01: /*
02: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
03: *
04: * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
05: *
06: * The contents of this file are subject to the terms of either the GNU
07: * General Public License Version 2 only ("GPL") or the Common Development
08: * and Distribution License("CDDL") (collectively, the "License"). You
09: * may not use this file except in compliance with the License. You can obtain
10: * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
11: * or glassfish/bootstrap/legal/LICENSE.txt. See the License for the specific
12: * language governing permissions and limitations under the License.
13: *
14: * When distributing the software, include this License Header Notice in each
15: * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
16: * Sun designates this particular file as subject to the "Classpath" exception
17: * as provided by Sun in the GPL Version 2 section of the License file that
18: * accompanied this code. If applicable, add the following below the License
19: * Header, with the fields enclosed by brackets [] replaced by your own
20: * identifying information: "Portions Copyrighted [year]
21: * [name of copyright owner]"
22: *
23: * Contributor(s):
24: *
25: * If you wish your version of this file to be governed by only the CDDL or
26: * only the GPL Version 2, indicate your decision by adding "[Contributor]
27: * elects to include this software in this distribution under the [CDDL or GPL
28: * Version 2] license." If you don't indicate a single choice of license, a
29: * recipient has the option to distribute your version of this file under
30: * either the CDDL, the GPL Version 2 or to extend the choice of license to
31: * its licensees as provided above. However, if you add GPL Version 2 code
32: * and therefore, elected the GPL Version 2 license, then the option applies
33: * only if the new code is made subject to such option by the copyright
34: * holder.
35: */
36:
37: package com.sun.tools.xjc.reader.gbind;
38:
39: import java.util.LinkedHashSet;
40:
41: /**
42: * Factory methods for {@link ElementSet}.
43: *
44: * @author Kohsuke Kawaguchi
45: */
46: public final class ElementSets {
47: /**
48: * Returns an union of two {@link ElementSet}s.
49: *
50: * This method performs better if lhs is bigger than rhs
51: */
52: public static ElementSet union(ElementSet lhs, ElementSet rhs) {
53: if (lhs.contains(rhs))
54: return lhs;
55: if (lhs == ElementSet.EMPTY_SET)
56: return rhs;
57: if (rhs == ElementSet.EMPTY_SET)
58: return lhs;
59: return new MultiValueSet(lhs, rhs);
60: }
61:
62: /**
63: * {@link ElementSet} that has multiple {@link Element}s in it.
64: *
65: * This isn't particularly efficient or anything, but it will do for now.
66: */
67: private static final class MultiValueSet extends
68: LinkedHashSet<Element> implements ElementSet {
69: public MultiValueSet(ElementSet lhs, ElementSet rhs) {
70: addAll(lhs);
71: addAll(rhs);
72: // not that anything will break with size==1 MultiValueSet,
73: // but it does suggest that we are missing an easy optimization
74: assert size() > 1;
75: }
76:
77: private void addAll(ElementSet lhs) {
78: if (lhs instanceof MultiValueSet) {
79: super .addAll((MultiValueSet) lhs);
80: } else {
81: for (Element e : lhs)
82: add(e);
83: }
84: }
85:
86: public boolean contains(ElementSet rhs) {
87: // this isn't complete but sound
88: return super .contains(rhs) || rhs == ElementSet.EMPTY_SET;
89: }
90:
91: public void addNext(Element element) {
92: for (Element e : this)
93: e.addNext(element);
94: }
95: }
96: }
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