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.ber.Asn1Container;
24 import org.apache.directory.api.asn1.ber.tlv.UniversalTag;
25 import org.apache.directory.api.asn1.util.Asn1StringUtils;
26
27
28 /**
29 * Define a transition between two states of a grammar. It stores the next
30 * state, and the action to execute while executing the transition.
31 *
32 * @param <C> The container type
33 *
34 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
35 */
36 public class GrammarTransition<C extends Asn1Container>
37 {
38 /** The action associated to the transition */
39 private Action<C> action;
40
41 /** The previous state */
42 private Enum<?> previousState;
43
44 /** The current state */
45 private Enum<?> currentState;
46
47 /** The current tag */
48 private int currentTag;
49
50
51 /**
52 * Creates a new GrammarTransition object.
53 *
54 * @param previousState the previous state
55 * @param currentState The current state
56 * @param currentTag the current TLV's tag
57 * @param action The action to execute. It could be null.
58 */
59 public GrammarTransition( Enum<?> previousState, Enum<?> currentState, int currentTag, Action<C> action )
60 {
61 this.previousState = previousState;
62 this.currentState = currentState;
63 this.action = action;
64 this.currentTag = currentTag;
65 }
66
67
68 /**
69 * Creates a new GrammarTransition object.
70 *
71 * @param previousState the previous state
72 * @param currentState The current state
73 * @param currentTag the current TLV's tag
74 */
75 public GrammarTransition( Enum<?> previousState, Enum<?> currentState, int currentTag )
76 {
77 this.previousState = previousState;
78 this.currentState = currentState;
79 this.currentTag = currentTag;
80 }
81
82
83 /**
84 * Creates a new GrammarTransition object.
85 *
86 * @param previousState the previous state
87 * @param currentState The current state
88 * @param currentTag the current TLV's tag
89 * @param action The action to execute. It could be null.
90 */
91 public GrammarTransition( Enum<?> previousState, Enum<?> currentState, UniversalTag currentTag, Action<C> action )
92 {
93 this.previousState = previousState;
94 this.currentState = currentState;
95 this.action = action;
96 this.currentTag = currentTag.getValue();
97 }
98
99
100 /**
101 * Creates a new GrammarTransition object.
102 *
103 * @param previousState the previous state
104 * @param currentState The current state
105 * @param currentTag the current TLV's tag
106 */
107 public GrammarTransition( Enum<?> previousState, Enum<?> currentState, UniversalTag currentTag )
108 {
109 this.previousState = previousState;
110 this.currentState = currentState;
111 this.currentTag = currentTag.getValue();
112 }
113
114
115 /**
116 * Tells if the transition has an associated action.
117 *
118 * @return <code>true</code> if an action has been associated to the transition
119 */
120 public boolean hasAction()
121 {
122 return action != null;
123 }
124
125
126 /**
127 * @return Returns the action associated with the transition
128 */
129 public Action<C> getAction()
130 {
131 return action;
132 }
133
134
135 /**
136 * @return The current state
137 */
138 public Enum<?> getCurrentState()
139 {
140 return currentState;
141 }
142
143
144 /**
145 * @return The previous state
146 */
147 public Enum<?> getPreviousState()
148 {
149 return previousState;
150 }
151
152
153 /**
154 * @return A representation of the transition as a string.
155 */
156 @Override
157 public String toString()
158 {
159 StringBuilder sb = new StringBuilder();
160
161 sb.append( "Transition from state <" ).append( previousState ).append( "> " );
162 sb.append( "to state <" ).append( currentState ).append( ">, " );
163 sb.append( "tag <" ).append( Asn1StringUtils.dumpByte( ( byte ) currentTag ) ).append( ">, " );
164 sb.append( "action : " );
165
166 if ( action == null )
167 {
168 sb.append( "no action" );
169 }
170 else
171 {
172 sb.append( action );
173 }
174
175 return sb.toString();
176 }
177 }