1 /*
2 * $Id: AppendIteratorFilter.java 471756 2006-11-06 15:01:43Z husted $
3 *
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21 package org.apache.struts2.util;
22
23 import java.util.ArrayList;
24 import java.util.Iterator;
25 import java.util.List;
26
27 import com.opensymphony.xwork2.Action;
28
29
30 /***
31 * A bean that takes several iterators and outputs them in sequence
32 *
33 * @see org.apache.struts2.components.AppendIterator
34 * @see org.apache.struts2.views.jsp.iterator.AppendIteratorTag
35 */
36 public class AppendIteratorFilter extends IteratorFilterSupport implements Iterator, Action {
37
38 List iterators = new ArrayList();
39
40 // Attributes ----------------------------------------------------
41 List sources = new ArrayList();
42
43
44 // Public --------------------------------------------------------
45 public void setSource(Object anIterator) {
46 sources.add(anIterator);
47 }
48
49 // Action implementation -----------------------------------------
50 public String execute() {
51 // Make source transformations
52 for (int i = 0; i < sources.size(); i++) {
53 Object source = sources.get(i);
54 iterators.add(getIterator(source));
55 }
56
57 return SUCCESS;
58 }
59
60 // Iterator implementation ---------------------------------------
61 public boolean hasNext() {
62 if (iterators.size() > 0) {
63 return (((Iterator) iterators.get(0)).hasNext());
64 } else {
65 return false;
66 }
67 }
68
69 public Object next() {
70 try {
71 return ((Iterator) iterators.get(0)).next();
72 } finally {
73 if (iterators.size() > 0) {
74 if (!((Iterator) iterators.get(0)).hasNext()) {
75 iterators.remove(0);
76 }
77 }
78 }
79 }
80
81 public void remove() {
82 throw new UnsupportedOperationException();
83 }
84 }