Java > Open Source Codes > org > apache > ldap > server > db > jdbm > JdbmMasterTable


1 /*
2  * Copyright 2004 The Apache Software Foundation
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  *
16  */
17 package org.apache.ldap.server.db.jdbm;
18
19
20 import jdbm.RecordManager;
21 import jdbm.helper.StringComparator;
22 import org.apache.ldap.common.util.BigIntegerComparator;
23 import org.apache.ldap.server.db.MasterTable;
24 import org.apache.ldap.server.schema.SerializableComparator;
25
26 import javax.naming.NamingException ;
27 import javax.naming.directory.Attributes ;
28 import java.math.BigInteger ;
29
30
31 /**
32  * The master table used to store the Attributes of entries.
33  *
34  * @author <a HREF="mailto:dev@directory.apache.org">Apache Directory Project</a>
35  * @version $Rev: 169198 $
36  */
37 public class JdbmMasterTable extends JdbmTable implements MasterTable
38 {
39     private static final StringComparator STRCOMP = new StringComparator();
40     private static final SerializableComparator BIG_INTEGER_COMPARATOR =
41         new SerializableComparator( "1.2.6.1.4.1.18060.1.1.1.2.2" )
42         {
43             private static final long serialVersionUID = 4048791282048841016L;
44
45             public int compare( Object o1, Object o2 )
46             {
47                 return BigIntegerComparator.INSTANCE.compare( o1, o2 );
48             }
49         };
50     private static final SerializableComparator STRING_COMPARATOR =
51         new SerializableComparator( "1.2.6.1.4.1.18060.1.1.1.2.3" )
52         {
53             private static final long serialVersionUID = 3258689922792961845L;
54
55             public int compare( Object o1, Object o2 )
56             {
57                 return STRCOMP.compare( o1, o2 );
58             }
59         };
60     /** */
61     private JdbmTable adminTbl = null;
62
63
64     /**
65      * Creates the master entry table using a Berkeley Db for the backing store.
66      *
67      * @param recMan the jdbm record manager
68      * @throws NamingException if there is an error opening the Db file.
69      */
70     public JdbmMasterTable( RecordManager recMan )
71         throws NamingException
72     {
73         super( DBF, recMan, BIG_INTEGER_COMPARATOR );
74         adminTbl = new JdbmTable( "admin", recMan, STRING_COMPARATOR );
75         String seqValue = ( String ) adminTbl.get( SEQPROP_KEY );
76         
77         if ( null == seqValue )
78         {
79             adminTbl.put( SEQPROP_KEY, BigInteger.ZERO.toString() );
80         }
81     }
82
83
84     /**
85      * Gets the Attributes of an entry from this MasterTable.
86      *
87      * @param id the BigInteger id of the entry to retrieve.
88      * @return the Attributes of the entry with operational attributes and all.
89      * @throws NamingException if there is a read error on the underlying Db.
90      */
91     public Attributes get( BigInteger id ) throws NamingException
92     {
93         return ( Attributes ) super.get( id );
94     }
95
96
97     /**
98      * Puts the Attributes of an entry into this master table at an index
99      * specified by id. Used both to create new entries and update existing
100      * ones.
101      *
102      * @param entry the Attributes of entry w/ operational attributes
103      * @param id the BigInteger id of the entry to put
104      * @return the Attributes of the entry put
105      * @throws NamingException if there is a write error on the underlying Db.
106      */
107     public Attributes put( Attributes entry, BigInteger id ) throws NamingException
108     {
109         return ( Attributes ) super.put( id, entry );
110     }
111
112
113     /**
114      * Deletes a entry from the master table at an index specified by id.
115      *
116      * @param id the BigInteger id of the entry to delete
117      * @return the Attributes of the deleted entry
118      * @throws NamingException if there is a write error on the underlying Db
119      */
120     public Attributes delete( BigInteger id ) throws NamingException
121     {
122         return ( Attributes ) super.remove( id );
123     }
124
125
126     /**
127      * Get's the current id value from this master database's sequence without
128      * affecting the seq.
129      *
130      * @return the current value.
131      * @throws NamingException if the admin table storing sequences cannot be
132      * read.
133      */
134     public BigInteger getCurrentId() throws NamingException
135     {
136         BigInteger id = null;
137
138         synchronized ( adminTbl )
139         {
140             id = new BigInteger ( ( String ) adminTbl.get( SEQPROP_KEY ) );
141             
142             if ( null == id )
143             {
144                 adminTbl.put( SEQPROP_KEY, BigInteger.ZERO.toString() );
145                 id = BigInteger.ZERO;
146             }
147         }
148
149         return id;
150     }
151
152
153     /**
154      * Get's the next value from this SequenceBDb. This has the side-effect of
155      * changing the current sequence values perminantly in memory and on disk.
156      * Master table sequence begins at BigInteger.ONE. The BigInteger.ZERO is
157      * used for the fictitious parent of the suffix root entry.
158      *
159      * @return the current value incremented by one.
160      * @throws NamingException if the admin table storing sequences cannot be
161      * read and writen to.
162      */
163     public BigInteger getNextId() throws NamingException
164     {
165         BigInteger lastVal = null;
166         BigInteger nextVal = null;
167
168         synchronized ( adminTbl )
169         {
170             lastVal = new BigInteger ( ( String )
171                 adminTbl.get( SEQPROP_KEY ) );
172             
173             if ( null == lastVal )
174             {
175                 adminTbl.put( SEQPROP_KEY, BigInteger.ONE.toString() );
176                 return BigInteger.ONE;
177             }
178             else
179             {
180                 nextVal = lastVal.add( BigInteger.ONE );
181                 adminTbl.put( SEQPROP_KEY, nextVal.toString() );
182             }
183         }
184
185         return nextVal;
186     }
187
188
189     /**
190      * Gets a persistant property stored in the admin table of this MasterTable.
191      *
192      * @param property the key of the property to get the value of
193      * @return the value of the property
194      * @throws NamingException when the underlying admin table cannot be read
195      */
196     public String getProperty( String property ) throws NamingException
197     {
198         synchronized ( adminTbl )
199         {
200             return ( String ) adminTbl.get( property );
201         }
202     }
203
204
205     /**
206      * Sets a persistant property stored in the admin table of this MasterTable.
207      *
208      * @param property the key of the property to set the value of
209      * @param value the value of the property
210      * @throws NamingException when the underlying admin table cannot be writen
211      */
212     public void setProperty( String property, String value ) throws NamingException
213     {
214         synchronized ( adminTbl )
215         {
216             adminTbl.put( property, value );
217         }
218     }
219 }
220

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