How to create search help attachment to the column ID_PERSON

Fig. 4.31 View types


We choose to create a database view named YVIEW_CMPETITION. At the

beginning of the view definition, we have to select the view base table (in our

case, the table YPERSON).

After the base table definition, we link this table by defining the joining condi-

tions. To create this link, we use the button Relationships (Fig.4.32).

As result, the join conditions are generated (Fig. 4.33).

In the next step, we have to select the fields we need in our view. We can enter

each field manually or we can use the Button Table fields (Fig. 4.34).

Fig. 4.32 Creating a view

Fig. 4.33 Joining conditions

4.6 Database View 49

After activation, we can see our view content using the Contents Button

(Fig. 4.35).

In this way, we have created a database view on the tables YPERSON and

YEU_COMPETITION (Fig. 4.36).

Fig. 4.34 View fields

Fig. 4.35 View content

Fig. 4.36 View definition on the database


By using this view, we can create the context node structure for our Web Dynpro

application and so we simultaneously select the logically connected data, from two

tables.

4.7 Table Type

We create a table type named YTABLE_TYPE, the line type being our YPERSON

table (Fig. 4.37).

For the line type, we can use an existing type (table, structure, view, . . .) or wecan enter the data type, length and number of decimals.

The typical use of table type is the declaration of an internal table.

Another example of using table type is to populate with values a context node via

a supply function. To be able to do this, we create a table type named YTABLE_

TYPE_STRUCTURE with the line type the structure YSTR_PERSON

(Fig. 4.38).

In the next chapter, we show how we can use this table type to populate a

context node.

Fig. 4.37 Creating a table type

Fig. 4.38 Table type line type structure

4.7 Table Type 51

4.8 Lock Object

We create a Lock Object for the database table YPERSON (Fig. 4.39). The lock

object name has to begin with the prefix E (from Enqueue).

Our case consists of exactly one table, and the lock argument is the primary key

of this table. The lock mode is set to write, but can be overwritten.

After the lock object activation, the ABAP Dictionary generates two Function

Modules, named ENQUEUE_ and DEQUEUE_. TheFunction Modules with enqueue prefix help us to set a lock, and the FunctionModules with dequeue prefix help us to release the locks.

With the SE37 transaction we can see the two generated Function Modules:ENQUEUE_EYPERSON and DEQUEUE_EYPERSON. Figure 4.40 shows the

structure of the Function Module required to set a lock.

Fig. 4.39 Lock object

Fig. 4.40 Function Module for lock setting


SAP offers a lock mechanism required to provide two transactions by simulta-

neously changing the same data in the database.

The lock table represents a table in the memory of the enqueue server and is used

to manage all the locks in the system. This lock table is checked every time when

the enqueue server receives a lock request. A program sends, to the lock table, the

key of the table entries it wants to lock; if no lock is set, the request is accepted and

the new lock is written in the lock table. If a lock is set, the request collides with an

existing lock and the request is rejected.

4.8 Lock Object 53

Chapter 5

Context Nodes and Attributes at Design Time

Well done is better than well said.

Benjamin Franklin

Abstract This chapter mainly focuses on the context nodes and attributes staticallyrealized at design time. In this respect, we will explain not only the role and

modality to create context nodes and attributes, but also the modality to access

the values stored in the attributes of the nodes.

An attribute is a context entity that has certain properties and can be directly created

in the root node CONTEXT, or as a child for another node. Usually, a node is used

to group more attributes that belong together. In Fig. 5.1, we present a context

example created in a view context.

A context node can have attributes or can hold other nodes, but a context

attribute cannot have other attributes or nodes. We create a hierarchical arrange-

ment that has, as the start point, the root node CONTEXT. This is automatically

created when the controller is initialized and all the nodes and attributes we created

are children of this root node.

Independent node

Independent nodeDependent node or child node for FACULTY

Attributes of STUDENT node

Attributes of ADDRESS node

Attributes of Faculty node

Attribute created in context

Fig. 5.1 Example of the structure of a View Context


55

The data hold in the context nodes and attributes are transient, they exist only for

the lifetime of the controller. After this, all the data are lost if we dont store them in

storage media (e.g. database table).

5.1 Attributes

To create an attribute, we have to select the node where the attribute should be

inserted (in this case, the root context node) and, with right-click, to open its context

menu (Fig. 5.2).

We have to enter the attribute properties name and type are required, but the

other settings are optional (Fig. 5.3).

As data type for an attribute, we can use a data type as string, xstring, d, i or we

can use the data type defined in the ABAP Dictionary. In our example, the attribute

type YDATEOFBIRTH is a data element defined in the ABAP Dictionary. In the

system, we find a list with all the data types we can use for an attribute (Fig. 5.4).

The coding presented in Listing 5.1 shows how we can access, in a method, the

value of the attribute created in the context node.

Fig. 5.2 Creating an attribute

Fig. 5.3 Defining the attribute properties

56 5 Context Nodes and Attributes at Design Time

We have defined a local variable named lv_dateofbirth of YDATEOFBIRTH

type, the same type as the attribute. We pass the value of the attribute DATEOF-

BIRTH in our local variable, by using the method get_attribute of the interface

if_wd_context_node. The interface if_wd_context_node has many methods we can

use to work with context nodes. We can see all the available methods of this

interface by double-clicking on the get_attribute method.

To set the value of an attribute, we can use the method set_attribute of the same

interface.

As can be seen in Fig. 5.4, the property Input Help Mode of the attribute is set

AUTOMATIC. This means that it is used the search help assigned to the data type

of the context attribute in the ABAP Dictionary. In principle, we have a data

element of D type. This is the reason why we will have a CALENDAR as input

help (Fig. 5.5).

Fig. 5.4 Searching for an attribute data type

DATA lv_dateofbirth type ydateofbirth.wd_context->get_attribute( EXPORTING name = 'DATEOFBIRTH'

IMPORTING value = lv_dateofbirth ).

Listing 5.1 Access of an attribute from context node

Fig. 5.5 Calendar input help

5.1 Attributes 57

The read-only property set no means that the attribute is not write- protected.

To put data on the screen and to read data from user, we connect the proper

UI Elements properties with the attributes or nodes. The data are stored in

the attributes, the UI Elements being the only object the user interacts with. For

our example, we have an UI Element InputField where the user enters his date

of birth. Web Dynpro Framework transports these data from the UI element

to the attribute DATEOFBIRTH when the user presses the SAVE Button, after

he enters the value. The attribute keeps the value for further processing. To be

able to access the value of this attribute in our methods, we have to pass this

value in a local variable (lv_dateofbirth). We can use this value, change it or

pass the new value back in the context (Fig. 5.6). This value is kept in the

context for the lifetime of the controller. Then, these data are lost if we dont

store them.

5.2 Nodes

We can directly create a node in the context root node or as child for other node.

In Fig. 5.7 we show how we can create a node.

ABAP Dictionary

Fig. 5.6 Connection among attribute, ABAP Dictionary, method and UI Element

Fig. 5.7 Creating a node


For each node we create, we have to set some properties, as: cardinality,

selection, etc. We can individually create the attributes for a node, or we can use

some repository objects from the ABAP Dictionary. For example, when we work

with tables, structures or views defined in the ABAP Dictionary, we can use them to

define our node, and the attributes will be automatically generated.

5.2.1 Creating a Node that Uses an ABAP DictionaryRepository Object

We create a context node that uses the ABAP Dictionary structure YSTR_PERSON

(Fig. 5.8).

The Button Add Attribute from Structure allows us to add all the structure

components or only a part of them (Fig. 5.9).

Fig. 5.8 Node properties

Fig. 5.9 Selecting components of Structure

5.2 Nodes 59

Because we need a proper attribute for all these structure components, we

select all of them. As result, we have created a node, the attributes being

automatically generated according to the structure components we have selected

(Fig. 5.10).

The properties of the node we have chosen are: cardinality 0. . .n, singleton yesand Init. Lead Selection yes.

The cardinality properties are very important, because they tell us how many

elements a context node may have at runtime. We have four possible values:

l 1. . .1 Exactly one context element is instantiatedl 0. . .1 Maximum one context element is instantiatedl 0. . .n Zero or more context elements are instantiatedl 1. . .n One or more context elements are instantiated

The singleton property can be set YES or NO. When a node is singleton at the

runtime, we have only one instance of this node. As usage example, for a non-

singleton node we can specify the context structure required for a Tree UI Element

sequential implementation.

The Lead Selection Initialization property determines if the lead selection should

be automatically set or manually programmed. In our case, this property is set

YES, meaning that the lead selection is AUTOMATIC and the first element of

this node it automatically selected. More details about lead selection Table UI

element.

For our node, we have defined the supply function named supply_student. Each

node may have a supply function defined for it and automatically called by the Web

Dynpro Framework. The scope of using a supply function is to populate a context

node. In certain cases, we can use the Hook Method wdDoInit instead of a supply

function. For more details, see the Hook Methods chapter.

The coding presented in Listing 5.2 shows how we can use the supply function

method to populate the context node STUDENT with three values.

We have defined two variables: ls_student and lt_student. Ls_student is of

type if_view_name=>element_student, where view_name represents theview name and student represents the node name. if_view_name represents

the programming interface for our view controller. By double-clicking on his

name or clicking on the icon Display Controller Interface ( ), we can see the

Fig. 5.10 Context nodeSTUDENT at design time


coding of this interface. Listing 5.3 shows a coding part for the context

node STUDENT.

As can be seen, Element_Student is of YSTR_PERSON type (our ABAP

Dictionary structure). But, when we manually create context nodes without dictio-

nary structure, in the view controller programming interface, a new structured type

is created (Listing 5.4).

This is why we use the following form to append values:

ls_student-firstname Ionescu.

constants:wdctx_Student type string value `STUDENT`.

types:Element_Student type YSTR_PERSON,Elements_Student type

standard table of Element_Studentwith default key.

..

Listing 5.3 Example of viewcontroller programming

interface

METHOD supply_student .DATA ls_student TYPE if_view_name=>element_student.DATA lt_student LIKE TABLE OF ls_student.ls_student-firstname = 'Ionescu'.ls_student-lastname = 'Ana Maria'.ls_student-dateofbirth = '19700309'.APPEND ls_student TO lt_student.ls_student-firstname = 'Marinescu'.ls_student-lastname = 'Loredana'.ls_student-dateofbirth = '19800523'.APPEND ls_student TO lt_student.ls_student-firstname = 'Marton'.ls_student-lastname = 'Luminita'.ls_student-dateofbirth = '19831108'.APPEND ls_student TO lt_student.node->bind_table(new_items = lt_student ).

ENDMETHOD.

Listing 5.2 Example ofsupply function Method

..types: begin of Element_Faculty, FACULTY_NAME type String, SPECIALIZATION type String, end of Element_Faculty,

Listing 5.4 Example of viewcontroller programming

interface

5.2 Nodes 61

The way we append values in an ABAP structure is:

structure_name-component_name valueWith the declaration DATA lt_student LIKE TABLE OF ls_student,we declare

an internal table. We use APPEND statement to add each new line at the end of the

last line of the internal table.

At the end, we use the bind_structure method to populate the node with values.

Instead of the declaration:

DATA ls_student TYPE if_view_name=>element_student.

we can use:

DATA ls_student TYPE wd_this->element_student.

In this way, we dont need the view name anymore, because we use the wd_thisself-reference.

The runtime structure is presented in Fig. 5.11.

The node STUDENT was set Singleton, it has only an instance at runtime and

the cardinality was set 0. . .n, meaning that, at runtime, we can have from zero to nelements. Because the lead selection was set YES, it was selected the first

element of the node.

To read, set or append a context node or attribute, we can use the Web Dynpro

Code Wizard (Fig. 5.12).

The option As table operation can be used in combination with the Read, Set

or Append options for a node that allows the usage of this combination. We can

read, for example, the entire context node STUDENT in an internal table.

DATA lt_student TYPE wd_this->elements_student.lr_node->get_static_attributes_table( IMPORTING table = lt_student).

Element 1

RootNode

Node STUDENTIonescuAna Maria19700309

MarinescuLoredana19800523

MartonLuminita19831108

Element 2

Element 3

Fig. 5.11 The runtime structure


In this case, the wizard has generated a variable lt_student of type wd_this->elements_student. In Listing 5.3 we saw that, in Interface Controller, besides the

definition of a variable, the Element_structure Framework has also defined a

variable Elements_Student, with the form:

Elements_Student typestandard table of Element_Studentwith default key.

This is the reason why the Wizard offers the possibility to read all the values

from the STUDENT node in lt_student.

As we have mentioned in the last chapter, we can use a table type to populate

with data a context node via a supply function. Our node STUDENT has its

attributes from the YSTR_PERSON structure. The table type YTABLE_TYPE_

STRUCTURE defined in the ABAP Dictionary has the same YSTR_PERSON

structure, as line type.

Listing 5.5 shows how we can use a table type to populate with data a con-

text node.

Fig. 5.12 Web Dynpro Code Wizard, reading a context node or attribute

METHOD supply .DATA: lt_student TYPE ytable_type_structure .DATA: ls_student TYPE ystr_person.ls_student-firstname = 'Ionescu'.ls_student-lastname = 'Ana Maria'.ls_student-dateofbirth = '19700309'.APPEND ls_student TO lt_student.ls_student-firstname = 'Marinescu'.ls_student-lastname = 'Loredana'.ls_student-dateofbirth = '19800523'.APPEND ls_student TO lt_student.node->bind_table( new_items = lt_student ).

ENDMETHOD.Listing 5.5 Example ofsupply function Method

5.2 Nodes 63

5.2.2 Working with Child Nodes

We create the context structure presented in Fig. 5.13.

It has a context node FACULTY, cardinality 1. . .1, Singleton with child nodeADDRESS, cardinality 1. . .1, Singleton and two attributes FACULTY_NAMEtype STRING and SPECIALIZATION type STRING.

We read data from the attributes of the node ADDRESS as a child node for

FACULTY. Listing 5.6 show

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