org.apache.jackrabbit.oak.plugins.migration.DescendantsIterator Maven / Gradle / Ivy
/*
* 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.jackrabbit.oak.plugins.migration;
import java.util.ArrayDeque;
import java.util.Deque;
import java.util.Iterator;
import org.apache.jackrabbit.commons.iterator.AbstractLazyIterator;
import org.apache.jackrabbit.oak.spi.state.ChildNodeEntry;
import org.apache.jackrabbit.oak.spi.state.NodeState;
public class DescendantsIterator extends AbstractLazyIterator {
private final Deque> stack = new ArrayDeque>();
private final int maxLevel;
public DescendantsIterator(NodeState root, int maxLevel) {
this.maxLevel = maxLevel;
stack.push(root.getChildNodeEntries().iterator());
}
@Override
protected NodeState getNext() {
if (!fillStack()) {
return null;
}
return stack.peekFirst().next().getNodeState();
}
private boolean fillStack() {
while (stack.size() < maxLevel || !stack.peekFirst().hasNext()) {
Iterator topIterator = stack.peekFirst();
if (topIterator.hasNext()) {
final NodeState nextNode = topIterator.next().getNodeState();
stack.push(nextNode.getChildNodeEntries().iterator());
} else {
stack.pop();
if (stack.isEmpty()) {
return false;
}
}
}
return true;
}
}