001/** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.camel.util; 018 019import java.util.Iterator; 020import java.util.NoSuchElementException; 021 022/** 023 * Compound iterator to iterate over multiple iterators sequentially. 024 */ 025public class CompoundIterator<T> implements Iterator<T> { 026 027 final Iterator<Iterator<T>> it; 028 Iterator<T> current; 029 030 public CompoundIterator(Iterable<Iterator<T>> it) { 031 this(it.iterator()); 032 } 033 034 public CompoundIterator(Iterator<Iterator<T>> it) { 035 this.it = it; 036 this.current = it.hasNext() ? it.next() : null; 037 } 038 039 @Override 040 public boolean hasNext() { 041 while (current != null) { 042 if (current.hasNext()) { 043 return true; 044 } else { 045 current = it.hasNext() ? it.next() : null; 046 } 047 048 } 049 return false; 050 } 051 052 @Override 053 public T next() { 054 if (current != null) { 055 return current.next(); 056 } 057 throw new NoSuchElementException(); 058 } 059 060 @Override 061 public void remove() { 062 current.remove(); 063 } 064}