- All Implemented Interfaces:
Appendable
,CharSequence
,Comparable<CharBuffer>
,Readable
This class defines four categories of operations upon char buffers:
Absolute and relative
get
andput
methods that read and write single chars;Absolute and relative
bulk get
methods that transfer contiguous sequences of chars from this buffer into an array;Absolute and relative
bulk put
methods that transfer contiguous sequences of chars from a char array, a string, or some other char buffer into this buffer;A method for
compacting
a char buffer.
Char buffers can be created either by allocation
, which allocates space for the buffer's
content, by wrapping
an existing
char array or string into a buffer, or by creating a
view of an existing byte buffer.
Like a byte buffer, a char buffer is either direct or non-direct. A
char buffer created via the wrap
methods of this class will
be non-direct. A char buffer created as a view of a byte buffer will
be direct if, and only if, the byte buffer itself is direct. Whether or not
a char buffer is direct may be determined by invoking the isDirect
method.
This class implements the CharSequence
interface so that
character buffers may be used wherever character sequences are accepted, for
example in the regular-expression package java.util.regex
.
The methods defined by CharSequence
operate relative to the current
position of the buffer when they are invoked.
Methods in this class that do not otherwise have a value to return are specified to return the buffer upon which they are invoked. This allows method invocations to be chained. The sequence of statements
cb.put("text/");
cb.put(subtype);
cb.put("; charset=");
cb.put(enc);
cb.put("text/").put(subtype).put("; charset=").put(enc);
Optional operations
Methods specified as optional operations throw a ReadOnlyBufferException when invoked on a read-only CharBuffer. The methods array and arrayOffset throw an UnsupportedOperationException if the CharBuffer is not backed by an accessible char array (irrespective of whether the CharBuffer is read-only).- Since:
- 1.4
-
Method Summary
Modifier and TypeMethodDescriptionstatic CharBuffer
allocate
(int capacity) Allocates a new char buffer.append
(char c) Appends the specified char to this buffer (optional operation).append
(CharSequence csq) Appends the specified character sequence to this buffer (optional operation).append
(CharSequence csq, int start, int end) Appends a subsequence of the specified character sequence to this buffer (optional operation).final char[]
array()
Returns the char array that backs this buffer (optional operation).final int
Returns the offset within this buffer's backing array of the first element of the buffer (optional operation).abstract CharBuffer
Creates a new, read-only char buffer that shares this buffer's content.final char
charAt
(int index) Reads the character at the given index relative to the current position.final CharBuffer
clear()
Clears this buffer.abstract CharBuffer
compact()
Compacts this buffer (optional operation).int
compareTo
(CharBuffer that) Compares this buffer to another.abstract CharBuffer
Creates a new char buffer that shares this buffer's content.boolean
Tells whether or not this buffer is equal to another object.final CharBuffer
flip()
Flips this buffer.abstract char
get()
Relative get method.get
(char[] dst) Relative bulk get method.get
(char[] dst, int offset, int length) Relative bulk get method.abstract char
get
(int index) Absolute get method.get
(int index, char[] dst) Absolute bulk get method.get
(int index, char[] dst, int offset, int length) Absolute bulk get method.final boolean
hasArray()
Tells whether or not this buffer is backed by an accessible char array.int
hashCode()
Returns the current hash code of this buffer.abstract boolean
isDirect()
Tells whether or not this char buffer is direct.final boolean
isEmpty()
Returnstrue
if this character buffer is empty.final int
length()
Returns the length of this character buffer.final CharBuffer
limit
(int newLimit) Sets this buffer's limit.final CharBuffer
mark()
Sets this buffer's mark at its position.int
mismatch
(CharBuffer that) Finds and returns the relative index of the first mismatch between this buffer and a given buffer.abstract ByteOrder
order()
Retrieves this buffer's byte order.final CharBuffer
position
(int newPosition) Sets this buffer's position.abstract CharBuffer
put
(char c) Relative put method (optional operation).final CharBuffer
put
(char[] src) Relative bulk put method (optional operation).put
(char[] src, int offset, int length) Relative bulk put method (optional operation).abstract CharBuffer
put
(int index, char c) Absolute put method (optional operation).put
(int index, char[] src) Absolute bulk put method (optional operation).put
(int index, char[] src, int offset, int length) Absolute bulk put method (optional operation).put
(int index, CharBuffer src, int offset, int length) Absolute bulk put method (optional operation).final CharBuffer
Relative bulk put method (optional operation).Relative bulk put method (optional operation).put
(CharBuffer src) Relative bulk put method (optional operation).int
read
(CharBuffer target) Attempts to read characters into the specified character buffer.final CharBuffer
reset()
Resets this buffer's position to the previously-marked position.final CharBuffer
rewind()
Rewinds this buffer.abstract CharBuffer
slice()
Creates a new char buffer whose content is a shared subsequence of this buffer's content.abstract CharBuffer
slice
(int index, int length) Creates a new char buffer whose content is a shared subsequence of this buffer's content.abstract CharBuffer
subSequence
(int start, int end) Creates a new character buffer that represents the specified subsequence of this buffer, relative to the current position.toString()
Returns a string containing the characters in this buffer.static CharBuffer
wrap
(char[] array) Wraps a char array into a buffer.static CharBuffer
wrap
(char[] array, int offset, int length) Wraps a char array into a buffer.static CharBuffer
wrap
(CharSequence csq) Wraps a character sequence into a buffer.static CharBuffer
wrap
(CharSequence csq, int start, int end) Wraps a character sequence into a buffer.Methods declared in class java.nio.Buffer
capacity, hasRemaining, isReadOnly, limit, position, remaining
Methods declared in class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
Methods declared in interface java.lang.CharSequence
chars, codePoints
-
Method Details
-
allocate
Allocates a new char buffer.The new buffer's position will be zero, its limit will be its capacity, its mark will be undefined, each of its elements will be initialized to zero, and its byte order will be the
native order
of the underlying hardware. It will have abacking array
, and itsarray offset
will be zero.- Parameters:
capacity
- The new buffer's capacity, in chars- Returns:
- The new char buffer
- Throws:
IllegalArgumentException
- If thecapacity
is a negative integer
-
wrap
Wraps a char array into a buffer.The new buffer will be backed by the given char array; that is, modifications to the buffer will cause the array to be modified and vice versa. The new buffer's capacity will be
array.length
, its position will beoffset
, its limit will beoffset + length
, its mark will be undefined, and its byte order will be thenative order
of the underlying hardware. Itsbacking array
will be the given array, and itsarray offset
will be zero.- Parameters:
array
- The array that will back the new bufferoffset
- The offset of the subarray to be used; must be non-negative and no larger thanarray.length
. The new buffer's position will be set to this value.length
- The length of the subarray to be used; must be non-negative and no larger thanarray.length - offset
. The new buffer's limit will be set tooffset + length
.- Returns:
- The new char buffer
- Throws:
IndexOutOfBoundsException
- If the preconditions on theoffset
andlength
parameters do not hold
-
wrap
Wraps a char array into a buffer.The new buffer will be backed by the given char array; that is, modifications to the buffer will cause the array to be modified and vice versa. The new buffer's capacity and limit will be
array.length
, its position will be zero, its mark will be undefined, and its byte order will be thenative order
of the underlying hardware. Itsbacking array
will be the given array, and itsarray offset
will be zero.- Parameters:
array
- The array that will back this buffer- Returns:
- The new char buffer
-
read
Attempts to read characters into the specified character buffer. The buffer is used as a repository of characters as-is: the only changes made are the results of a put operation. No flipping or rewinding of the buffer is performed.- Specified by:
read
in interfaceReadable
- Parameters:
target
- the buffer to read characters into- Returns:
- The number of characters added to the buffer, or -1 if this source of characters is at its end
- Throws:
IOException
- if an I/O error occursReadOnlyBufferException
- if target is a read only buffer- Since:
- 1.5
-
wrap
Wraps a character sequence into a buffer.The content of the new, read-only buffer will be the content of the given character sequence. The buffer's capacity will be
csq.length()
, its position will bestart
, its limit will beend
, and its mark will be undefined.- Parameters:
csq
- The character sequence from which the new character buffer is to be createdstart
- The index of the first character to be used; must be non-negative and no larger thancsq.length()
. The new buffer's position will be set to this value.end
- The index of the character following the last character to be used; must be no smaller thanstart
and no larger thancsq.length()
. The new buffer's limit will be set to this value.- Returns:
- The new character buffer
- Throws:
IndexOutOfBoundsException
- If the preconditions on thestart
andend
parameters do not hold
-
wrap
Wraps a character sequence into a buffer.The content of the new, read-only buffer will be the content of the given character sequence. The new buffer's capacity and limit will be
csq.length()
, its position will be zero, and its mark will be undefined.- Parameters:
csq
- The character sequence from which the new character buffer is to be created- Returns:
- The new character buffer
-
slice
Creates a new char buffer whose content is a shared subsequence of this buffer's content.The content of the new buffer will start at this buffer's current position. Changes to this buffer's content will be visible in the new buffer, and vice versa; the two buffers' position, limit, and mark values will be independent.
The new buffer's position will be zero, its capacity and its limit will be the number of chars remaining in this buffer, its mark will be undefined, and its byte order will be identical to that of this buffer. The new buffer will be direct if, and only if, this buffer is direct, and it will be read-only if, and only if, this buffer is read-only.
-
slice
Creates a new char buffer whose content is a shared subsequence of this buffer's content.The content of the new buffer will start at position
index
in this buffer, and will containlength
elements. Changes to this buffer's content will be visible in the new buffer, and vice versa; the two buffers' position, limit, and mark values will be independent.The new buffer's position will be zero, its capacity and its limit will be
length
, its mark will be undefined, and its byte order will be identical to that of this buffer. The new buffer will be direct if, and only if, this buffer is direct, and it will be read-only if, and only if, this buffer is read-only.- Specified by:
slice
in classBuffer
- Parameters:
index
- The position in this buffer at which the content of the new buffer will start; must be non-negative and no larger thanlimit()
length
- The number of elements the new buffer will contain; must be non-negative and no larger thanlimit() - index
- Returns:
- The new buffer
- Throws:
IndexOutOfBoundsException
- Ifindex
is negative or greater thanlimit()
,length
is negative, orlength > limit() - index
- Since:
- 13
-
duplicate
Creates a new char buffer that shares this buffer's content.The content of the new buffer will be that of this buffer. Changes to this buffer's content will be visible in the new buffer, and vice versa; the two buffers' position, limit, and mark values will be independent.
The new buffer's capacity, limit, position, mark values, and byte order will be identical to those of this buffer. The new buffer will be direct if, and only if, this buffer is direct, and it will be read-only if, and only if, this buffer is read-only.
-
asReadOnlyBuffer
Creates a new, read-only char buffer that shares this buffer's content.The content of the new buffer will be that of this buffer. Changes to this buffer's content will be visible in the new buffer; the new buffer itself, however, will be read-only and will not allow the shared content to be modified. The two buffers' position, limit, and mark values will be independent.
The new buffer's capacity, limit, position, mark values, and byte order will be identical to those of this buffer.
If this buffer is itself read-only then this method behaves in exactly the same way as the
duplicate
method.- Returns:
- The new, read-only char buffer
-
get
public abstract char get()Relative get method. Reads the char at this buffer's current position, and then increments the position.- Returns:
- The char at the buffer's current position
- Throws:
BufferUnderflowException
- If the buffer's current position is not smaller than its limit
-
put
Relative put method (optional operation).Writes the given char into this buffer at the current position, and then increments the position.
- Parameters:
c
- The char to be written- Returns:
- This buffer
- Throws:
BufferOverflowException
- If this buffer's current position is not smaller than its limitReadOnlyBufferException
- If this buffer is read-only
-
get
public abstract char get(int index) Absolute get method. Reads the char at the given index.- Parameters:
index
- The index from which the char will be read- Returns:
- The char at the given index
- Throws:
IndexOutOfBoundsException
- Ifindex
is negative or not smaller than the buffer's limit
-
put
Absolute put method (optional operation).Writes the given char into this buffer at the given index.
- Parameters:
index
- The index at which the char will be writtenc
- The char value to be written- Returns:
- This buffer
- Throws:
IndexOutOfBoundsException
- Ifindex
is negative or not smaller than the buffer's limitReadOnlyBufferException
- If this buffer is read-only
-
get
Relative bulk get method.This method transfers chars from this buffer into the given destination array. If there are fewer chars remaining in the buffer than are required to satisfy the request, that is, if
length
>
remaining()
, then no chars are transferred and aBufferUnderflowException
is thrown.Otherwise, this method copies
length
chars from this buffer into the given array, starting at the current position of this buffer and at the given offset in the array. The position of this buffer is then incremented bylength
.In other words, an invocation of this method of the form
src.get(dst, off, len)
has exactly the same effect as the loopfor (int i = off; i < off + len; i++) dst[i] = src.get();
- Parameters:
dst
- The array into which chars are to be writtenoffset
- The offset within the array of the first char to be written; must be non-negative and no larger thandst.length
length
- The maximum number of chars to be written to the given array; must be non-negative and no larger thandst.length - offset
- Returns:
- This buffer
- Throws:
BufferUnderflowException
- If there are fewer thanlength
chars remaining in this bufferIndexOutOfBoundsException
- If the preconditions on theoffset
andlength
parameters do not hold
-
get
Relative bulk get method.This method transfers chars from this buffer into the given destination array. An invocation of this method of the form
src.get(a)
behaves in exactly the same way as the invocationsrc.get(a, 0, a.length)
- Parameters:
dst
- The destination array- Returns:
- This buffer
- Throws:
BufferUnderflowException
- If there are fewer thanlength
chars remaining in this buffer
-
get
Absolute bulk get method.This method transfers
length
chars from this buffer into the given array, starting at the given index in this buffer and at the given offset in the array. The position of this buffer is unchanged.An invocation of this method of the form
src.get(index, dst, offset, length)
has exactly the same effect as the following loop except that it first checks the consistency of the supplied parameters and it is potentially much more efficient:for (int i = offset, j = index; i < offset + length; i++, j++) dst[i] = src.get(j);
- Parameters:
index
- The index in this buffer from which the first char will be read; must be non-negative and less thanlimit()
dst
- The destination arrayoffset
- The offset within the array of the first char to be written; must be non-negative and less thandst.length
length
- The number of chars to be written to the given array; must be non-negative and no larger than the smaller oflimit() - index
anddst.length - offset
- Returns:
- This buffer
- Throws:
IndexOutOfBoundsException
- If the preconditions on theindex
,offset
, andlength
parameters do not hold- Since:
- 13
-
get
Absolute bulk get method.This method transfers chars from this buffer into the given destination array. The position of this buffer is unchanged. An invocation of this method of the form
src.get(index, dst)
behaves in exactly the same way as the invocation:src.get(index, dst, 0, dst.length)
- Parameters:
index
- The index in this buffer from which the first char will be read; must be non-negative and less thanlimit()
dst
- The destination array- Returns:
- This buffer
- Throws:
IndexOutOfBoundsException
- Ifindex
is negative, not smaller thanlimit()
, orlimit() - index < dst.length
- Since:
- 13
-
put
Relative bulk put method (optional operation).This method transfers the chars remaining in the given source buffer into this buffer. If there are more chars remaining in the source buffer than in this buffer, that is, if
src.remaining()
>
remaining()
, then no chars are transferred and aBufferOverflowException
is thrown.Otherwise, this method copies n =
src.remaining()
chars from the given buffer into this buffer, starting at each buffer's current position. The positions of both buffers are then incremented by n.In other words, an invocation of this method of the form
dst.put(src)
has exactly the same effect as the loopwhile (src.hasRemaining()) dst.put(src.get());
- Parameters:
src
- The source buffer from which chars are to be read; must not be this buffer- Returns:
- This buffer
- Throws:
BufferOverflowException
- If there is insufficient space in this buffer for the remaining chars in the source bufferIllegalArgumentException
- If the source buffer is this bufferReadOnlyBufferException
- If this buffer is read-only
-
put
Absolute bulk put method (optional operation).This method transfers
length
chars into this buffer from the given source buffer, starting at the givenoffset
in the source buffer and the givenindex
in this buffer. The positions of both buffers are unchanged.In other words, an invocation of this method of the form
dst.put(index, src, offset, length)
has exactly the same effect as the loopfor (int i = offset, j = index; i < offset + length; i++, j++) dst.put(j, src.get(i));
- Parameters:
index
- The index in this buffer at which the first char will be written; must be non-negative and less thanlimit()
src
- The buffer from which chars are to be readoffset
- The index within the source buffer of the first char to be read; must be non-negative and less thansrc.limit()
length
- The number of chars to be read from the given buffer; must be non-negative and no larger than the smaller oflimit() - index
andsrc.limit() - offset
- Returns:
- This buffer
- Throws:
IndexOutOfBoundsException
- If the preconditions on theindex
,offset
, andlength
parameters do not holdReadOnlyBufferException
- If this buffer is read-only- Since:
- 16
-
put
Relative bulk put method (optional operation).This method transfers chars into this buffer from the given source array. If there are more chars to be copied from the array than remain in this buffer, that is, if
length
>
remaining()
, then no chars are transferred and aBufferOverflowException
is thrown.Otherwise, this method copies
length
chars from the given array into this buffer, starting at the given offset in the array and at the current position of this buffer. The position of this buffer is then incremented bylength
.In other words, an invocation of this method of the form
dst.put(src, off, len)
has exactly the same effect as the loopfor (int i = off; i < off + len; i++) dst.put(src[i]);
- Parameters:
src
- The array from which chars are to be readoffset
- The offset within the array of the first char to be read; must be non-negative and no larger thansrc.length
length
- The number of chars to be read from the given array; must be non-negative and no larger thansrc.length - offset
- Returns:
- This buffer
- Throws:
BufferOverflowException
- If there is insufficient space in this bufferIndexOutOfBoundsException
- If the preconditions on theoffset
andlength
parameters do not holdReadOnlyBufferException
- If this buffer is read-only
-
put
Relative bulk put method (optional operation).This method transfers the entire content of the given source char array into this buffer. An invocation of this method of the form
dst.put(a)
behaves in exactly the same way as the invocationdst.put(a, 0, a.length)
- Parameters:
src
- The source array- Returns:
- This buffer
- Throws:
BufferOverflowException
- If there is insufficient space in this bufferReadOnlyBufferException
- If this buffer is read-only
-
put
Absolute bulk put method (optional operation).This method transfers
length
chars from the given array, starting at the given offset in the array and at the given index in this buffer. The position of this buffer is unchanged.An invocation of this method of the form
dst.put(index, src, offset, length)
has exactly the same effect as the following loop except that it first checks the consistency of the supplied parameters and it is potentially much more efficient:for (int i = offset, j = index; i < offset + length; i++, j++) dst.put(j, src[i]);
- Parameters:
index
- The index in this buffer at which the first char will be written; must be non-negative and less thanlimit()
src
- The array from which chars are to be readoffset
- The offset within the array of the first char to be read; must be non-negative and less thansrc.length
length
- The number of chars to be read from the given array; must be non-negative and no larger than the smaller oflimit() - index
andsrc.length - offset
- Returns:
- This buffer
- Throws:
IndexOutOfBoundsException
- If the preconditions on theindex
,offset
, andlength
parameters do not holdReadOnlyBufferException
- If this buffer is read-only- Since:
- 13
-
put
Absolute bulk put method (optional operation).This method copies chars into this buffer from the given source array. The position of this buffer is unchanged. An invocation of this method of the form
dst.put(index, src)
behaves in exactly the same way as the invocation:dst.put(index, src, 0, src.length);
- Parameters:
index
- The index in this buffer at which the first char will be written; must be non-negative and less thanlimit()
src
- The array from which chars are to be read- Returns:
- This buffer
- Throws:
IndexOutOfBoundsException
- Ifindex
is negative, not smaller thanlimit()
, orlimit() - index < src.length
ReadOnlyBufferException
- If this buffer is read-only- Since:
- 13
-
put
Relative bulk put method (optional operation).This method transfers chars from the given string into this buffer. If there are more chars to be copied from the string than remain in this buffer, that is, if
end - start
>
remaining()
, then no chars are transferred and aBufferOverflowException
is thrown.Otherwise, this method copies n =
end
-start
chars from the given string into this buffer, starting at the givenstart
index and at the current position of this buffer. The position of this buffer is then incremented by n.In other words, an invocation of this method of the form
dst.put(src, start, end)
has exactly the same effect as the loopfor (int i = start; i < end; i++) dst.put(src.charAt(i));
- Parameters:
src
- The string from which chars are to be readstart
- The offset within the string of the first char to be read; must be non-negative and no larger thanstring.length()
end
- The offset within the string of the last char to be read, plus one; must be non-negative and no larger thanstring.length()
- Returns:
- This buffer
- Throws:
-