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 java.util.Collections;
27 import java.util.HashMap;
28 import java.util.Map;
29 import org.modeshape.common.util.CheckArg;
30
31 /**
32 *
33 */
34 public enum Operator {
35 EQUAL_TO("="),
36 NOT_EQUAL_TO("!="),
37 LESS_THAN("<"),
38 LESS_THAN_OR_EQUAL_TO("<="),
39 GREATER_THAN(">"),
40 GREATER_THAN_OR_EQUAL_TO(">="),
41 LIKE("LIKE");
42
43 private static final Map<String, Operator> OPERATORS_BY_SYMBOL;
44 static {
45 Map<String, Operator> opsBySymbol = new HashMap<String, Operator>();
46 for (Operator operator : Operator.values()) {
47 opsBySymbol.put(operator.symbol().toUpperCase(), operator);
48 }
49 opsBySymbol.put("<>", NOT_EQUAL_TO);
50 OPERATORS_BY_SYMBOL = Collections.unmodifiableMap(opsBySymbol);
51 }
52
53 private final String symbol;
54
55 private Operator( String symbol ) {
56 this.symbol = symbol;
57 }
58
59 /**
60 * Get the symbol for this operator
61 *
62 * @return the symbolic representation; never null
63 */
64 public String symbol() {
65 return symbol;
66 }
67
68 /**
69 * Get the equivalent operator if the operands are to be reversed.
70 *
71 * @return the reverse operator; never null
72 */
73 public Operator reverse() {
74 switch (this) {
75 case GREATER_THAN:
76 return LESS_THAN;
77 case GREATER_THAN_OR_EQUAL_TO:
78 return LESS_THAN_OR_EQUAL_TO;
79 case LESS_THAN:
80 return GREATER_THAN;
81 case LESS_THAN_OR_EQUAL_TO:
82 return GREATER_THAN_OR_EQUAL_TO;
83 case EQUAL_TO:
84 case LIKE:
85 case NOT_EQUAL_TO:
86 default:
87 return this;
88 }
89 }
90
91 /**
92 * Determine whether this operator is one that is used to define a range of values: {@link #LESS_THAN <},
93 * {@link #GREATER_THAN >}, {@link #LESS_THAN_OR_EQUAL_TO <=}, or {@link #GREATER_THAN_OR_EQUAL_TO >=}.
94 *
95 * @return true if this operator is a range operator, or false otherwise
96 */
97 public boolean isRangeOperator() {
98 switch (this) {
99 case GREATER_THAN:
100 case GREATER_THAN_OR_EQUAL_TO:
101 case LESS_THAN:
102 case LESS_THAN_OR_EQUAL_TO:
103 return true;
104 case EQUAL_TO:
105 case LIKE:
106 case NOT_EQUAL_TO:
107 default:
108 return false;
109 }
110 }
111
112 /**
113 * {@inheritDoc}
114 *
115 * @see java.lang.Enum#toString()
116 */
117 @Override
118 public String toString() {
119 return symbol;
120 }
121
122 /**
123 * Attempt to find the Operator given a symbol. The matching is done independent of case.
124 *
125 * @param symbol the symbol
126 * @return the Operator having the supplied symbol, or null if there is no Operator with the supplied symbol
127 * @throws IllegalArgumentException if the symbol is null
128 */
129 public static Operator forSymbol( String symbol ) {
130 CheckArg.isNotNull(symbol, "symbol");
131 return OPERATORS_BY_SYMBOL.get(symbol.toUpperCase());
132 }
133 }