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Java > Open Source Codes > org > springframework > webflow > definition > FlowDefinition


1 /*
2  * Copyright 2002-2006 the original author or authors.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package org.springframework.webflow.definition;
17
18 /**
19  * The definition of a flow, a program that when executed carries out the
20  * orchestration of a task on behalf of a single client.
21  * <p>
22  * A flow definition is a reusable, self-contained controller module that
23  * defines a blue print for an executable user task. Flows typically orchestrate
24  * controlled navigations or dialogs within web applications to guide users
25  * through fulfillment of a business process/goal that takes place over a series
26  * of steps, modeled as states.
27  * <p>
28  * Structurally a flow definition is composed of a set of states. A
29  * {@link StateDefinition state} is a point in a flow where a behavior is
30  * executed; for example, showing a view, executing an action, spawning a
31  * subflow, or terminating the flow. Different types of states execute different
32  * behaviors in a polymorphic fashion. Most states are
33  * {@link TransitionableStateDefinition transitionable states}, meaning they
34  * can respond to events by taking the flow from one state to another.
35  * <p>
36  * Each flow has exactly one {@link #getStartState() start state} which defines
37  * the starting point of the program.
38  * <p>
39  * This interface exposes the flow's identifier, states, and other definitional
40  * attributes. It is suitable for introspection by tools as well as user-code at
41  * flow execution time.
42  * <p>
43  * Flow definitions may be annotated with attributes.
44  *
45  * @author Keith Donald
46  * @author Erwin Vervaet
47  */
48 public interface FlowDefinition extends Annotated {
49
50     /**
51      * Returns the unique id of this flow.
52      * @return the flow id
53      */
54     public String JavaDoc getId();
55
56     /**
57      * Return this flow's starting point.
58      * @return the start state
59      */
60     public StateDefinition getStartState();
61
62     /**
63      * Returns the state definition with the specified id.
64      * @param id the state id
65      * @return the state definition
66      * @throws IllegalArgumentException if a state with this id does not exist
67      */
68     public StateDefinition getState(String JavaDoc id) throws IllegalArgumentException JavaDoc;
69 }
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