java.nio

Class Buffer

Known Direct Subclasses:
ByteBuffer, CharBuffer, DoubleBuffer, FloatBuffer, IntBuffer, LongBuffer, ShortBuffer

public abstract class Buffer
extends Object

Since:
1.4

Method Summary

abstract Object
array()
Returns the backing array of this buffer, if this buffer has one.
abstract int
arrayOffset()
For buffers that are backed by a Java array, this returns the offset into that array at which the buffer content starts.
int
capacity()
Retrieves the capacity of the buffer.
Buffer
clear()
Clears the buffer.
Buffer
flip()
Flips the buffer.
abstract boolean
hasArray()
Returns true if this buffer can provide a backing array, false otherwise.
boolean
hasRemaining()
Tells whether the buffer has remaining data to read or not.
abstract boolean
isDirect()
Returns true when this buffer is direct, false otherwise.
abstract boolean
isReadOnly()
Tells whether this buffer is read only or not.
int
limit()
Retrieves the current limit of the buffer.
Buffer
limit(int newLimit)
Sets this buffer's limit.
Buffer
mark()
Sets this buffer's mark at its position.
int
position()
Retrieves the current position of this buffer.
Buffer
position(int newPosition)
Sets this buffer's position.
int
remaining()
Returns the number of elements between the current position and the limit.
Buffer
reset()
Resets this buffer's position to the previously-marked position.
Buffer
rewind()
Rewinds this buffer.

Methods inherited from class java.lang.Object

clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

array

public abstract Object array()
Returns the backing array of this buffer, if this buffer has one. Modification to the array are directly visible in this buffer and vice versa.

If this is a read-only buffer, then a ReadOnlyBufferException is thrown because exposing the array would allow to circumvent the read-only property. If this buffer doesn't have an array, then an UnsupportedOperationException is thrown. Applications should check if this buffer supports a backing array by calling hasArray() first.

Returns:
the backing array of this buffer
Throws:
ReadOnlyBufferException - when this buffer is read only
UnsupportedOperationException - when this buffer does not provide a backing array
Since:
1.6

arrayOffset

public abstract int arrayOffset()
For buffers that are backed by a Java array, this returns the offset into that array at which the buffer content starts.
Returns:
the offset into the backing array at which the buffer content starts
Throws:
ReadOnlyBufferException - when this buffer is read only
UnsupportedOperationException - when this buffer does not provide a backing array
Since:
1.6

capacity

public final int capacity()
Retrieves the capacity of the buffer.
Returns:
the capacity of the buffer

clear

public final Buffer clear()
Clears the buffer.
Returns:
this buffer

flip

public final Buffer flip()
Flips the buffer.
Returns:
this buffer

hasArray

public abstract boolean hasArray()
Returns true if this buffer can provide a backing array, false otherwise. When true, application code can call array() to access this backing array.
Returns:
true if this buffer can provide a backing array, false otherwise
Since:
1.6

hasRemaining

public final boolean hasRemaining()
Tells whether the buffer has remaining data to read or not.
Returns:
true if the buffer contains remaining data to read, false otherwise

isDirect

public abstract boolean isDirect()
Returns true when this buffer is direct, false otherwise. A direct buffer is usually backed by a raw memory area instead of a Java array.
Returns:
true when this buffer is direct, false otherwise
Since:
1.6

isReadOnly

public abstract boolean isReadOnly()
Tells whether this buffer is read only or not.
Returns:
true if the buffer is read only, false otherwise

limit

public final int limit()
Retrieves the current limit of the buffer.
Returns:
the limit of the buffer

limit

public final Buffer limit(int newLimit)
Sets this buffer's limit.
Parameters:
newLimit - The new limit value; must be non-negative and no larger than this buffer's capacity.
Returns:
this buffer
Throws:
IllegalArgumentException - If the preconditions on newLimit do not hold.

mark

public final Buffer mark()
Sets this buffer's mark at its position.
Returns:
this buffer

position

public final int position()
Retrieves the current position of this buffer.
Returns:
the current position of this buffer

position

public final Buffer position(int newPosition)
Sets this buffer's position. If the mark is defined and larger than the new position then it is discarded.
Parameters:
newPosition - The new position value; must be non-negative and no larger than the current limit.
Returns:
this buffer
Throws:
IllegalArgumentException - If the preconditions on newPosition do not hold

remaining

public final int remaining()
Returns the number of elements between the current position and the limit.
Returns:
the number of remaining elements

reset

public final Buffer reset()
Resets this buffer's position to the previously-marked position.
Returns:
this buffer
Throws:
InvalidMarkException - If the mark has not been set.

rewind

public final Buffer rewind()
Rewinds this buffer. The position is set to zero and the mark is discarded.
Returns:
this buffer

Buffer.java -- Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc. This file is part of GNU Classpath. GNU Classpath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GNU Classpath is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNU Classpath; see the file COPYING. If not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. Linking this library statically or dynamically with other modules is making a combined work based on this library. Thus, the terms and conditions of the GNU General Public License cover the whole combination. As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version.