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     */
020    package org.apache.directory.shared.ldap.name;
021    
022    import java.io.IOException;
023    import java.io.ObjectInput;
024    import java.io.ObjectOutput;
025    
026    import org.apache.directory.shared.ldap.util.StringTools;
027    import org.slf4j.Logger;
028    import org.slf4j.LoggerFactory;
029    
030    /**
031     * A helper class which serialize and deserialize a DN
032     *
033     * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
034     * @version $Rev$, $Date$
035     */
036    public class LdapDNSerializer
037    {
038        /** The LoggerFactory used by this class */
039        protected static final Logger LOG = LoggerFactory.getLogger( LdapDNSerializer.class );
040    
041        /**
042         * Serialize a DN
043         * 
044         * We have to store a DN data efficiently. Here is the structure :
045         * 
046         * <li>upName</li> The User provided DN<p>
047         * <li>normName</li> May be null if the normName is equivalent to 
048         * the upName<p>
049         * <li>rdns</li> The rdn's List.<p>
050         * 
051         * for each rdn :
052         * <li>call the RDN write method</li>
053         * 
054         * @param dn The DN to serialize
055         * @param out the stream in which the DN will be serialized
056         * @throws IOException If we can't write in this stream
057         */
058        public static void serialize( LdapDN dn, ObjectOutput out ) throws IOException
059        {
060            if ( dn.getUpName() == null )
061            {
062                String message = "Cannot serialize a NULL DN";
063                LOG.error( message );
064                throw new IOException( message );
065            }
066            
067            // Write the UPName
068            out.writeUTF( dn.getUpName() );
069            
070            // Write the NormName if different
071            if ( dn.isNormalized() )
072            {
073                if ( dn.getUpName().equals( dn.getNormName() ) )
074                {
075                    out.writeUTF( "" );
076                }
077                else
078                {
079                    out.writeUTF( dn.getNormName() );
080                }
081            }
082            else
083            {
084                String message = "The DN should have been normalized before being serialized " + dn;
085                LOG.error( message );
086                throw new IOException( message );
087            }
088            
089            // Should we store the byte[] ???
090            
091            // Write the RDNs.
092            // First the number of RDNs
093            out.writeInt( dn.size() );
094            
095            // Loop on the RDNs
096            for ( Rdn rdn:dn.getRdns() )
097            {
098                RdnSerializer.serialize( rdn, out );
099            }
100        }
101    
102    
103        /**
104         * Deserialize a DN
105         * 
106         * We read back the data to create a new LdapDN. The structure 
107         * read is exposed in the {@link LdapDNSerializer#serialize(LdapDN, ObjectOutput)} 
108         * method<p>
109         * 
110         * @param in The input stream from which the DN is read
111         * @return a deserialized DN
112         * @throws IOException If the stream can't be read
113         */
114        public static LdapDN deserialize( ObjectInput in ) throws IOException
115        {
116            // Read the UPName
117            String upName = in.readUTF();
118            
119            // Read the NormName
120            String normName = in.readUTF();
121            
122            if ( normName.length() == 0 )
123            {
124                // As the normName is equal to the upName,
125                // we didn't saved the nbnormName on disk.
126                // restore it by copying the upName.
127                normName = upName;
128            }
129            
130            // Should we read the byte[] ???
131            byte[] bytes = StringTools.getBytesUtf8( upName );
132            
133            // Read the RDNs. Is it's null, the number will be -1.
134            int nbRdns = in.readInt();
135            
136            LdapDN dn = new LdapDN( upName, normName, bytes );
137            
138            for ( int i = 0; i < nbRdns; i++ )
139            {
140                Rdn rdn = RdnSerializer.deserialize( in );
141                dn.add( 0, rdn );
142            }
143        
144            return dn;
145        }
146    }