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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 org.apache.activemq.artemis.utils.collections;
import java.util.Iterator;
/**
* Provides an Abstract Iterator that works over multiple underlying iterators.
*
* @param type of the class of the iterator.
* @param type of the iterator
*/
abstract class MultiIteratorBase> implements Iterator {
private final I[] iterators;
private int index = -1;
MultiIteratorBase(I[] iterators) {
this.iterators = iterators;
}
@Override
public boolean hasNext() {
while (true) {
if (index != -1) {
I currentIterator = get(index);
if (currentIterator.hasNext()) {
return true;
}
}
int next = index + 1;
if (next < iterators.length) {
moveTo(next);
} else {
return false;
}
}
}
@Override
public E next() {
while (true) {
if (index != -1) {
I currentIterator = get(index);
if (currentIterator.hasNext()) {
return currentIterator.next();
}
}
int next = index + 1;
if (next < iterators.length) {
moveTo(next);
} else {
return null;
}
}
}
protected void moveTo(int index) {
this.index = index;
}
protected I get(int index) {
return iterators[index];
}
}