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1   /*
2    * #%L
3    * ComparisonOperator.java - mongodb-async-driver - Allanbank Consulting, Inc.
4    * %%
5    * Copyright (C) 2011 - 2014 Allanbank Consulting, Inc.
6    * %%
7    * Licensed under the Apache License, Version 2.0 (the "License");
8    * you may not use this file except in compliance with the License.
9    * You may obtain a copy of the License at
10   * 
11   *      http://www.apache.org/licenses/LICENSE-2.0
12   * 
13   * Unless required by applicable law or agreed to in writing, software
14   * distributed under the License is distributed on an "AS IS" BASIS,
15   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16   * See the License for the specific language governing permissions and
17   * limitations under the License.
18   * #L%
19   */
20  
21  package com.allanbank.mongodb.builder;
22  
23  import com.allanbank.mongodb.Version;
24  
25  /**
26   * ComparisonOperator provides an enumeration of all possible comparison
27   * operators.
28   * 
29   * @api.yes This enumeration is part of the driver's API. Public and protected
30   *          members will be deprecated for at least 1 non-bugfix release
31   *          (version numbers are <major>.<minor>.<bugfix>)
32   *          before being removed or modified.
33   * @copyright 2012-2013, Allanbank Consulting, Inc., All Rights Reserved
34   */
35  public enum ComparisonOperator implements Operator {
36      /** The equal operator. Note that this operator does not have a token. */
37      EQUALS(""),
38  
39      /** The greater than operator. */
40      GT("$gt"),
41  
42      /** The greater than or equal operator. */
43      GTE("$gte"),
44  
45      /** The less than operator. */
46      LT("$lt"),
47  
48      /** The less than or equal operator. */
49      LTE("$lte"),
50  
51      /** The not equal operator. */
52      NE("$ne");
53  
54      /** The operator's token to use when sending to the server. */
55      private final String myToken;
56  
57      /** The first MongoDB version to support the operator. */
58      private final Version myVersion;
59  
60      /**
61       * Creates a new ComparisonOperator.
62       * 
63       * @param token
64       *            The token to use when sending to the server.
65       */
66      private ComparisonOperator(final String token) {
67          this(token, null);
68      }
69  
70      /**
71       * Creates a new ComparisonOperator.
72       * 
73       * @param token
74       *            The token to use when sending to the server.
75       * @param version
76       *            The first MongoDB version to support the operator.
77       */
78      private ComparisonOperator(final String token, final Version version) {
79          myToken = token;
80          myVersion = version;
81      }
82  
83      /**
84       * The token for the operator that can be sent to the server.
85       * 
86       * @return The token for the operator.
87       */
88      @Override
89      public String getToken() {
90          return myToken;
91      }
92  
93      /**
94       * Returns the first MongoDB version to support the operator.
95       * 
96       * @return The first MongoDB version to support the operator. If
97       *         <code>null</code> then the version is not known and can be
98       *         assumed to be all currently supported versions.
99       */
100     @Override
101     public Version getVersion() {
102         return myVersion;
103     }
104 
105 }