01: /*
02: * Copyright 2004-2007 the original author or authors.
03: *
04: * Licensed under the Apache License, Version 2.0 (the "License");
05: * you may not use this file except in compliance with the License.
06: * You may obtain a copy of the License at
07: *
08: * http://www.apache.org/licenses/LICENSE-2.0
09: *
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 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 id)
69: throws IllegalArgumentException;
70: }
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