public abstract class DoubleBuffer extends Buffer implements Comparable<DoubleBuffer>
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.
| Modifier and Type | Method and Description |
|---|---|
static DoubleBuffer |
allocate(int capacity)
Allocates a new double buffer.
|
double[] |
array()
Returns the double array that backs this
buffer (optional operation).
|
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)
Relative bulk get method.
|
DoubleBuffer |
get(double[] dst,
int offset,
int length)
Relative bulk get method.
|
abstract double |
get(int index)
Absolute get method.
|
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.
|
abstract DoubleBuffer |
put(double d)
Relative put method (optional operation).
|
DoubleBuffer |
put(double[] src)
Relative bulk put method (optional operation).
|
DoubleBuffer |
put(double[] src,
int offset,
int length)
Relative bulk put method (optional operation).
|
DoubleBuffer |
put(DoubleBuffer 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.
|
public static DoubleBuffer allocate(int capacity)
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.
capacity - The new buffer's capacity, in doublesIllegalArgumentException - If the capacity is a negative integerpublic static DoubleBuffer wrap(double[] array, int offset, int length)
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.
array - The array that will back the new bufferoffset - 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 - 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.IndexOutOfBoundsException - If the preconditions on the offset and length
parameters do not holdpublic static DoubleBuffer wrap(double[] array)
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.
array - The array that will back this bufferpublic abstract DoubleBuffer slice()
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.
public abstract DoubleBuffer duplicate()
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.
public abstract DoubleBuffer asReadOnlyBuffer()
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.
public abstract double get()
BufferUnderflowException - If the buffer's current position is not smaller than its limitpublic abstract DoubleBuffer put(double d)
Writes the given double into this buffer at the current position, and then increments the position.
d - The double to be writtenBufferOverflowException - If this buffer's current position is not smaller than its limitReadOnlyBufferException - If this buffer is read-onlypublic abstract double get(int index)
index - The index from which the double will be readIndexOutOfBoundsException - If index is negative
or not smaller than the buffer's limitpublic abstract DoubleBuffer put(int index, double d)
Writes the given double into this buffer at the given index.
index - The index at which the double will be writtend - The double value to be writtenIndexOutOfBoundsException - If index is negative
or not smaller than the buffer's limitReadOnlyBufferException - If this buffer is read-onlypublic DoubleBuffer get(double[] dst, int offset, int length)
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():
dst - The array into which doubles are to be writtenoffset - The offset within the array of the first double to be
written; must be non-negative and no larger than
dst.lengthlength - The maximum number of doubles to be written to the given
array; must be non-negative and no larger than
dst.length - offsetBufferUnderflowException - If there are fewer than length doubles
remaining in this bufferIndexOutOfBoundsException - If the preconditions on the offset and length
parameters do not holdpublic DoubleBuffer get(double[] dst)
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) dst - The destination arrayBufferUnderflowException - If there are fewer than length doubles
remaining in this bufferpublic DoubleBuffer put(DoubleBuffer src)
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.src - The source buffer from which doubles are to be read;
must not be this bufferBufferOverflowException - If there is insufficient space in this buffer
for the remaining doubles in the source bufferIllegalArgumentException - If the source buffer is this bufferReadOnlyBufferException - If this buffer is read-onlypublic DoubleBuffer put(double[] src, int offset, int length)
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]);
src - The array from which doubles are to be readoffset - The offset within the array of the first double to be read;
must be non-negative and no larger than array.lengthlength - The number of doubles to be read from the given array;
must be non-negative and no larger than
array.length - offsetBufferOverflowException - If there is insufficient space in this bufferIndexOutOfBoundsException - If the preconditions on the offset and length
parameters do not holdReadOnlyBufferException - If this buffer is read-onlypublic final DoubleBuffer put(double[] src)
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) src - The source arrayBufferOverflowException - If there is insufficient space in this bufferReadOnlyBufferException - If this buffer is read-onlypublic final boolean hasArray()
If this method returns true then the array
and arrayOffset methods may safely be invoked.
public final double[] array()
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.
array in class BufferReadOnlyBufferException - If this buffer is backed by an array but is read-onlyUnsupportedOperationException - If this buffer is not backed by an accessible arraypublic final int arrayOffset()
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.
arrayOffset in class BufferReadOnlyBufferException - If this buffer is backed by an array but is read-onlyUnsupportedOperationException - If this buffer is not backed by an accessible arraypublic abstract DoubleBuffer compact()
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.
ReadOnlyBufferException - If this buffer is read-onlypublic abstract boolean isDirect()
public String toString()
public int hashCode()
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.
hashCode in class ObjectObject.equals(java.lang.Object),
System.identityHashCode(java.lang.Object)public boolean equals(Object ob)
Two double buffers are equal if, and only if,
They have the same element type,
They have the same number of remaining elements, and
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 Double.equals(Object).
A double buffer is not equal to any other type of object.
equals in class Objectob - The object to which this buffer is to be comparedObject.hashCode(),
HashMappublic int compareTo(DoubleBuffer that)
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
Double.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.
compareTo in interface Comparable<DoubleBuffer>that - the object to be compared.public abstract ByteOrder 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.
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