1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.jxpath.ri.axes;
18
19 import java.util.ArrayList;
20 import java.util.Iterator;
21
22 import org.apache.commons.jxpath.BasicNodeSet;
23 import org.apache.commons.jxpath.Pointer;
24 import org.apache.commons.jxpath.ri.EvalContext;
25 import org.apache.commons.jxpath.ri.model.NodePointer;
26
27 /**
28 * EvalContext that represents a union between other contexts - result
29 * of a union operation like (a | b)
30 *
31 * @author Dmitri Plotnikov
32 * @version $Revision: 1523199 $ $Date: 2013-09-14 11:45:47 +0200 (Sa, 14 Sep 2013) $
33 */
34 public class UnionContext extends NodeSetContext {
35 private EvalContext[] contexts;
36 private boolean prepared;
37
38 /**
39 * Create a new UnionContext.
40 * @param parentContext parent context
41 * @param contexts child contexts
42 */
43 public UnionContext(EvalContext parentContext, EvalContext[] contexts) {
44 super(parentContext, new BasicNodeSet());
45 this.contexts = contexts;
46 }
47
48 public int getDocumentOrder() {
49 return contexts.length > 1 ? 1 : super.getDocumentOrder();
50 }
51
52 public boolean setPosition(int position) {
53 if (!prepared) {
54 prepared = true;
55 BasicNodeSet nodeSet = (BasicNodeSet) getNodeSet();
56 ArrayList pointers = new ArrayList();
57 for (int i = 0; i < contexts.length; i++) {
58 EvalContext ctx = contexts[i];
59 while (ctx.nextSet()) {
60 while (ctx.nextNode()) {
61 NodePointer ptr = ctx.getCurrentNodePointer();
62 if (!pointers.contains(ptr)) {
63 pointers.add(ptr);
64 }
65 }
66 }
67 }
68 sortPointers(pointers);
69
70 for (Iterator it = pointers.iterator(); it.hasNext();) {
71 nodeSet.add((Pointer) it.next());
72 }
73 }
74 return super.setPosition(position);
75 }
76 }