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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.mina.example.tapedeck;
21  
22  import static org.apache.mina.statemachine.event.IoHandlerEvents.*;
23  
24  import org.apache.mina.core.future.IoFutureListener;
25  import org.apache.mina.core.session.IoSession;
26  import org.apache.mina.statemachine.StateControl;
27  import org.apache.mina.statemachine.annotation.IoHandlerTransition;
28  import org.apache.mina.statemachine.annotation.IoHandlerTransitions;
29  import org.apache.mina.statemachine.annotation.State;
30  import org.apache.mina.statemachine.context.AbstractStateContext;
31  import org.apache.mina.statemachine.context.StateContext;
32  import org.apache.mina.statemachine.event.Event;
33  
34  /**
35   * The actual state machine implementation for the tape deck server.
36   *
37   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
38   */
39  public class TapeDeckServer {
40      @State public static final String ROOT = "Root";
41      @State(ROOT) public static final String EMPTY = "Empty";
42      @State(ROOT) public static final String LOADED = "Loaded";
43      @State(ROOT) public static final String PLAYING = "Playing";
44      @State(ROOT) public static final String PAUSED = "Paused";
45      
46      private final String[] tapes = {
47              "The Knife - Silent Shout", 
48              "Kings of convenience - Riot on an empty street"
49      };
50      
51      static class TapeDeckContext extends AbstractStateContext {
52          public String tapeName;
53      }
54      
55      @IoHandlerTransition(on = SESSION_OPENED, in = EMPTY)
56      public void connect(IoSession session) {
57          session.write("+ Greetings from your tape deck!");
58      }
59      
60      @IoHandlerTransition(on = MESSAGE_RECEIVED, in = EMPTY, next = LOADED)
61      public void loadTape(TapeDeckContext context, IoSession session, LoadCommand cmd) {
62          if (cmd.getTapeNumber() < 1 || cmd.getTapeNumber() > tapes.length) {
63              session.write("- Unknown tape number: " + cmd.getTapeNumber());
64              StateControl.breakAndGotoNext(EMPTY);
65          } else {
66              context.tapeName = tapes[cmd.getTapeNumber() - 1];
67              session.write("+ \"" + context.tapeName + "\" loaded");
68          }
69      }
70  
71      @IoHandlerTransitions({
72          @IoHandlerTransition(on = MESSAGE_RECEIVED, in = LOADED, next = PLAYING),
73          @IoHandlerTransition(on = MESSAGE_RECEIVED, in = PAUSED, next = PLAYING)
74      })
75      public void playTape(TapeDeckContext context, IoSession session, PlayCommand cmd) {
76          session.write("+ Playing \"" + context.tapeName + "\"");
77      }
78      
79      @IoHandlerTransition(on = MESSAGE_RECEIVED, in = PLAYING, next = PAUSED)
80      public void pauseTape(TapeDeckContext context, IoSession session, PauseCommand cmd) {
81          session.write("+ \"" + context.tapeName + "\" paused");
82      }
83      
84      @IoHandlerTransition(on = MESSAGE_RECEIVED, in = PLAYING, next = LOADED)
85      public void stopTape(TapeDeckContext context, IoSession session, StopCommand cmd) {
86          session.write("+ \"" + context.tapeName + "\" stopped");
87      }
88      
89      @IoHandlerTransition(on = MESSAGE_RECEIVED, in = LOADED, next = EMPTY)
90      public void ejectTape(TapeDeckContext context, IoSession session, EjectCommand cmd) {
91          session.write("+ \"" + context.tapeName + "\" ejected");
92          context.tapeName = null;
93      }
94      
95      @IoHandlerTransition(on = MESSAGE_RECEIVED, in = ROOT)
96      public void listTapes(IoSession session, ListCommand cmd) {
97          StringBuilder response = new StringBuilder("+ (");
98          for (int i = 0; i < tapes.length; i++) {
99              response.append(i + 1).append(": ");
100             response.append('"').append(tapes[i]).append('"');
101             if (i < tapes.length - 1) {
102                 response.append(", ");
103             }
104         }
105         response.append(')');
106         session.write(response);
107     }
108     
109     @IoHandlerTransition(on = MESSAGE_RECEIVED, in = ROOT)
110     public void info(TapeDeckContext context, IoSession session, InfoCommand cmd) {
111         String state = context.getCurrentState().getId().toLowerCase();
112         if (context.tapeName == null) {
113             session.write("+ Tape deck is " + state + "");
114         } else {
115             session.write("+ Tape deck is " + state 
116                     + ". Current tape: \"" + context.tapeName + "\"");
117         }
118     }
119     
120     @IoHandlerTransition(on = MESSAGE_RECEIVED, in = ROOT)
121     public void quit(TapeDeckContext context, IoSession session, QuitCommand cmd) {
122         session.write("+ Bye! Please come back!").addListener(IoFutureListener.CLOSE);
123     }
124     
125     @IoHandlerTransition(on = MESSAGE_RECEIVED, in = ROOT, weight = 10)
126     public void error(Event event, StateContext context, IoSession session, Command cmd) {
127         session.write("- Cannot " + cmd.getName() 
128                 + " while " + context.getCurrentState().getId().toLowerCase());
129     }
130     
131     @IoHandlerTransition(on = EXCEPTION_CAUGHT, in = ROOT)
132     public void commandSyntaxError(IoSession session, CommandSyntaxException e) {
133         session.write("- " + e.getMessage());
134     }
135     
136     @IoHandlerTransition(on = EXCEPTION_CAUGHT, in = ROOT, weight = 10)
137     public void exceptionCaught(IoSession session, Exception e) {
138         e.printStackTrace();
139         session.close(true);
140     }
141     
142     @IoHandlerTransition(in = ROOT, weight = 100)
143     public void unhandledEvent() {
144     }
145     
146 }