stringbuffer (java platform se 7 )
DESCRIPTION
String bufferTRANSCRIPT
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Overview Package Class Use Tree Deprecated Index HelpJavaPlatformStandardEd.7
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Summary:Nested|Field|Constr|Method Detail:Field|Constr|Method
java.lang
ClassStringBuffer
java.lang.Objectjava.lang.StringBuffer
AllImplementedInterfaces:
Serializable,Appendable,CharSequence
public final class StringBufferextends Object
implements Serializable, CharSequence
Athreadsafe,mutablesequenceofcharacters.AstringbufferislikeaString,butcanbemodified.Atanypointintimeitcontainssomeparticularsequenceofcharacters,butthelengthandcontentofthesequencecanbechangedthroughcertainmethodcalls.
Stringbuffersaresafeforusebymultiplethreads.Themethodsaresynchronizedwherenecessarysothatalltheoperationsonanyparticularinstancebehaveasiftheyoccurinsomeserialorderthatisconsistentwiththeorderofthemethodcallsmadebyeachoftheindividualthreadsinvolved.
TheprincipaloperationsonaStringBufferaretheappendandinsertmethods,whichareoverloadedsoastoacceptdataofanytype.Eacheffectivelyconvertsagivendatumtoastringandthenappendsorinsertsthecharactersofthatstringtothestringbuffer.Theappendmethodalwaysaddsthesecharactersattheendofthebuffertheinsertmethodaddsthecharactersataspecifiedpoint.
Forexample,ifzreferstoastringbufferobjectwhosecurrentcontentsare"start",thenthemethodcallz.append("le")wouldcausethestringbuffertocontain"startle",whereasz.insert(4, "le")wouldalterthestringbuffertocontain"starlet".
Ingeneral,ifsbreferstoaninstanceofaStringBuffer,thensb.append(x)hasthesameeffectassb.insert(sb.length(),x).
Wheneveranoperationoccursinvolvingasourcesequence(suchasappendingorinsertingfromasourcesequence)thisclasssynchronizesonlyonthestringbufferperformingtheoperation,notonthesource.
Everystringbufferhasacapacity.Aslongasthelengthofthecharactersequencecontainedinthestringbufferdoesnotexceedthecapacity,itisnotnecessarytoallocateanewinternalbufferarray.Iftheinternalbufferoverflows,itisautomaticallymadelarger.AsofreleaseJDK5,thisclasshasbeensupplementedwithanequivalentclassdesignedforusebyasinglethread,StringBuilder.TheStringBuilderclassshouldgenerallybeusedinpreferencetothisone,asitsupportsallofthesameoperationsbutitisfaster,asitperformsnosynchronization.
Since:
JDK1.0
SeeAlso:
StringBuilder,String,SerializedForm
ConstructorSummary
Constructors
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ConstructorandDescription
StringBuffer()
Constructsastringbufferwithnocharactersinitandaninitialcapacityof16characters.StringBuffer(CharSequenceseq)
ConstructsastringbufferthatcontainsthesamecharactersasthespecifiedCharSequence.StringBuffer(intcapacity)
Constructsastringbufferwithnocharactersinitandthespecifiedinitialcapacity.StringBuffer(Stringstr)
Constructsastringbufferinitializedtothecontentsofthespecifiedstring.
MethodSummary
ModifierandType MethodandDescription
StringBuffer append(booleanb)
Appendsthestringrepresentationofthebooleanargumenttothesequence.StringBuffer append(charc)
Appendsthestringrepresentationofthecharargumenttothissequence.StringBuffer append(char[]str)
Appendsthestringrepresentationofthechararrayargumenttothissequence.StringBuffer append(char[]str, intoffset, intlen)
Appendsthestringrepresentationofasubarrayofthechararrayargumenttothissequence.
StringBuffer append(CharSequences)
AppendsthespecifiedCharSequencetothissequence.StringBuffer append(CharSequences, intstart, intend)
AppendsasubsequenceofthespecifiedCharSequencetothissequence.StringBuffer append(doubled)
Appendsthestringrepresentationofthedoubleargumenttothissequence.StringBuffer append(floatf)
Appendsthestringrepresentationofthefloatargumenttothissequence.StringBuffer append(inti)
Appendsthestringrepresentationoftheintargumenttothissequence.StringBuffer append(longlng)
Appendsthestringrepresentationofthelongargumenttothissequence.StringBuffer append(Objectobj)
AppendsthestringrepresentationoftheObjectargument.StringBuffer append(Stringstr)
Appendsthespecifiedstringtothischaractersequence.StringBuffer append(StringBuffersb)
AppendsthespecifiedStringBuffertothissequence.StringBuffer appendCodePoint(intcodePoint)
AppendsthestringrepresentationofthecodePointargumenttothissequence.int capacity()
Returnsthecurrentcapacity.char charAt(intindex)
Returnsthecharvalueinthissequenceatthespecifiedindex.
Methods
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int codePointAt(intindex)
Returnsthecharacter(Unicodecodepoint)atthespecifiedindex.int codePointBefore(intindex)
Returnsthecharacter(Unicodecodepoint)beforethespecifiedindex.int codePointCount(intbeginIndex, intendIndex)
ReturnsthenumberofUnicodecodepointsinthespecifiedtextrangeofthissequence.
StringBuffer delete(intstart, intend)
Removesthecharactersinasubstringofthissequence.StringBuffer deleteCharAt(intindex)
Removesthecharatthespecifiedpositioninthissequence.void ensureCapacity(intminimumCapacity)
Ensuresthatthecapacityisatleastequaltothespecifiedminimum.void getChars(intsrcBegin, intsrcEnd, char[]dst, intdstBegin)
Charactersarecopiedfromthissequenceintothedestinationcharacterarraydst.int indexOf(Stringstr)
Returnstheindexwithinthisstringofthefirstoccurrenceofthespecifiedsubstring.int indexOf(Stringstr, intfromIndex)
Returnstheindexwithinthisstringofthefirstoccurrenceofthespecifiedsubstring,startingatthespecifiedindex.
StringBuffer insert(intoffset, booleanb)
Insertsthestringrepresentationofthebooleanargumentintothissequence.StringBuffer insert(intoffset, charc)
Insertsthestringrepresentationofthecharargumentintothissequence.StringBuffer insert(intoffset, char[]str)
Insertsthestringrepresentationofthechararrayargumentintothissequence.StringBuffer insert(intindex, char[]str, intoffset, intlen)
Insertsthestringrepresentationofasubarrayofthestrarrayargumentintothissequence.
StringBuffer insert(intdstOffset, CharSequences)
InsertsthespecifiedCharSequenceintothissequence.StringBuffer insert(intdstOffset, CharSequences, intstart, intend)
InsertsasubsequenceofthespecifiedCharSequenceintothissequence.StringBuffer insert(intoffset, doubled)
Insertsthestringrepresentationofthedoubleargumentintothissequence.
StringBuffer insert(intoffset, floatf)
Insertsthestringrepresentationofthefloatargumentintothissequence.StringBuffer insert(intoffset, inti)
Insertsthestringrepresentationofthesecondintargumentintothissequence.StringBuffer insert(intoffset, longl)
Insertsthestringrepresentationofthelongargumentintothissequence.StringBuffer insert(intoffset, Objectobj)
InsertsthestringrepresentationoftheObjectargumentintothischaractersequence.
StringBuffer insert(intoffset, Stringstr)
Insertsthestringintothischaractersequence.int lastIndexOf(Stringstr)
Returnstheindexwithinthisstringoftherightmostoccurrenceofthespecifiedsubstring.
int lastIndexOf(Stringstr, intfromIndex)
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Returnstheindexwithinthisstringofthelastoccurrenceofthespecifiedsubstring.int length()
Returnsthelength(charactercount).int offsetByCodePoints(intindex, intcodePointOffset)
ReturnstheindexwithinthissequencethatisoffsetfromthegivenindexbycodePointOffsetcodepoints.
StringBuffer replace(intstart, intend, Stringstr)
ReplacesthecharactersinasubstringofthissequencewithcharactersinthespecifiedString.
StringBuffer reverse()
Causesthischaractersequencetobereplacedbythereverseofthesequence.void setCharAt(intindex, charch)
Thecharacteratthespecifiedindexissettoch.void setLength(intnewLength)
Setsthelengthofthecharactersequence.CharSequence subSequence(intstart, intend)
Returnsanewcharactersequencethatisasubsequenceofthissequence.String substring(intstart)
ReturnsanewStringthatcontainsasubsequenceofcharacterscurrentlycontainedinthischaractersequence.
String substring(intstart, intend)
ReturnsanewStringthatcontainsasubsequenceofcharacterscurrentlycontainedinthissequence.
String toString()
Returnsastringrepresentingthedatainthissequence.void trimToSize()
Attemptstoreducestorageusedforthecharactersequence.
Methodsinheritedfromclassjava.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
ConstructorDetail
StringBuffer
publicStringBuffer()
Constructsastringbufferwithnocharactersinitandaninitialcapacityof16characters.
StringBuffer
publicStringBuffer(intcapacity)
Constructsastringbufferwithnocharactersinitandthespecifiedinitialcapacity.
Parameters:
capacitytheinitialcapacity.
Throws:
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NegativeArraySizeExceptionifthecapacityargumentislessthan0.
StringBuffer
publicStringBuffer(Stringstr)
Constructsastringbufferinitializedtothecontentsofthespecifiedstring.Theinitialcapacityofthestringbufferis16plusthelengthofthestringargument.
Parameters:
strtheinitialcontentsofthebuffer.
Throws:
NullPointerExceptionifstrisnull
StringBuffer
publicStringBuffer(CharSequenceseq)
ConstructsastringbufferthatcontainsthesamecharactersasthespecifiedCharSequence.Theinitialcapacityofthestringbufferis16plusthelengthoftheCharSequenceargument.
IfthelengthofthespecifiedCharSequenceislessthanorequaltozero,thenanemptybufferofcapacity16isreturned.
Parameters:
seqthesequencetocopy.
Throws:
NullPointerExceptionifseqisnull
Since:
1.5
MethodDetail
length
publicintlength()
Returnsthelength(charactercount).
Specifiedby:
lengthininterfaceCharSequence
Returns:
thelengthofthesequenceofcharacterscurrentlyrepresentedbythisobject
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capacity
publicintcapacity()
Returnsthecurrentcapacity.Thecapacityistheamountofstorageavailablefornewlyinsertedcharacters,beyondwhichanallocationwilloccur.
Returns:
thecurrentcapacity
ensureCapacity
publicvoidensureCapacity(intminimumCapacity)
Ensuresthatthecapacityisatleastequaltothespecifiedminimum.Ifthecurrentcapacityislessthantheargument,thenanewinternalarrayisallocatedwithgreatercapacity.Thenewcapacityisthelargerof:
TheminimumCapacityargument.Twicetheoldcapacity,plus2.
IftheminimumCapacityargumentisnonpositive,thismethodtakesnoactionandsimplyreturns.
Parameters:
minimumCapacitytheminimumdesiredcapacity.
trimToSize
publicvoidtrimToSize()
Attemptstoreducestorageusedforthecharactersequence.Ifthebufferislargerthannecessarytoholditscurrentsequenceofcharacters,thenitmayberesizedtobecomemorespaceefficient.Callingthismethodmay,butisnotrequiredto,affectthevaluereturnedbyasubsequentcalltothecapacity()method.
Since:
1.5
setLength
publicvoidsetLength(intnewLength)
Setsthelengthofthecharactersequence.Thesequenceischangedtoanewcharactersequencewhoselengthisspecifiedbytheargument.ForeverynonnegativeindexklessthannewLength,thecharacteratindexkinthenewcharactersequenceisthesameasthecharacteratindexkintheoldsequenceifkislessthanthelengthoftheoldcharactersequenceotherwise,itisthenullcharacter'\u0000'.Inotherwords,ifthenewLengthargumentislessthanthecurrentlength,thelengthischangedtothespecifiedlength.
IfthenewLengthargumentisgreaterthanorequaltothecurrentlength,sufficientnullcharacters('\u0000')areappendedsothatlengthbecomesthenewLengthargument.
ThenewLengthargumentmustbegreaterthanorequalto0.
Parameters:
newLengththenewlength
Throws:
IndexOutOfBoundsExceptionifthenewLengthargumentisnegative.
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SeeAlso:
length()
charAt
publiccharcharAt(intindex)
Returnsthecharvalueinthissequenceatthespecifiedindex.Thefirstcharvalueisatindex0,thenextat
index1,andsoon,asinarrayindexing.
Theindexargumentmustbegreaterthanorequalto0,andlessthanthelengthofthissequence.
Ifthecharvaluespecifiedbytheindexisasurrogate,thesurrogatevalueisreturned.
Specifiedby:
charAtininterfaceCharSequence
Parameters:
indextheindexofthedesiredcharvalue.
Returns:
thecharvalueatthespecifiedindex.
Throws:
IndexOutOfBoundsExceptionifindexisnegativeorgreaterthanorequaltolength().
SeeAlso:
length()
codePointAt
publicintcodePointAt(intindex)
Returnsthecharacter(Unicodecodepoint)atthespecifiedindex.Theindexreferstocharvalues(Unicodecode
units)andrangesfrom0tolength() - 1.
Ifthecharvaluespecifiedatthegivenindexisinthehighsurrogaterange,thefollowingindexislessthanthe
lengthofthissequence,andthecharvalueatthefollowingindexisinthelowsurrogaterange,thenthe
supplementarycodepointcorrespondingtothissurrogatepairisreturned.Otherwise,thecharvalueatthegiven
indexisreturned.
Parameters:
indextheindextothecharvalues
Returns:
thecodepointvalueofthecharacterattheindex
Since:
1.5
codePointBefore
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publicintcodePointBefore(intindex)
Returnsthecharacter(Unicodecodepoint)beforethespecifiedindex.Theindexreferstocharvalues(Unicodecodeunits)andrangesfrom1tolength().
Ifthecharvalueat(index - 1)isinthelowsurrogaterange,(index - 2)isnotnegative,andthecharvalueat(index - 2)isinthehighsurrogaterange,thenthesupplementarycodepointvalueofthesurrogatepairisreturned.Ifthecharvalueatindex - 1isanunpairedlowsurrogateorahighsurrogate,thesurrogatevalueisreturned.
Parameters:
indextheindexfollowingthecodepointthatshouldbereturned
Returns:
theUnicodecodepointvaluebeforethegivenindex.
Since:
1.5
codePointCount
publicintcodePointCount(intbeginIndex,
intendIndex)
ReturnsthenumberofUnicodecodepointsinthespecifiedtextrangeofthissequence.ThetextrangebeginsatthespecifiedbeginIndexandextendstothecharatindexendIndex - 1.Thusthelength(inchars)ofthetextrangeisendIndex-beginIndex.Unpairedsurrogateswithinthissequencecountasonecodepointeach.
Parameters:
beginIndextheindextothefirstcharofthetextrange.
endIndextheindexafterthelastcharofthetextrange.
Returns:
thenumberofUnicodecodepointsinthespecifiedtextrange
Since:
1.5
offsetByCodePoints
publicintoffsetByCodePoints(intindex,
intcodePointOffset)
ReturnstheindexwithinthissequencethatisoffsetfromthegivenindexbycodePointOffsetcodepoints.UnpairedsurrogateswithinthetextrangegivenbyindexandcodePointOffsetcountasonecodepointeach.
Parameters:
indextheindextobeoffset
codePointOffsettheoffsetincodepoints
Returns:
theindexwithinthissequence
Since:
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1.5
getChars
publicvoidgetChars(intsrcBegin,
intsrcEnd,
char[]dst,
intdstBegin)
Charactersarecopiedfromthissequenceintothedestinationcharacterarraydst.ThefirstcharactertobecopiedisatindexsrcBeginthelastcharactertobecopiedisatindexsrcEnd-1.ThetotalnumberofcharacterstobecopiedissrcEnd-srcBegin.ThecharactersarecopiedintothesubarrayofdststartingatindexdstBeginandendingatindex:
dstbegin + (srcEnd-srcBegin) - 1
Parameters:
srcBeginstartcopyingatthisoffset.
srcEndstopcopyingatthisoffset.
dstthearraytocopythedatainto.
dstBeginoffsetintodst.
Throws:
NullPointerExceptionifdstisnull.
IndexOutOfBoundsExceptionifanyofthefollowingistrue:srcBeginisnegativedstBeginisnegativethesrcBeginargumentisgreaterthanthesrcEndargument.srcEndisgreaterthanthis.length().dstBegin+srcEnd-srcBeginisgreaterthandst.length
setCharAt
publicvoidsetCharAt(intindex,
charch)
Thecharacteratthespecifiedindexissettoch.Thissequenceisalteredtorepresentanewcharactersequencethatisidenticaltotheoldcharactersequence,exceptthatitcontainsthecharacterchatpositionindex.
Theindexargumentmustbegreaterthanorequalto0,andlessthanthelengthofthissequence.
Parameters:
indextheindexofthecharactertomodify.
chthenewcharacter.
Throws:
IndexOutOfBoundsExceptionifindexisnegativeorgreaterthanorequaltolength().
SeeAlso:
length()
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append
publicStringBufferappend(Objectobj)
AppendsthestringrepresentationoftheObjectargument.
TheoveralleffectisexactlyasiftheargumentwereconvertedtoastringbythemethodString.valueOf(Object),andthecharactersofthatstringwerethenappendedtothischaractersequence.
Parameters:
objanObject.
Returns:
areferencetothisobject.
append
publicStringBufferappend(Stringstr)
Appendsthespecifiedstringtothischaractersequence.
ThecharactersoftheStringargumentareappended,inorder,increasingthelengthofthissequencebythelengthoftheargument.Ifstrisnull,thenthefourcharacters"null"areappended.
Letnbethelengthofthischaractersequencejustpriortoexecutionoftheappendmethod.Thenthecharacteratindexkinthenewcharactersequenceisequaltothecharacteratindexkintheoldcharactersequence,ifkislessthannotherwise,itisequaltothecharacteratindexknintheargumentstr.
Parameters:
strastring.
Returns:
areferencetothisobject.
append
publicStringBufferappend(StringBuffersb)
AppendsthespecifiedStringBuffertothissequence.
ThecharactersoftheStringBufferargumentareappended,inorder,tothecontentsofthisStringBuffer,increasingthelengthofthisStringBufferbythelengthoftheargument.Ifsbisnull,thenthefourcharacters"null"areappendedtothisStringBuffer.
Letnbethelengthoftheoldcharactersequence,theonecontainedintheStringBufferjustpriortoexecutionoftheappendmethod.Thenthecharacteratindexkinthenewcharactersequenceisequaltothecharacteratindexkintheoldcharactersequence,ifkislessthannotherwise,itisequaltothecharacteratindexknintheargumentsb.
Thismethodsynchronizesonthis(thedestination)objectbutdoesnotsynchronizeonthesource(sb).
Parameters:
sbtheStringBuffertoappend.
Returns:
areferencetothisobject.
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Since:
1.4
append
publicStringBufferappend(CharSequences)
AppendsthespecifiedCharSequencetothissequence.
ThecharactersoftheCharSequenceargumentareappended,inorder,increasingthelengthofthissequencebythelengthoftheargument.
Theresultofthismethodisexactlythesameasifitwereaninvocationofthis.append(s,0,s.length())
Thismethodsynchronizesonthis(thedestination)objectbutdoesnotsynchronizeonthesource(s).
Ifsisnull,thenthefourcharacters"null"areappended.
Specifiedby:
appendininterfaceAppendable
Parameters:
stheCharSequencetoappend.
Returns:
areferencetothisobject.
Since:
1.5
append
publicStringBufferappend(CharSequences, intstart, intend)
AppendsasubsequenceofthespecifiedCharSequencetothissequence.
Charactersofthearguments,startingatindexstart,areappended,inorder,tothecontentsofthissequenceuptothe(exclusive)indexend.Thelengthofthissequenceisincreasedbythevalueofend - start.
Letnbethelengthofthischaractersequencejustpriortoexecutionoftheappendmethod.Thenthecharacteratindexkinthischaractersequencebecomesequaltothecharacteratindexkinthissequence,ifkislessthannotherwise,itisequaltothecharacteratindexk+startninthearguments.
Ifsisnull,thenthismethodappendscharactersasifthesparameterwasasequencecontainingthefourcharacters"null".
Specifiedby:
appendininterfaceAppendable
Parameters:
sthesequencetoappend.
startthestartingindexofthesubsequencetobeappended.
endtheendindexofthesubsequencetobeappended.
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Returns:
areferencetothisobject.
Throws:
IndexOutOfBoundsExceptionifstartisnegative,orstartisgreaterthanendorendisgreaterthans.length()
Since:
1.5
append
publicStringBufferappend(char[]str)
Appendsthestringrepresentationofthechararrayargumenttothissequence.
Thecharactersofthearrayargumentareappended,inorder,tothecontentsofthissequence.Thelengthofthissequenceincreasesbythelengthoftheargument.
TheoveralleffectisexactlyasiftheargumentwereconvertedtoastringbythemethodString.valueOf(char[]),andthecharactersofthatstringwerethenappendedtothischaractersequence.
Parameters:
strthecharacterstobeappended.
Returns:
areferencetothisobject.
append
publicStringBufferappend(char[]str,
intoffset,
intlen)
Appendsthestringrepresentationofasubarrayofthechararrayargumenttothissequence.
Charactersofthechararraystr,startingatindexoffset,areappended,inorder,tothecontentsofthissequence.Thelengthofthissequenceincreasesbythevalueoflen.
TheoveralleffectisexactlyasiftheargumentswereconvertedtoastringbythemethodString.valueOf(char[],int,int),andthecharactersofthatstringwerethenappendedtothischaractersequence.
Parameters:
strthecharacterstobeappended.
offsettheindexofthefirstchartoappend.
lenthenumberofcharstoappend.
Returns:
areferencetothisobject.
Throws:
IndexOutOfBoundsExceptionifoffset < 0orlen < 0oroffset+len > str.length
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append
publicStringBufferappend(booleanb)
Appendsthestringrepresentationofthebooleanargumenttothesequence.
TheoveralleffectisexactlyasiftheargumentwereconvertedtoastringbythemethodString.valueOf(boolean),andthecharactersofthatstringwerethenappendedtothischaractersequence.
Parameters:
baboolean.
Returns:
areferencetothisobject.
append
publicStringBufferappend(charc)
Appendsthestringrepresentationofthecharargumenttothissequence.
Theargumentisappendedtothecontentsofthissequence.Thelengthofthissequenceincreasesby1.
TheoveralleffectisexactlyasiftheargumentwereconvertedtoastringbythemethodString.valueOf(char),andthecharacterinthatstringwerethenappendedtothischaractersequence.
Specifiedby:
appendininterfaceAppendable
Parameters:
cachar.
Returns:
areferencetothisobject.
append
publicStringBufferappend(inti)
Appendsthestringrepresentationoftheintargumenttothissequence.
TheoveralleffectisexactlyasiftheargumentwereconvertedtoastringbythemethodString.valueOf(int),andthecharactersofthatstringwerethenappendedtothischaractersequence.
Parameters:
ianint.
Returns:
areferencetothisobject.
appendCodePoint
publicStringBufferappendCodePoint(intcodePoint)
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AppendsthestringrepresentationofthecodePointargumenttothissequence.
Theargumentisappendedtothecontentsofthissequence.ThelengthofthissequenceincreasesbyCharacter.charCount(codePoint).
TheoveralleffectisexactlyasiftheargumentwereconvertedtoachararraybythemethodCharacter.toChars(int)andthecharacterinthatarraywerethenappendedtothischaractersequence.
Parameters:
codePointaUnicodecodepoint
Returns:
areferencetothisobject.
Since:
1.5
append
publicStringBufferappend(longlng)
Appendsthestringrepresentationofthelongargumenttothissequence.
TheoveralleffectisexactlyasiftheargumentwereconvertedtoastringbythemethodString.valueOf(long),andthecharactersofthatstringwerethenappendedtothischaractersequence.
Parameters:
lngalong.
Returns:
areferencetothisobject.
append
publicStringBufferappend(floatf)
Appendsthestringrepresentationofthefloatargumenttothissequence.
TheoveralleffectisexactlyasiftheargumentwereconvertedtoastringbythemethodString.valueOf(float),andthecharactersofthatstringwerethenappendedtothischaractersequence.
Parameters:
fafloat.
Returns:
areferencetothisobject.
append
publicStringBufferappend(doubled)
Appendsthestringrepresentationofthedoubleargumenttothissequence.
Theoveralleffectisexactlyasiftheargumentwereconvertedtoastringbythemethod
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String.valueOf(double),andthecharactersofthatstringwerethenappendedtothischaractersequence.
Parameters:
dadouble.
Returns:
areferencetothisobject.
delete
publicStringBufferdelete(intstart,
intend)
Removesthecharactersinasubstringofthissequence.Thesubstringbeginsatthespecifiedstartandextendstothecharacteratindexend - 1ortotheendofthesequenceifnosuchcharacterexists.Ifstartisequaltoend,nochangesaremade.
Parameters:
startThebeginningindex,inclusive.
endTheendingindex,exclusive.
Returns:
Thisobject.
Throws:
StringIndexOutOfBoundsExceptionifstartisnegative,greaterthanlength(),orgreaterthanend.
Since:
1.2
deleteCharAt
publicStringBufferdeleteCharAt(intindex)
Removesthecharatthespecifiedpositioninthissequence.Thissequenceisshortenedbyonechar.
Note:Ifthecharacteratthegivenindexisasupplementarycharacter,thismethoddoesnotremovetheentirecharacter.Ifcorrecthandlingofsupplementarycharactersisrequired,determinethenumberofcharstoremovebycallingCharacter.charCount(thisSequence.codePointAt(index)),wherethisSequenceisthissequence.
Parameters:
indexIndexofchartoremove
Returns:
Thisobject.
Throws:
StringIndexOutOfBoundsExceptioniftheindexisnegativeorgreaterthanorequaltolength().
Since:
1.2
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replace
publicStringBufferreplace(intstart,
intend,
Stringstr)
ReplacesthecharactersinasubstringofthissequencewithcharactersinthespecifiedString.Thesubstringbeginsatthespecifiedstartandextendstothecharacteratindexend - 1ortotheendofthesequenceifnosuchcharacterexists.FirstthecharactersinthesubstringareremovedandthenthespecifiedStringisinsertedatstart.(ThissequencewillbelengthenedtoaccommodatethespecifiedStringifnecessary.)
Parameters:
startThebeginningindex,inclusive.
endTheendingindex,exclusive.
strStringthatwillreplacepreviouscontents.
Returns:
Thisobject.
Throws:
StringIndexOutOfBoundsExceptionifstartisnegative,greaterthanlength(),orgreaterthanend.
Since:
1.2
substring
publicStringsubstring(intstart)
ReturnsanewStringthatcontainsasubsequenceofcharacterscurrentlycontainedinthischaractersequence.Thesubstringbeginsatthespecifiedindexandextendstotheendofthissequence.
Parameters:
startThebeginningindex,inclusive.
Returns:
Thenewstring.
Throws:
StringIndexOutOfBoundsExceptionifstartislessthanzero,orgreaterthanthelengthofthisobject.
Since:
1.2
subSequence
publicCharSequencesubSequence(intstart,
intend)
Returnsanewcharactersequencethatisasubsequenceofthissequence.
Aninvocationofthismethodoftheform
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sb.subSequence(begin,end)
behavesinexactlythesamewayastheinvocation
sb.substring(begin,end)
ThismethodisprovidedsothatthisclasscanimplementtheCharSequenceinterface.
Specifiedby:
subSequenceininterfaceCharSequence
Parameters:
startthestartindex,inclusive.
endtheendindex,exclusive.
Returns:
thespecifiedsubsequence.
Throws:
IndexOutOfBoundsExceptionifstartorendarenegative,ifendisgreaterthanlength(),orifstartisgreaterthanend
Since:
1.4
substring
publicStringsubstring(intstart,
intend)
ReturnsanewStringthatcontainsasubsequenceofcharacterscurrentlycontainedinthissequence.Thesubstringbeginsatthespecifiedstartandextendstothecharacteratindexend - 1.
Parameters:
startThebeginningindex,inclusive.
endTheendingindex,exclusive.
Returns:
Thenewstring.
Throws:
StringIndexOutOfBoundsExceptionifstartorendarenegativeorgreaterthanlength(),orstartisgreaterthanend.
Since:
1.2
insert
publicStringBufferinsert(intindex,
char[]str,
intoffset,
intlen)
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Insertsthestringrepresentationofasubarrayofthestrarrayargumentintothissequence.Thesubarraybeginsatthespecifiedoffsetandextendslenchars.Thecharactersofthesubarrayareinsertedintothissequenceatthepositionindicatedbyindex.Thelengthofthissequenceincreasesbylenchars.
Parameters:
indexpositionatwhichtoinsertsubarray.
strAchararray.
offsettheindexofthefirstcharinsubarraytobeinserted.
lenthenumberofcharsinthesubarraytobeinserted.
Returns:
Thisobject
Throws:
StringIndexOutOfBoundsExceptionifindexisnegativeorgreaterthanlength(),oroffsetorlenarenegative,or(offset+len)isgreaterthanstr.length.
Since:
1.2
insert
publicStringBufferinsert(intoffset,
Objectobj)
InsertsthestringrepresentationoftheObjectargumentintothischaractersequence.
TheoveralleffectisexactlyasifthesecondargumentwereconvertedtoastringbythemethodString.valueOf(Object),andthecharactersofthatstringweretheninsertedintothischaractersequenceattheindicatedoffset.
Theoffsetargumentmustbegreaterthanorequalto0,andlessthanorequaltothelengthofthissequence.
Parameters:
offsettheoffset.
objanObject.
Returns:
areferencetothisobject.
Throws:
StringIndexOutOfBoundsExceptioniftheoffsetisinvalid.
insert
publicStringBufferinsert(intoffset,
Stringstr)
Insertsthestringintothischaractersequence.
ThecharactersoftheStringargumentareinserted,inorder,intothissequenceattheindicatedoffset,movingupanycharactersoriginallyabovethatpositionandincreasingthelengthofthissequencebythelengthoftheargument.Ifstrisnull,thenthefourcharacters"null"areinsertedintothissequence.
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Thecharacteratindexkinthenewcharactersequenceisequalto:
thecharacteratindexkintheoldcharactersequence,ifkislessthanoffsetthecharacteratindexk-offsetintheargumentstr,ifkisnotlessthanoffsetbutislessthanoffset+str.length()
thecharacteratindexk-str.length()intheoldcharactersequence,ifkisnotlessthanoffset+str.length()
Theoffsetargumentmustbegreaterthanorequalto0,andlessthanorequaltothelengthofthissequence.
Parameters:
offsettheoffset.
strastring.
Returns:
areferencetothisobject.
Throws:
StringIndexOutOfBoundsExceptioniftheoffsetisinvalid.
insert
publicStringBufferinsert(intoffset,
char[]str)
Insertsthestringrepresentationofthechararrayargumentintothissequence.
Thecharactersofthearrayargumentareinsertedintothecontentsofthissequenceatthepositionindicatedbyoffset.Thelengthofthissequenceincreasesbythelengthoftheargument.
TheoveralleffectisexactlyasifthesecondargumentwereconvertedtoastringbythemethodString.valueOf(char[]),andthecharactersofthatstringweretheninsertedintothischaractersequenceattheindicatedoffset.
Theoffsetargumentmustbegreaterthanorequalto0,andlessthanorequaltothelengthofthissequence.
Parameters:
offsettheoffset.
stracharacterarray.
Returns:
areferencetothisobject.
Throws:
StringIndexOutOfBoundsExceptioniftheoffsetisinvalid.
insert
publicStringBufferinsert(intdstOffset,
CharSequences)
InsertsthespecifiedCharSequenceintothissequence.
ThecharactersoftheCharSequenceargumentareinserted,inorder,intothissequenceattheindicatedoffset,movingupanycharactersoriginallyabovethatpositionandincreasingthelengthofthissequencebythelengthofthearguments.
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Theresultofthismethodisexactlythesameasifitwereaninvocationofthisobject'sinsert(dstOffset,s,0,
s.length())method.
Ifsisnull,thenthefourcharacters"null"areinsertedintothissequence.
Parameters:
dstOffsettheoffset.
sthesequencetobeinserted
Returns:
areferencetothisobject.
Throws:
IndexOutOfBoundsExceptioniftheoffsetisinvalid.
Since:
1.5
insert
publicStringBufferinsert(intdstOffset,
CharSequences,
intstart,
intend)
InsertsasubsequenceofthespecifiedCharSequenceintothissequence.
Thesubsequenceoftheargumentsspecifiedbystartandendareinserted,inorder,intothissequenceatthe
specifieddestinationoffset,movingupanycharactersoriginallyabovethatposition.Thelengthofthissequence
isincreasedbyend - start.
Thecharacteratindexkinthissequencebecomesequalto:
thecharacteratindexkinthissequence,ifkislessthandstOffsetthecharacteratindexk+start-dstOffsetinthearguments,ifkisgreaterthanorequaltodstOffsetbutislessthandstOffset+end-start
thecharacteratindexk-(end-start)inthissequence,ifkisgreaterthanorequaltodstOffset+end-start
ThedstOffsetargumentmustbegreaterthanorequalto0,andlessthanorequaltothelengthofthis
sequence.
Thestartargumentmustbenonnegative,andnotgreaterthanend.
Theendargumentmustbegreaterthanorequaltostart,andlessthanorequaltothelengthofs.
Ifsisnull,thenthismethodinsertscharactersasifthesparameterwasasequencecontainingthefour
characters"null".
Parameters:
dstOffsettheoffsetinthissequence.
sthesequencetobeinserted.
startthestartingindexofthesubsequencetobeinserted.
endtheendindexofthesubsequencetobeinserted.
Returns:
areferencetothisobject.
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Throws:
IndexOutOfBoundsExceptionifdstOffsetisnegativeorgreaterthanthis.length(),orstartorendarenegative,orstartisgreaterthanendorendisgreaterthans.length()
Since:
1.5
insert
publicStringBufferinsert(intoffset,
booleanb)
Insertsthestringrepresentationofthebooleanargumentintothissequence.
TheoveralleffectisexactlyasifthesecondargumentwereconvertedtoastringbythemethodString.valueOf(boolean),andthecharactersofthatstringweretheninsertedintothischaractersequenceattheindicatedoffset.
Theoffsetargumentmustbegreaterthanorequalto0,andlessthanorequaltothelengthofthissequence.
Parameters:
offsettheoffset.
baboolean.
Returns:
areferencetothisobject.
Throws:
StringIndexOutOfBoundsExceptioniftheoffsetisinvalid.
insert
publicStringBufferinsert(intoffset,
charc)
Insertsthestringrepresentationofthecharargumentintothissequence.
TheoveralleffectisexactlyasifthesecondargumentwereconvertedtoastringbythemethodString.valueOf(char),andthecharacterinthatstringweretheninsertedintothischaractersequenceattheindicatedoffset.
Theoffsetargumentmustbegreaterthanorequalto0,andlessthanorequaltothelengthofthissequence.
Parameters:
offsettheoffset.
cachar.
Returns:
areferencetothisobject.
Throws:
IndexOutOfBoundsExceptioniftheoffsetisinvalid.
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insert
publicStringBufferinsert(intoffset,
inti)
Insertsthestringrepresentationofthesecondintargumentintothissequence.
TheoveralleffectisexactlyasifthesecondargumentwereconvertedtoastringbythemethodString.valueOf(int),andthecharactersofthatstringweretheninsertedintothischaractersequenceattheindicatedoffset.
Theoffsetargumentmustbegreaterthanorequalto0,andlessthanorequaltothelengthofthissequence.
Parameters:
offsettheoffset.
ianint.
Returns:
areferencetothisobject.
Throws:
StringIndexOutOfBoundsExceptioniftheoffsetisinvalid.
insert
publicStringBufferinsert(intoffset,
longl)
Insertsthestringrepresentationofthelongargumentintothissequence.
TheoveralleffectisexactlyasifthesecondargumentwereconvertedtoastringbythemethodString.valueOf(long),andthecharactersofthatstringweretheninsertedintothischaractersequenceattheindicatedoffset.
Theoffsetargumentmustbegreaterthanorequalto0,andlessthanorequaltothelengthofthissequence.
Parameters:
offsettheoffset.
lalong.
Returns:
areferencetothisobject.
Throws:
StringIndexOutOfBoundsExceptioniftheoffsetisinvalid.
insert
publicStringBufferinsert(intoffset,
floatf)
Insertsthestringrepresentationofthefloatargumentintothissequence.
TheoveralleffectisexactlyasifthesecondargumentwereconvertedtoastringbythemethodString.valueOf(float),andthecharactersofthatstringweretheninsertedintothischaractersequenceat
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theindicatedoffset.
Theoffsetargumentmustbegreaterthanorequalto0,andlessthanorequaltothelengthofthissequence.
Parameters:
offsettheoffset.
fafloat.
Returns:
areferencetothisobject.
Throws:
StringIndexOutOfBoundsExceptioniftheoffsetisinvalid.
insert
publicStringBufferinsert(intoffset,
doubled)
Insertsthestringrepresentationofthedoubleargumentintothissequence.
TheoveralleffectisexactlyasifthesecondargumentwereconvertedtoastringbythemethodString.valueOf(double),andthecharactersofthatstringweretheninsertedintothischaractersequenceattheindicatedoffset.
Theoffsetargumentmustbegreaterthanorequalto0,andlessthanorequaltothelengthofthissequence.
Parameters:
offsettheoffset.
dadouble.
Returns:
areferencetothisobject.
Throws:
StringIndexOutOfBoundsExceptioniftheoffsetisinvalid.
indexOf
publicintindexOf(Stringstr)
Returnstheindexwithinthisstringofthefirstoccurrenceofthespecifiedsubstring.Theintegerreturnedisthesmallestvalueksuchthat:
this.toString().startsWith(str, k)
istrue.
Parameters:
stranystring.
Returns:
ifthestringargumentoccursasasubstringwithinthisobject,thentheindexofthefirstcharacterofthefirst
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suchsubstringisreturnedifitdoesnotoccurasasubstring,-1isreturned.
Throws:
NullPointerExceptionifstrisnull.
Since:
1.4
indexOf
publicintindexOf(Stringstr,
intfromIndex)
Returnstheindexwithinthisstringofthefirstoccurrenceofthespecifiedsubstring,startingatthespecifiedindex.Theintegerreturnedisthesmallestvaluekforwhich:
k >= Math.min(fromIndex, this.length()) &&
this.toString().startsWith(str, k)
Ifnosuchvalueofkexists,then1isreturned.
Parameters:
strthesubstringforwhichtosearch.
fromIndextheindexfromwhichtostartthesearch.
Returns:
theindexwithinthisstringofthefirstoccurrenceofthespecifiedsubstring,startingatthespecifiedindex.
Throws:
NullPointerExceptionifstrisnull.
Since:
1.4
lastIndexOf
publicintlastIndexOf(Stringstr)
Returnstheindexwithinthisstringoftherightmostoccurrenceofthespecifiedsubstring.Therightmostemptystring""isconsideredtooccurattheindexvaluethis.length().Thereturnedindexisthelargestvalueksuchthat
this.toString().startsWith(str, k)
istrue.
Parameters:
strthesubstringtosearchfor.
Returns:
ifthestringargumentoccursoneormoretimesasasubstringwithinthisobject,thentheindexofthefirstcharacterofthelastsuchsubstringisreturned.Ifitdoesnotoccurasasubstring,-1isreturned.
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Throws:
NullPointerExceptionifstrisnull.
Since:
1.4
lastIndexOf
publicintlastIndexOf(Stringstr,
intfromIndex)
Returnstheindexwithinthisstringofthelastoccurrenceofthespecifiedsubstring.Theintegerreturnedisthelargestvalueksuchthat:
k
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SubmitabugorfeatureForfurtherAPIreferenceanddeveloperdocumentation,seeJavaSEDocumentation.Thatdocumentationcontainsmoredetailed,developertargeteddescriptions,withconceptualoverviews,definitionsofterms,workarounds,andworkingcodeexamples.Copyright1993,2014,Oracleand/oritsaffiliates.Allrightsreserved.
toString
publicStringtoString()
Returnsastringrepresentingthedatainthissequence.AnewStringobjectisallocatedandinitializedtocontainthecharactersequencecurrentlyrepresentedbythisobject.ThisStringisthenreturned.SubsequentchangestothissequencedonotaffectthecontentsoftheString.
Specifiedby:
toStringininterfaceCharSequence
Returns:
astringrepresentationofthissequenceofcharacters.