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DoubleBuffer

public abstract class DoubleBuffer
extends Buffer implements Comparable<DoubleBuffer>

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


A double buffer.

This class defines four categories of operations upon double buffers:

  • Absolute and relative get and put methods that read and write single doubles;

  • Relative bulk get methods that transfer contiguous sequences of doubles from this buffer into an array; and

  • Relative bulk put methods that transfer contiguous sequences of doubles from a double array or some other double buffer into this buffer; and

  • Methods for compacting, duplicating, and slicing a double buffer.

Double buffers can be created either by allocation, which allocates space for the buffer's content, by wrapping an existing double array into a buffer, or by creating a view of an existing byte buffer.

Like a byte buffer, a double buffer is either direct or non-direct. A double buffer created via the wrap methods of this class will be non-direct. A double buffer created as a view of a byte buffer will be direct if, and only if, the byte buffer itself is direct. Whether or not a double buffer is direct may be determined by invoking the isDirect method.

Methods in this class that do not otherwise have a value to return are specified to return the buffer upon which they are invoked. This allows method invocations to be chained.

Summary

Public methods

static DoubleBuffer allocate(int capacity)

Allocates a new double buffer.

final double[] array()

Returns the double array that backs this buffer  (optional operation).

final int arrayOffset()

Returns the offset within this buffer's backing array of the first element of the buffer  (optional operation).

abstract DoubleBuffer asReadOnlyBuffer()

Creates a new, read-only double buffer that shares this buffer's content.

abstract DoubleBuffer compact()

Compacts this buffer  (optional operation).

int compareTo(DoubleBuffer that)

Compares this buffer to another.

abstract DoubleBuffer duplicate()

Creates a new double buffer that shares this buffer's content.

boolean equals(Object ob)

Tells whether or not this buffer is equal to another object.

abstract double get()

Relative get method.

DoubleBuffer get(double[] dst, int offset, int length)

Relative bulk get method.

DoubleBuffer get(double[] dst)

Relative bulk get method.

abstract double get(int index)

Absolute get method.

final boolean hasArray()

Tells whether or not this buffer is backed by an accessible double array.

int hashCode()

Returns the current hash code of this buffer.

abstract boolean isDirect()

Tells whether or not this double buffer is direct.

abstract ByteOrder order()

Retrieves this buffer's byte order.

DoubleBuffer put(DoubleBuffer src)

Relative bulk put method  (optional operation).

DoubleBuffer put(double[] src, int offset, int length)

Relative bulk put method  (optional operation).

abstract DoubleBuffer put(double d)

Relative put method  (optional operation).

final DoubleBuffer put(double[] src)

Relative bulk put method  (optional operation).

abstract DoubleBuffer put(int index, double d)

Absolute put method  (optional operation).

abstract DoubleBuffer slice()

Creates a new double buffer whose content is a shared subsequence of this buffer's content.

String toString()

Returns a string summarizing the state of this buffer.

static DoubleBuffer wrap(double[] array)

Wraps a double array into a buffer.

static DoubleBuffer wrap(double[] array, int offset, int length)

Wraps a double array into a buffer.

Inherited methods

From class java.nio.Buffer
From class java.lang.Object
From interface java.lang.Comparable

Public methods

allocate

Added in API level 1
DoubleBuffer allocate (int capacity)

Allocates a new double buffer.

The new buffer's position will be zero, its limit will be its capacity, its mark will be undefined, and each of its elements will be initialized to zero. It will have a backing array, and its array offset will be zero.

Parameters
capacity int: The new buffer's capacity, in doubles
Returns
DoubleBuffer The new double buffer
Throws
IllegalArgumentException If the capacity is a negative integer

array

Added in API level 1
double[] array ()

Returns the double array that backs this buffer  (optional operation).

Modifications to this buffer's content will cause the returned array's content to be modified, and vice versa.

Invoke the hasArray method before invoking this method in order to ensure that this buffer has an accessible backing array.

Returns
double[] The array that backs this buffer
Throws
ReadOnlyBufferException If this buffer is backed by an array but is read-only
UnsupportedOperationException If this buffer is not backed by an accessible array

arrayOffset

Added in API level 1
int arrayOffset ()

Returns the offset within this buffer's backing array of the first element of the buffer  (optional operation).

If this buffer is backed by an array then buffer position p corresponds to array index p + arrayOffset().

Invoke the hasArray method before invoking this method in order to ensure that this buffer has an accessible backing array.

Returns
int The offset within this buffer's array of the first element of the buffer
Throws
ReadOnlyBufferException If this buffer is backed by an array but is read-only
UnsupportedOperationException If this buffer is not backed by an accessible array

asReadOnlyBuffer

Added in API level 1
DoubleBuffer asReadOnlyBuffer ()

Creates a new, read-only double buffer that shares this buffer's content.

The content of the new buffer will be that of this buffer. Changes to this buffer's content will be visible in the new buffer; the new buffer itself, however, will be read-only and will not allow the shared content to be modified. The two buffers' position, limit, and mark values will be independent.

The new buffer's capacity, limit, position, and mark values will be identical to those of this buffer.

If this buffer is itself read-only then this method behaves in exactly the same way as the duplicate method.

Returns
DoubleBuffer The new, read-only double buffer

compact

Added in API level 1
DoubleBuffer compact ()

Compacts this buffer  (optional operation).

The doubles between the buffer's current position and its limit, if any, are copied to the beginning of the buffer. That is, the double at index p = position() is copied to index zero, the double at index p + 1 is copied to index one, and so forth until the double at index limit() - 1 is copied to index n = limit() - 1 - p. The buffer's position is then set to n+1 and its limit is set to its capacity. The mark, if defined, is discarded.

The buffer's position is set to the number of doubles copied, rather than to zero, so that an invocation of this method can be followed immediately by an invocation of another relative put method.

Returns
DoubleBuffer This buffer
Throws
ReadOnlyBufferException If this buffer is read-only

compareTo

Added in API level 1
int compareTo (DoubleBuffer that)

Compares this buffer to another.

Two double buffers are compared by comparing their sequences of remaining elements lexicographically, without regard to the starting position of each sequence within its corresponding buffer. Pairs of double elements are compared as if by invoking compare(double, double), except that -0.0 and 0.0 are considered to be equal. Double.NaN is considered by this method to be equal to itself and greater than all other double values (including Double.POSITIVE_INFINITY).

A double buffer is not comparable to any other type of object.

Parameters
that DoubleBuffer
Returns
int A negative integer, zero, or a positive integer as this buffer is less than, equal to, or greater than the given buffer

duplicate

Added in API level 1
DoubleBuffer duplicate ()

Creates a new double buffer that shares this buffer's content.

The content of the new buffer will be that of this buffer. Changes to this buffer's content will be visible in the new buffer, and vice versa; the two buffers' position, limit, and mark values will be independent.

The new buffer's capacity, limit, position, and mark values will be identical to those of this buffer. The new buffer will be direct if, and only if, this buffer is direct, and it will be read-only if, and only if, this buffer is read-only.

Returns
DoubleBuffer The new double buffer

equals

Added in API level 1
boolean equals (Object ob)

Tells whether or not this buffer is equal to another object.

Two double buffers are equal if, and only if,

  1. They have the same element type,

  2. They have the same number of remaining elements, and

  3. The two sequences of remaining elements, considered independently of their starting positions, are pointwise equal. This method considers two double elements a and b to be equal if (a == b) || (Double.isNaN(a) && Double.isNaN(b)). The values -0.0 and +0.0 are considered to be equal, unlike equals(Object).

A double buffer is not equal to any other type of object.

Parameters
ob Object: The object to which this buffer is to be compared
Returns
boolean true if, and only if, this buffer is equal to the given object

get

Added in API level 1
double get ()

Relative get method. Reads the double at this buffer's current position, and then increments the position.

Returns
double The double at the buffer's current position
Throws
BufferUnderflowException If the buffer's current position is not smaller than its limit

get

Added in API level 1
DoubleBuffer get (double[] dst, 
                int offset, 
                int length)

Relative bulk get method.

This method transfers doubles from this buffer into the given destination array. If there are fewer doubles remaining in the buffer than are required to satisfy the request, that is, if length > remaining(), then no doubles are transferred and a BufferUnderflowException is thrown.

Otherwise, this method copies length doubles from this buffer into the given array, starting at the current position of this buffer and at the given offset in the array. The position of this buffer is then incremented by length.

In other words, an invocation of this method of the form src.get(dst, off, len) has exactly the same effect as the loop

     for (int i = off; i < off + len; i++)
         dst[i] = src.get(); 
except that it first checks that there are sufficient doubles in this buffer and it is potentially much more efficient.

Parameters
dst double: The array into which doubles are to be written
offset int: The offset within the array of the first double to be written; must be non-negative and no larger than dst.length
length int: The maximum number of doubles to be written to the given array; must be non-negative and no larger than dst.length - offset
Returns
DoubleBuffer This buffer
Throws
BufferUnderflowException If there are fewer than length doubles remaining in this buffer
IndexOutOfBoundsException If the preconditions on the offset and length parameters do not hold

get

Added in API level 1
DoubleBuffer get (double[] dst)

Relative bulk get method.

This method transfers doubles from this buffer into the given destination array. An invocation of this method of the form src.get(a) behaves in exactly the same way as the invocation

     src.get(a, 0, a.length) 

Parameters
dst double
Returns
DoubleBuffer This buffer
Throws
BufferUnderflowException If there are fewer than length doubles remaining in this buffer

get

Added in API level 1
double get (int index)

Absolute get method. Reads the double at the given index.

Parameters
index int: The index from which the double will be read
Returns
double The double at the given index
Throws
IndexOutOfBoundsException If index is negative or not smaller than the buffer's limit

hasArray

Added in API level 1
boolean hasArray ()

Tells whether or not this buffer is backed by an accessible double array.

If this method returns true then the array and arrayOffset methods may safely be invoked.

Returns
boolean true if, and only if, this buffer is backed by an array and is not read-only

hashCode

Added in API level 1
int hashCode ()

Returns the current hash code of this buffer.

The hash code of a double buffer depends only upon its remaining elements; that is, upon the elements from position() up to, and including, the element at limit() - 1.

Because buffer hash codes are content-dependent, it is inadvisable to use buffers as keys in hash maps or similar data structures unless it is known that their contents will not change.

Returns
int The current hash code of this buffer

isDirect

Added in API level 1
boolean isDirect ()

Tells whether or not this double buffer is direct.

Returns
boolean true if, and only if, this buffer is direct

order

Added in API level 1
ByteOrder order ()

Retrieves this buffer's byte order.

The byte order of a double buffer created by allocation or by wrapping an existing double array is the native order of the underlying hardware. The byte order of a double buffer created as a view of a byte buffer is that of the byte buffer at the moment that the view is created.

Returns
ByteOrder This buffer's byte order

put

Added in API level 1
DoubleBuffer put (DoubleBuffer src)

Relative bulk put method  (optional operation).

This method transfers the doubles remaining in the given source buffer into this buffer. If there are more doubles remaining in the source buffer than in this buffer, that is, if src.remaining() > remaining(), then no doubles are transferred and a BufferOverflowException is thrown.

Otherwise, this method copies n = src.remaining() doubles from the given buffer into this buffer, starting at each buffer's current position. The positions of both buffers are then incremented by n.

In other words, an invocation of this method of the form dst.put(src) has exactly the same effect as the loop

     while (src.hasRemaining())
         dst.put(src.get()); 
except that it first checks that there is sufficient space in this buffer and it is potentially much more efficient.

Parameters
src DoubleBuffer: The source buffer from which doubles are to be read; must not be this buffer
Returns
DoubleBuffer This buffer
Throws
BufferOverflowException If there is insufficient space in this buffer for the remaining doubles in the source buffer
IllegalArgumentException If the source buffer is this buffer
ReadOnlyBufferException If this buffer is read-only

put

Added in API level 1
DoubleBuffer put (double[] src, 
                int offset, 
                int length)

Relative bulk put method  (optional operation).

This method transfers doubles into this buffer from the given source array. If there are more doubles to be copied from the array than remain in this buffer, that is, if length > remaining(), then no doubles are transferred and a BufferOverflowException is thrown.

Otherwise, this method copies length doubles from the given array into this buffer, starting at the given offset in the array and at the current position of this buffer. The position of this buffer is then incremented by length.

In other words, an invocation of this method of the form dst.put(src, off, len) has exactly the same effect as the loop

     for (int i = off; i < off + len; i++)
         dst.put(a[i]); 
except that it first checks that there is sufficient space in this buffer and it is potentially much more efficient.

Parameters
src double: The array from which doubles are to be read
offset int: The offset within the array of the first double to be read; must be non-negative and no larger than array.length
length int: The number of doubles to be read from the given array; must be non-negative and no larger than array.length - offset
Returns
DoubleBuffer This buffer
Throws
BufferOverflowException If there is insufficient space in this buffer
IndexOutOfBoundsException If the preconditions on the offset and length parameters do not hold
ReadOnlyBufferException If this buffer is read-only

put

Added in API level 1
DoubleBuffer put (double d)

Relative put method  (optional operation).

Writes the given double into this buffer at the current position, and then increments the position.

Parameters
d double: The double to be written
Returns
DoubleBuffer This buffer
Throws
BufferOverflowException If this buffer's current position is not smaller than its limit
ReadOnlyBufferException If this buffer is read-only

put

Added in API level 1
DoubleBuffer put (double[] src)

Relative bulk put method  (optional operation).

This method transfers the entire content of the given source double array into this buffer. An invocation of this method of the form dst.put(a) behaves in exactly the same way as the invocation

     dst.put(a, 0, a.length) 

Parameters
src double
Returns
DoubleBuffer This buffer
Throws
BufferOverflowException If there is insufficient space in this buffer
ReadOnlyBufferException If this buffer is read-only

put

Added in API level 1
DoubleBuffer put (int index, 
                double d)

Absolute put method  (optional operation).

Writes the given double into this buffer at the given index.

Parameters
index int: The index at which the double will be written
d double: The double value to be written
Returns
DoubleBuffer This buffer
Throws
IndexOutOfBoundsException If index is negative or not smaller than the buffer's limit
ReadOnlyBufferException If this buffer is read-only

slice

Added in API level 1
DoubleBuffer slice ()

Creates a new double buffer whose content is a shared subsequence of this buffer's content.

The content of the new buffer will start at this buffer's current position. Changes to this buffer's content will be visible in the new buffer, and vice versa; the two buffers' position, limit, and mark values will be independent.

The new buffer's position will be zero, its capacity and its limit will be the number of doubles remaining in this buffer, and its mark will be undefined. The new buffer will be direct if, and only if, this buffer is direct, and it will be read-only if, and only if, this buffer is read-only.

Returns
DoubleBuffer The new double buffer

toString

Added in API level 1
String toString ()

Returns a string summarizing the state of this buffer.

Returns
String A summary string

wrap

Added in API level 1
DoubleBuffer wrap (double[] array)

Wraps a double array into a buffer.

The new buffer will be backed by the given double array; that is, modifications to the buffer will cause the array to be modified and vice versa. The new buffer's capacity and limit will be array.length, its position will be zero, and its mark will be undefined. Its backing array will be the given array, and its array offset will be zero.

Parameters
array double: The array that will back this buffer
Returns
DoubleBuffer The new double buffer

wrap

Added in API level 1
DoubleBuffer wrap (double[] array, 
                int offset, 
                int length)

Wraps a double array into a buffer.

The new buffer will be backed by the given double array; that is, modifications to the buffer will cause the array to be modified and vice versa. The new buffer's capacity will be array.length, its position will be offset, its limit will be offset + length, and its mark will be undefined. Its backing array will be the given array, and its array offset will be zero.

Parameters
array double: The array that will back the new buffer
offset int: The offset of the subarray to be used; must be non-negative and no larger than array.length. The new buffer's position will be set to this value.
length int: The length of the subarray to be used; must be non-negative and no larger than array.length - offset. The new buffer's limit will be set to offset + length.
Returns
DoubleBuffer The new double buffer
Throws
IndexOutOfBoundsException If the preconditions on the offset and length parameters do not hold
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