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.codec.controls.search.pagedSearch;
021
022
023import org.apache.directory.api.asn1.DecoderException;
024import org.apache.directory.api.asn1.ber.grammar.AbstractGrammar;
025import org.apache.directory.api.asn1.ber.grammar.Grammar;
026import org.apache.directory.api.asn1.ber.grammar.GrammarAction;
027import org.apache.directory.api.asn1.ber.grammar.GrammarTransition;
028import org.apache.directory.api.asn1.ber.tlv.BerValue;
029import org.apache.directory.api.asn1.ber.tlv.IntegerDecoder;
030import org.apache.directory.api.asn1.ber.tlv.IntegerDecoderException;
031import org.apache.directory.api.asn1.ber.tlv.UniversalTag;
032import org.apache.directory.api.i18n.I18n;
033import org.apache.directory.api.util.Strings;
034import org.slf4j.Logger;
035import org.slf4j.LoggerFactory;
036
037
038/**
039 * This class implements the PagedSearchControl. All the actions are declared in
040 * this class. As it is a singleton, these declaration are only done once.
041 * 
042 * The decoded grammar is the following :
043 * 
044 * realSearchControlValue ::= SEQUENCE {
045 *     size   INTEGER,
046 *     cookie OCTET STRING,
047 * }
048 * 
049 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
050 */
051public final class PagedResultsGrammar extends AbstractGrammar<PagedResultsContainer>
052{
053    /** The logger */
054    static final Logger LOG = LoggerFactory.getLogger( PagedResultsGrammar.class );
055
056    /** Speedup for logs */
057    static final boolean IS_DEBUG = LOG.isDebugEnabled();
058
059    /** The instance of grammar. PagedSearchControlGrammar is a singleton */
060    private static Grammar<?> instance = new PagedResultsGrammar();
061
062
063    /**
064     * Creates a new PagedSearchControlGrammar object.
065     */
066    @SuppressWarnings("unchecked")
067    private PagedResultsGrammar()
068    {
069        setName( PagedResultsGrammar.class.getName() );
070
071        // Create the transitions table
072        super.transitions = new GrammarTransition[PagedResultsStates.LAST_PAGED_SEARCH_STATE.ordinal()][256];
073
074        /** 
075         * Transition from initial state to PagedSearch sequence
076         * realSearchControlValue ::= SEQUENCE OF {
077         *     ...
078         *     
079         * Nothing to do
080         */
081        super.transitions[PagedResultsStates.START_STATE.ordinal()][UniversalTag.SEQUENCE.getValue()] =
082            new GrammarTransition<PagedResultsContainer>( PagedResultsStates.START_STATE,
083                PagedResultsStates.PAGED_SEARCH_SEQUENCE_STATE,
084                UniversalTag.SEQUENCE.getValue(), null );
085
086        /** 
087         * Transition from PagedSearch sequence to size
088         * 
089         * realSearchControlValue ::= SEQUENCE OF {
090         *     size  INTEGER,  -- INTEGER (0..maxInt),
091         *     ...
092         *     
093         * Stores the size value
094         */
095        super.transitions[PagedResultsStates.PAGED_SEARCH_SEQUENCE_STATE.ordinal()][UniversalTag.INTEGER.getValue()] =
096            new GrammarTransition<PagedResultsContainer>( PagedResultsStates.PAGED_SEARCH_SEQUENCE_STATE,
097                PagedResultsStates.SIZE_STATE,
098                UniversalTag.INTEGER.getValue(),
099                new GrammarAction<PagedResultsContainer>( "Set PagedSearchControl size" )
100                {
101                    public void action( PagedResultsContainer container ) throws DecoderException
102                    {
103                        BerValue value = container.getCurrentTLV().getValue();
104
105                        try
106                        {
107                            // Check that the value is into the allowed interval
108                            int size = IntegerDecoder.parse( value, Integer.MIN_VALUE, Integer.MAX_VALUE );
109
110                            // We allow negative value to absorb a bug in some M$ client.
111                            // Those negative values will be transformed to Integer.MAX_VALUE.
112                            if ( size < 0 )
113                            {
114                                size = Integer.MAX_VALUE;
115                            }
116
117                            if ( IS_DEBUG )
118                            {
119                                LOG.debug( "size = " + size );
120                            }
121
122                            container.getDecorator().setSize( size );
123                        }
124                        catch ( IntegerDecoderException ide )
125                        {
126                            String msg = I18n.err( I18n.ERR_04050 );
127                            LOG.error( msg, ide );
128                            throw new DecoderException( msg, ide );
129                        }
130                    }
131                } );
132
133        /** 
134         * Transition from size to cookie
135         * realSearchControlValue ::= SEQUENCE OF {
136         *     ...
137         *     cookie   OCTET STRING
138         * }
139         *     
140         * Stores the cookie flag
141         */
142        super.transitions[PagedResultsStates.SIZE_STATE.ordinal()][UniversalTag.OCTET_STRING.getValue()] =
143            new GrammarTransition<PagedResultsContainer>( PagedResultsStates.SIZE_STATE,
144                PagedResultsStates.COOKIE_STATE, UniversalTag.OCTET_STRING.getValue(),
145                new GrammarAction<PagedResultsContainer>( "Set PagedSearchControl cookie" )
146                {
147                    public void action( PagedResultsContainer container ) throws DecoderException
148                    {
149                        BerValue value = container.getCurrentTLV().getValue();
150
151                        if ( container.getCurrentTLV().getLength() == 0 )
152                        {
153                            container.getDecorator().setCookie( Strings.EMPTY_BYTES );
154                        }
155                        else
156                        {
157                            container.getDecorator().setCookie( value.getData() );
158                        }
159
160                        // We can have an END transition
161                        container.setGrammarEndAllowed( true );
162                    }
163                } );
164    }
165
166
167    /**
168     * This class is a singleton.
169     * 
170     * @return An instance on this grammar
171     */
172    public static Grammar<?> getInstance()
173    {
174        return instance;
175    }
176}