/*
* Javolution - Java(TM) Solution for Real-Time and Embedded Systems
* Copyright (C) 2012 - Javolution (http://javolution.org/)
* All rights reserved.
*
* Permission to use, copy, modify, and distribute this software is
* freely granted, provided that this notice is preserved.
*/
package javolution.util.internal.collection;
import java.util.Iterator;
import javolution.util.function.Equality;
import javolution.util.function.Predicate;
import javolution.util.service.CollectionService;
/**
* A filtered view over a collection.
*/
public class FilteredCollectionImpl<E> extends CollectionView<E> {
/** Peeking ahead iterator. */
private class IteratorImpl implements Iterator<E> {
private boolean ahead; // Indicates if the iterator is ahead (on next element)
private final Predicate<? super E> filter;
private E next;
private final Iterator<E> targetIterator;
public IteratorImpl(Predicate<? super E> filter) {
this.filter = filter;
targetIterator = target().iterator();
}
@Override
public boolean hasNext() {
if (ahead) return true;
while (targetIterator.hasNext()) {
next = targetIterator.next();
if (filter.test(next)) {
ahead = true;
return true;
}
}
return false;
}
@Override
public E next() {
hasNext(); // Moves ahead.
ahead = false;
return next;
}
@Override
public void remove() {
targetIterator.remove();
}
}
private static final long serialVersionUID = 0x600L; // Version.
protected final Predicate<? super E> filter;
public FilteredCollectionImpl(CollectionService<E> target,
Predicate<? super E> filter) {
super(target);
this.filter = filter;
}
@Override
public boolean add(E element) {
if (!filter.test(element)) return false;
return target().add(element);
}
@Override
public Equality<? super E> comparator() {
return target().comparator();
}
@SuppressWarnings("unchecked")
@Override
public boolean contains(Object o) {
if (!filter.test((E) o)) return false;
return target().contains(o);
}
@Override
public Iterator<E> iterator() {
return new IteratorImpl(filter);
}
@SuppressWarnings("unchecked")
@Override
public boolean remove(Object o) {
if (!filter.test((E) o)) return false;
return target().remove(o);
}
@SuppressWarnings("unchecked")
@Override
public CollectionService<E>[] split(int n, boolean updateable) {
CollectionService<E>[] subTargets = target().split(n, updateable);
CollectionService<E>[] result = new CollectionService[subTargets.length];
for (int i = 0; i < subTargets.length; i++) {
result[i] = new FilteredCollectionImpl<E>(subTargets[i], filter);
}
return result;
}
}