1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
|
/*
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*
*/
package org.apache.qpid.server.store;
import java.util.EnumMap;
import java.util.Map;
import org.apache.qpid.server.store.StateManager.Transition;
public class StateManager
{
private State _state = State.INITIAL;
private EventListener _eventListener;
private static final Map<State,Map<State, Transition>> _validTransitions = new EnumMap<State, Map<State, Transition>>(State.class);
static class Transition
{
private final Event _event;
private final State _endState;
private final State _startState;
public Transition(State startState, State endState, Event event)
{
_event = event;
_startState = startState;
_endState = endState;
Map<State, Transition> stateTransitions = _validTransitions.get(startState);
if(stateTransitions == null)
{
stateTransitions = new EnumMap<State, Transition>(State.class);
_validTransitions.put(startState, stateTransitions);
}
stateTransitions.put(endState, this);
}
public Event getEvent()
{
return _event;
}
public State getStartState()
{
return _startState;
}
public State getEndState()
{
return _endState;
}
}
public static final Transition INITIALISE = new Transition(State.INITIAL, State.INITIALISING, Event.BEFORE_INIT);
public static final Transition INITALISE_COMPLETE = new Transition(State.INITIALISING, State.INITIALISED, Event.AFTER_INIT);
public static final Transition ACTIVATE = new Transition(State.INITIALISED, State.ACTIVATING, Event.BEFORE_ACTIVATE);
public static final Transition ACTIVATE_COMPLETE = new Transition(State.ACTIVATING, State.ACTIVE, Event.AFTER_ACTIVATE);
public static final Transition CLOSE_INITIALISED = new Transition(State.INITIALISED, State.CLOSING, Event.BEFORE_CLOSE);;
public static final Transition CLOSE_ACTIVE = new Transition(State.ACTIVE, State.CLOSING, Event.BEFORE_CLOSE);
public static final Transition CLOSE_QUIESCED = new Transition(State.QUIESCED, State.CLOSING, Event.BEFORE_CLOSE);
public static final Transition CLOSE_COMPLETE = new Transition(State.CLOSING, State.CLOSED, Event.AFTER_CLOSE);
public static final Transition PASSIVATE = new Transition(State.ACTIVE, State.INITIALISED, Event.BEFORE_PASSIVATE);
public static final Transition QUIESCE = new Transition(State.ACTIVE, State.QUIESCING, Event.BEFORE_QUIESCE);
public static final Transition QUIESCE_COMPLETE = new Transition(State.QUIESCING, State.QUIESCED, Event.AFTER_QUIESCE);
public static final Transition RESTART = new Transition(State.QUIESCED, State.ACTIVATING, Event.BEFORE_RESTART);
public StateManager(final EventManager eventManager)
{
this(new EventListener()
{
@Override
public void event(Event event)
{
eventManager.notifyEvent(event);
}
});
}
public StateManager(EventListener eventListener)
{
_eventListener = eventListener;
}
public synchronized State getState()
{
return _state;
}
public synchronized void attainState(State desired)
{
Transition transition = null;
final Map<State, Transition> stateTransitionMap = _validTransitions.get(_state);
if(stateTransitionMap != null)
{
transition = stateTransitionMap.get(desired);
}
if(transition == null)
{
throw new IllegalStateException("No valid transition from state " + _state + " to state " + desired);
}
_state = desired;
_eventListener.event(transition.getEvent());
}
public synchronized boolean isInState(State testedState)
{
return _state.equals(testedState);
}
public synchronized boolean isNotInState(State testedState)
{
return !isInState(testedState);
}
public synchronized void checkInState(State checkedState)
{
if (isNotInState(checkedState))
{
throw new IllegalStateException("Unexpected state. Was : " + _state + " but expected : " + checkedState);
}
}
}
|
