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1   package org.apache.torque.oid;
2   
3   /*
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *   http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.
20   */
21  
22  import org.apache.torque.adapter.DB;
23  import org.apache.torque.adapter.IDMethod;
24  
25  /***
26   * A factory which instantiates {@link
27   * org.apache.torque.oid.IdGenerator} implementations.
28   *
29   * @author <a href="mailto:dlr@collab.net">Daniel Rall</a>
30   * @version $Id: IDGeneratorFactory.java 476550 2006-11-18 16:08:37Z tfischer $
31   */
32  public class IDGeneratorFactory
33  {
34      /***
35       * Private constructor to prevent initialisation.
36       *
37       * This class contains only static methods and thus should not be
38       * instantiated.
39       */
40      private IDGeneratorFactory()
41      {
42      }
43  
44      /***
45       * The list of ID generation method types which have associated
46       * {@link org.apache.torque.oid.IdGenerator} implementations.
47       */
48      public static final String[] ID_GENERATOR_METHODS =
49      {
50          IDMethod.NATIVE, IDMethod.AUTO_INCREMENT, IDMethod.SEQUENCE
51      };
52  
53      /***
54       * Factory method which instantiates {@link
55       * org.apache.torque.oid.IdGenerator} implementations based on the
56       * return value of the provided adapter's {@link
57       * org.apache.torque.adapter.DB#getIDMethodType()} method.
58       * Returns <code>null</code> for unknown types.
59       *
60       * @param dbAdapter The type of adapter to create an ID generator for.
61       * @return The appropriate ID generator (possibly <code>null</code>).
62       */
63      public static IdGenerator create(DB dbAdapter, String name)
64      {
65          String idMethod = dbAdapter.getIDMethodType();
66          if (IDMethod.AUTO_INCREMENT.equals(idMethod))
67          {
68              return new AutoIncrementIdGenerator(dbAdapter, name);
69          }
70          else if (IDMethod.SEQUENCE.equals(idMethod))
71          {
72              return new SequenceIdGenerator(dbAdapter, name);
73          }
74          else
75          {
76              return null;
77          }
78      }
79  }