TupleSerialMarshalledKeyCreator


1   /*-
2    * See the file LICENSE for redistribution information.
3    *
4    * Copyright (c) 2000,2006 Oracle.  All rights reserved.
5    *
6    * $Id: TupleSerialMarshalledKeyCreator.java,v 1.25 2006/10/30 21:14:08 bostic Exp $
7    */
8   
9   package com.sleepycat.bind.serial;
10  
11  import com.sleepycat.bind.tuple.MarshalledTupleKeyEntity;
12  import com.sleepycat.bind.tuple.TupleInput;
13  import com.sleepycat.bind.tuple.TupleOutput;
14  
15  /**
16   * A concrete key creator that works in conjunction with a {@link
17   * TupleSerialMarshalledBinding}.  This key creator works by calling the
18   * methods of the {@link MarshalledTupleKeyEntity} interface to create and
19   * clear the index key fields.
20   *
21   * @author Mark Hayes
22   */
23  public class TupleSerialMarshalledKeyCreator extends TupleSerialKeyCreator {
24  
25      private TupleSerialMarshalledBinding binding;
26      private String   keyName;
27  
28      /**
29       * Creates a tuple-serial marshalled key creator.
30       *
31       * @param binding is the binding used for the tuple-serial entity.
32       *
33       * @param keyName is the key name passed to the {@link
34       * MarshalledTupleKeyEntity#marshalSecondaryKey} method to identify the
35       * index key.
36       */
37      public TupleSerialMarshalledKeyCreator(TupleSerialMarshalledBinding
38                                             binding,
39                                             String   keyName) {
40  
41          super(binding.dataBinding);
42          this.binding = binding;
43          this.keyName = keyName;
44  
45          if (dataBinding == null) {
46              throw new NullPointerException  ("dataBinding may not be null");
47          }
48      }
49  
50      // javadoc is inherited
51      public boolean createSecondaryKey(TupleInput primaryKeyInput,
52                                        Object   dataInput,
53                                        TupleOutput indexKeyOutput) {
54  
55          /*
56           * The primary key is unmarshalled before marshalling the index key, to
57           * account for cases where the index key includes fields taken from the
58           * primary key.
59           */
60          MarshalledTupleKeyEntity entity = (MarshalledTupleKeyEntity)
61              binding.entryToObject(primaryKeyInput, dataInput);
62  
63          return entity.marshalSecondaryKey(keyName, indexKeyOutput);
64      }
65  
66      // javadoc is inherited
67      public Object   nullifyForeignKey(Object   dataInput) {
68  
69          MarshalledTupleKeyEntity entity = (MarshalledTupleKeyEntity)
70              binding.entryToObject(null, dataInput);
71  
72          return entity.nullifyForeignKey(keyName) ? dataInput : null;
73      }
74  }
75
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