uk.ac.starlink.util

Class GenericNioBuffer

java.lang.Object

uk.ac.starlink.util.GenericNioBuffer

public class GenericNioBuffer
extends java.lang.Object

Convenience class which wraps one of the NIO <Type>Buffer classes to provide generic functionality. Using this class merely allows one to invoke some of the methods which are defined on all the specific buffer types but not on the Buffer superclass itself without a lot of pesky typecasting.

Constructor Summary

Constructors

Constructor and Description
GenericNioBuffer(java.nio.Buffer buf) Construct a GenericNioBuffer based on an existing Buffer.

Method Summary

Modifier and Type	Method and Description
java.lang.Object	array() Returns the primitive 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).
java.nio.Buffer	duplicate() Creates a new buffer that shares this buffer's content.
void	get(java.lang.Object dst) Generic relative bulk get method.
void	get(java.lang.Object dst, int offset, int length) Generic relative bulk get method.
java.nio.Buffer	getBuffer() Returns the buffer object on which this generic buffer is based.
java.lang.Class<?>	getElementClass() Returns the class object of the primitive type that the buffer holds.
boolean	hasArray() Tells whether or not this buffer is backed by an accessible primitive array.
void	put(java.lang.Object src) Generic relative bulk put method.
void	put(java.lang.Object src, int offset, int length) Generic relative bulk put method.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

GenericNioBuffer

public GenericNioBuffer(java.nio.Buffer buf)

Construct a GenericNioBuffer based on an existing Buffer.

Parameters:

buf - the NIO buffer

Method Detail

getBuffer

public java.nio.Buffer getBuffer()

Returns the buffer object on which this generic buffer is based.

Returns:

the buffer set at construction

get

public void get(java.lang.Object dst)

Generic relative bulk get method. Fils a given destination array with primitives transferred from this buffer.

Parameters:

dst - an array of primitives matching the type of the nio Buffer

See Also:

DoubleBuffer.get(double[])

get

public void get(java.lang.Object dst,
                int offset,
                int length)

Generic relative bulk get method. Transfers a given number of primitives from this buffer into the given destination array starting at a given offset into the array.

Parameters:

dst - an array of primitives matching the type of the nio Buffer

offset - the offset within the array of the first primitive to be written

length - the number of primitives to be transferred

See Also:

DoubleBuffer.get(double[],int,int)

put

public void put(java.lang.Object src)

Generic relative bulk put method. Transfers the entire content of the given source array into this buffer.

Parameters:

src - an array of primitives matching the type of the nio Buffer

See Also:

DoubleBuffer.put(double[])

put

public void put(java.lang.Object src,
                int offset,
                int length)

Generic relative bulk put method. Transfers a given number of primitives from the given source array starting at a given point into this buffer.

Parameters:

src - an array of primitives matching the type of the nio Buffer

offset - the offset within the array of the first primitive to be read

length - the number of primitives to tranfer

See Also:

DoubleBuffer.put(double[],int,int)

duplicate

public java.nio.Buffer duplicate()

Creates a new 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 buffer. Note it is a java.nio.Buffer and not a copy of this GenericNioBuffer

See Also:

DoubleBuffer.duplicate()

hasArray

public boolean hasArray()

Tells whether or not this buffer is backed by an accessible primitive 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

See Also:

DoubleBuffer.hasArray()

array

public java.lang.Object array()

Returns the primitive 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:

java.nio.ReadOnlyBufferException - if this buffer is backed by an array but is read-only

java.lang.UnsupportedOperationException - if this buffer is not backed by an accessible array

arrayOffset

public 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:

java.nio.ReadOnlyBufferException - if this buffer is backed by an array but is read-only

java.lang.UnsupportedOperationException - if this buffer is not backed by an accessible array

getElementClass

public java.lang.Class<?> getElementClass()

Returns the class object of the primitive type that the buffer holds. Thus double.class is returned if the base buffer is a DoubleBuffer etc.

Returns:

the class of the primitive elements that this buffer holds