001/*
002 *   Licensed to the Apache Software Foundation (ASF) under one
003 *   or more contributor license agreements.  See the NOTICE file
004 *   distributed with this work for additional information
005 *   regarding copyright ownership.  The ASF licenses this file
006 *   to you under the Apache License, Version 2.0 (the
007 *   "License"); you may not use this file except in compliance
008 *   with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 *   Unless required by applicable law or agreed to in writing,
013 *   software distributed under the License is distributed on an
014 *   "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 *   KIND, either express or implied.  See the License for the
016 *   specific language governing permissions and limitations
017 *   under the License.
018 *
019 */
020package org.apache.directory.server.xdbm;
021
022
023import java.util.Comparator;
024import java.util.concurrent.atomic.AtomicInteger;
025
026import org.apache.directory.api.ldap.model.exception.LdapException;
027import org.apache.directory.api.ldap.model.schema.SchemaManager;
028import org.apache.directory.server.core.api.partition.PartitionTxn;
029import org.apache.directory.server.i18n.I18n;
030
031
032/**
033 * A Abstract Table implementation aggregating the methods common with all the 
034 * different Table implementation.
035 *
036 * @param <K> The key
037 * @param <V> The stored value
038 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
039 */
040public abstract class AbstractTable<K, V> implements Table<K, V>
041{
042    /** the name of this table */
043    protected final String name;
044
045    /** The global SchemaManager */
046    protected SchemaManager schemaManager;
047
048    /** a key comparator for the keys in this Table */
049    protected final Comparator<K> keyComparator;
050
051    /** a value comparator for the values in this Table */
052    protected final Comparator<V> valueComparator;
053
054    /** the current count of Tuples in this Table */
055    protected long count;
056
057    /** whether or not this table allows for duplicates */
058    protected boolean allowsDuplicates;
059
060    /** A counter used to differ the commit on disk after N operations */
061    protected AtomicInteger commitNumber;
062
063
064    /**
065     * Create an instance of Table
066     * 
067     * @param schemaManager The server schemaManager
068     * @param name the name of the table
069     * @param keyComparator a key comparator
070     * @param valueComparator a value comparator
071     */
072    protected AbstractTable( SchemaManager schemaManager, String name, Comparator<K> keyComparator,
073        Comparator<V> valueComparator )
074    {
075        this.schemaManager = schemaManager;
076        this.name = name;
077
078        if ( keyComparator == null )
079        {
080            throw new IllegalArgumentException( I18n.err( I18n.ERR_591 ) );
081        }
082        else
083        {
084            this.keyComparator = keyComparator;
085        }
086
087        this.valueComparator = valueComparator;
088
089        commitNumber = new AtomicInteger( 0 );
090    }
091
092
093    /**
094     * {@inheritDoc}
095     */
096    public Comparator<K> getKeyComparator()
097    {
098        return keyComparator;
099    }
100
101
102    /**
103     * {@inheritDoc}
104     */
105    public Comparator<V> getValueComparator()
106    {
107        return valueComparator;
108    }
109
110
111    /**
112     * {@inheritDoc}
113     */
114    public String getName()
115    {
116        return name;
117    }
118
119
120    /**
121     * {@inheritDoc}
122     */
123    public long count( PartitionTxn transaction ) throws LdapException
124    {
125        return count;
126    }
127
128
129    /**
130     * {@inheritDoc}
131     */
132    @Override
133    public long greaterThanCount( PartitionTxn transaction, K key ) throws LdapException
134    {
135        // take a best guess
136        return Math.min( count, 10L );
137    }
138
139
140    /**
141     * {@inheritDoc}
142     */
143    @Override
144    public long lessThanCount( PartitionTxn transaction, K key ) throws LdapException
145    {
146        // take a best guess
147        return Math.min( count, 10L );
148    }
149
150
151    /**
152     * {@inheritDoc}
153     */
154    @Override
155    public boolean isDupsEnabled()
156    {
157        return allowsDuplicates;
158    }
159
160
161    /**
162     * @see Object#toString()
163     */
164    public String toString()
165    {
166        StringBuilder sb = new StringBuilder();
167
168        sb.append( "Name    : " ).append( name ).append( '\n' );
169        sb.append( "NbElems : " ).append( count ).append( '\n' );
170        sb.append( "Dups    : " ).append( allowsDuplicates ).append( '\n' );
171        sb.append( "Key     : " ).append( keyComparator.getClass().getName() ).append( '\n' );
172        sb.append( "Value   : " ).append( valueComparator.getClass().getName() ).append( '\n' );
173
174        return sb.toString();
175    }
176}