2009/05/20 - Apache Shale has been retired.

For more information, please explore the Attic.


1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to you under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  
18  package org.apache.shale.dialog.basic.config;
19  
20  import java.util.HashMap;
21  import java.util.Iterator;
22  import java.util.Map;
23  import org.apache.shale.dialog.basic.model.Dialog;
24  import org.apache.shale.dialog.basic.model.State;
25  import org.apache.shale.dialog.basic.model.Transition;
26  
27  /***
28   * <p>Abstract base class for {@link State} definitions.  Each state is owned
29   * by exactly one owning {@link Dialog}.  While an application
30   * is running, {@link Dialog} (and the constituent {@link State}s and
31   * other configuration information) is immutable, so that it may be
32   * shared by multiple simultaneous paths of execution.</p>
33   *
34   * @since 1.0.4
35   */
36  
37  public abstract class AbstractState implements State {
38  
39  
40      // ------------------------------------------------------ Instance Variables
41  
42  
43      /***
44       * <p>The {@link Dialog} that owns this {@link State} instance.</p>
45       */
46      private Dialog dialog = null;
47  
48  
49      /***
50       * <p>The identifier of this {@link State}, which must be unique among
51       * all {@link State}s within the owning {@link Dialog}.</p>
52       */
53      private String name = null;
54  
55  
56      /***
57       * <p>The {@link Transition}s owned by this {@link State}, keyed by
58       * outcome.  <strong>FIXME</strong> - a different strategy will be needed
59       * if {@link Transition}s become more complex and manage their own
60       * criteria.</p>
61       */
62      private Map transitions = new HashMap();
63  
64  
65      // -------------------------------------------------------------- Properties
66  
67  
68      /***
69       * {@inheritDoc}
70       */
71      public Dialog getDialog() {
72  
73          return this.dialog;
74  
75      }
76  
77  
78      /***
79       * {@inheritDoc}
80       */
81      public String getName() {
82  
83          return this.name;
84  
85      }
86  
87  
88      /***
89       * {@inheritDoc}
90       */
91      public Iterator getTransitionOutcomes() {
92  
93          return this.transitions.keySet().iterator();
94  
95      }
96  
97  
98      // ---------------------------------------------------------- Public Methods
99  
100 
101     /***
102      * <p>Return the {@link Transition} for the specified logical outcome,
103      * if any; otherwise, return <code>null</code>.</p>
104      *
105      * @param outcome Logical outcome for which to return a {@link Transition}
106      * @return The matching {@link Transition}
107      */
108     public Transition findTransition(String outcome) {
109 
110         return (Transition) transitions.get(outcome);
111 
112     }
113 
114 
115     // --------------------------------------------------- Configuration Methods
116 
117 
118     /***
119      * <p>Add the specified {@link Transition} to the {@link Transition}s owned
120      * by this {@link State}.</p>
121      *
122      * @param transition {@link Transition} to be added
123      *
124      * @exception IllegalArgumentException if the specified {@link Transition}
125      *  cannot be added to this {@link State}
126      */
127     public void addTransition(Transition transition) throws IllegalArgumentException {
128 
129         // FIXME - addTransition() - ignore duplicate outcomes for now
130         transitions.put(transition.getOutcome(), transition);
131 
132     }
133 
134 
135     /***
136      * <p>Remove the specified {@link Transition} from the {@link Transition}s
137      * owned by this {@link State}, if it is currently registered.  Otherwise,
138      * do nothing.</p>
139      *
140      * @param transition {@link Transition} to be removed
141      */
142     public void removeTransition(Transition transition) {
143 
144         transitions.remove(transition.getOutcome());
145 
146     }
147 
148 
149     /***
150      * <p>Set the {@link Dialog} that owns this {@link State}.</p>
151      *
152      * @param dialog New owning {@link Dialog}
153      */
154     public void setDialog(Dialog dialog) {
155 
156         this.dialog = dialog;
157 
158     }
159 
160 
161 
162     /***
163      * <p>Set the identifier of this {@link State}, which must be unique
164      * among the {@link State}s owned by the same {@link Dialog}.</p>
165      *
166      * @param name New identifier
167      */
168     public void setName(String name) {
169 
170         this.name = name;
171 
172     }
173 
174 
175 }