java.nio
Class DoubleBuffer

java.lang.Object
  java.nio.Buffer
      java.nio.DoubleBuffer

All Implemented Interfaces:

Comparable<DoubleBuffer>

Direct Known Subclasses:

DoubleArrayBuffer, DoubleToByteBufferAdapter

public abstract class DoubleBuffer
extends Buffer
implements Comparable<DoubleBuffer>

A buffer of doubles.

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

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

Field Summary

Fields inherited from class java.nio.Buffer

_elementSizeShift, capacity, limit, mark, position, UNSET_MARK

Constructor Summary

DoubleBuffer(int capacity)
Constructs a DoubleBuffer with given capacity.

Method Summary

(package private) Object	_array() Returns the array associated with this buffer, or null if none exists.
(package private) int	_arrayOffset() Returns the offset into the backing array, if one exists, otherwise 0.
static DoubleBuffer	allocate(int capacity) Creates a double buffer based on a new allocated double array.
double[]	array() Returns the double array which this buffer is based on, if there's one.
int	arrayOffset() Returns the offset of the double array which this buffer is based on, if there's one.
abstract DoubleBuffer	asReadOnlyBuffer() Returns a readonly buffer that shares content with this buffer.
abstract DoubleBuffer	compact() Compacts this double buffer.
int	compareTo(DoubleBuffer otherBuffer) Compare the remaining doubles of this buffer to another double buffer's remaining doubles.
abstract DoubleBuffer	duplicate() Returns a duplicated buffer that shares content with this buffer.
boolean	equals(Object other) Tests whether this double buffer equals to another object.
abstract double	get() Returns the double at the current position and increase the position by 1.
DoubleBuffer	get(double[] dest) Reads doubles from the current position into the specified double array and increase the position by the number of doubles read.
DoubleBuffer	get(double[] dest, int off, int len) Reads doubles from the current position into the specified double array, starting from the specified offset, and increase the position by the number of doubles read.
abstract double	get(int index) Returns a double at the specified index, and the position is not changed.
boolean	hasArray() Returns whether this buffer is based on a double array and is read/write.
int	hashCode() Hash code is calculated from the remaining doubles.
abstract boolean	isDirect() Returns true if this buffer is direct.
abstract ByteOrder	order() Returns the byte order used by this buffer when converting doubles from/to bytes.
(package private) abstract double[]	protectedArray() Child class implements this method to realize array().
(package private) abstract int	protectedArrayOffset() Child class implements this method to realize arrayOffset().
(package private) abstract boolean	protectedHasArray() Child class implements this method to realize hasArray().
abstract DoubleBuffer	put(double d) Writes the given double to the current position and increase the position by 1.
DoubleBuffer	put(double[] src) Writes doubles in the given double array to the current position and increase the position by the number of doubles written.
DoubleBuffer	put(double[] src, int off, int len) Writes doubles in the given double array, starting from the specified offset, to the current position and increase the position by the number of doubles written.
DoubleBuffer	put(DoubleBuffer src) Writes all the remaining doubles of the src double buffer to this buffer's current position, and increase both buffers' position by the number of doubles copied.
abstract DoubleBuffer	put(int index, double d) Write a double to the specified index of this buffer and the position is not changed.
abstract DoubleBuffer	slice() Returns a sliced buffer that shares content with this buffer.
String	toString() Returns a string represents the state of this double buffer.
static DoubleBuffer	wrap(double[] array) Creates a new double buffer by wrapping the given double array.
static DoubleBuffer	wrap(double[] array, int start, int len) Creates new a double buffer by wrapping the given double array.

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

Constructor Detail

DoubleBuffer

DoubleBuffer(int capacity)

Constructs a DoubleBuffer with given capacity.

Parameters:

capacity - The capacity of the buffer

Method Detail

allocate

public static DoubleBuffer allocate(int capacity)

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

Parameters:

capacity - The capacity of the new buffer

Returns:

The created double buffer

Throws:

IllegalArgumentException - If capacity is less than zero

wrap

public static DoubleBuffer wrap(double[] array)

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

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

Parameters:

array - The double array which the new buffer will be based on

Returns:

The created double buffer

wrap

public static DoubleBuffer wrap(double[] array,
                                int start,
                                int len)

Creates new a double buffer by wrapping the given double 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 double 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 double buffer

Throws:

IndexOutOfBoundsException - If either start or len is invalid

array

public final double[] array()

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

Returns:

The double 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

arrayOffset

public final int arrayOffset()

Returns the offset of the double 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 double 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

_array

Object _array()

Description copied from class: Buffer

Returns the array associated with this buffer, or null if none exists. Each typed subclass (ByteBuffer, CharBuffer, etc.) overrides this method to call its array() method with appropriate checks.

Overrides:

_array in class Buffer

Returns:

a primitive array or null

_arrayOffset

int _arrayOffset()

Description copied from class: Buffer

Returns the offset into the backing array, if one exists, otherwise 0. Each typed subclass (ByteBuffer, CharBuffer, etc.) overrides this method to call its arrayOffset() method with appropriate checks.

Overrides:

_arrayOffset in class Buffer

Returns:

the array offset, or 0

asReadOnlyBuffer

public abstract DoubleBuffer 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.

compact

public abstract DoubleBuffer compact()

Compacts this double buffer.

The remaining doubles 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

compareTo

public int compareTo(DoubleBuffer otherBuffer)

Compare the remaining doubles of this buffer to another double buffer's remaining doubles.

Specified by:

compareTo in interface Comparable<DoubleBuffer>

Parameters:

otherBuffer - Another double 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 double buffer

duplicate

public abstract DoubleBuffer 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.

equals

public boolean equals(Object other)

Tests whether this double buffer equals to another object.

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

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

Overrides:

equals in class Object

Parameters:

other - the object to be compared against

Returns:

Whether this double buffer equals to another object.

See Also:

Object.hashCode()

get

public abstract double get()

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

Returns:

The double at the current position.

Throws:

BufferUnderflowException - If the position is equal or greater than limit

get

public DoubleBuffer get(double[] dest)

Reads doubles from the current position into the specified double array and increase the position by the number of doubles read.

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

Parameters:

dest - The destination double array

Returns:

This buffer

Throws:

BufferUnderflowException - if dest.length is greater than remaining()

get

public DoubleBuffer get(double[] dest,
                        int off,
                        int len)

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

Parameters:

dest - The target double array

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

len - The number of doubles 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()

get

public abstract double get(int index)

Returns a double 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 double at the specified index.

Throws:

IndexOutOfBoundsException - If index is invalid

hasArray

public final boolean hasArray()

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

If this buffer is readonly, then false is returned.

Returns:

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

hashCode

public int hashCode()

Hash code is calculated from the remaining doubles.

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

Overrides:

hashCode in class Object

Returns:

The hash code calculated from the remaining doubles.

See Also:

Object.equals(java.lang.Object)

isDirect

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

Returns:

True if this buffer is direct.

order

public abstract ByteOrder order()

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

protectedArray

abstract double[] protectedArray()

Child class implements this method to realize array().

Returns:

see array()

protectedArrayOffset

abstract int protectedArrayOffset()

Child class implements this method to realize arrayOffset().

Returns:

see arrayOffset()

protectedHasArray

abstract boolean protectedHasArray()

Child class implements this method to realize hasArray().

Returns:

see hasArray()

put

public abstract DoubleBuffer put(double d)

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

Parameters:

d - The double 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

put

public final DoubleBuffer put(double[] src)

Writes doubles in the given double array to the current position and increase the position by the number of doubles written.

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

Parameters:

src - The source double 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

put

public DoubleBuffer put(double[] src,
                        int off,
                        int len)

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

Parameters:

src - The source double array

off - The offset of double array, must be no less than zero and no greater than src.length

len - The number of doubles 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

put

public DoubleBuffer put(DoubleBuffer src)

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

Parameters:

src - The source double 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

put

public abstract DoubleBuffer put(int index,
                                 double d)

Write a double 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

d - The double to write

Returns:

This buffer

Throws:

IndexOutOfBoundsException - If index is invalid

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

slice

public abstract DoubleBuffer 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.

toString

public String toString()

Returns a string represents the state of this double buffer.

Overrides:

toString in class Object

Returns:

A string represents the state of this double buffer.