package org.infinispan.util;
import java.util.Collection;
import java.util.Iterator;
import java.util.Set;
import org.infinispan.container.DataContainer;
/**
* 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
* @deprecated DataContainer keySet method will be removed in the future. See {@link DataContainer#keySet()}
*/
@Deprecated
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();
}
@Override
public boolean isEmpty() {
// We don't check size since it isn't constant and most likely allocates an iterator anyways.
return !container.iterator().hasNext();
}
@Override
public boolean contains(Object o) {
return container.containsKey(o);
}
@Override
public Iterator<Object> iterator() {
if (keySet == null) keySet = container.keySet();
return keySet.iterator();
}
@Override
public Object[] toArray() {
if (keySet == null) keySet = container.keySet();
return keySet.toArray();
}
@Override
public <T> T[] toArray(T[] a) {
if (keySet == null) keySet = container.keySet();
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");
}
}