| State.java |
1 /*
2 * State.java
3 *
4 * Copyright (c) 1998-2005, The University of Sheffield.
5 *
6 * This file is part of GATE (see http://gate.ac.uk/), and is free
7 * software, licenced under the GNU Library General Public License,
8 * Version 2, June 1991 (in the distribution as file licence.html,
9 * and also available at http://gate.ac.uk/gate/licence.html).
10 *
11 * Valentin Tablan, 11/Apr/2000
12 *
13 * $Id: State.java,v 1.39 2005/01/11 13:51:34 ian Exp $
14 */
15
16 package gate.fsm;
17
18 import java.util.Iterator;
19
20 import gate.jape.*;
21 import gate.util.SimpleArraySet;
22
23 /**
24 * This class implements a Finite State Machine state.
25 *
26 */
27 public class State implements JapeConstants {
28
29 /** Debug flag
30 */
31 private static final boolean DEBUG = false;
32
33 /**
34 * Build a new state.
35 */
36 public State() {
37 myIndex = State.index++;
38 isFinal = false;
39 }
40
41 /**
42 * Reports if this state is a final one.
43 * Note: A state has an associated action if and only if it is final.
44 */
45 public boolean isFinal() {
46 return isFinal;
47 }
48
49 /**
50 * Gets the set of transitions for this state.
51 *
52 * @return a Set contining objects of type gate.fsm.Transition
53 */
54 // >>> DAM, was Set
55 /*
56 public Set getTransitions() {
57 return transitions;
58 }
59 */
60 // >>> DAM, TransArray optimization
61 public SimpleArraySet getTransitions() {
62 return transitions;
63 }
64 // >>> DAM, end
65 /** Sets the action associated to this FINAL state. An action is actually
66 * a gate.jape.RightHandSide object.
67 * NOTE: only a final state has an associated action so after a call to this
68 * method this state will be a final one.
69 */
70 protected void setAction(RightHandSide rhs) {
71 action = rhs;
72 isFinal = (action != null);
73 }
74
75 /** Sets the value for fileIndex. File index is the index in the jape
76 * definition file of the rule that contains as right hand side the action
77 * associated to this state. This value is only intended for final states.
78 */
79 protected void setFileIndex(int i) { fileIndex = i; }
80
81 /** Sets the value for priority. Priority is the priority in the jape
82 * definition file of the rule that contains as right hand side the action
83 * associated to this state. This value is only intended for final states.
84 */
85 protected void setPriority(int i) { priority = i; }
86
87 /**
88 * Gets the action associated to this state.
89 *
90 * @return a RightHandSide object
91 */
92 public RightHandSide getAction() {
93 return action;
94 }
95
96 /**
97 * Returns the index in the definition file of the rule that generated this
98 * state.
99 * The value for fileIndex is correct only on final states!
100 */
101 int getFileIndex() { return fileIndex; }
102
103 /**
104 * Returns the priority in the definition file of the rule that generated
105 * this state.
106 * This value is correct only on final states!
107 */
108 int getPriority() { return priority; }
109
110 /**
111 * Adds a new transition to the list of outgoing transitions for this state.
112 *
113 * @param transition the transition to be added
114 */
115 public void addTransition(Transition transition) {
116 transitions.add(transition);
117 } // addTransition
118
119 /**
120 * Gets the index of this state. Each state has a unique index (a int value).
121 * This value is not actually used by any of the algorithms. It is useful only
122 * as a way of refering to states in string representations so it is used by
123 * toString and GML related methods.
124 *
125 * @return the index associated to this state
126 */
127 protected int getIndex() {
128 return myIndex;
129 }// getIndex
130
131 /**
132 * Returns a GML (graph modelling language) representation for the edges
133 * corresponding to transitions departing from this state in the
134 * transition graph of the FSM to which this state belongs
135 *
136 * @return a string value contining the GML text
137 */
138 public String getEdgesGML() {
139 /// String res = "";
140 StringBuffer res = new StringBuffer(gate.Gate.STRINGBUFFER_SIZE);
141
142 Iterator transIter = transitions.iterator();
143 BasicPatternElement bpe;
144
145 while(transIter.hasNext()) {
146 Transition currentTrans = (Transition)transIter.next();
147 /* res += "edge [ source " + myIndex +
148 " target " + currentTrans.getTarget().getIndex() +
149 " label \"" + currentTrans.shortDesc() + ":";
150 */
151 res.append("edge [ source ");
152 res.append(myIndex);
153 res.append(" target ");
154 res.append(currentTrans.getTarget().getIndex());
155 res.append(" label \"");
156 res.append(currentTrans.shortDesc());
157 res.append(":");
158
159 bpe = currentTrans.getConstraints();
160 if(bpe == null) ///res += "null";
161 res.append("null");
162 else ///res += bpe.shortDesc();
163 res.append(bpe.shortDesc());
164 /// res += " :" + currentTrans.getBindings() + "\" ]\n";
165 res.append(" :");
166 res.append(currentTrans.getBindings());
167 res.append("\" ]\n");
168 }
169 return res.toString();
170 } // getEdgesGML
171
172 /**
173 * Returns a textual description of this state
174 *
175 * @return a String value.
176 */
177 public String toString() {
178 /// String res = "State " + myIndex;
179 StringBuffer res = new StringBuffer(gate.Gate.STRINGBUFFER_SIZE);
180
181 if(isFinal()) ///res += "\nFinal!";
182 res.append("\nFinal!");
183
184 ///res += "\nTransitions:\n";
185 res.append("\nTransitions:\n");
186
187 Iterator transIter = transitions.iterator();
188 while(transIter.hasNext()){
189 ///res += transIter.next().toString();
190 res.append(transIter.next().toString());
191 }
192 return res.toString();
193 }
194
195
196 /**
197 * A set of objects of type gata.fsm.Transition representing the outgoing
198 * transitions.
199 */
200 // >>> DAM was
201 /*
202 private Set transitions = new HashSet();
203 */
204 // >>> DAM, TransArray optimization
205 private SimpleArraySet transitions = new SimpleArraySet();
206 // >>> DAM, end
207
208 /**
209 * Is this state a final one?
210 */
211 protected boolean isFinal = false;
212
213 /**
214 * The right hand side associated to the rule for which this state recognizes
215 * the lhs.
216 */
217 protected RightHandSide action = null;
218
219 /**
220 * The unique index of this state.
221 */
222 protected int myIndex;
223
224 /**
225 * The class data member used for generating unique indices for State
226 * instances.
227 */
228 protected static int index = 0;
229
230 /**
231 * The index in the definition file of the rule that was used for creating
232 * this state.
233 * NOTE: this member is consistent only for FINAL STATES!
234 */
235 protected int fileIndex = 0;
236
237 /**
238 * The priority of the rule from which this state derived.
239 *
240 */
241 protected int priority = -1;
242
243 } // State
244