flex2.compiler.util.IteratorList.java Source code

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Here is the source code for flex2.compiler.util.IteratorList.java

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/*
 *
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (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.apache.org/licenses/LICENSE-2.0
 *
 *  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 flex2.compiler.util;

import org.apache.commons.collections.iterators.IteratorChain;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.Collections;

/**
 * Utility wrapper for IteratorChain, culls empty adds and exploits
 * singletons.
 */
public class IteratorList extends ArrayList<Iterator> {
    private static final long serialVersionUID = -5093248926480065063L;

    public boolean add(Iterator iter) {
        if (iter.hasNext()) {
            return super.add(iter);
        }
        return false;
    }

    public Iterator toIterator() {
        switch (size()) {
        case 0:
            return Collections.emptyList().iterator();
        case 1:
            return get(0);
        default:
            return new IteratorChain(this);
        }
    }
}