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IntBuffer.javaAPI DocphoneME MR2 API (J2ME)27588Wed May 02 18:00:46 BST 2007java.nio

IntBuffer

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 {@link #get() get} and {@link #put(int) put} methods that read and write single ints;

  • Relative {@link #get(int[]) bulk get} methods that transfer contiguous sequences of ints from this buffer into an array;

  • Relative {@link #put(int[]) 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 {@link #slice 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 {@link #wrap(int[]) 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 {@link #isDirect 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.

Fields Summary
ByteBufferImpl
parent
int[]
array
int
arrayOffset
boolean
isDirect
boolean
disposed
Constructors Summary
IntBuffer()
Constructs a new IntBuffer.


             
     
Methods Summary
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 {@link #hasArray hasArray} method before invoking this method in order to ensure that this buffer has an accessible backing array.

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

	if (array == null) {
	    throw new UnsupportedOperationException();
	}
	return array;
    
public final intarrayOffset()
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 {@link #hasArray hasArray} method before invoking this method in order to ensure that this buffer has an accessible backing array.

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

	if (array == null) {
	    throw new UnsupportedOperationException();
	}
	return arrayOffset;
    
public intcompareTo(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.

return
A negative integer, zero, or a positive integer as this buffer is less than, equal to, or greater than the given buffer.
throws
ClassCastException If the argument is not an int buffer.

        IntBuffer that = (IntBuffer)ob;
	int n = this.position() + Math.min(this.remaining(), that.remaining());
	for (int i = this.position(), j = that.position(); i < n; i++, j++) {
	    int v1 = this.get(i);
	    int v2 = that.get(j);
	    if (v1 == v2)
		continue;
	    if ((v1 != v1) && (v2 != v2)) 	// For float and double
		continue;
	    if (v1 < v2)
		return -1;
	    return +1;
	}
	return this.remaining() - that.remaining();
    
public booleanequals(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.

param
ob The object to which this buffer is to be compared.
return
true if, and only if, this buffer is equal to the given object.

	if (!(ob instanceof IntBuffer))
	    return false;
	IntBuffer that = (IntBuffer)ob;
	if (this.remaining() != that.remaining())
	    return false;
	int p = this.position();
	for (int i = this.limit() - 1, j = that.limit() - 1; i >= p; i--, j--) {
	    int v1 = this.get(i);
	    int v2 = that.get(j);
	    if (v1 != v2) {
		if ((v1 != v1) && (v2 != v2))	// For float and double
		    continue;
		return false;
	    }
	}
	return true;
    
public java.nio.IntBufferget(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) 

return
This buffer.
throws
BufferUnderflowException If there are fewer than length ints remaining in this buffer.

	return get(dst, 0, dst.length);
    
public abstract intget()
Relative get method. Reads the int at this buffer's current position, and then increments the position.

return
The int at the buffer's current position.
throws
BufferUnderflowException If the buffer's current position is not smaller than its limit.

public abstract intget(int index)
Absolute get method. Reads the int at the given index.

param
index The index from which the int will be read.
return
The int at the given index.
throws
IndexOutOfBoundsException If index is negative or not smaller than the buffer's limit.

public java.nio.IntBufferget(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 {@link 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.

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

        if (offset < 0 || offset > dst.length ||
            length < 0 || length > dst.length - offset) {
            throw new IndexOutOfBoundsException();
        }
        if (limit - position < length) {
            throw new BufferUnderflowException();
        }

        int bytePtr = arrayOffset + (position << 2);
	if (isDirect) {
	    ByteBufferImpl._getInts(bytePtr, dst, offset, length);
	} else if (array != null) {
	    System.arraycopy(array, arrayOffset + position,
                             dst, offset, length);
	} else {
            for (int i = 0; i < length; i++) {
                dst[offset++] = parent.getInt(bytePtr);
                bytePtr += 4;
            }
        }
	position += length;
	return this;
    
public final booleanhasArray()
Tells whether or not this buffer is backed by an accessible int array.

If this method returns true then the {@link #array() array} and {@link #arrayOffset() arrayOffset} methods may safely be invoked.

return
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.

	return array != null;
    
public inthashCode()
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.

return
The current hash code of this buffer

	int h = 1;
	int p = position();
	for (int i = limit() - 1; i >= p; i--)
	    h = 31 * h + (int)get(i);
	return h;
    
public abstract booleanisDirect()
Tells whether or not this int buffer is direct.

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

public java.nio.IntBufferput(java.nio.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 {@link 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.

param
src The source buffer from which ints are to be read; must not be this buffer.
return
This buffer.
throws
BufferOverflowException If there is insufficient space in this buffer for the remaining ints in the source buffer.
throws
IllegalArgumentException If the source buffer is this buffer.
throws
ReadOnlyBufferException If this buffer is read-only. JSR 239 does not support read-only buffer or the ReadOnlyBufferException class.

        if (src == this) {
            throw new IllegalArgumentException();
        }
	
	IntBufferImpl srci = (IntBufferImpl)src;

	int length = srci.limit - srci.position;
        if (length > this.limit - this.position) {
            throw new BufferOverflowException();
        }
	if (isDirect && srci.isDirect) {
	    ByteBufferImpl._copyBytes(srci.arrayOffset +
                                      (srci.position << 2),
                                      this.arrayOffset +
                                      (this.position << 2),
                                      (length << 2));
	} else if (isDirect && !srci.isDirect) {
            if (srci.array != null) {
                ByteBufferImpl._putInts(this.arrayOffset +
                                        (this.position << 2),
                                        srci.array,
                                        srci.arrayOffset + srci.position,
                                        length);
            } else {
                byte[] srcArray = srci.parent.array;
                int srciArrayOffset = srci.parent.arrayOffset +
                    srci.arrayOffset +
                    (srci.position << 2);
                
                ByteBufferImpl._putBytes(this.arrayOffset +
                                         (this.position << 2),
                                         srcArray,
                                         srciArrayOffset,
                                         4*length);
            }
	} else if (!isDirect && srci.isDirect) {
            if (array != null) {
                ByteBufferImpl._getInts(srci.arrayOffset +
                                        (srci.position << 2),
                                        this.array,
                                        this.arrayOffset + this.position,
                                        length);
            } else {
                byte[] dstArray = parent.array;
                int dstArrayOffset = parent.arrayOffset +
                    arrayOffset +
                    (position << 2);
                
                ByteBufferImpl._getBytes(srci.arrayOffset +
                                         (srci.position << 2),
                                         dstArray,
                                         dstArrayOffset,
                                         4*length);
            }
	} else if (!isDirect && !srci.isDirect) {
            if (array != null && srci.array != null) {
                System.arraycopy(srci.array,
                                 srci.arrayOffset + srci.position,
                                 this.array,
                                 this.arrayOffset + this.position,
                                 length);
            } else {
                for (int i = 0; i < length; i++) {
                    put(i, srci.get(i));
                }
            }
	}
	
	srci.position += length;
	this.position += length;
	return this;
    
public java.nio.IntBufferput(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 {@link 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.

param
src The array from which ints are to be read.
param
offset The offset within the array of the first int to be read; must be non-negative and no larger than array.length.
param
length The number of ints to be read from the given array; must be non-negative and no larger than array.length - offset.
return
This buffer.
throws
BufferOverflowException If there is insufficient space in this buffer.
throws
IndexOutOfBoundsException If the preconditions on the offset and length parameters do not hold.
throws
ReadOnlyBufferException If this buffer is read-only. JSR 239 does not support read-only buffer or the ReadOnlyBufferException class.

        if (offset < 0 || offset > src.length ||
            length < 0 || length > src.length - offset) {
            throw new IndexOutOfBoundsException();
        }
        if (length > limit - position) {
            throw new BufferOverflowException();
        }

        int bytePtr = arrayOffset + (position << 2);
	if (isDirect) {
	    ByteBufferImpl._putInts(bytePtr, src, offset, length);
	} else if (array != null) {
	    System.arraycopy(src, offset,
			     array, arrayOffset + position, length);
	} else {
            for (int i = 0; i < length; i++) {
                parent.putInt(bytePtr, src[offset++]);
                bytePtr += 4;
            }
        }
	position += length;
	return this;
    
public final java.nio.IntBufferput(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) 

return
This buffer.
throws
BufferOverflowException If there is insufficient space in this buffer.
throws
ReadOnlyBufferException If this buffer is read-only. JSR 239 does not support read-only buffer or the ReadOnlyBufferException class.

	return put(src, 0, src.length);
    
public abstract java.nio.IntBufferput(int i)
Relative put method  (optional operation).

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

param
i The int to be written.
return
This buffer.
throws
BufferOverflowException If this buffer's current position is not smaller than its limit.
throws
ReadOnlyBufferException If this buffer is read-only. JSR 239 does not support read-only buffer or the ReadOnlyBufferException class.

public abstract java.nio.IntBufferput(int index, int i)
Absolute put method  (optional operation).

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

param
index The index at which the int will be written.
param
i The int value to be written.
return
This buffer.
throws
IndexOutOfBoundsException If index is negative or not smaller than the buffer's limit.
throws
ReadOnlyBufferException If this buffer is read-only. JSR 239 does not support read-only buffer or the ReadOnlyBufferException class.

public abstract java.nio.IntBufferslice()
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.

return
The new int buffer.

public java.lang.StringtoString()
Returns a string summarizing the state of this buffer.

return
A summary string

        return "java.nio.IntBuffer[" +
            "pos=" + position() +
            "lim=" + limit() +
            "cap=" + capacity() +
            "]";
    
public static java.nio.IntBufferwrap(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 {@link #array backing array} will be the given array, and its {@link #arrayOffset array offset} will be zero.

param
array The array that will back the new buffer
param
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.
param
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.
return
The new int buffer
throws
IndexOutOfBoundsException If the preconditions on the offset and length parameters do not hold

        if (offset < 0 || offset > array.length ||
            length < 0 || length > array.length - offset) {
            throw new IndexOutOfBoundsException();
        }
        
        IntBufferImpl ibi =
            new IntBufferImpl(null, array.length, array, 0, false);
        ibi.position(offset);
        ibi.limit(offset + length);
        return ibi;
    
public static java.nio.IntBufferwrap(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 {@link #array backing array} will be the given array, and its {@link #arrayOffset array offset} will be zero.

param
array The array that will back this buffer
return
The new int buffer

	return wrap(array, 0, array.length);