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.base;
18
19
20 import org.apache.commons.workflow.Activity;
21 import org.apache.commons.workflow.Context;
22 import org.apache.commons.workflow.Owner;
23 import org.apache.commons.workflow.Step;
24 import org.apache.commons.workflow.StepException;
25
26
27 /**
28 * <p><strong>BaseStep</strong> is a convenient base class for more sophisticated
29 * <code>Step</code> implementations. It includes management of the static
30 * relationships of Steps to each other, and to their owning Activity, but
31 * requires the implementation to provide an <code>execute()</code> method.
32 *
33 * @version $Revision: 155475 $ $Date: 2005-02-26 13:31:11 +0000 (Sat, 26 Feb 2005) $
34 * @author Craig R. McClanahan
35 */
36
37 public abstract class BaseStep implements Step {
38
39
40 // ----------------------------------------------------- Instance Variables
41
42
43 /**
44 * The unique identifier (within this Activity) of this Step.
45 */
46 protected String id = null;
47
48
49 /**
50 * The next Step in our associated Activity.
51 */
52 protected Step nextStep = null;
53
54
55 /**
56 * The Activity or Block that owns this Step.
57 */
58 protected Owner owner = null;
59
60
61
62 /**
63 * The previous Step in our associated Activity.
64 */
65 protected Step previousStep = null;
66
67
68
69 // ------------------------------------------------------------- Properties
70
71
72 /**
73 * Return the unique identifier (within this Activity or Block)
74 * of this Step.
75 */
76 public String getId() {
77
78 return (this.id);
79
80 }
81
82
83 /**
84 * Set the unique identifier (within this Activity or Block)
85 * of this Step.
86 *
87 * @param id The new unique identifier
88 */
89 public void setId(String id) {
90
91 this.id = id;
92
93 }
94
95
96 /**
97 * Return the next Step in our associated Activity or Block.
98 */
99 public Step getNextStep() {
100
101 return (this.nextStep);
102
103 }
104
105
106 /**
107 * Set the next Step in our associated Activity or Block.
108 *
109 * @param nextStep The new next Step
110 */
111 public void setNextStep(Step nextStep) {
112
113 this.nextStep = nextStep;
114
115 }
116
117
118 /**
119 * Return the Activity or Block that owns this Step.
120 */
121 public Owner getOwner() {
122
123 return (this.owner);
124
125 }
126
127
128 /**
129 * Set the Activity or Block that owns this Step.
130 *
131 * @param owner The new owning Activity or Block
132 */
133 public void setOwner(Owner owner) {
134
135 this.owner = owner;
136
137 }
138
139
140 /**
141 * Return the previous Step in our associated Activity or Block.
142 */
143 public Step getPreviousStep() {
144
145 return (this.previousStep);
146
147 }
148
149
150 /**
151 * Set the previous Step in our associated Activity or Block.
152 *
153 * @param previousStep The new previous Step
154 */
155 public void setPreviousStep(Step previousStep) {
156
157 this.previousStep = previousStep;
158
159 }
160
161
162 // --------------------------------------------------------- Public Methods
163
164
165 /**
166 * Perform the executable actions related to this Step, in the context of
167 * the specified Context.
168 *
169 * @param context The Context that is tracking our execution state
170 *
171 * @exception StepException if a processing error has occurred
172 */
173 public abstract void execute(Context context) throws StepException;
174
175
176 }