Android
java.nio
public abstract class

java.nio.CharBuffer

java.lang.Object
java.nio.Buffer
java.nio.CharBuffer Appendable CharSequence Comparable<T> Readable

A buffer of chars.

A char buffer can be created in either of the following ways:

  • Allocate a new char array and create a buffer based on it;
  • Wrap an existing char array to create a new buffer;
  • Wrap an existing char sequence to create a new buffer;
  • Use ByteBuffer.asCharBuffer to create a char buffer based on a byte buffer.

Summary

Public Methods

      static    CharBuffer  allocate(int capacity)
Creates a char buffer based on a new allocated char array.
          CharBuffer  append(char c)
Append the given character.
          CharBuffer  append(CharSequence csq)
Append the given CharSequence.
          CharBuffer  append(CharSequence csq, int start, int end)
Append part of the given CharSequence.
    final      char[]  array()
Returns the char array which this buffer is based on, if there's one.
    final      int  arrayOffset()
Returns the offset of the char array which this buffer is based on, if there's one.
abstract          CharBuffer  asReadOnlyBuffer()
Returns a readonly buffer that shares content with this buffer.
    final      char  charAt(int index)
Returns the character located at the specified index in the buffer.
abstract          CharBuffer  compact()
Compacts this char buffer.
          int  compareTo(CharBuffer otherBuffer)
Compare the remaining chars of this buffer to another char buffer's remaining chars.
abstract          CharBuffer  duplicate()
Returns a duplicated buffer that shares content with this buffer.
          boolean  equals(Object other)
Tests whether this char buffer equals to another object.
abstract          char  get()
Returns the char at the current position and increase the position by 1.
          CharBuffer  get(char[] dest)
Reads chars from the current position into the specified char array and increase the position by the number of chars read.
abstract          char  get(int index)
Returns a char at the specified index, and the position is not changed.
          CharBuffer  get(char[] dest, int off, int len)
Reads chars from the current position into the specified char array, starting from the specified offset, and increase the position by the number of chars read.
    final      boolean  hasArray()
Returns whether this buffer is based on a char array and is read/write.
          int  hashCode()
Hash code is calculated from the remaining chars.
abstract          boolean  isDirect()
Returns true if this buffer is direct.
    final      int  length()
Returns the number of remaining chars.
abstract          ByteOrder  order()
Returns the byte order used by this buffer when converting chars from/to bytes.
          CharBuffer  put(char[] src, int off, int len)
Writes chars in the given char array, starting from the specified offset, to the current position and increase the position by the number of chars written.
abstract          CharBuffer  put(int index, char c)
Write a char to the specified index of this buffer and the position is not changed.
abstract          CharBuffer  put(char c)
Writes the given char to the current position and increase the position by 1.
          CharBuffer  put(CharBuffer src)
Writes all the remaining chars of the src char buffer to this buffer's current position, and increase both buffers' position by the number of chars copied.
    final      CharBuffer  put(char[] src)
Writes chars in the given char array to the current position and increase the position by the number of chars written.
    final      CharBuffer  put(String str)
Write all chars of the give string to the current position of this buffer, and increase the position by the length of string.
          CharBuffer  put(String str, int start, int end)
Write chars of the given string to the current position of this buffer, and increase the position by the number of chars written.
          int  read(CharBuffer target)
Reads the characters into the given CharBuffer.
abstract          CharBuffer  slice()
Returns a sliced buffer that shares content with this buffer.
abstract          CharSequence  subSequence(int start, int end)
Returns a new char buffer represents a sub-sequence of this buffer's current remaining content.
          String  toString()
Returns a string represents the current remaining chars of this buffer.
      static    CharBuffer  wrap(char[] array, int start, int len)
Creates new a char buffer by wrapping the given char array.
      static    CharBuffer  wrap(CharSequence chseq)
Creates a new char buffer by wrapping the given char sequence.
      static    CharBuffer  wrap(char[] array)
Creates a new char buffer by wrapping the given char array.
      static    CharBuffer  wrap(CharSequence chseq, int start, int end)
Creates a new char buffer by wrapping the given char sequence.
Methods inherited from class java.nio.Buffer
Methods inherited from class java.lang.Object
Methods inherited from interface java.lang.Appendable
Methods inherited from interface java.lang.CharSequence
Methods inherited from interface java.lang.Comparable
Methods inherited from interface java.lang.Readable

Details

Public Methods

public static CharBuffer allocate(int capacity)

Creates a char buffer based on a new allocated char array.

Parameters

capacity The capacity of the new buffer

Returns

  • The created char buffer

Throws

IllegalArgumentException If capacity is less than zero

public CharBuffer append(char c)

Append the given character.

See Also

public CharBuffer append(CharSequence csq)

Append the given CharSequence.

The behaviour of this method depends on the implementation class of Appendable.

If the give CharSequence is null, the sequence is treated as String "null".

public CharBuffer append(CharSequence csq, int start, int end)

Append part of the given CharSequence.

If the given CharSequence is not null, this method behaves same as the following statement:

    out.append(csq.subSequence(start, end)) 

If the give CharSequence is null, the sequence is treated as String "null".

public final char[] array()

Returns the char array which this buffer is based on, if there's one.

Returns

  • The char array which this buffer is based on

Throws

ReadOnlyBufferException If this buffer is based on an array, but it is readonly
UnsupportedOperationException If this buffer is not based on an array

public final int arrayOffset()

Returns the offset of the char array which this buffer is based on, if there's one.

The offset is the index of the array corresponds to the zero position of the buffer.

Returns

  • The offset of the char array which this buffer is based on

Throws

ReadOnlyBufferException If this buffer is based on an array, but it is readonly
UnsupportedOperationException If this buffer is not based on an array

public abstract CharBuffer asReadOnlyBuffer()

Returns a readonly buffer that shares content with this buffer.

The returned buffer is guaranteed to be a new instance, even this buffer is readonly itself. The new buffer's position, limit, capacity and mark are the same as this buffer.

The new buffer shares content with this buffer, which means this buffer's change of content will be visible to the new buffer. The two buffer's position, limit and mark are independent.

Returns

  • A readonly version of this buffer.

public final char charAt(int index)

Returns the character located at the specified index in the buffer. The index value is referenced from the current buffer position.

Parameters

index The index referenced from the current buffer position. It must not be less than zero but less than the value obtained from a call to remaining()

Returns

  • the character located at the specified index (referenced from the current position) in the buffer.

Throws

IndexOutOfBoundsException If the index is invalid

public abstract CharBuffer compact()

Compacts this char buffer.

The remaining chars will be moved to the head of the buffer, staring from position zero. Then the position is set to remaining(); the limit is set to capacity; the mark is cleared.

Returns

  • This buffer

Throws

ReadOnlyBufferException If no changes may be made to the contents of this buffer

public int compareTo(CharBuffer otherBuffer)

Compare the remaining chars of this buffer to another char buffer's remaining chars.

Parameters

otherBuffer Another char buffer

Returns

  • a negative value if this is less than other; 0 if this equals to other; a positive value if this is greater than other

Throws

ClassCastException If other is not a char buffer

public abstract CharBuffer duplicate()

Returns a duplicated buffer that shares content with this buffer.

The duplicated buffer's position, limit, capacity and mark are the same as this buffer. The duplicated buffer's readonly property and byte order are same as this buffer too.

The new buffer shares content with this buffer, which means either buffer's change of content will be visible to the other. The two buffer's position, limit and mark are independent.

Returns

  • A duplicated buffer that shares content with this buffer.

public boolean equals(Object other)

Tests whether this char buffer equals to another object.

If other is not a char buffer, then false is returned.

Two char buffers are equals if, and only if, their remaining chars are exactly the same. Position, limit, capacity and mark are not considered.

Parameters

other the object to be compared against

Returns

  • Whether this char buffer equals to another object.

public abstract char get()

Returns the char at the current position and increase the position by 1.

Returns

  • The char at the current position.

Throws

BufferUnderflowException If the position is equal or greater than limit

public CharBuffer get(char[] dest)

Reads chars from the current position into the specified char array and increase the position by the number of chars read.

Calling this method has the same effect as get(dest, 0, dest.length).

Parameters

dest The destination char array

Returns

  • This buffer

Throws

BufferUnderflowException if dest.length is greater than remaining()

public abstract char get(int index)

Returns a char at the specified index, and the position is not changed.

Parameters

index The index, must be no less than zero and less than limit

Returns

  • A char at the specified index.

Throws

IndexOutOfBoundsException If index is invalid

public CharBuffer get(char[] dest, int off, int len)

Reads chars from the current position into the specified char array, starting from the specified offset, and increase the position by the number of chars read.

Parameters

dest The target char array
off The offset of the char array, must be no less than zero and no greater than dest.length
len The number of chars to read, must be no less than zero and no greater than dest.length - off

Returns

  • This buffer

Throws

IndexOutOfBoundsException If either off or len is invalid
BufferUnderflowException If len is greater than remaining()

public final boolean hasArray()

Returns whether this buffer is based on a char array and is read/write.

If this buffer is readonly, then false is returned.

Returns

  • Whether this buffer is based on a char array and is read/write.

public int hashCode()

Hash code is calculated from the remaining chars.

Position, limit, capacity and mark don't affect the hash code.

Returns

  • The hash code calculated from the remaining chars.

public abstract boolean isDirect()

Returns true if this buffer is direct.

A direct buffer will try its best to take advantage of native memory APIs and it may not stay in java heap, thus not affected by GC.

A char buffer is direct, if it is based on a byte buffer and the byte buffer is direct.

Returns

  • True if this buffer is direct.

public final int length()

Returns the number of remaining chars.

Returns

  • The number of remaining chars.

public abstract ByteOrder order()

Returns the byte order used by this buffer when converting chars from/to bytes.

If this buffer is not based on a byte buffer, then always return the platform's native byte order.

Returns

  • The byte order used by this buffer when converting chars from/to bytes.

public CharBuffer put(char[] src, int off, int len)

Writes chars in the given char array, starting from the specified offset, to the current position and increase the position by the number of chars written.

Parameters

src The source char array
off The offset of char array, must be no less than zero and no greater than src.length
len The number of chars to write, must be no less than zero and no greater than src.length - off

Returns

  • This buffer

Throws

BufferOverflowException If remaining() is less than len
IndexOutOfBoundsException If either off or len is invalid
ReadOnlyBufferException If no changes may be made to the contents of this buffer

public abstract CharBuffer put(int index, char c)

Write a char to the specified index of this buffer and the position is not changed.

Parameters

index The index, must be no less than zero and less than the limit
c The char to write

Returns

  • This buffer

Throws

IndexOutOfBoundsException If index is invalid
ReadOnlyBufferException If no changes may be made to the contents of this buffer

public abstract CharBuffer put(char c)

Writes the given char to the current position and increase the position by 1.

Parameters

c The char to write

Returns

  • This buffer

Throws

BufferOverflowException If position is equal or greater than limit
ReadOnlyBufferException If no changes may be made to the contents of this buffer

public CharBuffer put(CharBuffer src)

Writes all the remaining chars of the src char buffer to this buffer's current position, and increase both buffers' position by the number of chars copied.

Parameters

src The source char buffer

Returns

  • This buffer

Throws

BufferOverflowException If src.remaining() is greater than this buffer's remaining()
IllegalArgumentException If src is this buffer
ReadOnlyBufferException If no changes may be made to the contents of this buffer

public final CharBuffer put(char[] src)

Writes chars in the given char array to the current position and increase the position by the number of chars written.

Calling this method has the same effect as put(src, 0, src.length).

Parameters

src The source char array

Returns

  • This buffer

Throws

BufferOverflowException If remaining() is less than src.length
ReadOnlyBufferException If no changes may be made to the contents of this buffer

public final CharBuffer put(String str)

Write all chars of the give string to the current position of this buffer, and increase the position by the length of string.

Calling this method has the same effect as put(str, 0, str.length()).

Parameters

str The string to write

Returns

  • This buffer

Throws

BufferOverflowException If remaining() is less than the length of string
ReadOnlyBufferException If no changes may be made to the contents of this buffer

public CharBuffer put(String str, int start, int end)

Write chars of the given string to the current position of this buffer, and increase the position by the number of chars written.

Parameters

str The string to write
start The first char to write, must be no less than zero and no greater than str.length()
end The last char to write (excluding), must be less than start and no greater than str.length()

Returns

  • This buffer

Throws

BufferOverflowException If remaining is less than end - start
IndexOutOfBoundsException If either start or end is invalid
ReadOnlyBufferException If no changes may be made to the contents of this buffer

public int read(CharBuffer target)

Reads the characters into the given CharBuffer. The maximum number of characters read is CharBuffer.remaining().

Throws

IOException

See Also

public abstract CharBuffer slice()

Returns a sliced buffer that shares content with this buffer.

The sliced buffer's capacity will be this buffer's remaining(), and its zero position will correspond to this buffer's current position. The new buffer's position will be 0, limit will be its capacity, and its mark is unset. The new buffer's readonly property and byte order are same as this buffer.

The new buffer shares content with this buffer, which means either buffer's change of content will be visible to the other. The two buffer's position, limit and mark are independent.

Returns

  • A sliced buffer that shares content with this buffer.

public abstract CharSequence subSequence(int start, int end)

Returns a new char buffer represents a sub-sequence of this buffer's current remaining content.

The new buffer's position will be position() + start, limit will be position() + end, capacity will be same as this buffer. The new buffer's readonly property and byte order are same as this buffer.

The new buffer shares content with this buffer, which means either buffer's change of content will be visible to the other. The two buffer's position, limit and mark are independent.

Parameters

start The start index of the sub-sequence, referenced from the current buffer position. Must not be less than zero and not greater than the value obtained from a call to remaining().
end The end index of the sub-sequence, referenced from the current buffer position. Must not be less than start and not be greater than the value obtained from a call to remaining()

Returns

  • A new char buffer represents a sub-sequence of this buffer's current remaining content.

Throws

IndexOutOfBoundsException If either start or end is invalid

public String toString()

Returns a string represents the current remaining chars of this buffer.

Returns

  • A string represents the current remaining chars of this buffer.

public static CharBuffer wrap(char[] array, int start, int len)

Creates new a char buffer by wrapping the given char array.

The new buffer's position will be start, limit will be start + len, capacity will be the length of the array.

Parameters

array The char array which the new buffer will be based on
start The start index, must be no less than zero and no greater than array.length
len The length, must be no less than zero and no greater than array.length - start

Returns

  • The created char buffer

Throws

IndexOutOfBoundsException If either start or len is invalid

public static CharBuffer wrap(CharSequence chseq)

Creates a new char buffer by wrapping the given char sequence.

Calling this method has the same effect as wrap(chseq, 0, chseq.length()).

Parameters

chseq The char sequence which the new buffer will be based on

Returns

  • The created char buffer

public static CharBuffer wrap(char[] array)

Creates a new char buffer by wrapping the given char array.

Calling this method has the same effect as wrap(array, 0, array.length).

Parameters

array The char array which the new buffer will be based on

Returns

  • The created char buffer

public static CharBuffer wrap(CharSequence chseq, int start, int end)

Creates a new char buffer by wrapping the given char sequence.

The new buffer's position will be start, limit will be end, capacity will be the length of the char sequence. The new buffer is readonly.

Parameters

chseq The char sequence which the new buffer will be based on
start The start index, must be no less than zero and no greater than chseq.length()
end The end index, must be no less than start and no greater than chseq.length()

Returns

  • The created char buffer

Throws

IndexOutOfBoundsException If either start or end is invalid
Copyright 2007 Google Inc. Build 0.9_r1-98467 - 14 Aug 2008 18:56