1 /*
2 * Copyright 1999-2001,2004 The Apache Software Foundation.
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
17 package org.apache.commons.workflow;
18
19
20 /**
21 * <p>A <strong>Step</strong> represents a single executable action that
22 * can occur during the completion of an Activity. The dynamic execution
23 * of the implementation of this Step happens within the <code>execute()</code>
24 * method -- everything else about a Step is part of its static definition,
25 * which is shared among all users of the owning Activity.</p>
26 *
27 * @version $Revision: 155475 $ $Date: 2005-02-26 13:31:11 +0000 (Sat, 26 Feb 2005) $
28 * @author Craig R. McClanahan
29 */
30
31 public interface Step {
32
33
34 // ------------------------------------------------------------- Properties
35
36
37 /**
38 * Return the unique identifier (within this Activity) of this Step.
39 */
40 public String getId();
41
42
43 /**
44 * Set the unique identifier (within this Activity) of this Step.
45 *
46 * @param id The new unique identifier
47 */
48 public void setId(String id);
49
50
51 /**
52 * Return the next Step in our associated Activity or Block.
53 */
54 public Step getNextStep();
55
56
57 /**
58 * Set the next Step in our associated Activity or Block.
59 *
60 * @param nextStep The new next Step
61 */
62 public void setNextStep(Step nextStep);
63
64
65 /**
66 * Return the Activity or Block that owns this Step.
67 */
68 public Owner getOwner();
69
70
71 /**
72 * Set the Activity or Block that owns this Step.
73 *
74 * @param owner The new owning Activity or Block
75 */
76 public void setOwner(Owner owner);
77
78
79 /**
80 * Return the previous Step in our associated Activity or Block.
81 */
82 public Step getPreviousStep();
83
84
85 /**
86 * Set the previous Step in our associated Activity or Block.
87 *
88 * @param previousStep The new previous Step
89 */
90 public void setPreviousStep(Step previousStep);
91
92
93 // --------------------------------------------------------- Public Methods
94
95
96 /**
97 * Perform the executable actions related to this Step, in the context of
98 * the specified Context.
99 *
100 * @param context The Context that is tracking our execution state
101 *
102 * @exception StepException if a processing error has occurred
103 */
104 public void execute(Context context) throws StepException;
105
106
107 }