| /* |
| * Copyright 2017 HugeGraph Authors |
| * |
| * 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 com.baidu.hugegraph.iterator; |
| |
| import java.util.Iterator; |
| import java.util.function.Function; |
| |
| public class FilterIterator<T> extends WrappedIterator<T> { |
| |
| private final Iterator<T> originIterator; |
| private final Function<T, Boolean> filterCallback; |
| |
| public FilterIterator(Iterator<T> origin, Function<T, Boolean> filter) { |
| this.originIterator = origin; |
| this.filterCallback = filter; |
| } |
| |
| @Override |
| protected Iterator<T> originIterator() { |
| return this.originIterator; |
| } |
| |
| @Override |
| protected final boolean fetch() { |
| while (this.originIterator.hasNext()) { |
| T next = this.originIterator.next(); |
| // Do filter |
| if (next != null && this.filterCallback.apply(next)) { |
| assert this.current == none(); |
| this.current = next; |
| return true; |
| } |
| } |
| return false; |
| } |
| } |