/*
 * 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 org.apache.sling.feature.apiregions.model;

import java.util.Iterator;

final class JoinedIterator<E> implements Iterator<E> {

    private final Iterator<Iterable<E>> iterator;

    private Iterator<E> currentIterator;

    public JoinedIterator(Iterator<Iterable<E>> iterator) {
        this.iterator = iterator;
        currentIterator = null;
    }

    @Override
    public boolean hasNext() {
        if (currentIterator == null) {
            if (iterator.hasNext()) {
                currentIterator = iterator.next().iterator();
            } else {
                return false;
            }
        }

        while (!currentIterator.hasNext() && iterator.hasNext()) {
            currentIterator = iterator.next().iterator();
        }

        return currentIterator.hasNext();
    }

    @Override
    public E next() {
        return currentIterator.next();
    }

}