1 /*
2 * ModeShape (http://www.modeshape.org)
3 * See the COPYRIGHT.txt file distributed with this work for information
4 * regarding copyright ownership. Some portions may be licensed
5 * to Red Hat, Inc. under one or more contributor license agreements.
6 * See the AUTHORS.txt file in the distribution for a full listing of
7 * individual contributors.
8 *
9 * ModeShape is free software. Unless otherwise indicated, all code in ModeShape
10 * is licensed to you under the terms of the GNU Lesser General Public License as
11 * published by the Free Software Foundation; either version 2.1 of
12 * the License, or (at your option) any later version.
13 *
14 * ModeShape is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with this software; if not, write to the Free
21 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
22 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
23 */
24 package org.modeshape.graph.query.model;
25
26 import net.jcip.annotations.Immutable;
27 import org.modeshape.common.util.CheckArg;
28 import org.modeshape.common.util.HashCode;
29
30 /**
31 * A constraint that evaluates to true only when a named property exists on a node.
32 */
33 @Immutable
34 public class PropertyExistence extends Constraint {
35 private static final long serialVersionUID = 1L;
36
37 private final SelectorName selectorName;
38 private final String propertyName;
39 private final int hc;
40
41 /**
42 * Create a constraint requiring that a property exist on a node.
43 *
44 * @param selectorName the name of the node selector
45 * @param propertyName the name of the property that must exist
46 */
47 public PropertyExistence( SelectorName selectorName,
48 String propertyName ) {
49 CheckArg.isNotNull(selectorName, "selectorName");
50 CheckArg.isNotNull(propertyName, "propertyName");
51 this.selectorName = selectorName;
52 this.propertyName = propertyName;
53 this.hc = HashCode.compute(this.selectorName, this.propertyName);
54 }
55
56 /**
57 * Get the name of the selector.
58 *
59 * @return the selector name; never null
60 */
61 public final SelectorName getSelectorName() {
62 return selectorName;
63 }
64
65 /**
66 * Get the name of the property.
67 *
68 * @return the property name; never null
69 */
70 public final String getPropertyName() {
71 return propertyName;
72 }
73
74 /**
75 * {@inheritDoc}
76 *
77 * @see java.lang.Object#toString()
78 */
79 @Override
80 public String toString() {
81 return Visitors.readable(this);
82 }
83
84 /**
85 * {@inheritDoc}
86 *
87 * @see java.lang.Object#hashCode()
88 */
89 @Override
90 public int hashCode() {
91 return hc;
92 }
93
94 /**
95 * {@inheritDoc}
96 *
97 * @see java.lang.Object#equals(java.lang.Object)
98 */
99 @Override
100 public boolean equals( Object obj ) {
101 if (obj == this) return true;
102 if (obj instanceof PropertyExistence) {
103 PropertyExistence that = (PropertyExistence)obj;
104 if (this.hc != that.hc) return false;
105 return this.selectorName.equals(that.selectorName) && this.propertyName.equals(that.propertyName);
106 }
107 return false;
108 }
109
110 /**
111 * {@inheritDoc}
112 *
113 * @see org.modeshape.graph.query.model.Visitable#accept(org.modeshape.graph.query.model.Visitor)
114 */
115 public void accept( Visitor visitor ) {
116 visitor.visit(this);
117 }
118 }