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Copyright © 2007 Sun Microsystems, Inc. All rights reserved.

java.nio
Class IntBuffer

java.lang.Object
  java.nio.Buffer
      java.nio.IntBuffer

All Implemented Interfaces:

Comparable

public abstract class IntBuffer

extends Buffer

implements Comparable

An int buffer.

This class is provided as part of the JSR 239 NIO Buffer building block. It is a subset of the java.nio.IntBuffer class in Java(TM) Standard Edition version 1.4.2. Differences are noted in bold italic. The class documentation may make reference to classes that are not present in the building block.

I/O channels, marking and resetting, and read-only buffers are not supported. Allocation of non-direct int buffers, compaction, and duplication are not supported. The following methods are omitted:

• IntBuffer allocate(int capacity)
• IntBuffer compact()
• IntBuffer duplicate()
• Buffer mark()
• Buffer reset()
• boolean isReadOnly()
• IntBuffer asReadOnlyBuffer()

This class defines four categories of operations upon int buffers:

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

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

• Relative bulk put methods that transfer contiguous sequences of ints from an int array or some other int buffer into this buffer; and

• Methods for compacting, duplicating, and slicing an int buffer. JSR 239 does not support compacting and duplicating buffers.

Int buffers can be created either by allocation, which allocates space for the buffer's content, by wrapping an existing int array into a buffer, or by creating a view of an existing byte buffer. JSR 239 supports allocation of ByteBuffers only.

Like a byte buffer, an int buffer is either direct or non-direct. A int buffer created via the wrap methods of this class will be non-direct. An int 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 an int 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.

Method Summary

int[]	array() Returns the int 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).
int	compareTo(java.lang.Object ob) Compares this buffer to another.
boolean	equals(java.lang.Object ob) Tells whether or not this buffer is equal to another object.
abstract int	get() Relative get method.
abstract int	get(int index) Absolute get method.
IntBuffer	get(int[] dst) Relative bulk get method.
IntBuffer	get(int[] dst, int offset, int length) Relative bulk get method.
boolean	hasArray() Tells whether or not this buffer is backed by an accessible int array.
int	hashCode() Returns the current hash code of this buffer.
abstract boolean	isDirect() Tells whether or not this int buffer is direct.
abstract IntBuffer	put(int i) Relative put method (optional operation).
IntBuffer	put(int[] src) Relative bulk put method (optional operation).
IntBuffer	put(int[] src, int offset, int length) Relative bulk put method (optional operation).
IntBuffer	put(IntBuffer src) Relative bulk put method (optional operation).
abstract IntBuffer	put(int index, int i) Absolute put method (optional operation).
abstract IntBuffer	slice() Creates a new int buffer whose content is a shared subsequence of this buffer's content.
java.lang.String	toString() Returns a string summarizing the state of this buffer.
static IntBuffer	wrap(int[] array) Wraps an int array into a buffer.
static IntBuffer	wrap(int[] array, int offset, int length) Wraps an int array into a buffer.

Methods inherited from class java.nio.Buffer

capacity, clear, flip, hasRemaining, limit, limit, position, position, remaining, rewind

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Method Detail

wrap

public static IntBuffer wrap(int[] array,
                             int offset,
                             int length)

Wraps an int array into a buffer.

The new buffer will be backed by the given int 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 - The array that will back the new buffer

offset - 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.

Returns:

The new int buffer

Throws:

java.lang.IndexOutOfBoundsException - If the preconditions on the offset and length parameters do not hold

wrap

public static IntBuffer wrap(int[] array)

Wraps an int array into a buffer.

The new buffer will be backed by the given int 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 - The array that will back this buffer

Returns:

The new int buffer

slice

public abstract IntBuffer slice()

Creates a new int 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. JSR 239 does not support the mark.

The new buffer's position will be zero, its capacity and its limit will be the number of ints 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. JSR 239 does not support the mark or read-only buffers.

Returns:

The new int buffer.

get

public abstract int get()

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

Returns:

The int at the buffer's current position.

Throws:

BufferUnderflowException - If the buffer's current position is not smaller than its limit.

put

public abstract IntBuffer put(int i)

Relative put method (optional operation).

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

Parameters:

i - The int to be written.

Returns:

This buffer.

Throws:

BufferOverflowException - If this buffer's current position is not smaller than its limit.

ReadOnlyBufferException - If this buffer is read-only. JSR 239 does not support read-only buffer or the ReadOnlyBufferException class.

get

public abstract int get(int index)

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

Parameters:

index - The index from which the int will be read.

Returns:

The int at the given index.

Throws:

java.lang.IndexOutOfBoundsException - If index is negative or not smaller than the buffer's limit.

put

public abstract IntBuffer put(int index,
                              int i)

Absolute put method (optional operation).

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

Parameters:

index - The index at which the int will be written.

i - The int value to be written.

Returns:

This buffer.

Throws:

java.lang.IndexOutOfBoundsException - If index is negative or not smaller than the buffer's limit.

ReadOnlyBufferException - If this buffer is read-only. JSR 239 does not support read-only buffer or the ReadOnlyBufferException class.

get

public IntBuffer get(int[] dst,
                     int offset,
                     int length)

Relative bulk get method.

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

Otherwise, this method copies length ints 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 ints in this buffer and it is potentially much more efficient.

Parameters:

dst - The array into which ints are to be written.

offset - The offset within the array of the first int to be written; must be non-negative and no larger than dst.length.

length - The maximum number of ints to be written to the given array; must be non-negative and no larger than dst.length - offset.

Returns:

This buffer.

Throws:

BufferUnderflowException - If there are fewer than dst.length ints remaining in this buffer.

java.lang.IndexOutOfBoundsException - If the preconditions on the offset and length parameters do not hold.

get

public IntBuffer get(int[] dst)

Relative bulk get method.

This method transfers ints 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) 

Returns:

This buffer.

Throws:

BufferUnderflowException - If there are fewer than length ints remaining in this buffer.

put

public IntBuffer put(IntBuffer src)

Relative bulk put method (optional operation).

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

Otherwise, this method copies n = src.remaining() ints 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 - The source buffer from which ints are to be read; must not be this buffer.

Returns:

This buffer.

Throws:

BufferOverflowException - If there is insufficient space in this buffer for the remaining ints in the source buffer.

java.lang.IllegalArgumentException - If the source buffer is this buffer.

ReadOnlyBufferException - If this buffer is read-only. JSR 239 does not support read-only buffer or the ReadOnlyBufferException class.

put

public IntBuffer put(int[] src,
                     int offset,
                     int length)

Relative bulk put method (optional operation).

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

Otherwise, this method copies length ints 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 - The array from which ints are to be read.

offset - The offset within the array of the first int to be read; must be non-negative and no larger than array.length.

length - The number of ints to be read from the given array; must be non-negative and no larger than array.length - offset.

Returns:

This buffer.

Throws:

BufferOverflowException - If there is insufficient space in this buffer.

java.lang.IndexOutOfBoundsException - If the preconditions on the offset and length parameters do not hold.

ReadOnlyBufferException - If this buffer is read-only. JSR 239 does not support read-only buffer or the ReadOnlyBufferException class.

put

public final IntBuffer put(int[] src)

Relative bulk put method (optional operation).

This method transfers the entire content of the given source int 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) 

Returns:

This buffer.

Throws:

BufferOverflowException - If there is insufficient space in this buffer.

ReadOnlyBufferException - If this buffer is read-only. JSR 239 does not support read-only buffer or the ReadOnlyBufferException class.

hasArray

public final boolean hasArray()

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

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

Returns:

true if, and only if, this buffer is backed by an array and is not read-only. JSR 239 does not support read-only buffers.

array

public final int[] array()

Returns the int 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:

The array that backs this buffer.

Throws:

ReadOnlyBufferException - If this buffer is read-only. JSR 239 does not support read-only buffer or the ReadOnlyBufferException class.

UnsupportedOperationException - If this buffer is not backed by an accessible array.

arrayOffset

public final 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:

The offset within this buffer's array of the first element of the buffer.

Throws:

ReadOnlyBufferException - If this buffer is read-only. JSR 239 does not support read-only buffer or the ReadOnlyBufferException class.

UnsupportedOperationException - If this buffer is not backed by an accessible array.

isDirect

public abstract boolean isDirect()

Tells whether or not this int buffer is direct.

Returns:

true if, and only if, this buffer is direct.

toString

public java.lang.String toString()

Returns a string summarizing the state of this buffer.

Returns:

A summary string

hashCode

public int hashCode()

Returns the current hash code of this buffer.

The hash code of an int 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:

The current hash code of this buffer

See Also:

Object.equals(java.lang.Object), Hashtable

equals

public boolean equals(java.lang.Object ob)

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

Two int 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.

An int buffer is not equal to any other type of object.

Parameters:

ob - The object to which this buffer is to be compared.

Returns:

true if, and only if, this buffer is equal to the given object.

See Also:

Boolean.hashCode(), Hashtable

compareTo

public int compareTo(java.lang.Object ob)

Compares this buffer to another.

Two int buffers are compared by comparing their sequences of remaining elements lexicographically, without regard to the starting position of each sequence within its corresponding buffer.

An int buffer is not comparable to any other type of object.

Specified by:

compareTo in interface Comparable

Parameters:

ob - the Object to be compared.

Returns:

A negative integer, zero, or a positive integer as this buffer is less than, equal to, or greater than the given buffer.

Throws:

java.lang.ClassCastException - If the argument is not an int buffer.