/*
* JBoss, Home of Professional Open Source.
* Copyright 2009, Red Hat Middleware LLC, and individual contributors
* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.system.server.profileservice.repository.clustered.metadata;
import java.io.IOException;
import java.io.Serializable;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.SortedSet;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;
/**
* Base class for objects that maintain a sorted collection of child
* {@link Identifiable} metadata and also provide efficient lookup capability
* based on a child item's {@link Identifiable#getId() id}.
*
* @author Brian Stansberry
*
* @version $Revision: $
*/
public abstract class AbstractSortedMetadataContainer<K, T extends Identifiable<K>>
implements Serializable
{
/** The serialVersionUID */
private static final long serialVersionUID = 7130572488073615772L;
protected SortedSet<T> sortedItems = new TreeSet<T>();
private transient Map<K, T> itemMap = new ConcurrentHashMap<K, T>();
private transient Collection<T> exposedCollection = new MetadataCollection();
// --------------------------------------------------------------- Protected
/**
* Gets a collection that can be exposed to external callers. Modifications
* to the collection affect the internal state of this object. The
* iterator exposed by this collection will provide items ordered by
* the natural ordering of <code>T</code>. The returned collection is not
* thread safe.
*/
protected Collection<T> getExposedCollection()
{
return exposedCollection;
}
/**
* Gets the metadata object identified by <code>key</code>.
*
* @param key the key
* @return the metadata, or <code>null</code> if <code>key</code> is unknown.
*/
protected T getContainedMetadata(K key)
{
return itemMap.get(key);
}
/**
* Gets an unmodifiable view of the {@link Identifiable#getId() ids} of the
* metadata stored in this container.
*
* @return the ids. Will not be <code>null</code>.
*/
protected Set<K> getContainedMetadataIds()
{
return Collections.unmodifiableSet(itemMap.keySet());
}
// ----------------------------------------------------------------- Private
private void readObject(java.io.ObjectInputStream in)
throws IOException, ClassNotFoundException
{
in.defaultReadObject();
exposedCollection = new MetadataCollection();
itemMap = new ConcurrentHashMap<K, T>();
for (T item : sortedItems)
{
itemMap.put(item.getId(), item);
}
}
private class MetadataCollection implements Collection<T>
{
public boolean add(T toAdd)
{
K id = toAdd.getId();
T existing = itemMap.put(id, toAdd);
boolean change = (toAdd.equals(existing) == false);
if (change)
{
if (existing != null)
{
sortedItems.remove(existing);
}
sortedItems.add(toAdd);
}
return change;
}
public boolean addAll(Collection<? extends T> c)
{
boolean mod = false;
for (T t : c)
{
if (add(t))
{
mod = true;
}
}
return mod;
}
public void clear()
{
itemMap.clear();
sortedItems.clear();
}
public boolean contains(Object o)
{
return sortedItems.contains(o);
}
public boolean containsAll(Collection<?> c)
{
return sortedItems.containsAll(c);
}
public boolean isEmpty()
{
return sortedItems.isEmpty();
}
public Iterator<T> iterator()
{
return new MetadataCollectionIterator();
}
public boolean remove(Object toRemove)
{
boolean result = sortedItems.remove(toRemove);
if (result)
{
@SuppressWarnings("unchecked")
T item = (T) toRemove;
itemMap.remove(item.getId());
}
return result;
}
public boolean removeAll(Collection<?> c)
{
boolean mod = false;
for (Object o : c)
{
if (remove(o))
{
mod = true;
}
}
return mod;
}
public boolean retainAll(Collection<?> c)
{
throw new UnsupportedOperationException("retainAll is not supported");
}
public int size()
{
return sortedItems.size();
}
public Object[] toArray()
{
return sortedItems.toArray();
}
public <E> E[] toArray(E[] a)
{
return sortedItems.toArray(a);
}
public boolean equals(Object other)
{
if (other == this)
{
return true;
}
if (other instanceof Collection)
{
Collection<?> o = (Collection<?>) other;
return sortedItems.size() == o.size() && sortedItems.containsAll(o);
}
return false;
}
public int hashCode()
{
return sortedItems.hashCode();
}
}
private class MetadataCollectionIterator implements Iterator<T>
{
private final Iterator<T> delegate = AbstractSortedMetadataContainer.this.sortedItems.iterator();
private T lastReturned;
public boolean hasNext()
{
return delegate.hasNext();
}
public T next()
{
this.lastReturned = delegate.next();
return this.lastReturned;
}
public void remove()
{
this.delegate.remove();
AbstractSortedMetadataContainer.this.itemMap.remove(this.lastReturned.getId());
}
}
}