File	Doc	Category	Size	Date	Package
Cache.java	API Doc	Example	6662	Sun Jun 23 17:40:22 BST 2002	org.dasein.util

Cache

• java.lang.Object

Fields Summary
private HashMap	cache A hash map indexing references by unique keys.

Constructors Summary
public Cache() /* * Constructs a new empty cache. */ super();

Methods Summary
public boolean	add(java.lang.Object ob) Unsupported. param ob ignored return never returns throws java.lang.UnsupportedOperationException always throw new UnsupportedOperationException();
public boolean	addAll(java.util.Collection coll) Unsupported. param coll ignored return never returns throws java.lang.UnsupportedOperationException always throw new UnsupportedOperationException();
public void	cache(java.lang.Object key, java.lang.Object val) Caches the specified object identified by the specified key. param key a unique key for this object param val the object to be cached cache.put(key, new SoftReference(val));
public void	clear() Clears the entire cache. cache.clear();
public boolean	contains(java.lang.Object ob) Checks the specified object against the cache and verifies that it is in the cache. This method will return false if the object was once in the cache but has expired due to inactivity. param ob the object to check for in the cache return true if the object is in the cache Iterator it = cache.values().iterator(); while( it.hasNext() ) { SoftReference ref = (SoftReference)it.next(); Object item = ref.get(); if( item != null && ob.equals(item) ) { return true; } } return false;
public boolean	containsAll(java.util.Collection coll) Checks the passed in collection and determines if all elements of that collection are contained within this cache. Care should be taken in reading too much into a failure. If one of the elements was once in this cache but has expired due to inactivity, this method will return false. param coll the collection to test return true if all elements of the tested collection are in the cache Iterator it = coll.iterator(); while( it.hasNext() ) { if( !contains(it.next()) ) { return false; } } return true;
public boolean	containsKey(java.lang.Object key) Checks if an object with the specified key is in the cache. param key the object's identifier return true if the object is in the cache if( !cache.containsKey(key) ) { return false; } else { SoftReference ref = (SoftReference)cache.get(key); if( ref.get() == null ) { release(key); return false; } return true; }
public java.lang.Object	get(java.lang.Object key) Provides the cached object identified by the specified key. This method will return null if the specified object is not in the cache. param key the unique identifier of the desired object return the cached object or null SoftReference ref = (SoftReference)cache.get(key); Object ob; if( ref == null ) { return null; } ob = ref.get(); if( ob == null ) { release(key); } return ob;
public boolean	isEmpty() return true if the cache is empty return cache.isEmpty();
public java.util.Iterator	iterator() Provides all of the valid objects in the cache. This method will not be the snappiest method in the world. return all valid objects in the cache return toList().iterator();
public void	release(java.lang.Object key) Releases the specified object from the cache. param key the unique identified for the item to release cache.remove(key);
public boolean	remove(java.lang.Object ob) Unsupported. param ob ignored return never returns throws java.lang.UnsupportedOperationException always throw new UnsupportedOperationException();
public boolean	removeAll(java.util.Collection coll) Unsupported. param coll ignored return never returns throws java.lang.UnsupportedOperationException always throw new UnsupportedOperationException();
public boolean	retainAll(java.util.Collection coll) Unsupported. param coll ignored return never returns throws java.lang.UnsupportedOperationException always throw new UnsupportedOperationException();
public int	size() return the number of elements in the cache return toList().size();
public java.lang.Object[]	toArray() return the cache as an array return toList().toArray();
public java.lang.Object[]	toArray(java.lang.Object[] arr) return the cache as an array return toList().toArray(arr);
private java.util.ArrayList	toList() return the cache as an array Iterator it = cache.values().iterator(); ArrayList tmp = new ArrayList(); while( it.hasNext() ) { SoftReference ref = (SoftReference)it.next(); Object ob = ref.get(); if( ob != null ) { tmp.add(ob); } } return tmp;