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.i18n.I18n;
027    import org.apache.directory.shared.ldap.util.StringTools;
028    import org.slf4j.Logger;
029    import org.slf4j.LoggerFactory;
030    
031    /**
032     * A helper class which serialize and deserialize a DN
033     *
034     * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
035     * @version $Rev$, $Date$
036     */
037    public class DnSerializer
038    {
039        /** The LoggerFactory used by this class */
040        protected static final Logger LOG = LoggerFactory.getLogger( DnSerializer.class );
041    
042        /**
043         * Serialize a DN
044         * 
045         * We have to store a DN data efficiently. Here is the structure :
046         * 
047         * <li>upName</li> The User provided DN<p>
048         * <li>normName</li> May be null if the normName is equivalent to 
049         * the upName<p>
050         * <li>rdns</li> The rdn's List.<p>
051         * 
052         * for each rdn :
053         * <li>call the RDN write method</li>
054         * 
055         * @param dn The DN to serialize
056         * @param out the stream in which the DN will be serialized
057         * @throws IOException If we can't write in this stream
058         */
059        public static void serialize( DN dn, ObjectOutput out ) throws IOException
060        {
061            if ( dn.getName() == null )
062            {
063                String message = "Cannot serialize a NULL DN";
064                LOG.error( message );
065                throw new IOException( message );
066            }
067            
068            // Write the UPName
069            out.writeUTF( dn.getName() );
070            
071            // Write the NormName if different
072            if ( dn.isNormalized() )
073            {
074                if ( dn.getName().equals( dn.getNormName() ) )
075                {
076                    out.writeUTF( "" );
077                }
078                else
079                {
080                    out.writeUTF( dn.getNormName() );
081                }
082            }
083            else
084            {
085                String message = I18n.err( I18n.ERR_04212, dn );
086                LOG.error( message );
087                throw new IOException( message );
088            }
089            
090            // Should we store the byte[] ???
091            
092            // Write the RDNs.
093            // First the number of RDNs
094            out.writeInt( dn.size() );
095            
096            // Loop on the RDNs
097            for ( RDN rdn:dn.getRdns() )
098            {
099                RdnSerializer.serialize( rdn, out );
100            }
101        }
102    
103    
104        /**
105         * Deserialize a DN
106         * 
107         * We read back the data to create a new DN. The structure 
108         * read is exposed in the {@link DnSerializer#serialize(DN, ObjectOutput)} 
109         * method<p>
110         * 
111         * @param in The input stream from which the DN is read
112         * @return a deserialized DN
113         * @throws IOException If the stream can't be read
114         */
115        public static DN deserialize( ObjectInput in ) throws IOException
116        {
117            // Read the UPName
118            String upName = in.readUTF();
119            
120            // Read the NormName
121            String normName = in.readUTF();
122            
123            if ( normName.length() == 0 )
124            {
125                // As the normName is equal to the upName,
126                // we didn't saved the nbnormName on disk.
127                // restore it by copying the upName.
128                normName = upName;
129            }
130            
131            // Should we read the byte[] ???
132            byte[] bytes = StringTools.getBytesUtf8( upName );
133            
134            // Read the RDNs. Is it's null, the number will be -1.
135            int nbRdns = in.readInt();
136            
137            DN dn = new DN( upName, normName, bytes );
138            
139            for ( int i = 0; i < nbRdns; i++ )
140            {
141                RDN rdn = RdnSerializer.deserialize( in );
142                dn.add( 0, rdn );
143            }
144        
145            return dn;
146        }
147    }