public final classStringBuilderextendsObjectimplementsSerializable,CharSequence
StringBuffer
, but with no guarantee of synchronization. This class is designed for use as a drop-in replacement forStringBuffer
in places where the string buffer was being used by a single thread (as is generally the case). Where possible, it is recommended that this class be used in preference toStringBuffer
as it will be faster under most implementations.The principal operations on aStringBuilder
are theappend
andinsert
methods, which are overloaded so as to accept data of any type. Each effectively converts a given datum to a string and then appends or inserts the characters of that string to the string builder. Theappend
method always adds these characters at the end of the builder; theinsert
method adds the characters at a specified point.
For example, ifz
refers to a string builder object whose current contents are "start
", then the method callz.append("le")
would cause the string builder to contain "startle
", whereasz.insert(4, "le")
would alter the string builder to contain "starlet
".
In general, if sb refers to an instance of aStringBuilder
, thensb.append(x)
has the same effect assb.insert(sb.length(), x)
.
Every string builder has a capacity. As long as the length of the character sequence contained in the string builder does not exceed the capacity, it is not necessary to allocate a new internal buffer. If the internal buffer overflows, it is automatically made larger.
Instances ofStringBuilder
are not safe for use by multiple threads. If such synchronization is required then it is recommended thatStringBuffer
be used.
Unless otherwise noted, passing anull
argument to a constructor or method in this class will cause aNullPointerException
to be thrown.
StringBuffer
,String
,Serialized FormConstructor | Description |
---|---|
StringBuilder() | Constructs a string builder with no characters in it and an initial capacity of 16 characters. |
StringBuilder(CharSequence seq) | Constructs a string builder that contains the same characters as the specified CharSequence . |
StringBuilder(int capacity) | Constructs a string builder with no characters in it and an initial capacity specified by the capacity argument. |
StringBuilder(String str) | Constructs a string builder initialized to the contents of the specified string. |
Modifier and Type | Method | Description |
---|---|---|
StringBuilder | append(boolean b) | Appends the string representation of the boolean argument to the sequence. |
StringBuilder | append(char c) | Appends the string representation of the char argument to this sequence. |
StringBuilder | append(char[] str) | Appends the string representation of the char array argument to this sequence. |
StringBuilder | append(char[] str, int offset, int len) | Appends the string representation of a subarray of the char array argument to this sequence. |
StringBuilder | append(CharSequence s) | Appends the specified character sequence to thisAppendable. |
StringBuilder | append(CharSequence s, int start, int end) | Appends a subsequence of the specified CharSequence to this sequence. |
StringBuilder | append(double d) | Appends the string representation of the double argument to this sequence. |
StringBuilder | append(float f) | Appends the string representation of the float argument to this sequence. |
StringBuilder | append(int i) | Appends the string representation of the int argument to this sequence. |
StringBuilder | append(long lng) | Appends the string representation of the long argument to this sequence. |
StringBuilder | append(Object obj) | Appends the string representation of the Object argument. |
StringBuilder | append(String str) | Appends the specified string to this character sequence. |
StringBuilder | append(StringBuffer sb) | Appends the specified StringBuffer to this sequence. |
StringBuilder | appendCodePoint(int codePoint) | Appends the string representation of the codePoint argument to this sequence. |
int | capacity() | Returns the current capacity. |
char | charAt(int index) | Returns the char value in this sequence at the specified index. |
int | codePointAt(int index) | Returns the character (Unicode code point) at the specified index. |
int | codePointBefore(int index) | Returns the character (Unicode code point) before the specified index. |
int | codePointCount(int beginIndex, int endIndex) | Returns the number of Unicode code points in the specified text range of this sequence. |
StringBuilder | delete(int start, int end) | Removes the characters in a substring of this sequence. |
StringBuilder | deleteCharAt(int index) | Removes the char at the specified position in this sequence. |
void | ensureCapacity(int minimumCapacity) | Ensures that the capacity is at least equal to the specified minimum. |
void | getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin) | Characters are copied from this sequence into the destination character array dst . |
int | indexOf(String str) | Returns the index within this string of the first occurrence of the specified substring. |
int | indexOf(String str, int fromIndex) | Returns the index within this string of the first occurrence of the specified substring, starting at the specified index. |
StringBuilder | insert(int offset, boolean b) | Inserts the string representation of the boolean argument into this sequence. |
StringBuilder | insert(int offset, char c) | Inserts the string representation of the char argument into this sequence. |
StringBuilder | insert(int offset, char[] str) | Inserts the string representation of the char array argument into this sequence. |
StringBuilder | insert(int index, char[] str, int offset, int len) | Inserts the string representation of a subarray of the str array argument into this sequence. |
StringBuilder | insert(int dstOffset,CharSequence s) | Inserts the specified CharSequence into this sequence. |
StringBuilder | insert(int dstOffset,CharSequence s, int start, int end) | Inserts a subsequence of the specified CharSequence into this sequence. |
StringBuilder | insert(int offset, double d) | Inserts the string representation of the double argument into this sequence. |
StringBuilder | insert(int offset, float f) | Inserts the string representation of the float argument into this sequence. |
StringBuilder | insert(int offset, int i) | Inserts the string representation of the second int argument into this sequence. |
StringBuilder | insert(int offset, long l) | Inserts the string representation of the long argument into this sequence. |
StringBuilder | insert(int offset,Object obj) | Inserts the string representation of the Object argument into this character sequence. |
StringBuilder | insert(int offset,String str) | Inserts the string into this character sequence. |
int | lastIndexOf(String str) | Returns the index within this string of the rightmost occurrence of the specified substring. |
int | lastIndexOf(String str, int fromIndex) | Returns the index within this string of the last occurrence of the specified substring. |
int | length() | Returns the length (character count). |
int | offsetByCodePoints(int index, int codePointOffset) | Returns the index within this sequence that is offset from the given index bycodePointOffset code points. |
StringBuilder | replace(int start, int end,String str) | Replaces the characters in a substring of this sequence with characters in the specified String . |
StringBuilder | reverse() | Causes this character sequence to be replaced by the reverse of the sequence. |
void | setCharAt(int index, char ch) | The character at the specified index is set to ch . |
void | setLength(int newLength) | Sets the length of the character sequence. |
CharSequence | subSequence(int start, int end) | Returns a new character sequence that is a subsequence of this sequence. |
String | substring(int start) | Returns a new String that contains a subsequence of characters currently contained in this character sequence. |
String | substring(int start, int end) | Returns a new String that contains a subsequence of characters currently contained in this sequence. |
String | toString() | Returns a string representing the data in this sequence. |
void | trimToSize() | Attempts to reduce storage used for the character sequence. |
clone,equals,finalize,getClass,hashCode,notify,notifyAll,wait,wait,wait
charAt,chars,codePoints,length,subSequence
public StringBuilder()
public StringBuilder(int capacity)
capacity
argument.capacity
- the initial capacity.NegativeArraySizeException
- if thecapacity
argument is less than0
.public StringBuilder(String str)
16
plus the length of the string argument.str
- the initial contents of the buffer.public StringBuilder(CharSequence seq)
CharSequence
. The initial capacity of the string builder is16
plus the length of theCharSequence
argument.seq
- the sequence to copy.public StringBuilder append(Object obj)
Object
argument. The overall effect is exactly as if the argument were converted to a string by the methodString.valueOf(Object)
, and the characters of that string were thenappended
to this character sequence.
obj
- anObject
.public StringBuilder append(String str)
The characters of theString
argument are appended, in order, increasing the length of this sequence by the length of the argument. Ifstr
isnull
, then the four characters"null"
are appended.
Letn be the length of this character sequence just prior to execution of theappend
method. Then the character at indexk in the new character sequence is equal to the character at indexk in the old character sequence, ifk is less thann; otherwise, it is equal to the character at indexk-n in the argumentstr
.
str
- a string.public StringBuilder append(StringBuffer sb)
StringBuffer
to this sequence. The characters of theStringBuffer
argument are appended, in order, to this sequence, increasing the length of this sequence by the length of the argument. Ifsb
isnull
, then the four characters"null"
are appended to this sequence.
Letn be the length of this character sequence just prior to execution of theappend
method. Then the character at indexk in the new character sequence is equal to the character at indexk in the old character sequence, ifk is less thann; otherwise, it is equal to the character at indexk-n in the argumentsb
.
sb
- theStringBuffer
to append.public StringBuilder append(CharSequence s)
Appendable
Depending on which class implements the character sequencecsq, the entire sequence may not be appended. For instance, ifcsq is aCharBuffer
then the subsequence to append is defined by the buffer's position and limit.
append
in interface Appendable
s
- The character sequence to append. Ifcsq isnull, then the four characters"null" are appended to this Appendable.public StringBuilder append(CharSequence s, int start, int end)
CharSequence
to this sequence. Characters of the arguments
, starting at indexstart
, are appended, in order, to the contents of this sequence up to the (exclusive) indexend
. The length of this sequence is increased by the value ofend - start
.
Letn be the length of this character sequence just prior to execution of theappend
method. Then the character at indexk in this character sequence becomes equal to the character at indexk in this sequence, ifk is less thann; otherwise, it is equal to the character at indexk+start-n in the arguments
.
Ifs
isnull
, then this method appends characters as if the s parameter was a sequence containing the four characters"null"
.
append
in interface Appendable
s
- the sequence to append.start
- the starting index of the subsequence to be appended.end
- the end index of the subsequence to be appended.IndexOutOfBoundsException
- ifstart
is negative, orstart
is greater thanend
orend
is greater thans.length()
public StringBuilder append(char[] str)
char
array argument to this sequence.The characters of the array argument are appended, in order, to the contents of this sequence. The length of this sequence increases by the length of the argument.
The overall effect is exactly as if the argument were converted to a string by the methodString.valueOf(char[])
, and the characters of that string were thenappended
to this character sequence.
str
- the characters to be appended.public StringBuilder append(char[] str, int offset, int len)
char
array argument to this sequence. Characters of thechar
arraystr
, starting at indexoffset
, are appended, in order, to the contents of this sequence. The length of this sequence increases by the value oflen
.
The overall effect is exactly as if the arguments were converted to a string by the methodString.valueOf(char[],int,int)
, and the characters of that string were thenappended
to this character sequence.
str
- the characters to be appended.offset
- the index of the firstchar
to append.len
- the number ofchar
s to append.IndexOutOfBoundsException
- ifoffset < 0
orlen < 0
oroffset+len > str.length
public StringBuilder append(boolean b)
boolean
argument to the sequence. The overall effect is exactly as if the argument were converted to a string by the methodString.valueOf(boolean)
, and the characters of that string were thenappended
to this character sequence.
b
- aboolean
.public StringBuilder append(char c)
char
argument to this sequence. The argument is appended to the contents of this sequence. The length of this sequence increases by1
.
The overall effect is exactly as if the argument were converted to a string by the methodString.valueOf(char)
, and the character in that string were thenappended
to this character sequence.
append
in interface Appendable
c
- achar
.public StringBuilder append(int i)
int
argument to this sequence. The overall effect is exactly as if the argument were converted to a string by the methodString.valueOf(int)
, and the characters of that string were thenappended
to this character sequence.
i
- anint
.public StringBuilder append(long lng)
long
argument to this sequence. The overall effect is exactly as if the argument were converted to a string by the methodString.valueOf(long)
, and the characters of that string were thenappended
to this character sequence.
lng
- along
.public StringBuilder append(float f)
float
argument to this sequence. The overall effect is exactly as if the argument were converted to a string by the methodString.valueOf(float)
, and the characters of that string were thenappended
to this character sequence.
f
- afloat
.public StringBuilder append(double d)
double
argument to this sequence. The overall effect is exactly as if the argument were converted to a string by the methodString.valueOf(double)
, and the characters of that string were thenappended
to this character sequence.
d
- adouble
.public StringBuilder appendCodePoint(int codePoint)
codePoint
argument to this sequence. The argument is appended to the contents of this sequence. The length of this sequence increases byCharacter.charCount(codePoint)
.
The overall effect is exactly as if the argument were converted to achar
array by the methodCharacter.toChars(int)
and the character in that array were thenappended
to this character sequence.
codePoint
- a Unicode code pointpublic StringBuilder delete(int start, int end)
start
and extends to the character at indexend - 1
or to the end of the sequence if no such character exists. Ifstart
is equal toend
, no changes are made.start
- The beginning index, inclusive.end
- The ending index, exclusive.StringIndexOutOfBoundsException
- ifstart
is negative, greater thanlength()
, or greater thanend
.public StringBuilder deleteCharAt(int index)
char
at the specified position in this sequence. This sequence is shortened by onechar
.Note: If the character at the given index is a supplementary character, this method does not remove the entire character. If correct handling of supplementary characters is required, determine the number ofchar
s to remove by callingCharacter.charCount(thisSequence.codePointAt(index))
, wherethisSequence
is this sequence.
index
- Index ofchar
to removeStringIndexOutOfBoundsException
- if theindex
is negative or greater than or equal tolength()
.public StringBuilder replace(int start, int end,String str)
String
. The substring begins at the specifiedstart
and extends to the character at indexend - 1
or to the end of the sequence if no such character exists. First the characters in the substring are removed and then the specifiedString
is inserted atstart
. (This sequence will be lengthened to accommodate the specified String if necessary.)start
- The beginning index, inclusive.end
- The ending index, exclusive.str
- String that will replace previous contents.StringIndexOutOfBoundsException
- ifstart
is negative, greater thanlength()
, or greater thanend
.public StringBuilder insert(int index, char[] str, int offset, int len)
str
array argument into this sequence. The subarray begins at the specifiedoffset
and extendslen
char
s. The characters of the subarray are inserted into this sequence at the position indicated byindex
. The length of this sequence increases bylen
char
s.index
- position at which to insert subarray.str
- Achar
array.offset
- the index of the firstchar
in subarray to be inserted.len
- the number ofchar
s in the subarray to be inserted.StringIndexOutOfBoundsException
- ifindex
is negative or greater thanlength()
, oroffset
orlen
are negative, or(offset+len)
is greater thanstr.length
.public StringBuilder insert(int offset,Object obj)
Object
argument into this character sequence. The overall effect is exactly as if the second argument were converted to a string by the methodString.valueOf(Object)
, and the characters of that string were theninserted
into this character sequence at the indicated offset.
Theoffset
argument must be greater than or equal to0
, and less than or equal to thelength of this sequence.
offset
- the offset.obj
- anObject
.StringIndexOutOfBoundsException
- if the offset is invalid.public StringBuilder insert(int offset,String str)
The characters of theString
argument are inserted, in order, into this sequence at the indicated offset, moving up any characters originally above that position and increasing the length of this sequence by the length of the argument. Ifstr
isnull
, then the four characters"null"
are inserted into this sequence.
The character at indexk in the new character sequence is equal to:
offset
-offset
in the argumentstr
, ifk is not less thanoffset
but is less thanoffset+str.length()
-str.length()
in the old character sequence, ifk is not less thanoffset+str.length()
Theoffset
argument must be greater than or equal to0
, and less than or equal to thelength of this sequence.
offset
- the offset.str
- a string.StringIndexOutOfBoundsException
- if the offset is invalid.public StringBuilder insert(int offset, char[] str)
char
array argument into this sequence. The characters of the array argument are inserted into the contents of this sequence at the position indicated byoffset
. The length of this sequence increases by the length of the argument.
The overall effect is exactly as if the second argument were converted to a string by the methodString.valueOf(char[])
, and the characters of that string were theninserted
into this character sequence at the indicated offset.
Theoffset
argument must be greater than or equal to0
, and less than or equal to thelength of this sequence.
offset
- the offset.str
- a character array.StringIndexOutOfBoundsException
- if the offset is invalid.public StringBuilder insert(int dstOffset,CharSequence s)
CharSequence
into this sequence. The characters of theCharSequence
argument are inserted, in order, into this sequence at the indicated offset, moving up any characters originally above that position and increasing the length of this sequence by the length of the argument s.
The result of this method is exactly the same as if it were an invocation of this object'sinsert
(dstOffset, s, 0, s.length()) method.
Ifs
isnull
, then the four characters"null"
are inserted into this sequence.
dstOffset
- the offset.s
- the sequence to be insertedIndexOutOfBoundsException
- if the offset is invalid.public StringBuilder insert(int dstOffset,CharSequence s, int start, int end)
CharSequence
into this sequence. The subsequence of the arguments
specified bystart
andend
are inserted, in order, into this sequence at the specified destination offset, moving up any characters originally above that position. The length of this sequence is increased byend - start
.
The character at indexk in this sequence becomes equal to:
dstOffset
+start-dstOffset
in the arguments
, ifk is greater than or equal todstOffset
but is less thandstOffset+end-start
-(end-start)
in this sequence, ifk is greater than or equal todstOffset+end-start
ThedstOffset
argument must be greater than or equal to0
, and less than or equal to thelength of this sequence.
The start argument must be nonnegative, and not greater thanend
.
The end argument must be greater than or equal tostart
, and less than or equal to the length of s.
Ifs
isnull
, then this method inserts characters as if the s parameter was a sequence containing the four characters"null"
.
dstOffset
- the offset in this sequence.s
- the sequence to be inserted.start
- the starting index of the subsequence to be inserted.end
- the end index of the subsequence to be inserted.IndexOutOfBoundsException
- ifdstOffset
is negative or greater thanthis.length()
, orstart
orend
are negative, orstart
is greater thanend
orend
is greater thans.length()
public StringBuilder insert(int offset, boolean b)
boolean
argument into this sequence. The overall effect is exactly as if the second argument were converted to a string by the methodString.valueOf(boolean)
, and the characters of that string were theninserted
into this character sequence at the indicated offset.
Theoffset
argument must be greater than or equal to0
, and less than or equal to thelength of this sequence.
offset
- the offset.b
- aboolean
.StringIndexOutOfBoundsException
- if the offset is invalid.public StringBuilder insert(int offset, char c)
char
argument into this sequence. The overall effect is exactly as if the second argument were converted to a string by the methodString.valueOf(char)
, and the character in that string were theninserted
into this character sequence at the indicated offset.
Theoffset
argument must be greater than or equal to0
, and less than or equal to thelength of this sequence.
offset
- the offset.c
- achar
.IndexOutOfBoundsException
- if the offset is invalid.public StringBuilder insert(int offset, int i)
int
argument into this sequence. The overall effect is exactly as if the second argument were converted to a string by the methodString.valueOf(int)
, and the characters of that string were theninserted
into this character sequence at the indicated offset.
Theoffset
argument must be greater than or equal to0
, and less than or equal to thelength of this sequence.
offset
- the offset.i
- anint
.StringIndexOutOfBoundsException
- if the offset is invalid.public StringBuilder insert(int offset, long l)
long
argument into this sequence. The overall effect is exactly as if the second argument were converted to a string by the methodString.valueOf(long)
, and the characters of that string were theninserted
into this character sequence at the indicated offset.
Theoffset
argument must be greater than or equal to0
, and less than or equal to thelength of this sequence.
offset
- the offset.l
- along
.StringIndexOutOfBoundsException
- if the offset is invalid.public StringBuilder insert(int offset, float f)
float
argument into this sequence. The overall effect is exactly as if the second argument were converted to a string by the methodString.valueOf(float)
, and the characters of that string were theninserted
into this character sequence at the indicated offset.
Theoffset
argument must be greater than or equal to0
, and less than or equal to thelength of this sequence.
offset
- the offset.f
- afloat
.StringIndexOutOfBoundsException
- if the offset is invalid.public StringBuilder insert(int offset, double d)
double
argument into this sequence. The overall effect is exactly as if the second argument were converted to a string by the methodString.valueOf(double)
, and the characters of that string were theninserted
into this character sequence at the indicated offset.
Theoffset
argument must be greater than or equal to0
, and less than or equal to thelength of this sequence.
offset
- the offset.d
- adouble
.StringIndexOutOfBoundsException
- if the offset is invalid.public int indexOf(String str)
this.toString().startsWith(str, <i>k</i>)
istrue
.str
- any string.-1
is returned.public int indexOf(String str, int fromIndex)
k
for which: k >= Math.min(fromIndex, this.length()) && this.toString().startsWith(str, k)
If no such value ofk exists, then -1 is returned.str
- the substring for which to search.fromIndex
- the index from which to start the search.public int lastIndexOf(String str)
this.length()
. The returned index is the largest valuek such that this.toString().startsWith(str, k)
is true.str
- the substring to search for.-1
is returned.public int lastIndexOf(String str, int fromIndex)
k <= Math.min(fromIndex, this.length()) && this.toString().startsWith(str, k)
If no such value ofk exists, then -1 is returned.str
- the substring to search for.fromIndex
- the index to start the search from.public StringBuilder reverse()
char
values) just prior to execution of thereverse
method. Then the character at indexk in the new character sequence is equal to the character at indexn-k-1 in the old character sequence.Note that the reverse operation may result in producing surrogate pairs that were unpaired low-surrogates and high-surrogates before the operation. For example, reversing "\uDC00\uD800" produces "\uD800\uDC00" which is a valid surrogate pair.
public String toString()
String
object is allocated and initialized to contain the character sequence currently represented by this object. ThisString
is then returned. Subsequent changes to this sequence do not affect the contents of theString
.toString
in interface CharSequence
public int length()
length
in interface CharSequence
public int capacity()
public void ensureCapacity(int minimumCapacity)
minimumCapacity
argument.2
.minimumCapacity
argument is nonpositive, this method takes no action and simply returns. Note that subsequent operations on this object can reduce the actual capacity below that requested here.minimumCapacity
- the minimum desired capacity.public void trimToSize()
capacity()
method.public void setLength(int newLength)
newLength
, the character at indexk in the new character sequence is the same as the character at indexk in the old sequence ifk is less than the length of the old character sequence; otherwise, it is the null character'\u0000'
. In other words, if thenewLength
argument is less than the current length, the length is changed to the specified length. If thenewLength
argument is greater than or equal to the current length, sufficient null characters ('\u0000'
) are appended so that length becomes thenewLength
argument.
ThenewLength
argument must be greater than or equal to0
.
newLength
- the new lengthIndexOutOfBoundsException
- if thenewLength
argument is negative.public char charAt(int index)
char
value in this sequence at the specified index. The firstchar
value is at index0
, the next at index1
, and so on, as in array indexing. The index argument must be greater than or equal to0
, and less than the length of this sequence.
If thechar
value specified by the index is asurrogate, the surrogate value is returned.
charAt
in interface CharSequence
index
- the index of the desiredchar
value.char
value at the specified index.IndexOutOfBoundsException
- ifindex
is negative or greater than or equal tolength()
.public int codePointAt(int index)
char
values (Unicode code units) and ranges from0
tolength()
- 1
. If thechar
value specified at the given index is in the high-surrogate range, the following index is less than the length of this sequence, and thechar
value at the following index is in the low-surrogate range, then the supplementary code point corresponding to this surrogate pair is returned. Otherwise, thechar
value at the given index is returned.
index
- the index to thechar
valuesindex
IndexOutOfBoundsException
- if theindex
argument is negative or not less than the length of this sequence.public int codePointBefore(int index)
char
values (Unicode code units) and ranges from1
tolength()
. If thechar
value at(index - 1)
is in the low-surrogate range,(index - 2)
is not negative, and thechar
value at(index - 2)
is in the high-surrogate range, then the supplementary code point value of the surrogate pair is returned. If thechar
value atindex - 1
is an unpaired low-surrogate or a high-surrogate, the surrogate value is returned.
index
- the index following the code point that should be returnedIndexOutOfBoundsException
- if theindex
argument is less than 1 or greater than the length of this sequence.public int codePointCount(int beginIndex, int endIndex)
beginIndex
and extends to thechar
at indexendIndex - 1
. Thus the length (inchar
s) of the text range isendIndex-beginIndex
. Unpaired surrogates within this sequence count as one code point each.beginIndex
- the index to the firstchar
of the text range.endIndex
- the index after the lastchar
of the text range.IndexOutOfBoundsException
- if thebeginIndex
is negative, orendIndex
is larger than the length of this sequence, orbeginIndex
is larger thanendIndex
.public int offsetByCodePoints(int index, int codePointOffset)
index
bycodePointOffset
code points. Unpaired surrogates within the text range given byindex
andcodePointOffset
count as one code point each.index
- the index to be offsetcodePointOffset
- the offset in code pointsIndexOutOfBoundsException
- ifindex
is negative or larger then the length of this sequence, or ifcodePointOffset
is positive and the subsequence starting withindex
has fewer thancodePointOffset
code points, or ifcodePointOffset
is negative and the subsequence beforeindex
has fewer than the absolute value ofcodePointOffset
code points.public void getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin)
dst
. The first character to be copied is at indexsrcBegin
; the last character to be copied is at indexsrcEnd-1
. The total number of characters to be copied issrcEnd-srcBegin
. The characters are copied into the subarray ofdst
starting at indexdstBegin
and ending at index: dstbegin + (srcEnd-srcBegin) - 1
srcBegin
- start copying at this offset.srcEnd
- stop copying at this offset.dst
- the array to copy the data into.dstBegin
- offset intodst
.IndexOutOfBoundsException
- if any of the following is true:srcBegin
is negativedstBegin
is negativesrcBegin
argument is greater than thesrcEnd
argument.srcEnd
is greater thanthis.length()
.dstBegin+srcEnd-srcBegin
is greater thandst.length
public void setCharAt(int index, char ch)
ch
. This sequence is altered to represent a new character sequence that is identical to the old character sequence, except that it contains the characterch
at positionindex
. The index argument must be greater than or equal to0
, and less than the length of this sequence.
index
- the index of the character to modify.ch
- the new character.IndexOutOfBoundsException
- ifindex
is negative or greater than or equal tolength()
.public String substring(int start)
String
that contains a subsequence of characters currently contained in this character sequence. The substring begins at the specified index and extends to the end of this sequence.start
- The beginning index, inclusive.StringIndexOutOfBoundsException
- ifstart
is less than zero, or greater than the length of this object.public CharSequence subSequence(int start, int end)
An invocation of this method of the form
sb.subSequence(begin, end)
behaves in exactly the same way as the invocation sb.substring(begin, end)
This method is provided so that this class can implement theCharSequence
interface.subSequence
in interface CharSequence
start
- the start index, inclusive.end
- the end index, exclusive.IndexOutOfBoundsException
- ifstart
orend
are negative, ifend
is greater thanlength()
, or ifstart
is greater thanend
public String substring(int start, int end)
String
that contains a subsequence of characters currently contained in this sequence. The substring begins at the specifiedstart
and extends to the character at indexend - 1
.start
- The beginning index, inclusive.end
- The ending index, exclusive.StringIndexOutOfBoundsException
- ifstart
orend
are negative or greater thanlength()
, orstart
is greater thanend
.