1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 *
19 */
20 package org.apache.directory.api.asn1.ber.grammar;
21
22
23 import org.apache.directory.api.asn1.DecoderException;
24 import org.apache.directory.api.asn1.ber.Asn1Container;
25 import org.apache.directory.api.asn1.util.Asn1StringUtils;
26 import org.apache.directory.api.i18n.I18n;
27 import org.slf4j.Logger;
28 import org.slf4j.LoggerFactory;
29
30
31 /**
32 * The abstract Grammar which is the Mother of all the grammars. It contains
33 * the transitions table.
34 *
35 * @param C The container type
36 *
37 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
38 */
39 public abstract class AbstractGrammar<C extends Asn1Container> implements Grammar<C>
40 {
41 /** The logger */
42 private static final Logger LOG = LoggerFactory.getLogger( AbstractGrammar.class );
43
44 /** Speedup for logs */
45 private static final boolean IS_DEBUG = LOG.isDebugEnabled();
46
47 /**
48 * Table of transitions. It's a two dimension array, the first dimension
49 * indices the states, the second dimension indices the Tag value, so it is
50 * 256 wide.
51 */
52 protected GrammarTransition<C>[][] transitions;
53
54 /** The grammar name */
55 private String name;
56
57
58 /** Default constructor */
59 public AbstractGrammar()
60 {
61 }
62
63
64 /**
65 * {@inheritDoc}
66 */
67 public String getName()
68 {
69 return name;
70 }
71
72
73 /**
74 * {@inheritDoc}
75 */
76 public void setName( String name )
77 {
78 this.name = name;
79 }
80
81
82 /**
83 * Get the transition associated with the state and tag
84 *
85 * @param state The current state
86 * @param tag The current tag
87 * @return A valid transition if any, or null.
88 */
89 public GrammarTransition<C> getTransition( Enum<?> state, int tag )
90 {
91 return transitions[state.ordinal()][tag & 0x00FF];
92 }
93
94
95 /**
96 * {@inheritDoc}
97 */
98 public void executeAction( C container ) throws DecoderException
99 {
100
101 Enum<?> currentState = container.getTransition();
102 // We have to deal with the special case of a GRAMMAR_END state
103 if ( ( ( States ) currentState ).isEndState() )
104 {
105 return;
106 }
107
108 byte tagByte = container.getCurrentTLV().getTag();
109
110 // We will loop until no more actions are to be executed
111 @SuppressWarnings("unchecked")
112 GrammarTransition<C> transition = ( ( AbstractGrammar<C> ) container.getGrammar() ).getTransition(
113 currentState,
114 tagByte );
115
116 if ( transition == null )
117 {
118 String errorMessage = I18n.err( I18n.ERR_00001_BAD_TRANSITION_FROM_STATE, currentState,
119 Asn1StringUtils.dumpByte( tagByte ) );
120
121 LOG.error( errorMessage );
122
123 // If we have no more grammar on the stack, then this is an
124 // error
125 throw new DecoderException( errorMessage );
126 }
127
128 if ( IS_DEBUG )
129 {
130 LOG.debug( transition.toString() );
131 }
132
133 if ( transition.hasAction() )
134 {
135 Action<C> action = transition.getAction();
136 action.action( container );
137 }
138
139 container.setTransition( transition.getCurrentState() );
140 }
141 }