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
29 /**
30 *
31 */
32 @Immutable
33 public abstract class Selector implements Source {
34 private static final long serialVersionUID = 1L;
35
36 private final SelectorName name;
37 private final SelectorName alias;
38
39 /**
40 * Create a selector with a name.
41 *
42 * @param name the name for this selector
43 * @throws IllegalArgumentException if the selector name is null
44 */
45 protected Selector( SelectorName name ) {
46 CheckArg.isNotNull(name, "name");
47 this.name = name;
48 this.alias = null;
49 }
50
51 /**
52 * Create a selector with the supplied name and alias.
53 *
54 * @param name the name for this selector
55 * @param alias the alias for this selector; may be null
56 * @throws IllegalArgumentException if the selector name is null
57 */
58 protected Selector( SelectorName name,
59 SelectorName alias ) {
60 CheckArg.isNotNull(name, "name");
61 this.name = name;
62 this.alias = alias;
63 }
64
65 /**
66 * Get the name for this selector.
67 *
68 * @return the selector name; never null
69 */
70 public SelectorName name() {
71 return name;
72 }
73
74 /**
75 * Get the alias name for this source, if there is one.
76 *
77 * @return the alias name, or null if there is none.
78 */
79 public SelectorName alias() {
80 return alias;
81 }
82
83 /**
84 * Get the alias if this selector has one, or the name.
85 *
86 * @return the alias or name; never null
87 */
88 public SelectorName aliasOrName() {
89 return alias != null ? alias : name;
90 }
91
92 /**
93 * Determine if this selector has an alias.
94 *
95 * @return true if this selector has an alias, or false otherwise.
96 */
97 public boolean hasAlias() {
98 return alias != null;
99 }
100 }