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Provides a single jar containing all JAITools modules which you can
use instead of including individual modules in your project. Note:
It does not include the Jiffle scripting language or Jiffle image
operator.
/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2001-2004 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowledgement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgement may appear in the software itself,
* if and wherever such third-party acknowledgements normally appear.
*
* 4. The names "The Jakarta Project", "Commons", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact [email protected].
*
* 5. Products derived from this software may not be called "Apache"
* nor may "Apache" appear in their names without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
*
* An implementation of a Map which has a maximum size and uses a Least Recently Used
* algorithm to remove items from the Map when the maximum size is reached and new items are added.
*
*
*
* A synchronized version can be obtained with:
* Collections.synchronizedMap( theMapToSynchronize )
* If it will be accessed by multiple threads, you _must_ synchronize access
* to this Map. Even concurrent get(Object) operations produce indeterminate
* behaviour.
*
*
*
* Unlike the Collections 1.0 version, this version of LRUMap does use a true
* LRU algorithm. The keys for all gets and puts are moved to the front of
* the list. LRUMap is now a subclass of SequencedHashMap, and the "LRU"
* key is now equivalent to LRUMap.getFirst().
*
*
* @deprecated Moved to map subpackage. Due to be removed in v4.0.
* @since Commons Collections 1.0
* @version $Revision: 1.22 $ $Date: 2004/01/14 21:43:04 $
*
* @author James Strachan
* @author Morgan Delagrange
*/
public class LRUMap extends SequencedHashMap implements Externalizable {
private int maximumSize = 0;
/**
* Default constructor, primarily for the purpose of
* de-externalization. This constructors sets a default
* LRU limit of 100 keys, but this value may be overridden
* internally as a result of de-externalization.
*/
public LRUMap() {
this( 100 );
}
/**
* Create a new LRUMap with a maximum capacity of i.
* Once i capacity is achieved, subsequent gets
* and puts will push keys out of the map. See .
*
* @param i Maximum capacity of the LRUMap
*/
public LRUMap(int i) {
super( i );
maximumSize = i;
}
/**
* Get the value for a key from the Map. The key
* will be promoted to the Most Recently Used position.
* Note that get(Object) operations will modify
* the underlying Collection. Calling get(Object)
* inside of an iteration over keys, values, etc. is
* currently unsupported.
*
* @param key Key to retrieve
* @return Returns the value. Returns null if the key has a
* null value or if the key has no value.
*/
public Object get(Object key) {
if(!containsKey(key)) return null;
Object value = remove(key);
super.put(key,value);
return value;
}
/**
* Removes the key and its Object from the Map.
*
* (Note: this may result in the "Least Recently Used"
* object being removed from the Map. In that case,
* the removeLRU() method is called. See javadoc for
* removeLRU() for more details.)
*
* @param key Key of the Object to add.
* @param value Object to add
* @return Former value of the key
*/
public Object put( Object key, Object value ) {
int mapSize = size();
Object retval = null;
if ( mapSize >= maximumSize ) {
// don't retire LRU if you are just
// updating an existing key
if (!containsKey(key)) {
// lets retire the least recently used item in the cache
removeLRU();
}
}
retval = super.put(key,value);
return retval;
}
/**
* This method is used internally by the class for
* finding and removing the LRU Object.
*/
protected void removeLRU() {
Object key = getFirstKey();
// be sure to call super.get(key), or you're likely to
// get infinite promotion recursion
Object value = super.get(key);
remove(key);
processRemovedLRU(key,value);
}
/**
* Subclasses of LRUMap may hook into this method to
* provide specialized actions whenever an Object is
* automatically removed from the cache. By default,
* this method does nothing.
*
* @param key key that was removed
* @param value value of that key (can be null)
*/
protected void processRemovedLRU(Object key, Object value) {
}
// Externalizable interface
//-------------------------------------------------------------------------
public void readExternal( ObjectInput in ) throws IOException, ClassNotFoundException {
maximumSize = in.readInt();
int size = in.readInt();
for( int i = 0; i < size; i++ ) {
Object key = in.readObject();
Object value = in.readObject();
put(key,value);
}
}
public void writeExternal( ObjectOutput out ) throws IOException {
out.writeInt( maximumSize );
out.writeInt( size() );
for( Iterator iterator = keySet().iterator(); iterator.hasNext(); ) {
Object key = iterator.next();
out.writeObject( key );
// be sure to call super.get(key), or you're likely to
// get infinite promotion recursion
Object value = super.get( key );
out.writeObject( value );
}
}
// Properties
//-------------------------------------------------------------------------
/** Getter for property maximumSize.
* @return Value of property maximumSize.
*/
public int getMaximumSize() {
return maximumSize;
}
/** Setter for property maximumSize.
* @param maximumSize New value of property maximumSize.
*/
public void setMaximumSize(int maximumSize) {
this.maximumSize = maximumSize;
while (size() > maximumSize) {
removeLRU();
}
}
// add a serial version uid, so that if we change things in the future
// without changing the format, we can still deserialize properly.
private static final long serialVersionUID = 2197433140769957051L;
}