StringBuffer (Java Platform SE 7 )

6/22/2015 StringBuffer (Java Platform SE 7 )

http://docs.oracle.com/javase/7/docs/api/java/lang/StringBuffer.html 1/26

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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



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



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)



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:



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



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.



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



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:



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()



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:


append

publicStringBufferappend(StringBuffersb)

AppendsthespecifiedStringBuffertothissequence.

ThecharactersoftheStringBufferargumentareappended,inorder,tothecontentsofthisStringBuffer,increasingthelengthofthisStringBufferbythelengthoftheargument.Ifsbisnull,thenthefourcharacters"null"areappendedtothisStringBuffer.

Letnbethelengthoftheoldcharactersequence,theonecontainedintheStringBufferjustpriortoexecutionoftheappendmethod.Thenthecharacteratindexkinthenewcharactersequenceisequaltothecharacteratindexkintheoldcharactersequence,ifkislessthannotherwise,itisequaltothecharacteratindexknintheargumentsb.

Thismethodsynchronizesonthis(thedestination)objectbutdoesnotsynchronizeonthesource(sb).

Parameters:

sbtheStringBuffertoappend.

Returns:




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:


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:


Parameters:

sthesequencetoappend.

startthestartingindexofthesubsequencetobeappended.

endtheendindexofthesubsequencetobeappended.



Returns:


Throws:

IndexOutOfBoundsExceptionifstartisnegative,orstartisgreaterthanendorendisgreaterthans.length()

Since:

1.5

append

publicStringBufferappend(char[]str)

Appendsthestringrepresentationofthechararrayargumenttothissequence.

Thecharactersofthearrayargumentareappended,inorder,tothecontentsofthissequence.Thelengthofthissequenceincreasesbythelengthoftheargument.

TheoveralleffectisexactlyasiftheargumentwereconvertedtoastringbythemethodString.valueOf(char[]),andthecharactersofthatstringwerethenappendedtothischaractersequence.

Parameters:

strthecharacterstobeappended.

Returns:


append

publicStringBufferappend(char[]str,

intoffset,

intlen)

Appendsthestringrepresentationofasubarrayofthechararrayargumenttothissequence.

Charactersofthechararraystr,startingatindexoffset,areappended,inorder,tothecontentsofthissequence.Thelengthofthissequenceincreasesbythevalueoflen.

TheoveralleffectisexactlyasiftheargumentswereconvertedtoastringbythemethodString.valueOf(char[],int,int),andthecharactersofthatstringwerethenappendedtothischaractersequence.

Parameters:

strthecharacterstobeappended.

offsettheindexofthefirstchartoappend.

lenthenumberofcharstoappend.

Returns:


Throws:

IndexOutOfBoundsExceptionifoffset < 0orlen < 0oroffset+len > str.length



append

publicStringBufferappend(booleanb)

Appendsthestringrepresentationofthebooleanargumenttothesequence.

TheoveralleffectisexactlyasiftheargumentwereconvertedtoastringbythemethodString.valueOf(boolean),andthecharactersofthatstringwerethenappendedtothischaractersequence.

Parameters:

baboolean.

Returns:


append

publicStringBufferappend(charc)

Appendsthestringrepresentationofthecharargumenttothissequence.

Theargumentisappendedtothecontentsofthissequence.Thelengthofthissequenceincreasesby1.

TheoveralleffectisexactlyasiftheargumentwereconvertedtoastringbythemethodString.valueOf(char),andthecharacterinthatstringwerethenappendedtothischaractersequence.

Specifiedby:


Parameters:

cachar.

Returns:


append

publicStringBufferappend(inti)

Appendsthestringrepresentationoftheintargumenttothissequence.

TheoveralleffectisexactlyasiftheargumentwereconvertedtoastringbythemethodString.valueOf(int),andthecharactersofthatstringwerethenappendedtothischaractersequence.

Parameters:

ianint.

Returns:


appendCodePoint

publicStringBufferappendCodePoint(intcodePoint)



AppendsthestringrepresentationofthecodePointargumenttothissequence.

Theargumentisappendedtothecontentsofthissequence.ThelengthofthissequenceincreasesbyCharacter.charCount(codePoint).

TheoveralleffectisexactlyasiftheargumentwereconvertedtoachararraybythemethodCharacter.toChars(int)andthecharacterinthatarraywerethenappendedtothischaractersequence.

Parameters:

codePointaUnicodecodepoint

Returns:


Since:

1.5

append

publicStringBufferappend(longlng)

Appendsthestringrepresentationofthelongargumenttothissequence.

TheoveralleffectisexactlyasiftheargumentwereconvertedtoastringbythemethodString.valueOf(long),andthecharactersofthatstringwerethenappendedtothischaractersequence.

Parameters:

lngalong.

Returns:


append

publicStringBufferappend(floatf)

Appendsthestringrepresentationofthefloatargumenttothissequence.

TheoveralleffectisexactlyasiftheargumentwereconvertedtoastringbythemethodString.valueOf(float),andthecharactersofthatstringwerethenappendedtothischaractersequence.

Parameters:

fafloat.

Returns:


append

publicStringBufferappend(doubled)

Appendsthestringrepresentationofthedoubleargumenttothissequence.

Theoveralleffectisexactlyasiftheargumentwereconvertedtoastringbythemethod



String.valueOf(double),andthecharactersofthatstringwerethenappendedtothischaractersequence.

Parameters:

dadouble.

Returns:


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



replace

publicStringBufferreplace(intstart,

intend,

Stringstr)

ReplacesthecharactersinasubstringofthissequencewithcharactersinthespecifiedString.Thesubstringbeginsatthespecifiedstartandextendstothecharacteratindexend - 1ortotheendofthesequenceifnosuchcharacterexists.FirstthecharactersinthesubstringareremovedandthenthespecifiedStringisinsertedatstart.(ThissequencewillbelengthenedtoaccommodatethespecifiedStringifnecessary.)

Parameters:



strStringthatwillreplacepreviouscontents.

Returns:

Thisobject.

Throws:

StringIndexOutOfBoundsExceptionifstartisnegative,greaterthanlength(),orgreaterthanend.

Since:

1.2

substring

publicStringsubstring(intstart)

ReturnsanewStringthatcontainsasubsequenceofcharacterscurrentlycontainedinthischaractersequence.Thesubstringbeginsatthespecifiedindexandextendstotheendofthissequence.

Parameters:


Returns:

Thenewstring.

Throws:

StringIndexOutOfBoundsExceptionifstartislessthanzero,orgreaterthanthelengthofthisobject.

Since:

1.2

subSequence

publicCharSequencesubSequence(intstart,

intend)

Returnsanewcharactersequencethatisasubsequenceofthissequence.

Aninvocationofthismethodoftheform



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:



Returns:

Thenewstring.

Throws:

StringIndexOutOfBoundsExceptionifstartorendarenegativeorgreaterthanlength(),orstartisgreaterthanend.

Since:

1.2

insert

publicStringBufferinsert(intindex,

char[]str,

intoffset,

intlen)



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:


Throws:

StringIndexOutOfBoundsExceptioniftheoffsetisinvalid.

insert


Stringstr)

Insertsthestringintothischaractersequence.

ThecharactersoftheStringargumentareinserted,inorder,intothissequenceattheindicatedoffset,movingupanycharactersoriginallyabovethatpositionandincreasingthelengthofthissequencebythelengthoftheargument.Ifstrisnull,thenthefourcharacters"null"areinsertedintothissequence.



Thecharacteratindexkinthenewcharactersequenceisequalto:

thecharacteratindexkintheoldcharactersequence,ifkislessthanoffsetthecharacteratindexk-offsetintheargumentstr,ifkisnotlessthanoffsetbutislessthanoffset+str.length()

thecharacteratindexk-str.length()intheoldcharactersequence,ifkisnotlessthanoffset+str.length()


Parameters:

offsettheoffset.

strastring.

Returns:


Throws:


insert


char[]str)

Insertsthestringrepresentationofthechararrayargumentintothissequence.

Thecharactersofthearrayargumentareinsertedintothecontentsofthissequenceatthepositionindicatedbyoffset.Thelengthofthissequenceincreasesbythelengthoftheargument.

TheoveralleffectisexactlyasifthesecondargumentwereconvertedtoastringbythemethodString.valueOf(char[]),andthecharactersofthatstringweretheninsertedintothischaractersequenceattheindicatedoffset.


Parameters:

offsettheoffset.

stracharacterarray.

Returns:


Throws:


insert

publicStringBufferinsert(intdstOffset,

CharSequences)

InsertsthespecifiedCharSequenceintothissequence.

ThecharactersoftheCharSequenceargumentareinserted,inorder,intothissequenceattheindicatedoffset,movingupanycharactersoriginallyabovethatpositionandincreasingthelengthofthissequencebythelengthofthearguments.



Theresultofthismethodisexactlythesameasifitwereaninvocationofthisobject'sinsert(dstOffset,s,0,

s.length())method.

Ifsisnull,thenthefourcharacters"null"areinsertedintothissequence.

Parameters:

dstOffsettheoffset.

sthesequencetobeinserted

Returns:


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:




Throws:

IndexOutOfBoundsExceptionifdstOffsetisnegativeorgreaterthanthis.length(),orstartorendarenegative,orstartisgreaterthanendorendisgreaterthans.length()

Since:

1.5

insert


booleanb)

Insertsthestringrepresentationofthebooleanargumentintothissequence.

TheoveralleffectisexactlyasifthesecondargumentwereconvertedtoastringbythemethodString.valueOf(boolean),andthecharactersofthatstringweretheninsertedintothischaractersequenceattheindicatedoffset.


Parameters:

offsettheoffset.

baboolean.

Returns:


Throws:


insert


charc)

Insertsthestringrepresentationofthecharargumentintothissequence.

TheoveralleffectisexactlyasifthesecondargumentwereconvertedtoastringbythemethodString.valueOf(char),andthecharacterinthatstringweretheninsertedintothischaractersequenceattheindicatedoffset.


Parameters:

offsettheoffset.

cachar.

Returns:


Throws:

IndexOutOfBoundsExceptioniftheoffsetisinvalid.



insert


inti)

Insertsthestringrepresentationofthesecondintargumentintothissequence.

TheoveralleffectisexactlyasifthesecondargumentwereconvertedtoastringbythemethodString.valueOf(int),andthecharactersofthatstringweretheninsertedintothischaractersequenceattheindicatedoffset.


Parameters:

offsettheoffset.

ianint.

Returns:


Throws:


insert


longl)

Insertsthestringrepresentationofthelongargumentintothissequence.

TheoveralleffectisexactlyasifthesecondargumentwereconvertedtoastringbythemethodString.valueOf(long),andthecharactersofthatstringweretheninsertedintothischaractersequenceattheindicatedoffset.


Parameters:

offsettheoffset.

lalong.

Returns:


Throws:


insert


floatf)

Insertsthestringrepresentationofthefloatargumentintothissequence.

TheoveralleffectisexactlyasifthesecondargumentwereconvertedtoastringbythemethodString.valueOf(float),andthecharactersofthatstringweretheninsertedintothischaractersequenceat



theindicatedoffset.


Parameters:

offsettheoffset.

fafloat.

Returns:


Throws:


insert


doubled)

Insertsthestringrepresentationofthedoubleargumentintothissequence.

TheoveralleffectisexactlyasifthesecondargumentwereconvertedtoastringbythemethodString.valueOf(double),andthecharactersofthatstringweretheninsertedintothischaractersequenceattheindicatedoffset.


Parameters:

offsettheoffset.

dadouble.

Returns:


Throws:


indexOf

publicintindexOf(Stringstr)

Returnstheindexwithinthisstringofthefirstoccurrenceofthespecifiedsubstring.Theintegerreturnedisthesmallestvalueksuchthat:

this.toString().startsWith(str, k)

istrue.

Parameters:

stranystring.

Returns:

ifthestringargumentoccursasasubstringwithinthisobject,thentheindexofthefirstcharacterofthefirst



suchsubstringisreturnedifitdoesnotoccurasasubstring,-1isreturned.

Throws:

NullPointerExceptionifstrisnull.

Since:

1.4

indexOf

publicintindexOf(Stringstr,

intfromIndex)

Returnstheindexwithinthisstringofthefirstoccurrenceofthespecifiedsubstring,startingatthespecifiedindex.Theintegerreturnedisthesmallestvaluekforwhich:

k >= Math.min(fromIndex, this.length()) &&


Ifnosuchvalueofkexists,then1isreturned.

Parameters:

strthesubstringforwhichtosearch.

fromIndextheindexfromwhichtostartthesearch.

Returns:

theindexwithinthisstringofthefirstoccurrenceofthespecifiedsubstring,startingatthespecifiedindex.

Throws:


Since:

1.4

lastIndexOf

publicintlastIndexOf(Stringstr)

Returnstheindexwithinthisstringoftherightmostoccurrenceofthespecifiedsubstring.Therightmostemptystring""isconsideredtooccurattheindexvaluethis.length().Thereturnedindexisthelargestvalueksuchthat


istrue.

Parameters:

strthesubstringtosearchfor.

Returns:

ifthestringargumentoccursoneormoretimesasasubstringwithinthisobject,thentheindexofthefirstcharacterofthelastsuchsubstringisreturned.Ifitdoesnotoccurasasubstring,-1isreturned.



Throws:


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.

StringBuffer (Java Platform SE 7 )

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