java.nio
Class Buffer

java.lang.Object
  java.nio.Buffer

Direct Known 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, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

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

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

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

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

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

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

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