| /*- |
| * 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.query.iterator; |
| |
| import java.util.ArrayList; |
| import java.util.Iterator; |
| |
| import org.apache.sling.query.LazyList; |
| import org.apache.sling.query.api.TreeProvider; |
| import org.apache.sling.query.api.function.Option; |
| |
| public class DescendantsIterator<T> extends AbstractIterator<Option<T>> { |
| |
| private final Iterator<Option<T>> input; |
| |
| private Option<T> current; |
| |
| private Iterator<T> descendants; |
| |
| private final TreeProvider<T> provider; |
| |
| public DescendantsIterator(Iterator<Option<T>> input, Iterator<T> descendants, TreeProvider<T> provider) { |
| this.input = input; |
| this.current = null; |
| this.descendants = new ArrayList<T>(new LazyList<T>(descendants)).iterator(); |
| this.provider = provider; |
| } |
| |
| @Override |
| protected Option<T> getElement() { |
| if (current == null) { |
| if (input.hasNext()) { |
| current = input.next(); |
| } else { |
| return null; |
| } |
| } |
| return getDescendant(); |
| } |
| |
| private Option<T> getDescendant() { |
| while (descendants.hasNext()) { |
| T descendantCandidate = descendants.next(); |
| if (provider.isDescendant(current.getElement(), descendantCandidate)) { |
| descendants.remove(); |
| return Option.of(descendantCandidate, current.getArgumentId()); |
| } |
| } |
| Option<T> result = Option.empty(current.getArgumentId()); |
| current = null; |
| return result; |
| } |
| } |