org.apache.commons.collections

Class BufferUtils

public class BufferUtils extends Object

Provides utility methods and decorators for Buffer instances.

Since: Commons Collections 2.1

Version: $Revision: 348808 $ $Date: 2005-11-24 21:35:09 +0000 (Thu, 24 Nov 2005) $

Author: Paul Jack Stephen Colebourne

Field Summary
static BufferEMPTY_BUFFER
An empty unmodifiable buffer.
Constructor Summary
BufferUtils()
BufferUtils should not normally be instantiated.
Method Summary
static BufferblockingBuffer(Buffer buffer)
Returns a synchronized buffer backed by the given buffer that will block on get and remove operations.
static BufferblockingBuffer(Buffer buffer, long timeoutMillis)
Returns a synchronized buffer backed by the given buffer that will block on get and remove operations until timeout expires.
static BufferboundedBuffer(Buffer buffer, int maximumSize)
Returns a synchronized buffer backed by the given buffer that will block on Buffer and Buffer until enough object(s) are removed from the buffer to allow the object(s) to be added and still maintain the maximum size.
static BufferboundedBuffer(Buffer buffer, int maximumSize, long timeoutMillis)
Returns a synchronized buffer backed by the given buffer that will block on Buffer and Buffer until enough object(s) are removed from the buffer to allow the object(s) to be added and still maintain the maximum size or the timeout expires.
static BufferpredicatedBuffer(Buffer buffer, Predicate predicate)
Returns a predicated (validating) buffer backed by the given buffer.
static BuffersynchronizedBuffer(Buffer buffer)
Returns a synchronized buffer backed by the given buffer.
static BuffertransformedBuffer(Buffer buffer, Transformer transformer)
Returns a transformed buffer backed by the given buffer.
static BuffertypedBuffer(Buffer buffer, Class type)
Returns a typed buffer backed by the given buffer.
static BufferunmodifiableBuffer(Buffer buffer)
Returns an unmodifiable buffer backed by the given buffer.

Field Detail

EMPTY_BUFFER

public static final Buffer EMPTY_BUFFER
An empty unmodifiable buffer.

Constructor Detail

BufferUtils

public BufferUtils()
BufferUtils should not normally be instantiated.

Method Detail

blockingBuffer

public static Buffer blockingBuffer(Buffer buffer)
Returns a synchronized buffer backed by the given buffer that will block on get and remove operations. If the buffer is empty, then the get and remove operations will block until new elements are added to the buffer, rather than immediately throwing a BufferUnderflowException.

Parameters: buffer the buffer to synchronize, must not be null

Returns: a blocking buffer backed by that buffer

Throws: IllegalArgumentException if the Buffer is null

blockingBuffer

public static Buffer blockingBuffer(Buffer buffer, long timeoutMillis)
Returns a synchronized buffer backed by the given buffer that will block on get and remove operations until timeout expires. If the buffer is empty, then the get and remove operations will block until new elements are added to the buffer, rather than immediately throwing a BufferUnderflowException.

Parameters: buffer the buffer to synchronize, must not be null timeoutMillis the timeout value in milliseconds, zero or less for no timeout

Returns: a blocking buffer backed by that buffer

Throws: IllegalArgumentException if the Buffer is null

Since: Commons Collections 3.2

boundedBuffer

public static Buffer boundedBuffer(Buffer buffer, int maximumSize)
Returns a synchronized buffer backed by the given buffer that will block on Buffer and Buffer until enough object(s) are removed from the buffer to allow the object(s) to be added and still maintain the maximum size.

Parameters: buffer the buffer to make bounded, must not be null maximumSize the maximum size

Returns: a bounded buffer backed by the given buffer

Throws: IllegalArgumentException if the given buffer is null

Since: Commons Collections 3.2

boundedBuffer

public static Buffer boundedBuffer(Buffer buffer, int maximumSize, long timeoutMillis)
Returns a synchronized buffer backed by the given buffer that will block on Buffer and Buffer until enough object(s) are removed from the buffer to allow the object(s) to be added and still maintain the maximum size or the timeout expires.

Parameters: buffer the buffer to make bounded, must not be null maximumSize the maximum size timeoutMillis the timeout value in milliseconds, zero or less for no timeout

Returns: a bounded buffer backed by the given buffer

Throws: IllegalArgumentException if the given buffer is null

Since: Commons Collections 3.2

predicatedBuffer

public static Buffer predicatedBuffer(Buffer buffer, Predicate predicate)
Returns a predicated (validating) buffer backed by the given buffer.

Only objects that pass the test in the given predicate can be added to the buffer. Trying to add an invalid object results in an IllegalArgumentException. It is important not to use the original buffer after invoking this method, as it is a backdoor for adding invalid objects.

Parameters: buffer the buffer to predicate, must not be null predicate the predicate used to evaluate new elements, must not be null

Returns: a predicated buffer

Throws: IllegalArgumentException if the Buffer or Predicate is null

synchronizedBuffer

public static Buffer synchronizedBuffer(Buffer buffer)
Returns a synchronized buffer backed by the given buffer. Much like the synchronized collections returned by java.util.Collections, you must manually synchronize on the returned buffer's iterator to avoid non-deterministic behavior:
 Buffer b = BufferUtils.synchronizedBuffer(myBuffer);
 synchronized (b) {
     Iterator i = b.iterator();
     while (i.hasNext()) {
         process (i.next());
     }
 }
 

Parameters: buffer the buffer to synchronize, must not be null

Returns: a synchronized buffer backed by that buffer

Throws: IllegalArgumentException if the Buffer is null

transformedBuffer

public static Buffer transformedBuffer(Buffer buffer, Transformer transformer)
Returns a transformed buffer backed by the given buffer.

Each object is passed through the transformer as it is added to the Buffer. It is important not to use the original buffer after invoking this method, as it is a backdoor for adding untransformed objects.

Parameters: buffer the buffer to predicate, must not be null transformer the transformer for the buffer, must not be null

Returns: a transformed buffer backed by the given buffer

Throws: IllegalArgumentException if the Buffer or Transformer is null

typedBuffer

public static Buffer typedBuffer(Buffer buffer, Class type)
Returns a typed buffer backed by the given buffer.

Only elements of the specified type can be added to the buffer.

Parameters: buffer the buffer to predicate, must not be null type the type to allow into the buffer, must not be null

Returns: a typed buffer

Throws: IllegalArgumentException if the buffer or type is null

unmodifiableBuffer

public static Buffer unmodifiableBuffer(Buffer buffer)
Returns an unmodifiable buffer backed by the given buffer.

Parameters: buffer the buffer to make unmodifiable, must not be null

Returns: an unmodifiable buffer backed by that buffer

Throws: IllegalArgumentException if the Buffer is null

Copyright © 2001-2008 Apache Software Foundation. All Rights Reserved.