public final class StringBuffer extends Object implements Serializable, CharSequence
String, but can be modified. At any
point in time it contains some particular sequence of characters, but
the length and content of the sequence can be changed through certain
method calls.
String buffers are safe for use by multiple threads. The methods are synchronized where necessary so that all the operations on any particular instance behave as if they occur in some serial order that is consistent with the order of the method calls made by each of the individual threads involved.
The principal operations on a StringBuffer are the
append and insert 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 buffer. The
append method always adds these characters at the end
of the buffer; the insert method adds the characters at
a specified point.
For example, if z refers to a string buffer object
whose current contents are "start", then
the method call z.append("le") would cause the string
buffer to contain "startle", whereas
z.insert(4, "le") would alter the string buffer to
contain "starlet".
In general, if sb refers to an instance of a StringBuffer,
then sb.append(x) has the same effect as
sb.insert(sb.length(), x).
Whenever an operation occurs involving a source sequence (such as
appending or inserting from a source sequence), this class synchronizes
only on the string buffer performing the operation, not on the source.
Note that while StringBuffer is designed to be safe to use
concurrently from multiple threads, if the constructor or the
append or insert operation is passed a source sequence
that is shared across threads, the calling code must ensure
that the operation has a consistent and unchanging view of the source
sequence for the duration of the operation.
This could be satisfied by the caller holding a lock during the
operation's call, by using an immutable source sequence, or by not
sharing the source sequence across threads.
Every string buffer has a capacity. As long as the length of the character sequence contained in the string buffer does not exceed the capacity, it is not necessary to allocate a new internal buffer array. If the internal buffer overflows, it is automatically made larger.
Unless otherwise noted, passing a null argument to a constructor
or method in this class will cause a NullPointerException to be
thrown.
As of release JDK 5, this class has been supplemented with an equivalent
class designed for use by a single thread, StringBuilder. The
StringBuilder class should generally be used in preference to
this one, as it supports all of the same operations but it is faster, as
it performs no synchronization.
StringBuilder,
String,
Serialized Form| Constructor and Description |
|---|
StringBuffer()
Constructs a string buffer with no characters in it and an
initial capacity of 16 characters.
|
StringBuffer(CharSequence seq)
Constructs a string buffer that contains the same characters
as the specified
CharSequence. |
StringBuffer(int capacity)
Constructs a string buffer with no characters in it and
the specified initial capacity.
|
StringBuffer(String str)
Constructs a string buffer initialized to the contents of the
specified string.
|
| Modifier and Type | Method and Description |
|---|---|
StringBuffer |
append(boolean b)
Appends the string representation of the
boolean
argument to the sequence. |
StringBuffer |
append(char c)
Appends the string representation of the
char
argument to this sequence. |
StringBuffer |
append(char[] str)
Appends the string representation of the
char array
argument to this sequence. |
StringBuffer |
append(char[] str,
int offset,
int len)
Appends the string representation of a subarray of the
char array argument to this sequence. |
StringBuffer |
append(CharSequence s)
Appends the specified
CharSequence to this
sequence. |
StringBuffer |
append(CharSequence s,
int start,
int end)
Appends a subsequence of the specified
CharSequence to this
sequence. |
StringBuffer |
append(double d)
Appends the string representation of the
double
argument to this sequence. |
StringBuffer |
append(float f)
Appends the string representation of the
float
argument to this sequence. |
StringBuffer |
append(int i)
Appends the string representation of the
int
argument to this sequence. |
StringBuffer |
append(long lng)
Appends the string representation of the
long
argument to this sequence. |
StringBuffer |
append(Object obj)
Appends the string representation of the
Object argument. |
StringBuffer |
append(String str)
Appends the specified string to this character sequence.
|
StringBuffer |
append(StringBuffer sb)
Appends the specified
StringBuffer to this sequence. |
StringBuffer |
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.
|
StringBuffer |
delete(int start,
int end)
Removes the characters in a substring of this sequence.
|
StringBuffer |
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.
|
StringBuffer |
insert(int offset,
boolean b)
Inserts the string representation of the
boolean
argument into this sequence. |
StringBuffer |
insert(int offset,
char c)
Inserts the string representation of the
char
argument into this sequence. |
StringBuffer |
insert(int offset,
char[] str)
Inserts the string representation of the
char array
argument into this sequence. |
StringBuffer |
insert(int index,
char[] str,
int offset,
int len)
Inserts the string representation of a subarray of the
str
array argument into this sequence. |
StringBuffer |
insert(int dstOffset,
CharSequence s)
Inserts the specified
CharSequence into this sequence. |
StringBuffer |
insert(int dstOffset,
CharSequence s,
int start,
int end)
Inserts a subsequence of the specified
CharSequence into
this sequence. |
StringBuffer |
insert(int offset,
double d)
Inserts the string representation of the
double
argument into this sequence. |
StringBuffer |
insert(int offset,
float f)
Inserts the string representation of the
float
argument into this sequence. |
StringBuffer |
insert(int offset,
int i)
Inserts the string representation of the second
int
argument into this sequence. |
StringBuffer |
insert(int offset,
long l)
Inserts the string representation of the
long
argument into this sequence. |
StringBuffer |
insert(int offset,
Object obj)
Inserts the string representation of the
Object
argument into this character sequence. |
StringBuffer |
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 by codePointOffset code
points. |
StringBuffer |
replace(int start,
int end,
String str)
Replaces the characters in a substring of this sequence
with characters in the specified
String. |
StringBuffer |
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, waitchars, codePointspublic StringBuffer()
public StringBuffer(int capacity)
capacity - the initial capacity.NegativeArraySizeException - if the capacity
argument is less than 0.public StringBuffer(String str)
16 plus the length of the string argument.str - the initial contents of the buffer.public StringBuffer(CharSequence seq)
CharSequence. The initial capacity of
the string buffer is 16 plus the length of the
CharSequence argument.
If the length of the specified CharSequence is
less than or equal to zero, then an empty buffer of capacity
16 is returned.
seq - the sequence to copy.public int length()
length in interface CharSequencepublic 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
index k in the new character sequence is the same as the
character at index k in the old sequence if k is less
than the length of the old character sequence; otherwise, it is the
null character '\u0000'.
In other words, if the newLength argument is less than
the current length, the length is changed to the specified length.
If the newLength argument is greater than or equal
to the current length, sufficient null characters
('\u0000') are appended so that
length becomes the newLength argument.
The newLength argument must be greater than or equal
to 0.
newLength - the new lengthIndexOutOfBoundsException - if the
newLength argument is negative.length()public char charAt(int index)
char value in this sequence at the specified index.
The first char value is at index 0, the next at index
1, and so on, as in array indexing.
The index argument must be greater than or equal to
0, and less than the length of this sequence.
If the char value specified by the index is a
surrogate, the surrogate
value is returned.
charAt in interface CharSequenceindex - the index of the desired char value.char value at the specified index.IndexOutOfBoundsException - if index is
negative or greater than or equal to length().length()public int codePointAt(int index)
char values
(Unicode code units) and ranges from 0 to
length()- 1.
If the char value specified at the given index
is in the high-surrogate range, the following index is less
than the length of this sequence, and the
char value at the following index is in the
low-surrogate range, then the supplementary code point
corresponding to this surrogate pair is returned. Otherwise,
the char value at the given index is returned.
index - the index to the char valuesindexpublic int codePointBefore(int index)
char values
(Unicode code units) and ranges from 1 to length().
If the char value at (index - 1)
is in the low-surrogate range, (index - 2) is not
negative, and the char value at (index -
2) is in the high-surrogate range, then the
supplementary code point value of the surrogate pair is
returned. If the char value at index -
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 returnedpublic int codePointCount(int beginIndex,
int endIndex)
beginIndex and extends to the char at
index endIndex - 1. Thus the length (in
chars) of the text range is
endIndex-beginIndex. Unpaired surrogates within
this sequence count as one code point each.beginIndex - the index to the first char of
the text range.endIndex - the index after the last char of
the text range.public int offsetByCodePoints(int index,
int codePointOffset)
index by codePointOffset code
points. Unpaired surrogates within the text range given by
index and codePointOffset count as
one code point each.index - the index to be offsetcodePointOffset - the offset in code pointspublic void getChars(int srcBegin,
int srcEnd,
char[] dst,
int dstBegin)
dst. The first character to
be copied is at index srcBegin; the last character to
be copied is at index srcEnd-1. The total number of
characters to be copied is srcEnd-srcBegin. The
characters are copied into the subarray of dst starting
at index dstBegin 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 into dst.IndexOutOfBoundsException - if any of the following is true:
srcBegin is negative
dstBegin is negative
srcBegin argument is greater than
the srcEnd argument.
srcEnd is greater than
this.length().
dstBegin+srcEnd-srcBegin is greater than
dst.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
character ch at position index.
The index argument must be greater than or equal to
0, and less than the length of this sequence.
index - the index of the character to modify.ch - the new character.IndexOutOfBoundsException - if index is
negative or greater than or equal to length().length()public StringBuffer append(Object obj)
Object argument.
The overall effect is exactly as if the argument were converted
to a string by the method String.valueOf(Object),
and the characters of that string were then
appended to this character sequence.
obj - an Object.public StringBuffer append(String str)
The characters of the String argument are appended, in
order, increasing the length of this sequence by the length of the
argument. If str is null, then the four
characters "null" are appended.
Let n be the length of this character sequence just prior to
execution of the append method. Then the character at
index k in the new character sequence is equal to the character
at index k in the old character sequence, if k is less
than n; otherwise, it is equal to the character at index
k-n in the argument str.
str - a string.public StringBuffer append(StringBuffer sb)
StringBuffer to this sequence.
The characters of the StringBuffer argument are appended,
in order, to the contents of this StringBuffer, increasing the
length of this StringBuffer by the length of the argument.
If sb is null, then the four characters
"null" are appended to this StringBuffer.
Let n be the length of the old character sequence, the one
contained in the StringBuffer just prior to execution of the
append method. Then the character at index k in
the new character sequence is equal to the character at index k
in the old character sequence, if k is less than n;
otherwise, it is equal to the character at index k-n in the
argument sb.
This method synchronizes on this, the destination
object, but does not synchronize on the source (sb).
sb - the StringBuffer to append.public StringBuffer append(CharSequence s)
CharSequence to this
sequence.
The characters of the CharSequence argument are appended,
in order, increasing the length of this sequence by the length of the
argument.
The result of this method is exactly the same as if it were an invocation of this.append(s, 0, s.length());
This method synchronizes on this, the destination
object, but does not synchronize on the source (s).
If s is null, then the four characters
"null" are appended.
append in interface Appendables - the CharSequence to append.public StringBuffer append(CharSequence s, int start, int end)
CharSequence to this
sequence.
Characters of the argument s, starting at
index start, are appended, in order, to the contents of
this sequence up to the (exclusive) index end. The length
of this sequence is increased by the value of end - start.
Let n be the length of this character sequence just prior to
execution of the append method. Then the character at
index k in this character sequence becomes equal to the
character at index k in this sequence, if k is less than
n; otherwise, it is equal to the character at index
k+start-n in the argument s.
If s is null, then this method appends
characters as if the s parameter was a sequence containing the four
characters "null".
append in interface Appendables - 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 - if
start is negative, or
start is greater than end or
end is greater than s.length()public StringBuffer 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 method String.valueOf(char[]),
and the characters of that string were then
appended to this character sequence.
str - the characters to be appended.public StringBuffer append(char[] str, int offset, int len)
char array argument to this sequence.
Characters of the char array str, starting at
index offset, are appended, in order, to the contents
of this sequence. The length of this sequence increases
by the value of len.
The overall effect is exactly as if the arguments were converted
to a string by the method String.valueOf(char[],int,int),
and the characters of that string were then
appended to this character sequence.
str - the characters to be appended.offset - the index of the first char to append.len - the number of chars to append.IndexOutOfBoundsException - if offset < 0 or len < 0
or offset+len > str.lengthpublic StringBuffer append(boolean b)
boolean
argument to the sequence.
The overall effect is exactly as if the argument were converted
to a string by the method String.valueOf(boolean),
and the characters of that string were then
appended to this character sequence.
b - a boolean.public StringBuffer append(char c)
char
argument to this sequence.
The argument is appended to the contents of this sequence.
The length of this sequence increases by 1.
The overall effect is exactly as if the argument were converted
to a string by the method String.valueOf(char),
and the character in that string were then
appended to this character sequence.
append in interface Appendablec - a char.public StringBuffer append(int i)
int
argument to this sequence.
The overall effect is exactly as if the argument were converted
to a string by the method String.valueOf(int),
and the characters of that string were then
appended to this character sequence.
i - an int.public StringBuffer appendCodePoint(int codePoint)
codePoint
argument to this sequence.
The argument is appended to the contents of this sequence.
The length of this sequence increases by
Character.charCount(codePoint).
The overall effect is exactly as if the argument were
converted to a char array by the method
Character.toChars(int) and the character in that array
were then appended to this character
sequence.
codePoint - a Unicode code pointpublic StringBuffer append(long lng)
long
argument to this sequence.
The overall effect is exactly as if the argument were converted
to a string by the method String.valueOf(long),
and the characters of that string were then
appended to this character sequence.
lng - a long.public StringBuffer append(float f)
float
argument to this sequence.
The overall effect is exactly as if the argument were converted
to a string by the method String.valueOf(float),
and the characters of that string were then
appended to this character sequence.
f - a float.public StringBuffer append(double d)
double
argument to this sequence.
The overall effect is exactly as if the argument were converted
to a string by the method String.valueOf(double),
and the characters of that string were then
appended to this character sequence.
d - a double.public StringBuffer delete(int start, int end)
start and extends to
the character at index end - 1 or to the end of the
sequence if no such character exists. If
start is equal to end, no changes are made.start - The beginning index, inclusive.end - The ending index, exclusive.StringIndexOutOfBoundsException - if start
is negative, greater than length(), or
greater than end.public StringBuffer deleteCharAt(int index)
char at the specified position in this
sequence. This sequence is shortened by one char.
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 of chars to remove by calling
Character.charCount(thisSequence.codePointAt(index)),
where thisSequence is this sequence.
index - Index of char to removeStringIndexOutOfBoundsException - if the index
is negative or greater than or equal to
length().public StringBuffer replace(int start, int end, String str)
String. The substring
begins at the specified start and extends to the character
at index end - 1 or to the end of the
sequence if no such character exists. First the
characters in the substring are removed and then the specified
String is inserted at start. (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 - if start
is negative, greater than length(), or
greater than end.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 - if start 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)
sb.substring(begin, end)CharSequence interface.subSequence in interface CharSequencestart - the start index, inclusive.end - the end index, exclusive.IndexOutOfBoundsException - if start or end are negative,
if end is greater than length(),
or if start is greater than endpublic String substring(int start, int end)
String that contains a subsequence of
characters currently contained in this sequence. The
substring begins at the specified start and
extends to the character at index end - 1.start - The beginning index, inclusive.end - The ending index, exclusive.StringIndexOutOfBoundsException - if start
or end are negative or greater than
length(), or start is
greater than end.public StringBuffer insert(int index, char[] str, int offset, int len)
str
array argument into this sequence. The subarray begins at the
specified offset and extends len chars.
The characters of the subarray are inserted into this sequence at
the position indicated by index. The length of this
sequence increases by len chars.index - position at which to insert subarray.str - A char array.offset - the index of the first char in subarray to
be inserted.len - the number of chars in the subarray to
be inserted.StringIndexOutOfBoundsException - if index
is negative or greater than length(), or
offset or len are negative, or
(offset+len) is greater than
str.length.public StringBuffer 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 method String.valueOf(Object),
and the characters of that string were then
inserted into this character
sequence at the indicated offset.
The offset argument must be greater than or equal to
0, and less than or equal to the length
of this sequence.
offset - the offset.obj - an Object.StringIndexOutOfBoundsException - if the offset is invalid.public StringBuffer insert(int offset, String str)
The characters of the String 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. If
str is null, then the four characters
"null" are inserted into this sequence.
The character at index k in the new character sequence is equal to:
offset
-offset in the
argument str, if k is not less than
offset but is less than offset+str.length()
-str.length() in the
old character sequence, if k is not less than
offset+str.length()
The offset argument must be greater than or equal to
0, and less than or equal to the length
of this sequence.
offset - the offset.str - a string.StringIndexOutOfBoundsException - if the offset is invalid.public StringBuffer 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 by
offset. 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 method String.valueOf(char[]),
and the characters of that string were then
inserted into this character
sequence at the indicated offset.
The offset argument must be greater than or equal to
0, and less than or equal to the length
of this sequence.
offset - the offset.str - a character array.StringIndexOutOfBoundsException - if the offset is invalid.public StringBuffer insert(int dstOffset, CharSequence s)
CharSequence into this sequence.
The characters of the CharSequence 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's
insert(dstOffset, s, 0, s.length())
method.
If s is null, 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 StringBuffer insert(int dstOffset, CharSequence s, int start, int end)
CharSequence into
this sequence.
The subsequence of the argument s specified by
start and end 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 by end - start.
The character at index k in this sequence becomes equal to:
dstOffset
+start-dstOffset in
the argument s, if k is greater than or equal to
dstOffset but is less than dstOffset+end-start
-(end-start) in this
sequence, if k is greater than or equal to
dstOffset+end-start
The dstOffset argument must be greater than or equal to
0, and less than or equal to the length
of this sequence.
The start argument must be nonnegative, and not greater than
end.
The end argument must be greater than or equal to
start, and less than or equal to the length of s.
If s is null, 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 - if dstOffset
is negative or greater than this.length(), or
start or end are negative, or
start is greater than end or
end is greater than s.length()public StringBuffer 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 method String.valueOf(boolean),
and the characters of that string were then
inserted into this character
sequence at the indicated offset.
The offset argument must be greater than or equal to
0, and less than or equal to the length
of this sequence.
offset - the offset.b - a boolean.StringIndexOutOfBoundsException - if the offset is invalid.public StringBuffer 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 method String.valueOf(char),
and the character in that string were then
inserted into this character
sequence at the indicated offset.
The offset argument must be greater than or equal to
0, and less than or equal to the length
of this sequence.
offset - the offset.c - a char.IndexOutOfBoundsException - if the offset is invalid.public StringBuffer 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 method String.valueOf(int),
and the characters of that string were then
inserted into this character
sequence at the indicated offset.
The offset argument must be greater than or equal to
0, and less than or equal to the length
of this sequence.
offset - the offset.i - an int.StringIndexOutOfBoundsException - if the offset is invalid.public StringBuffer 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 method String.valueOf(long),
and the characters of that string were then
inserted into this character
sequence at the indicated offset.
The offset argument must be greater than or equal to
0, and less than or equal to the length
of this sequence.
offset - the offset.l - a long.StringIndexOutOfBoundsException - if the offset is invalid.public StringBuffer 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 method String.valueOf(float),
and the characters of that string were then
inserted into this character
sequence at the indicated offset.
The offset argument must be greater than or equal to
0, and less than or equal to the length
of this sequence.
offset - the offset.f - a float.StringIndexOutOfBoundsException - if the offset is invalid.public StringBuffer 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 method String.valueOf(double),
and the characters of that string were then
inserted into this character
sequence at the indicated offset.
The offset argument must be greater than or equal to
0, and less than or equal to the length
of this sequence.
offset - the offset.d - a double.StringIndexOutOfBoundsException - if the offset is invalid.public int indexOf(String str)
this.toString().startsWith(str, <i>k</i>)
true.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)
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 value k such that
this.toString().startsWith(str, k)
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)
str - the substring to search for.fromIndex - the index to start the search from.public StringBuffer reverse()
char values) just prior to
execution of the reverse method. Then the
character at index k in the new character sequence is
equal to the character at index n-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. This String is then returned. Subsequent
changes to this sequence do not affect the contents of the
String.toString in interface CharSequence Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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