xml and web services with groovy

XML and WebServices with Groovy

Dr Paul King, ASERT: @paulk_asert, [email protected]

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What is Groovy?

• “Groovy is like a super version

of Java. It can leverage Java's

enterprise capabilities but also

has cool productivity features like closures,

DSL support, builders and dynamic typing.”

Groovy = Java – boiler plate code+ optional dynamic typing+ closures+ domain specific languages+ builders+ metaprogramming

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Growing Acceptance …

A slow and steady start but now gaining in

momentum, maturity and mindshare

Now free

… Growing Acceptance …

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SpringOne2gx_Oct2009 - 4


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Groovy and Grails downloads:

70-90K per month and growing


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Source: http://www.grailspodcast.com/

Source: http://www.micropoll.com/akira/mpresult/501697-116746


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SpringOne2gx_Oct2009 - 7http://www.java.net

http://www.jroller.com/scolebourne/entry/devoxx_2008_whiteboard_votes


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SpringOne2gx_Oct2009 - 8http://www.leonardoborges.com/writings

What alternative JVM language are you using or intending to use


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http://it-republik.de/jaxenter/quickvote/results/1/poll/44 (translated using http://babelfish.yahoo.com)

… Growing Acceptance


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Better XML Manipulation...

AUG 2009 - 11

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<records>

<car name='HSV Maloo' make='Holden' year='2006'>

<country>Australia</country>

<record type='speed'>Production Pickup Truck with speed of 271kph</record>

</car>

<car name='P50' make='Peel' year='1962'>

<country>Isle of Man</country>

<record type='size'>Smallest Street-Legal Car at 99cm wide and 59 kg weight</record>

</car>

<car name='Royale' make='Bugatti' year='1931'>

<country>France</country>

<record type='price'>Most Valuable Car at $15 million</record>

</car>

</records>

records.xml

...Better XML Manipulation...

AUG 2009 - 12

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import org.w3c.dom.Document;import org.w3c.dom.NodeList;import org.w3c.dom.Node;import org.xml.sax.SAXException;

import javax.xml.parsers.DocumentBuilderFactory;import javax.xml.parsers.DocumentBuilder;import javax.xml.parsers.ParserConfigurationException;import java.io.File;import java.io.IOException;

public class FindYearsJava {public static void main(String[] args) {

DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();try {

DocumentBuilder builder = builderFactory.newDocumentBuilder();Document document = builder.parse(new File("records.xml"));NodeList list = document.getElementsByTagName("car");for (int i = 0; i < list.getLength(); i++) {

Node n = list.item(i);Node year = n.getAttributes().getNamedItem("year");System.out.println("year = " + year.getTextContent());

}} catch (ParserConfigurationException e) {

e.printStackTrace();} catch (SAXException e) {

e.printStackTrace();} catch (IOException e) {

e.printStackTrace();}

}}

...Better XML Manipulation...

AUG 2009 - 13

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import org.w3c.dom.Document;import org.w3c.dom.NodeList;import org.w3c.dom.Node;import org.xml.sax.SAXException;

import javax.xml.parsers.DocumentBuilderFactory;import javax.xml.parsers.DocumentBuilder;import javax.xml.parsers.ParserConfigurationException;import java.io.File;import java.io.IOException;

public class FindYearsJava {public static void main(String[] args) {

DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();try {

DocumentBuilder builder = builderFactory.newDocumentBuilder();Document document = builder.parse(new File("records.xml"));NodeList list = document.getElementsByTagName("car");for (int i = 0; i < list.getLength(); i++) {

Node n = list.item(i);Node year = n.getAttributes().getNamedItem("year");System.out.println("year = " + year.getTextContent());

}} catch (ParserConfigurationException e) {

e.printStackTrace();} catch (SAXException e) {

e.printStackTrace();} catch (IOException e) {

e.printStackTrace();}

}}

boilerplate

...Better XML Manipulation

AUG 2009 - 14

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def records = new XmlParser().parse("records.xml")records.car.each {

println "year = ${it.@year}"}

year = 2006year = 1962year = 1931

SpringOne 2GX 2009. All rights reserved. Do not distribute without permission.

XML

Groovy and XML ...

• Reading XML

– Special Groovy support:

XmlParser, XmlSlurper, DOMCategory

– Or Groovy sugar for your current favorites:

DOM, SAX, StAX, DOM4J, JDom, XOM, XPath,

XSLT, XQuery, etc.

• Creating XML

– Special Groovy support:

MarkupBuilder and StreamingMarkupBuilder

– Or again, enhanced syntax for your current

favorites

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... Groovy and XML ...

• Updating XML

– Using above: read followed by create

– Can be done with XmlParser, XmlSlurper,

DOMCategory

– Or with your Java favorites

• Verifying XML

– Also DTD, W3C XML Schema, Relax NG in a

similar fashion to Java mechanisms for these

features

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... Groovy and XML

• So many technologies – how to choose?

– Normally just use XmlSlurper and

StreamingMarkupBuilder

– Or if you want a DOM, use XmlParser and

MarkupBuilder or DOMBuilder

– Or if you must have a W3C DOM, use

DOMCategory

– Or if you expect to have a large amount of

legacy or Java parsing code, you can stick

with your favorite Java XML API/stack

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An Xml Example ...

import groovy.xml.dom.DOMCategory

class Flights {static final String XML = '''

<trip><flight hours="13">

<from>Brisbane</from><to>Los Angeles</to>

</flight><flight hours="4">

<from>Los Angeles</from><to>New Orleans</to>

</flight></trip>

'''...

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... An Xml Example

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...static final Reader getReader() {

new StringReader(XML)}static final Set getCities(flights) {

Set cities = []use(DOMCategory) {

flights.each { f ->cities += f.to[0].text()cities += f.from[0].text()

}}cities

}}

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You can mostly ignore

the details here for now.

We’ll cover DOMCategory

in more detail shortly.

XmlParser

def trip = new XmlParser().parseText(Flights.XML)assert trip.flight[0].to.text() == 'Los Angeles'assert trip.flight[1].@hours == '4'

Set cities = trip.flight.from*.text() +trip.flight.to*.text()

assert cities == ['Brisbane', 'Los Angeles','New Orleans'] as Set

assert trip.flight.@hours == ['13', '4']assert trip.flight.@hours*.toInteger().sum() == 17

• Builds an in-memory DOM tree

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XmlParser – Under the covers• For a JavaBean, this Groovy expression:

• Is “roughly” converted to:

where getFlight() and getTo() return a List

• But for XML Parser, it overrides this mechanism

and “roughly” converts to:

where getByName is a Groovy method similar to

getElementsByTagName in org.w3c.dom.Element

trip.flight[0].to[0].text()

trip.getflight().get(0).getTo().get(0).text()

trip.getByName('flight').get(0).getByName('to').get(0).text()

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XmlSlurper...

• The same again using XmlSlurper– Mostly identical syntax and capabilities

– But features lazy evaluation of expressions

– Consider this for streaming scenarios

def trip = new XmlSlurper().parseText(Flights.XML)assert trip.flight[0].to.text() == 'Los Angeles'assert trip.flight[1].@hours == '4'

Set cities = trip.flight.from*.text() +trip.flight.to*.text()

assert cities == ['Brisbane', 'Los Angeles','New Orleans'] as Set

assert [email protected]() == ['13', '4']assert trip.flight.@hours*.toInteger().sum() == 17

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...XmlSlurper...

• What does Lazy mean?

def trip = new XmlSlurper().parseText(Flights.XML)def moreThanFiveHours = { f -> [email protected]() > 5 }def arrivingLax = { f -> f.to == 'Los Angeles' }def departingOz = { f -> f.from == 'Brisbane' }

def longFlights = trip.flight.findAll(moreThanFiveHours)def longLaxFlights = longFlights.findAll(arrivingLax)def longOzLaxFlights = longLaxFlights.findAll(departingOz)assert longOzLaxFlights.@hours == '13'

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• This may look puzzling at first– But the good news is you don’t normally have to care

def trip = new XmlSlurper().parseText(Flights.XML)def moreThanFiveHours = { f -> [email protected]() > 5 }def arrivingLax = { f -> f.to == 'Los Angeles' }def departingOz = { f -> f.from == 'Brisbane' }

def longFlights = trip.flight.findAll(moreThanFiveHours)def longLaxFlights = longFlights.findAll(arrivingLax)def longOzLaxFlights = longLaxFlights.findAll(departingOz)assert longOzLaxFlights.@hours == '13'

Light-weight scanning here

Lazy expression storage

but deferred evaluationUsage triggers evaluation

...XmlSlurper

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class Books {

static final String XML = '''

<rdf:rdf xmlns:bibterm="http://www.book-stuff.com/terms/"

xmlns:dc="http://purl.org/dc/elements/1.0/"

xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">

<rdf:description rdf:about="http://www.book-stuff.com/bib">

<bibterm:book rdf:parseType="Resource">

<bibterm:year>2007</bibterm:year>

<dc:title>Groovy in Action</dc:title>

<bibterm:author rdf:parseType="Resource">

<bibterm:last>König</bibterm:last>

<bibterm:first>Dierk</bibterm:first>

</bibterm:author>

<rdf:comment>

Coauthors: Andrew Glover, Paul King,

Guillaume Laforge and Jon Skeet

</rdf:comment>

</bibterm:book>

</rdf:description>

</rdf:rdf>

''' ...

A Namespace Example

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• Recommended syntax:

• Options

// use string style matching (exact match on prefix or wildcard or URI)assert b.'bibterm:year'.text() == '2007'assert b.'*:year'.text() == '2007'assert b.'http://www.book-stuff.com/terms/:year'.text() == '2007'

// Namespace is a QName factory but you can use QName directlydef bibtermYear = new QName('http://www.book-stuff.com/terms/', 'year')assert b[bibtermYear].text() == '2007'

// use QName with wildcardsdef anyYear = new QName('*', 'year')assert b[anyYear].text() == '2007'

import groovy.xml.*def book = new XmlParser().parseText(Books.XML)def rdf = new Namespace('http://www.w3.org/1999/02/22-rdf-syntax-ns#')def dc = new Namespace('http://purl.org/dc/elements/1.0/')def bibterm = new Namespace('http://www.book-stuff.com/terms/')def b = book[rdf.description][bibterm.book]assert b[dc.title].text() == 'Groovy in Action'assert b[bibterm.year].text() == '2007'

XmlParser and Namespaces

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def book = new XmlSlurper().parseText(Books.XML)book.declareNamespace(

rdf: 'http://www.w3.org/1999/02/22-rdf-syntax-ns#',dc: 'http://purl.org/dc/elements/1.0/',bibterm: 'http://www.book-stuff.com/terms/')

def b = book.'rdf:description'.'bibterm:book'assert b.'dc:title' == 'Groovy in Action'assert b.'bibterm:year' == '2007'

XmlSlurper and Namespaces

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Other GPath Features• Similar syntax for XmlSlurper and DOMCategory

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def trip = new XmlParser().parseText(Flights.XML)assert trip.'**'*.name() ==

['trip', 'flight', 'from', 'to', 'flight', 'from', 'to']assert trip.depthFirst()*.name() ==

['trip', 'flight', 'from', 'to', 'flight', 'from', 'to']assert trip.breadthFirst()*.name() ==

['trip', 'flight', 'flight', 'from', 'to', 'from', 'to']assert trip.'**'.from*.text() == ['Brisbane', 'Los Angeles']

What about non-XML?@Grab('nekohtml:nekohtml:1.9.6.2')

import org.cyberneko.html.parsers.SAXParser

def neko = new SAXParser()neko.setFeature('http://xml.org/sax/features/namespaces', false)def page = new XmlParser(neko).parse('http://groovy.codehaus.org/')def data = page.depthFirst().A.'@href'.grep{

it != null && it.endsWith('.html')}data.each { println it }

http://groovy.javanicus.com/search.html

http://www.dcs.napier.ac.uk/~cs05/groovy/groovy.html

http://www.ej-technologies.com/products/jprofiler/overview.html

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def neko = new SAXParser() // alternate style

def page = new XmlSlurper(neko).parse('http://groovy.codehaus.org/')def data = page.depthFirst().grep{

it.name() == 'A' && [email protected]().endsWith('.html')}.'@href'data.each { println it }

Raw DOM

import groovy.xml.DOMBuilder

def trip = DOMBuilder.parse(Flights.reader).documentElementdef flights = trip.getElementsByTagName('flight')

def dest = flights.item(0).getElementsByTagName('to').item(0)assert dest.firstChild.nodeValue == 'Los Angeles'

assert flights.item(1).getAttribute('hours') == '4'

assert Flights.getCities(flights) ==['Brisbane', 'Los Angeles', 'New Orleans'] as Set

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DOM plus metaprogramming

import groovy.xml.DOMBuilderimport org.w3c.dom.Element

def trip = DOMBuilder.parse(Flights.reader).documentElement

Element.metaClass.element = { t, i ->delegate.getElementsByTagName(t).item(i) }

Element.metaClass.text = {-> delegate.firstChild.nodeValue }

assert trip.element('flight', 0).element('to', 0).text() =='Los Angeles'

assert trip.element('flight', 1).getAttribute('hours') == '4'

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DOMCategory

import groovy.xml.DOMBuilderimport groovy.xml.dom.DOMCategory

def doc = DOMBuilder.parse(Flights.reader)def trip = doc.documentElement

use(DOMCategory) {assert trip.flight[0].to[0].text() ==

'Los Angeles'assert trip.flight[1].'@hours' == '4'assert Flights.getCities(trip.flight) ==

['Brisbane', 'Los Angeles','New Orleans'] as Set

}

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DOM4J

@Grab('dom4j:dom4j:1.6.1')import org.dom4j.io.SAXReader

def trip = new SAXReader().read(Flights.reader).rootElement

assert trip.elements()[0].elementText('to') == 'Los Angeles'assert trip.elements()[1].attributeValue('hours') == '4'

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JDOM

@Grab('org.jdom:jdom:1.1')import org.jdom.input.SAXBuilder

def b = new SAXBuilder()def trip = b.build(Flights.reader).rootElement

assert trip.children[0].getChildText('to') == 'Los Angeles'assert trip.children[1].getAttribute('hours').value == '4'

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XOM

@Grab('xom:xom:1.1')

import nu.xom.Builder

def doc = new Builder().build(Flights.reader)

def flights = doc.rootElement.childElements

def to = flights.get(0).getFirstChildElement('to')

assert to.value == 'Los Angeles'

def hours = flights.get(1).getAttribute('hours')

assert hours.value == '4'

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StAXimport static javax.xml.stream.XMLInputFactory.newInstance as staxFactoryimport javax.xml.stream.XMLStreamReader as StaxReader

def flights = []def flightdef seenTagStaxReader.metaClass.attr = { s -> delegate.getAttributeValue(null, s) }

def reader = staxFactory().createXMLStreamReader(Flights.reader)while (reader.hasNext()) {

def name = reader.localNameif (reader.startElement) {

if (name == 'flight') flight = [hours:reader.attr('hours')]else if (name in ['from', 'to']) seenTag = name

} else if (reader.characters) {if (seenTag) flight[seenTag] = reader.text

} else if (reader.endElement) {if (name == 'flight') flights += flightseenTag = null

}reader.next()

}

assert flights[0].to == 'Los Angeles'assert flights[1].hours == '4'

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import javax.xml.parsers.SAXParserFactoryimport org.xml.sax.*import org.xml.sax.helpers.DefaultHandler

class TripHandler extends DefaultHandler {def flights = []private flight, seenTag

void startElement(String ns, String localName, String qName, Attributes atts) {if (qName == 'flight') flight = [hours:atts.getValue('hours')]else if (qName in ['from', 'to']) seenTag = qName

}

public void endElement(String uri, String localName, String qName) {if (qName == 'flight') flights += flightseenTag = null

}

public void characters(char[] ch, int start, int length) {if (seenTag) flight[seenTag] = new String(ch, start, length)

}}

def handler = new TripHandler()def reader = SAXParserFactory.newInstance().newSAXParser().xMLReaderreader.setContentHandler(handler)reader.parse(new InputSource(Flights.reader))

assert handler.flights[0].to == 'Los Angeles'assert handler.flights[1].hours == '4'

SAX

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XPath

import javax.xml.xpath.*import groovy.xml.DOMBuilder

def xpath = XPathFactory.newInstance().newXPath()def trip = DOMBuilder.parse(Flights.reader).documentElementassert xpath.evaluate('flight/to/text()', trip) ==

'Los Angeles'assert xpath.evaluate('flight[2]/@hours', trip) == '4'

def flights = xpath.evaluate( 'flight', trip,XPathConstants.NODESET )

def hoursAsInt = { n ->xpath.evaluate('@hours', n).toInteger() }

assert flights.collect(hoursAsInt).sum() == 17

assert Flights.getCities(flights) == ['Brisbane','Los Angeles', 'New Orleans'] as Set

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XPath with DOMCategory

import groovy.xml.DOMBuilderimport groovy.xml.dom.DOMCategoryimport static javax.xml.xpath.XPathConstants.*

def trip = DOMBuilder.parse(Flight.reader).documentElementuse (DOMCategory) {

assert trip.xpath('flight/to/text()') == 'Los Angeles'assert trip.xpath('flight[2]/@hours', NUMBER) == 4flights = trip.xpath('flight', NODESET)def hoursAsNum = { n -> n.xpath('@hours', NUMBER) }assert flights.collect(hoursAsNum).sum() == 17

}

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Xalan XPath

@Grab('xalan:xalan:2.7.1')import static org.apache.xpath.XPathAPI.*import groovy.xml.DOMBuilder

def trip = DOMBuilder.parse(Flights.reader).documentElement

assert eval(trip, 'flight/to/text()').str() =='Los Angeles'

assert eval(trip, 'flight[2]/@hours').str() == '4'

def flights = selectNodeList(trip, '//flight')def hoursAsInt = { n ->

eval(n, '@hours').str().toInteger() }assert flights.collect(hoursAsInt).sum() == 17


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Jaxen XPath

@Grab('jaxen#jaxen;1.1.1')import org.jaxen.dom.DOMXPathimport groovy.xml.DOMBuilder

def trip = DOMBuilder.parse(Flights.reader).documentElementassert new DOMXPath('flight/to/text()').

stringValueOf(trip) == 'Los Angeles'assert new DOMXPath('flight[2]/@hours').

stringValueOf(trip) == '4'

def flights = new DOMXPath('flight').selectNodes(trip)def hoursAsInt = { n ->

new DOMXPath('@hours').numberValueOf(n) }assert flights.collect(hoursAsInt).sum() == 17


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JSR 225 - XQJ

import net.sf.saxon.xqj.SaxonXQDataSourceimport javax.xml.xquery.XQSequenceXQSequence.metaClass.collect = { Closure c ->

def items = []while (delegate.next()) items += c(delegate)items

}def asString = { seq -> seq.getItemAsString(null) }def hourAttr = { it.item.node.getAttribute('hours') as int }def flights = "document { ${Flights.XML} }"def exp =

new SaxonXQDataSource().connection.createExpression()def seq = exp.executeQuery("$flights/trip/flight/to/text()")assert seq.collect(asString) == ['Los Angeles',

'New Orleans']seq = exp.executeQuery("$flights/trip/flight")assert seq.collect(hourAttr).sum() == 17

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import static javax.xml.transform.TransformerFactory.newInstance as xsltFactoryimport javax.xml.transform.stream.*def xslt = '''<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"><xsl:template match="/trip"><html><body><h1>Flights</h1><ul><xsl:apply-templates select="flight"/>

</ul></body>

</html></xsl:template><xsl:template match="flight"><li><xsl:value-of select="from"/> => <xsl:value-of select="to"/>

</li></xsl:template>

</xsl:stylesheet>'''.trim()def transformer = xsltFactory().newTransformer(

new StreamSource(new StringReader(xslt)))transformer.transform(new StreamSource(Flights.reader),

new StreamResult(System.out))

XSLT...

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import static javax.xml.transform.TransformerFactory.newInstance as xsltFactoryimport javax.xml.transform.stream.*def xslt = '''<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"><xsl:template match="/trip"><html><body><h1>Flights</h1><ul><xsl:apply-templates select="flight"/>

</ul></body>

</html></xsl:template><xsl:template match="flight"><li><xsl:value-of select="from"/> => <xsl:value-of select="to"/>

</li></xsl:template>

</xsl:stylesheet>'''.trim()def transformer = xsltFactory().newTransformer(

new StreamSource(new StringReader(xslt)))transformer.transform(new StreamSource(Flights.reader),

new StreamResult(System.out))

...XSLT

<html>

<body>

<h1>Flights</h1>

<ul>

<li>Brisbane => Los Angeles</li>

<li>Los Angeles => New Orleans</li>

</ul>

</body>

</html>

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MarkupBuilder

import groovy.xml.MarkupBuilder

def writer = new StringWriter()def xml = new MarkupBuilder(writer)xml.flights {

flight(hours:13) {from('Brisbane')to('Los Angeles')

}flight(hours:4) {

from('Los Angeles')to('New Orleans')

}}println writer

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StreamingMarkupBuilder

import groovy.xml.StreamingMarkupBuilder

def writer = new StreamingMarkupBuilder().bind {flights {

flight(hours: 13) {from('Brisbane')to('Los Angeles')

}flight(hours: 4) {


}}

}println writer

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DOMBuilder

import groovy.xml.*

def builder = DOMBuilder.newInstance()def root = builder.flights {


}flight(hours: 4) {


}}new XmlNodePrinter().print(root)

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MarkupBuilder with Namespaces

import groovy.xml.MarkupBuilder

def writer = new StringWriter()def xml = new MarkupBuilder(writer)xml.'rdf:description'(

'xmlns:bibterm': "http://www.book-stuff.com/terms/",'xmlns:dc': "http://purl.org/dc/elements/1.0/",'xmlns:rdf': "http://www.w3.org/1999/02/22-rdf-syntax-

ns#") {'bibterm:book' {

'dc:title'('Groovy in Action')'bibterm:year'('2007')

}}println writer

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<rdf:description xmlns:dc='http://purl.org/dc/elements/1.0/'

xmlns:rdf='http://www.w3.org/1999/02/22-rdf-syntax-ns#'

xmlns:bibterm='http://www.book-stuff.com/terms/'>

<bibterm:book>



</bibterm:book>

</rdf:description>

StreamingMarkupBuilder with Namespaces

import groovy.xml.*

XmlUtil.serialize(new StreamingMarkupBuilder().bind {mkp.declareNamespace(

bibterm: "http://www.book-stuff.com/terms/",dc: "http://purl.org/dc/elements/1.0/",rdf: "http://www.w3.org/1999/02/22-rdf-syntax-ns#")

'rdf:description' {'bibterm:book' {

'dc:title'('Groovy in Action')'bibterm:year'('2007')

}}

}, System.out)

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<bibterm:book>



</bibterm:book>

</rdf:description>

DOMBuilder with Namespaces

import groovy.xml.DOMBuilder

def b = DOMBuilder.newInstance()def root = b.'rdf:description'(

'xmlns:bibterm': "http://www.book-stuff.com/terms/",'xmlns:dc': "http://purl.org/dc/elements/1.0/",'xmlns:rdf': "http://www.w3.org/1999/02/22-rdf-syntax-ns#") {

'bibterm:book' {'dc:title'('Groovy in Action')'bibterm:year'('2007')


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<bibterm:book>



</bibterm:book>

</rdf:description>

DOMBuilder with NamespaceBuilder

import groovy.xml.*def b = NamespaceBuilder.newInstance(DOMBuilder.newInstance())b.namespace('http://www.book-stuff.com/terms/', 'bibterm')b.namespace('http://purl.org/dc/elements/1.0/', 'dc')b.namespace('http://www.w3.org/1999/02/22-rdf-syntax-ns#', 'rdf')

def root = b.'rdf:description' {'bibterm:book' {'dc:title'('Groovy in Action')'bibterm:year'('2007')


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<?xml version="1.0" encoding="UTF-8"?>

<rdf:description xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">

<bibterm:book xmlns:bibterm="http://www.book-stuff.com/terms/">

<dc:title xmlns:dc="http://purl.org/dc/elements/1.0/">Groovy in Action</dc:title>


</bibterm:book>

</rdf:description>

StaxBuilder

import javax.xml.stream.XMLOutputFactoryimport groovy.xml.StaxBuilder

def factory = XMLOutputFactory.newInstance()def writer = new StringWriter()def xmlwriter = factory.createXMLStreamWriter(writer)def builder = new StaxBuilder(xmlwriter)builder.flights {


}flight(hours: 4) {


}}println writer

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StaxBuilder for non-XML (JSON)@Grab('org.codehaus.jettison#jettison;1.1')

import org.codehaus.jettison.mapped.*

import groovy.xml.StaxBuilder

def writer = new StringWriter()

def con = new MappedNamespaceConvention()

def mappedWriter = new MappedXMLStreamWriter(con,

writer)

def builder = new StaxBuilder(mappedWriter)

builder.flights {

flight(hours: 13) {

from('Brisbane')

to('Los Angeles')

}

flight(hours: 4) {

from('Los Angeles')

to('New Orleans')

}

}

println writer

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{"flights":{"flight":[

{ "@hours":"13",

"from":"Brisbane",

"to":"Los Angeles" },

{ "@hours":"4",

"from":"Los Angeles",

"to":"New Orleans" }

]}}

Updating XML

<shopping>

<category type="groceries">

<item>Chocolate</item>

<item>Coffee</item>

</category>

<category type="supplies">

<item>Paper</item>

<item quantity="4">Pens</item>

</category>

<category type="present">

<item when="Aug 10">

Kathryn's Birthday

</item>

</category>

</shopping>

<shopping>

<category type="groceries">

<item>Luxury Chocolate</item>

<item>Luxury Coffee</item>

</category>

<category type="supplies">

<item>Paper</item>

<item quantity="6"

when="Urgent">Pens</item>

</category>

<category type="present">

<item>Mum's Birthday</item>

<item when="Oct 15">

Monica's Birthday

</item>

</category>

</shopping>

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Updating with XmlParser

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...def root = new XmlParser().parseText(Shopping.XML)

// modify groceries: luxury items pleaseroot.category.find{ it.@type == 'groceries' }.item.each{ g ->

g.value = 'Luxury ' + g.text()}

// modify supplies: we need extra pens nowroot.category.find{

it.@type == 'supplies'}.item.findAll{ it.text() == 'Pens' }.each{ p ->

p.@quantity = [email protected]() + 2p.@when = 'Urgent'

}

// modify presents: August has come and gonedef presents = root.category.find{ it.@type == 'present' }presents.children().clear()presents.appendNode('item', "Mum's Birthday")presents.appendNode('item', [when:'Oct 15'], "Monica's Birthday")...

Updating with XmlSlurper...// modify groceries: luxury items pleasedef groceries = root.category.find{ it.@type == 'groceries' }(0..<groceries.item.size()).each {

groceries.item[it] = 'Luxury ' + groceries.item[it]}

// modify supplies: we need extra pens nowroot.category.find{

it.@type == 'supplies'}.item.findAll{ it.text() == 'Pens' }.each { p ->

p.@quantity = ([email protected]() + 2).toString()p.@when = 'Urgent'

}

// modify presents: August has come and goneroot.category.find{ it.@type == 'present' }.replaceNode{ node ->

category(type:'present'){item("Mum's Birthday")item("Monica's Birthday", when:'Oct 15')

}}...

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Updating with DOMCategoryuse(DOMCategory) {

// modify groceries: luxury items pleasedef groceries = root.category.find{ it.'@type' == 'groceries' }.itemgroceries.each { g ->

g.value = 'Luxury ' + g.text()}

// modify supplies: we need extra pens nowdef supplies = root.category.find{ it.'@type' == 'supplies' }.itemsupplies.findAll{ it.text() == 'Pens' }.each { p ->

p['@quantity'] = p.'@quantity'.toInteger() + 2p['@when'] = 'Urgent'

}

// modify presents: August has come and gonedef presents = root.category.find{ it.'@type' == 'present' }presents.item.each { presents.removeChild(it) }presents.appendNode('item', "Mum's Birthday")presents.appendNode('item', [when:'Oct 15'], "Monica's Birthday")...

}

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Validating against a DTD...def xml = '''<!DOCTYPE records [

<!ELEMENT car (country,record)><!ATTLIST car

make NMTOKEN #REQUIREDname CDATA #REQUIREDyear NMTOKEN #REQUIRED

><!ELEMENT country (#PCDATA)><!ELEMENT record (#PCDATA)><!ATTLIST record type NMTOKEN #REQUIRED><!ELEMENT records (car+)>

]><records><car name="HSV Maloo" make="Holden" year="2006"><country>Australia</country><record

type="speed">Production Pickup Truck with speed of 271kph</record></car>...

</records>'''.trim()

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...Validating against a DTD

def validating = truedef namespaceAware = false

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new XmlParser(validating, namespaceAware).parseText(xml)

new XmlSlurper(validating, namespaceAware).parseText(xml)

import groovy.xml.DOMBuilderDOMBuilder.parse(new StringReader(xml), validating, namespaceAware)

Validating against a W3C Schema...def xsd = '''<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified">

<xs:element name="records"><xs:complexType>

<xs:sequence><xs:element maxOccurs="unbounded" ref="car"/>

</xs:sequence></xs:complexType>

</xs:element><xs:element name="car">

<xs:complexType><xs:sequence>

<xs:element ref="country"/><xs:element ref="record"/>

</xs:sequence><xs:attribute name="make" use="required" type="xs:NCName"/><xs:attribute name="name" use="required"/><xs:attribute name="year" use="required" type="xs:integer"/>

</xs:complexType></xs:element><xs:element name="country" type="xs:string"/><xs:element name="record">

<xs:complexType mixed="true"><xs:attribute name="type" use="required" type="xs:NCName"/>

</xs:complexType></xs:element>

</xs:schema>'''.trim()

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...Validating against a W3C Schema

import static javax.xml.XMLConstants.W3C_XML_SCHEMA_NS_URIimport javax.xml.transform.stream.StreamSourceimport javax.xml.validation.SchemaFactory

def factory = SchemaFactory.newInstance(W3C_XML_SCHEMA_NS_URI)// println factory.isSchemaLanguageSupported(W3C_XML_SCHEMA_NS_URI)

def schema =factory.newSchema(new StreamSource(new StringReader(xsd)))

def validator = schema.newValidator()validator.validate(

new StreamSource(new StringReader(XmlExamples.CAR_RECORDS)))

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Validating against a RelaxNG Schema...def rng = '''<grammar xmlns="http://relaxng.org/ns/structure/1.0"

datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes"><start>

<ref name="records"/></start><define name="car">

<element name="car"><attribute name="make">

<data type="token"/></attribute><attribute name="name">

<text/></attribute><attribute name="year">

<data type="integer"/></attribute><ref name="country"/><ref name="record"/>

</element></define><define name="country">

<element name="country"><text/>

</element></define>...

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...<define name="record">

<element name="record"><attribute name="type">

<data type="token"/></attribute><text/>

</element></define><define name="records">

<element name="records"><oneOrMore>

<ref name="car"/></oneOrMore>

</element></define>

</grammar>'''.trim()

...Validating against a RelaxNG Schema

// require isorelax.jar, isorelax-jaxp-bridge.jar// require one of Jing, MSV, ...import static javax.xml.XMLConstants.RELAXNG_NS_URIimport javax.xml.transform.stream.StreamSourceimport javax.xml.validation.SchemaFactory

def factory = SchemaFactory.newInstance(RELAXNG_NS_URI)def schema =

factory.newSchema(new StreamSource(new StringReader(rng)))def validator = schema.newValidator()validator.validate(new StreamSource(new StringReader(CAR_RECORDS)))

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Groovy and Web Services

• SOAP Web Services

– GroovySOAP using XFire for Java 1.4

– GroovyWS using CXF for Java 1.5+

– JAXB out of the box for Java 6

– CXF, Axis2, Spring Web Services

• RESTful Options– Restlet.org, RESTlet DSL, roll your own

– JAX-RS: Jersey, CXF, JBoss RESTeasy

• Frameworks layered upon SOA

– Synapse, Tuscany, ServiceMix

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GroovySOAP

• XFire based

• Java 1.4

class MathService {double add(double a, double b) {

a + b}double square(double c) {

c * c}

} import groovy.net.soap.SoapServer

def server = new SoapServer('localhost', 6789)server.setNode('MathService')server.start()

import groovy.net.soap.SoapClient

def url = 'http://localhost:6789/MathServiceInterface?wsdl'def math = new SoapClient(url)assert math.add(1.0, 2.0) == 3.0assert math.square(3.0) == 9.0

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GroovyWS

• CXF based

• Java 1.5+

class MathService {double add(double a, double b) {

a + b}double square(double c) {

c * c}

}import groovyx.net.ws.WSServerdef server = new WSServer()server.setNode MathService.name,

"http://localhost:6980/MathService"

import groovyx.net.ws.WSClientdef url = "http://localhost:6980/MathService?wsdl"def proxy = new WSClient(url, this.class.classLoader)def result = proxy.add(1.0d, 2.0d)assert result == 3.0dresult = proxy.square(3.0d)assert result == 9.0d

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JAXB Server

import javax.xml.ws.Endpointimport javax.jws.WebServiceimport javax.jws.soap.SOAPBindingimport javax.jws.WebMethod

@WebService(name="Echo", serviceName="EchoService",targetNamespace="http://jaxws.asert.com")

@SOAPBinding(style=SOAPBinding.Style.RPC)class EchoImpl {

@WebMethod(operationName = "echo")String echo(String message) {

println "Received: $message""\nYou said: " + message

}}

Endpoint.publish("http://localhost:8080/Echo", new EchoImpl())println 'EchoService published and running ...'

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JAXB Client

• JAXB Client

• Build instructions

import javax.xml.namespace.QNameimport com.asert.jaxws.EchoService

def url = new URL("http://localhost:8080/Echo?wsdl")def qname = new QName("http://jaxws.asert.com", "EchoService")def echoServer = new EchoService(url, qname).echoPortprintln echoServer.echo("Today is ${new Date()}")

wsimport -d ../build -p com.asert.jaxws http://localhost:8080/Echo?wsdl

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Raw CXF• Apache CXF helps you build and develop

services. You can use frontend programming

APIs, like JAX-WS and support is provided for

SOAP, XML/HTTP, RESTful HTTP, ...

over HTTP, JMS, JBI, ...

– Follow instructions for Java but there is also

some special things you can do with Groovy

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Axis2• Apache Axis is a comprehensive

implementation of SOAP

– Follow the instructions for Java but use

Groovy instead and precompile

– Use GroovyShell to call script at runtime

• Another article:

– http://www.developer.com/services/article.ph

p/10928_3570031_2

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RESTful options• Several Options

– Already supported in discussed

frameworks, e.g. CXF

– Groovy Restlet DSLhttp://docs.codehaus.org/display/GROOVY/GroovyRestlet

– Jersey

http://wikis.sun.com/display/Jersey/Main

– restlet.org

http://www.restlet.org

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restlet.orgimport org.restlet.*import org.restlet.data.*class MailboxResource extends Restlet {

void handle(Request request, Response response) {switch (request.method) {

case Method.GET:handleGet(request, response)break

case Method.PUT:handlePut(request, response)break

case Method.POST:handlePost(request, response)break

default:// The request method is not allowed; set an error statusresponse.setStatus(Status.CLIENT_ERROR_METHOD_NOT_ALLOWED)response.setAllowedMethods([Method.GET, Method.PUT, Method.POST] as Set)

}}void handleGet(request, response) {

response.setEntity("Hello, world!", MediaType.TEXT_PLAIN)}

// ...

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GroovyRestlet DSLbuilder.component {current.servers.add(protocol.HTTP, 8182)application(uri: "") {router {def guard = guard(uri: "/docs", scheme: challengeScheme.HTTP_BASIC,

realm: "Restlet Tutorials")guard.secrets.put("scott", "tiger".toCharArray())guard.next = directory(root: "", autoAttach: false)restlet(uri: "/users/{user}", handle: {req, resp ->resp.setEntity("Account of user \"${req.attributes.get('user')}\"",

mediaType.TEXT_PLAIN)})restlet(uri: "/users/{user}/orders", handle: {req, resp ->resp.setEntity("Orders or user \"${req.attributes.get('user')}\"",

mediaType.TEXT_PLAIN)})restlet(uri: "/users/{user}/orders/{order}", handle: {req, resp ->def attrs = req.attributesdef message ="Order \"${attrs.get('order')}\" for User \"${attrs.get('user')}\""resp.setEntity(message, mediaType.TEXT_PLAIN)

})}

}}.start() Source: http://docs.codehaus.org/display/GROOVY/GroovyRestlet

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Jersey...package com.asert

import javax.ws.rs.GETimport javax.ws.rs.Pathimport javax.ws.rs.Producesimport static com.sun.jersey.api.container.grizzly.GrizzlyWebContainerFactory.*

@Path ("/helloworld")class HelloWorldResource {

@GET @Produces("text/plain")String getPlainMessage() {

"Hello World"}

}

def baseUri = "http://localhost:9998/"def initParams = ["com.sun.jersey.config.property.packages": "com.asert"]

println """Starting grizzly with Jersey...App WADL available at ${baseUri}application.wadlApp available at ${baseUri}helloworld"""create(baseUri, initParams)

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...Jersey...import javax.ws.rs.PathParamimport javax.xml.bind.annotation.*

class PrettyXml {static print(node) {

def writer = new StringWriter()new XmlNodePrinter(new PrintWriter(writer)).print(node)writer.toString()

}}

@XmlRootElement@XmlAccessorType (XmlAccessType.FIELD)class FlightInfoBean {

@XmlAttribute String hours@XmlElement String from, tostatic populate(num) {

def trip = new XmlParser().parse(Flights.reader)def f = trip.flight[num as int]new FlightInfoBean(hours:f.@hours,

from:f.from.text(),to:f.to.text())

}}

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...Jersey@Path("/flight/xml/{flightnum}")class FlightInfoXml {

@GET @Produces("text/xml")String getXmlMessage(@PathParam('flightnum') String num) {

def trip = new XmlParser().parse(Flights.reader)PrettyXml.print(trip.flight[num as int])

}}

@Path("/flight/json/{flightnum}")class FlightInfoJson {

@GET @Produces("application/json")FlightInfoBean getJsonMessage(@PathParam('flightnum') String num) {

FlightInfoBean.populate(num)}

}

@Path("/flight/atom/{flightnum}")class FlightInfoAtom {

@GET @Produces("application/atom")FlightInfoBean getAtomMessage(@PathParam('flightnum') String num) {

FlightInfoBean.populate(num)}

}

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Jersey output

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> curl http://localhost:9998/helloworld

Hello World

> curl http://localhost:9998/flight/xml/1

<flight hours="4">

<from>

Los Angeles

</from>

<to>

New Orleans

</to>

</flight>

> curl http://localhost:9998/flight/json/1

{"@hours":"4","from":"Los Angeles","to":"New Orleans"}

> curl http://localhost:9998/flight/atom/1

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>

<flightInfoBean hours="4">

<from>Los Angeles</from>

<to>New Orleans</to>

</flightInfoBean>

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Synapse• Apache Synapse is a simple, lightweight and

high performance Enterprise Service Bus (ESB)

with support for XML, Web services, binary and

text formats

– Groovy scripting, endpoints, Synapse DSL

– https://svn.apache.org/repos/asf/synapse/

trunk/java/src/site/resources/presentations/

makingsoagroovyfremantle.pdf

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ServiceMix• ServiceMix is an open source Enterprise Service

Bus (ESB) combining Service Oriented

Architecture (SOA), Event Driven Architecture

(EDA) and Java Business Integration (JBI)

functionality

– You can use ServiceMix Scripting

– You can use legacy ScriptComponent and

GroovyComponent

– You can write Groovy JBI components

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Tuscany...• Tuscany embodies Service Component

Architecture (SCA) which defines a simple,

service-based model for construction, assembly

and deployment of a network of services

(existing and new ones) that are defined in a

language-neutral way.”

– You can define your services using Groovy

either using Java mechanisms

or Scripting integration

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...Tuscany...

<composite ...>

<component name="CalculatorServiceComponent" .../>

<component name="AddServiceComponent" .../>

<component name="SubtractServiceComponent">

<tuscany:implementation.java

class="calculator.SubtractServiceImpl"/>

</component>

<component name="MultiplyServiceComponent">

<tuscany:implementation.script language="groovy">

def multiply(n1, n2) {

n1 * n2

}

</tuscany:implementation.script>

</component>

<component name="DivideServiceComponent">

<tuscany:implementation.script

script="calculator/DivideServiceImpl.groovy"/>

</component>

</composite>

Compile your Groovy using groovyc

(with or without annotations) then

treat just like normal Java. Need

groovy jar in your runtime classpath.

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...Tuscany

<composite ...>

<component name="CalculatorServiceComponent" .../>

<component name="AddServiceComponent" .../>

<component name="SubtractServiceComponent">

<tuscany:implementation.java

class="calculator.SubtractServiceImpl"/>

</component>

<component name="MultiplyServiceComponent">

<tuscany:implementation.script language="groovy">

def multiply(n1, n2) {

n1 * n2

}

</tuscany:implementation.script>

</component>

<component name="DivideServiceComponent">

<tuscany:implementation.script

script="calculator/DivideServiceImpl.groovy"/>

</component>

</composite>

With Groovy scripts either

embedded or in files – no

compilation necessary.

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More Information: on the web

• Web sites– http://groovy.codehaus.org

– http://grails.codehaus.org

– http://pleac.sourceforge.net/pleac_groovy (many examples)

– http://www.asert.com.au/training/java/GV110.htm (workshop)

• Mailing list for users– [email protected]

• Information portals– http://www.aboutgroovy.org

– http://www.groovyblogs.org

• Documentation (1000+ pages)– Getting Started Guide, User Guide, Developer Guide, Testing

Guide, Cookbook Examples, Advanced Usage Guide

• Books– Several to choose from ...

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http://groovy.codehaus.org/

http://grails.codehaus.org/

http://pleac.sourceforge.net/pleac_groovy

http://www.asert.com.au/training/java/GV110.htm

http://www.aboutgroovy.org/

http://www.groovyblogs.org/

xml and web services with groovy

Technology