org.mandarax.rt.FilteredIterator.java Source code

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Here is the source code for org.mandarax.rt.FilteredIterator.java

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/*
 * Copyright 2010 Jens Dietrich Licensed under the GNU AFFERO GENERAL PUBLIC LICENSE, Version 3
 * (the "License"); you may not use this file except in compliance with the
 * License. You may obtain a copy of the License at
 * http://www.gnu.org/licenses/agpl.html Unless required by applicable law
 * or agreed to in writing, software distributed under the License is
 * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */

package org.mandarax.rt;

import com.google.common.base.Predicate;
import static com.google.common.base.Preconditions.checkNotNull;

/**
 * Simple filtered iterator.
 * @author jens dietrich
 */
public class FilteredIterator<T> extends com.google.common.collect.AbstractIterator<T>
        implements ResourceIterator<T> {
    private ResourceIterator<T> unfiltered = null;
    private Predicate<? super T> predicate = null;
    private boolean closed = false;

    public FilteredIterator(ResourceIterator<T> unfiltered, Predicate<? super T> predicate) {
        super();
        this.unfiltered = unfiltered;
        this.predicate = predicate;
    }

    @Override
    protected T computeNext() {
        if (closed)
            throw new IteratorClosedException();

        checkNotNull(unfiltered);
        checkNotNull(predicate);
        while (unfiltered.hasNext()) {
            T element = unfiltered.next();
            if (predicate.apply(element)) {
                return element;
            }
        }
        return endOfData();
    }

    @Override
    public synchronized void close() {
        closed = true;
        unfiltered.close();
    }

}