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.statemachine;
21
22 import org.apache.mina.statemachine.event.Event;
23 import org.apache.mina.statemachine.transition.Transition;
24
25 /**
26 * Allows for programmatic control of a state machines execution.
27 * <p>
28 * The <code>*Now()</code> family of methods move to a new {@link State}
29 * immediately and let the new {@link State} handle the current {@link Event}.
30 * The <code>*Next()</code> family on the other hand let the new {@link State}
31 * handle the next {@link Event} which is generated which make these method the
32 * programmatic equivalent of using the {@link org.apache.mina.statemachine.annotation.Transition} annotation.
33 * </p>
34 * <p>
35 * Using the <code>breakAndCall*()</code> and <code>breakAndReturn*</code> methods one
36 * can create sub state machines which behave very much like sub routines.
37 * When calling a state the current state (or the specified <code>returnTo</code>
38 * state) will be pushed on a stack. When returning from a state the last pushed
39 * state will be popped from the stack and used as the new state.
40 * </p>
41 *
42 * @author The Apache MINA Project (dev@mina.apache.org)
43 */
44 public class StateControl {
45
46 /**
47 * Breaks the execution of the current {@link Transition} and tries to
48 * find another {@link Transition} with higher weight or a {@link Transition}
49 * of a parent {@link State} which can handle the current {@link Event}.
50 */
51 public static void breakAndContinue() {
52 throw new BreakAndContinueException();
53 }
54
55 /**
56 * Breaks the execution of the current {@link Transition} and lets the
57 * {@link State} with the specified id handle the <strong>current</strong> {@link Event}.
58 *
59 * @param state the id of the {@link State} to go to.
60 */
61 public static void breakAndGotoNow(String state) {
62 throw new BreakAndGotoException(state, true);
63 }
64
65 /**
66 * Breaks the execution of the current {@link Transition} and lets the
67 * {@link State} with the specified id handle the <strong>next</strong> {@link Event}.
68 * Using this method is the programmatic equivalent of using the
69 * {@link org.apache.mina.statemachine.annotation.Transition} annotation.
70 *
71 * @param state the id of the {@link State} to go to.
72 */
73 public static void breakAndGotoNext(String state) {
74 throw new BreakAndGotoException(state, false);
75 }
76
77 /**
78 * Breaks the execution of the current {@link Transition} and lets the
79 * {@link State} with the specified id handle the <strong>current</strong> {@link Event}.
80 * Before moving to the new state the current state will be recorded. The
81 * next call to {@link #breakAndReturnNow()} or {@link #breakAndReturnNext()}
82 * will return to the current state.
83 *
84 * @param state the id of the {@link State} to call.
85 */
86 public static void breakAndCallNow(String state) {
87 throw new BreakAndCallException(state, true);
88 }
89
90 /**
91 * Breaks the execution of the current {@link Transition} and lets the
92 * {@link State} with the specified id handle the <strong>next</strong> {@link Event}.
93 * Before moving to the new state the current state will be recorded. The
94 * next call to {@link #breakAndReturnNow()} or {@link #breakAndReturnNext()}
95 * will return to the current state.
96 *
97 * @param state the id of the {@link State} to call.
98 */
99 public static void breakAndCallNext(String state) {
100 throw new BreakAndCallException(state, false);
101 }
102
103 /**
104 * Breaks the execution of the current {@link Transition} and lets the
105 * {@link State} with the specified id handle the <strong>current</strong> {@link Event}.
106 * Before moving to the new state the current state will be recorded. The
107 * next call to {@link #breakAndReturnNow()} or {@link #breakAndReturnNext()}
108 * will return to the specified <code>returnTo</code> state.
109 *
110 * @param state the id of the {@link State} to call.
111 * @param returnTo the id of the {@link State} to return to.
112 */
113 public static void breakAndCallNow(String state, String returnTo) {
114 throw new BreakAndCallException(state, returnTo, true);
115 }
116
117 /**
118 * Breaks the execution of the current {@link Transition} and lets the
119 * {@link State} with the specified id handle the <strong>next</strong> {@link Event}.
120 * Before moving to the new state the current state will be recorded. The
121 * next call to {@link #breakAndReturnNow()} or {@link #breakAndReturnNext()}
122 * will return to the specified <code>returnTo</code> state.
123 *
124 * @param state the id of the {@link State} to call.
125 * @param returnTo the id of the {@link State} to return to.
126 */
127 public static void breakAndCallNext(String state, String returnTo) {
128 throw new BreakAndCallException(state, returnTo, false);
129 }
130
131 /**
132 * Breaks the execution of the current {@link Transition} and lets the
133 * last recorded {@link State} handle the <strong>current</strong> {@link Event}.
134 */
135 public static void breakAndReturnNow() {
136 throw new BreakAndReturnException(true);
137 }
138
139 /**
140 * Breaks the execution of the current {@link Transition} and lets the
141 * last recorded {@link State} handle the <strong>next</strong> {@link Event}.
142 */
143 public static void breakAndReturnNext() {
144 throw new BreakAndReturnException(false);
145 }
146 }