/*
* JBoss, Home of Professional Open Source
* Copyright 2010 Red Hat Inc. and/or its affiliates and other
* contributors as indicated by the @author tags. All rights reserved.
* See the copyright.txt 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.infinispan.util;
import org.infinispan.container.DataContainer;
import java.util.Collection;
import java.util.Iterator;
import java.util.Set;
/**
* A Set view of keys in a data container, which is read-only and has efficient contains(), unlike some data container
* ley sets.
*
* @author Manik Surtani
* @since 4.1
*/
public class ReadOnlyDataContainerBackedKeySet implements Set<Object> {
final DataContainer container;
Set<Object> keySet;
public ReadOnlyDataContainerBackedKeySet(DataContainer container) {
this.container = container;
}
@Override
public int size() {
return container.size(null);
}
@Override
public boolean isEmpty() {
return container.size(null) == 0;
}
@Override
public boolean contains(Object o) {
return container.containsKey(o, null);
}
@Override
public Iterator<Object> iterator() {
if (keySet == null) keySet = container.keySet(null);
return keySet.iterator();
}
@Override
public Object[] toArray() {
if (keySet == null) keySet = container.keySet(null);
return keySet.toArray();
}
@Override
public <T> T[] toArray(T[] a) {
if (keySet == null) keySet = container.keySet(null);
return keySet.toArray(a);
}
@Override
public boolean add(Object o) {
throw new UnsupportedOperationException("Immutable");
}
@Override
public boolean remove(Object o) {
throw new UnsupportedOperationException("Immutable");
}
@Override
public boolean containsAll(Collection<?> c) {
boolean ca = true;
for (Object o: c) {
ca = ca && contains(o);
if (!ca) return false;
}
return ca;
}
@Override
public boolean addAll(Collection<?> c) {
throw new UnsupportedOperationException("Immutable");
}
@Override
public boolean retainAll(Collection<?> c) {
throw new UnsupportedOperationException("Immutable");
}
@Override
public boolean removeAll(Collection<?> c) {
throw new UnsupportedOperationException("Immutable");
}
@Override
public void clear() {
throw new UnsupportedOperationException("Immutable");
}
}