java.nio
Class DirectByteBuffer

java.lang.Object
  java.nio.Buffer
      java.nio.ByteBuffer
          java.nio.BaseByteBuffer
              java.nio.DirectByteBuffer

All Implemented Interfaces:

Comparable<ByteBuffer>, org.apache.harmony.nio.internal.DirectBuffer

Direct Known Subclasses:

ReadOnlyDirectByteBuffer, ReadWriteDirectByteBuffer

abstract class DirectByteBuffer
extends BaseByteBuffer
implements org.apache.harmony.nio.internal.DirectBuffer

DirectByteBuffer, ReadWriteDirectByteBuffer and ReadOnlyDirectByteBuffer compose the implementation of platform memory based byte buffers.

DirectByteBuffer implements all the shared readonly methods and is extended by the other two classes.

All methods are marked final for runtime performance.

Nested Class Summary

(package private) static class

DirectByteBuffer.SafeAddress

Field Summary

protected int	offset
protected DirectByteBuffer.SafeAddress	safeAddress

Fields inherited from class java.nio.ByteBuffer

order

Fields inherited from class java.nio.Buffer

_elementSizeShift, capacity, limit, mark, position, UNSET_MARK

Constructor Summary

DirectByteBuffer(DirectByteBuffer.SafeAddress address, int capacity, int offset)

DirectByteBuffer(int capacity)

Method Summary

void	addressValidityCheck()
void	free() Explicitly free the memory used by this direct byte buffer.
byte	get() Returns the byte at the current position and increase the position by 1.
ByteBuffer	get(byte[] dest, int off, int len) Reads bytes from the current position into the specified byte array, starting from the specified offset, and increase the position by the number of bytes read.
byte	get(int index) Returns a byte at the specified index, and the position is not changed.
org.apache.harmony.luni.platform.PlatformAddress	getBaseAddress()
int	getByteCapacity()
double	getDouble() Returns the double at the current position and increase the position by 8.
double	getDouble(int index) Returns the double at the specified index.
org.apache.harmony.luni.platform.PlatformAddress	getEffectiveAddress() Returns the platform address of the start of this buffer instance.
float	getFloat() Returns the float at the current position and increase the position by 4.
float	getFloat(int index) Returns the float at the specified index.
int	getInt() Returns the int at the current position and increase the position by 4.
int	getInt(int index) Returns the int at the specified index.
long	getLong() Returns the long at the current position and increase the position by 8.
long	getLong(int index) Returns the long at the specified index.
short	getShort() Returns the short at the current position and increase the position by 2.
short	getShort(int index) Returns the short at the specified index.
boolean	isAddressValid()
boolean	isDirect() Returns true if this buffer is direct.
protected byte[]	protectedArray() Child class implements this method to realize array().
protected int	protectedArrayOffset() Child class implements this method to realize arrayOffset().
protected boolean	protectedHasArray() Child class implements this method to realize hasArray().

Methods inherited from class java.nio.BaseByteBuffer

asCharBuffer, asDoubleBuffer, asFloatBuffer, asIntBuffer, asLongBuffer, asShortBuffer, getChar, getChar, putChar, putChar

Methods inherited from class java.nio.ByteBuffer

_array, _arrayOffset, allocate, allocateDirect, array, arrayOffset, asReadOnlyBuffer, compact, compareTo, duplicate, equals, get, hasArray, hashCode, order, order, orderImpl, put, put, put, put, put, putDouble, putDouble, putFloat, putFloat, putInt, putInt, putLong, putLong, putShort, putShort, slice, toString, wrap, wrap

Methods inherited from class java.nio.Buffer

capacity, clear, flip, hasRemaining, isReadOnly, limit, limit, mark, position, position, remaining, reset, rewind

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

safeAddress

protected final DirectByteBuffer.SafeAddress safeAddress

offset

protected final int offset

Constructor Detail

DirectByteBuffer

DirectByteBuffer(int capacity)

DirectByteBuffer

DirectByteBuffer(DirectByteBuffer.SafeAddress address,
                 int capacity,
                 int offset)

Method Detail

get

public final ByteBuffer get(byte[] dest,
                            int off,
                            int len)

Description copied from class: ByteBuffer

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

Overrides:

get in class ByteBuffer

Parameters:

dest - The target byte array

off - The offset of the byte array, must be no less than zero and no greater than dest.length

len - The number of bytes to read, must be no less than zero and no greater than dest.length - off

Returns:

This buffer

get

public final byte get()

Description copied from class: ByteBuffer

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

Specified by:

get in class ByteBuffer

Returns:

The byte at the current position.

get

public final byte get(int index)

Description copied from class: ByteBuffer

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

Specified by:

get in class ByteBuffer

Parameters:

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

Returns:

A byte at the specified index.

getDouble

public final double getDouble()

Description copied from class: ByteBuffer

Returns the double at the current position and increase the position by 8.

The 8 bytes start from the current position are composed into a double according to current byte order and returned. The position increases by 8.

Specified by:

getDouble in class ByteBuffer

Returns:

The double at the current position.

getDouble

public final double getDouble(int index)

Description copied from class: ByteBuffer

Returns the double at the specified index.

The 8 bytes start from the specified index are composed into a double according to current byte order and returned. The position is not changed.

Specified by:

getDouble in class ByteBuffer

Parameters:

index - The index, must be no less than zero and equal or less than limit - 8

Returns:

The double at the specified index.

getFloat

public final float getFloat()

Description copied from class: ByteBuffer

Returns the float at the current position and increase the position by 4.

The 4 bytes start from the current position are composed into a float according to current byte order and returned. The position increases by 4.

Specified by:

getFloat in class ByteBuffer

Returns:

The float at the current position.

getFloat

public final float getFloat(int index)

Description copied from class: ByteBuffer

Returns the float at the specified index.

The 4 bytes start from the specified index are composed into a float according to current byte order and returned. The position is not changed.

Specified by:

getFloat in class ByteBuffer

Parameters:

index - The index, must be no less than zero and equal or less than limit - 4

Returns:

The float at the specified index.

getInt

public final int getInt()

Description copied from class: ByteBuffer

Returns the int at the current position and increase the position by 4.

The 4 bytes start from the current position are composed into a int according to current byte order and returned. The position increases by 4.

Specified by:

getInt in class ByteBuffer

Returns:

The int at the current position.

getInt

public final int getInt(int index)

Description copied from class: ByteBuffer

Returns the int at the specified index.

The 4 bytes start from the specified index are composed into a int according to current byte order and returned. The position is not changed.

Specified by:

getInt in class ByteBuffer

Parameters:

index - The index, must be no less than zero and equal or less than limit - 4

Returns:

The int at the specified index.

getLong

public final long getLong()

Description copied from class: ByteBuffer

Returns the long at the current position and increase the position by 8.

The 8 bytes start from the current position are composed into a long according to current byte order and returned. The position increases by 8.

Specified by:

getLong in class ByteBuffer

Returns:

The long at the current position.

getLong

public final long getLong(int index)

Description copied from class: ByteBuffer

Returns the long at the specified index.

The 8 bytes start from the specified index are composed into a long according to current byte order and returned. The position is not changed.

Specified by:

getLong in class ByteBuffer

Parameters:

index - The index, must be no less than zero and equal or less than limit - 8

Returns:

The long at the specified index.

getShort

public final short getShort()

Description copied from class: ByteBuffer

Returns the short at the current position and increase the position by 2.

The 2 bytes start from the current position are composed into a short according to current byte order and returned. The position increases by 2.

Specified by:

getShort in class ByteBuffer

Returns:

The short at the current position.

getShort

public final short getShort(int index)

Description copied from class: ByteBuffer

Returns the short at the specified index.

The 2 bytes start from the specified index are composed into a short according to current byte order and returned. The position is not changed.

Specified by:

getShort in class ByteBuffer

Parameters:

index - The index, must be no less than zero and equal or less than limit - 2

Returns:

The short at the specified index.

isDirect

public final boolean isDirect()

Description copied from class: ByteBuffer

Returns true if this buffer is direct.

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

Specified by:

isDirect in class ByteBuffer

Returns:

True if this buffer is direct.

isAddressValid

public final boolean isAddressValid()

Specified by:

isAddressValid in interface org.apache.harmony.nio.internal.DirectBuffer

addressValidityCheck

public final void addressValidityCheck()

Specified by:

addressValidityCheck in interface org.apache.harmony.nio.internal.DirectBuffer

getBaseAddress

public final org.apache.harmony.luni.platform.PlatformAddress getBaseAddress()

Specified by:

getBaseAddress in interface org.apache.harmony.nio.internal.DirectBuffer

getEffectiveAddress

public final org.apache.harmony.luni.platform.PlatformAddress getEffectiveAddress()

Returns the platform address of the start of this buffer instance. You must not attempt to free the returned address!! It may not be an address that was explicitly malloc'ed (i.e. if this buffer is the result of a split); and it may be memory shared by multiple buffers.

If you can guarantee that you want to free the underlying memory call the #free() method on this instance -- generally applications will rely on the garbage collector to autofree this memory.

Specified by:

getEffectiveAddress in interface org.apache.harmony.nio.internal.DirectBuffer

Returns:

the effective address of the start of the buffer.

Throws:

IllegalStateException - if this buffer address is known to have been freed previously.

free

public final void free()

Explicitly free the memory used by this direct byte buffer. If the memory has already been freed then this is a no-op. Once the memory has been freed then operations requiring access to the memory will throw an IllegalStateException.

Note this is is possible that the memory is freed by code that reaches into the address and explicitly frees it 'beneith' us -- this is bad form.

Specified by:

free in interface org.apache.harmony.nio.internal.DirectBuffer

protectedArray

protected final byte[] protectedArray()

Description copied from class: ByteBuffer

Child class implements this method to realize array().

Specified by:

protectedArray in class ByteBuffer

Returns:

see array()

protectedArrayOffset

protected final int protectedArrayOffset()

Description copied from class: ByteBuffer

Child class implements this method to realize arrayOffset().

Specified by:

protectedArrayOffset in class ByteBuffer

Returns:

see arrayOffset()

protectedHasArray

protected final boolean protectedHasArray()

Description copied from class: ByteBuffer

Child class implements this method to realize hasArray().

Specified by:

protectedHasArray in class ByteBuffer

Returns:

see hasArray()

getByteCapacity

public final int getByteCapacity()

Specified by:

getByteCapacity in interface org.apache.harmony.nio.internal.DirectBuffer