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.api.ldap.model.schema.comparators;
021
022
023import org.apache.directory.api.i18n.I18n;
024import org.apache.directory.api.ldap.model.exception.LdapException;
025import org.apache.directory.api.ldap.model.exception.LdapInvalidDnException;
026import org.apache.directory.api.ldap.model.name.Dn;
027import org.apache.directory.api.ldap.model.schema.LdapComparator;
028import org.apache.directory.api.ldap.model.schema.SchemaManager;
029
030
031/**
032 * Compare two DNs
033 * 
034 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
035 */
036public class DnComparator extends LdapComparator<Object>
037{
038    /** The serial version UID */
039    private static final long serialVersionUID = 2L;
040
041    /** A reference to the schema manager */
042    private transient SchemaManager schemaManager;
043
044    /**
045     * Creates a new instance of DnComparator.
046     * 
047     * @param oid The Comparator's OID
048     */
049    public DnComparator( String oid )
050    {
051        super( oid );
052    }
053
054
055    /**
056     * Compare two String DNs
057     *  
058     * @param dn1 The first DN
059     * @param dn2 The second DN
060     * 
061     * @return -1 i the first DN is inferior to the second DN, 1 if the second DN is superior, 0 of they are equal
062     */
063    public int compare( String dn1, String dn2 )
064    {
065        if ( dn1 == null )
066        {
067            if ( dn2 == null )
068            {
069                return 0;
070            }
071            else
072            {
073                return -1;
074            }
075        }
076        
077        return dn1.compareTo( dn2 );
078    }
079
080
081    /**
082     * {@inheritDoc}
083     */
084    @Override
085    public int compare( Object obj0, Object obj1 )
086    {
087        if ( ( obj0 instanceof String ) && ( obj1 instanceof String ) )
088        {
089            return compare( ( String ) obj0, ( String ) obj1 );
090        }
091        
092        Dn dn0 = null;
093        Dn dn1 = null;
094
095        try
096        {
097            dn0 = getDn( obj0 );
098            dn1 = getDn( obj1 );
099        }
100        catch ( LdapException e )
101        {
102            // -- what do we do here ?
103            return -1;
104        }
105
106        int dn0Size = dn0.getRdns().size();
107        int dn1Size = dn1.getRdns().size();
108        
109        // check the equality first, cause
110        // when both DNs are equal checking isAncestorOf() returns true
111        if ( dn0.equals( dn1 ) )
112        {
113            return 0;
114        }
115        else if ( dn0Size > dn1Size )
116        {
117            return -1;
118        }
119        else if ( dn1Size > dn0Size )
120        {
121            return 1;
122        }
123
124        for ( int i = dn0Size - 1; i >= 0; i-- )
125        {
126            int comp = dn0.getRdn( i ).compareTo( dn1.getRdn( i ) );
127            
128            if ( comp != 0 )
129            {
130                return comp;
131            }
132        }
133        
134        return 0;
135    }
136
137
138    private Dn getDn( Object obj ) throws LdapInvalidDnException
139    {
140        Dn dn;
141
142        if ( obj instanceof Dn )
143        {
144            dn = ( Dn ) obj;
145
146            dn = dn.isSchemaAware() ? dn : new Dn( schemaManager, dn );
147        }
148        else if ( obj instanceof String )
149        {
150            dn = new Dn( schemaManager, ( String ) obj );
151        }
152        else
153        {
154            throw new IllegalStateException( I18n.err( I18n.ERR_13720_CANNOT_HANDLE_DN_COMPARISONS, obj == null ? null : obj.getClass() ) );
155        }
156
157        return dn;
158    }
159
160
161    /**
162     * {@inheritDoc}
163     */
164    @Override
165    public void setSchemaManager( SchemaManager schemaManager )
166    {
167        this.schemaManager = schemaManager;
168    }
169}