| /*- |
| * 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.impl.iterator; |
| |
| import java.util.Iterator; |
| |
| import org.apache.sling.query.api.internal.ElementToIteratorFunction; |
| import org.apache.sling.query.api.internal.Option; |
| |
| /** |
| * This iterator evaluates each element from the source iterator, expanding it using given function. |
| */ |
| public class ExpandingIterator<T> extends AbstractIterator<Option<T>> { |
| |
| private final ElementToIteratorFunction<T> function; |
| |
| private final Iterator<Option<T>> parentIterator; |
| |
| private Option<T> parentElement; |
| |
| private Iterator<T> currentIterator; |
| |
| public ExpandingIterator(ElementToIteratorFunction<T> expandingFunction, |
| Iterator<Option<T>> sourceIterator) { |
| this.function = expandingFunction; |
| this.parentIterator = sourceIterator; |
| } |
| |
| @Override |
| protected Option<T> getElement() { |
| if (currentIterator != null && currentIterator.hasNext()) { |
| return Option.of(currentIterator.next(), parentElement.getArgumentId()); |
| } |
| while (parentIterator.hasNext()) { |
| parentElement = parentIterator.next(); |
| if (parentElement.isEmpty()) { |
| return parentElement; |
| } |
| currentIterator = function.apply(parentElement.getElement()); |
| if (currentIterator.hasNext()) { |
| return getElement(); |
| } else { |
| return Option.empty(parentElement.getArgumentId()); |
| } |
| } |
| return null; |
| } |
| } |