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IntBuffer (Java Platform SE 6) - JDK 5 Documentation v6.0, Java 2 SDK 英文文档


Java™ Platform
Standard Ed. 6

java.nio
Class IntBuffer

java.lang.Object
  extended by java.nio.Buffer
      extended by java.nio.IntBuffer
All Implemented Interfaces:
Comparable<IntBuffer>

public abstract class IntBuffer
extends Buffer
implements Comparable<IntBuffer>

An int buffer.

This class defines four categories of operations upon int 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.

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.

Since:
1.4

Method Summary
static IntBuffer allocate(int capacity)
          Allocates a new int buffer.
 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).
abstract  IntBuffer asReadOnlyBuffer()
          Creates a new, read-only int buffer that shares this buffer's content.
abstract  IntBuffer compact()
          Compacts this buffer  (optional operation).
 int compareTo(IntBuffer that)
          Compares this buffer to another.
abstract  IntBuffer duplicate()
          Creates a new int buffer that shares this buffer's content.
 boolean equals(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  ByteOrder order()
          Retrieves this buffer's byte order.
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.
 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, isReadOnly, limit, limit, mark, position, position, remaining, reset, rewind
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 

Method Detail

allocate

public static IntBuffer allocate(int capacity)
Allocates a new int buffer.

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

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

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:
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.

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.

Returns:
The new int buffer

duplicate

public abstract IntBuffer duplicate()
Creates a new int 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:
The new int buffer

asReadOnlyBuffer

public abstract IntBuffer asReadOnlyBuffer()
Creates a new, read-only int 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:
The new, read-only 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

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:
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:
IndexOutOfBoundsException - If index is negative or not smaller than the buffer's limit
ReadOnlyBufferException - If this buffer is read-only

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 length ints remaining in this buffer
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
IllegalArgumentException - If the source buffer is this buffer
ReadOnlyBufferException - If this buffer is read-only

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
IndexOutOfBoundsException - If the preconditions on the offset and length parameters do not hold
ReadOnlyBufferException - If this buffer is read-only

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

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.

Specified by:
hasArray in class Buffer
Returns:
true if, and only if, this buffer is backed by an array and is not read-only

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.

Specified by:
array in class Buffer
Returns:
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

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.

Specified by:
arrayOffset in class Buffer
Returns:
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

compact

public abstract IntBuffer compact()
Compacts this buffer  (optional operation).

The ints between the buffer's current position and its limit, if any, are copied to the beginning of the buffer. That is, the int at index p = position() is copied to index zero, the int at index p + 1 is copied to index one, and so forth until the int 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 ints 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:
This buffer
Throws:
ReadOnlyBufferException - If this buffer is read-only

isDirect

public abstract boolean isDirect()
Tells whether or not this int buffer is direct.

Specified by:
isDirect in class Buffer
Returns:
true if, and only if, this buffer is direct

toString

public String toString()
Returns a string summarizing the state of this buffer.

Overrides:
toString in class Object
Returns:
A summary string

hashCode

public int hashCode()
Returns the current hash code of this buffer.

The hash code of a 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.

Overrides:
hashCode in class Object
Returns:
The current hash code of this buffer
See Also:
Object.equals(java.lang.Object), Hashtable

equals

public boolean equals(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.

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

Overrides:
equals in class 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:
Object.hashCode(), Hashtable

compareTo

public int compareTo(IntBuffer that)
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.

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

Specified by:
compareTo in interface Comparable<IntBuffer>
Parameters:
that - 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

order

public abstract ByteOrder order()
Retrieves this buffer's byte order.

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

Returns:
This buffer's byte order

Java™ Platform
Standard Ed. 6

Submit a bug or feature
For further API reference and developer documentation, see Java SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2006 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.