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.core;
18
19
20 import org.apache.commons.workflow.Context;
21 import org.apache.commons.workflow.Descriptor;
22 import org.apache.commons.workflow.Step;
23 import org.apache.commons.workflow.StepException;
24
25
26 /**
27 * <p>Evaluate properties specified by the associated Descriptors, and
28 * transfer control to the specified step if ALL of them are
29 * <code>true</code> (if boolean) or not null (if Object). To avoid
30 * non-deterministic evaluation stack behavior, all of the specified
31 * Descriptors are always evaluated.</p>
32 *
33 * <p>Supported Attributes:</p>
34 * <ul>
35 * <li><strong>step</strong> - Identifier of the Step to which control
36 * should be transferred if the condition is met.</li>
37 * </ul>
38 *
39 * @version $Revision: 155475 $ $Date: 2005-02-26 13:31:11 +0000 (Sat, 26 Feb 2005) $
40 * @author Craig R. McClanahan
41 */
42
43 public class AndStep extends GotoStep {
44
45
46 // ----------------------------------------------------------= Constructors
47
48
49 /**
50 * Construct a default instance of this Step.
51 */
52 public AndStep() {
53
54 super();
55
56 }
57
58
59 /**
60 * Construct an instance of this Step with the specified identifier.
61 *
62 * @param id Step identifier
63 */
64 public AndStep(String id) {
65
66 this(id, null, null);
67
68 }
69
70
71 /**
72 * Construct a fully configured instance of this Step.
73 *
74 * @param id Step identifier of this step
75 * @param step Step identifier to which control should be redirected
76 */
77 public AndStep(String id, String step) {
78
79 this(id, step, null);
80
81 }
82
83
84 /**
85 * Construct a fully configured instance of this Step.
86 *
87 * @param id Step identifier of this step
88 * @param step Step identifier to which control should be redirected
89 * @param descriptor Initial descriptor to be added
90 */
91 public AndStep(String id, String step, Descriptor descriptor) {
92
93 super();
94 setId(id);
95 setStep(step);
96 addDescriptor(descriptor);
97
98 }
99
100
101 // --------------------------------------------------------- Public Methods
102
103
104 /**
105 * Perform the executable actions related to this Step, in the context of
106 * the specified Context.
107 *
108 * @param context The Context that is tracking our execution state
109 *
110 * @exception StepException if a processing error has occurred
111 */
112 public void execute(Context context) throws StepException {
113
114 // Process all associated descriptors
115 boolean condition = true;
116 Descriptor descriptors[] = findDescriptors();
117 for (int i = 0; i < descriptors.length; i++) {
118 Object value = descriptors[i].get(context);
119 if (value == null)
120 condition = false;
121 else if ((value instanceof Boolean) &&
122 !((Boolean) value).booleanValue())
123 condition = false;
124 }
125
126 // Conditionally forward control to the specified step
127 if (condition) {
128 Step next = getOwner().findStep(this.step);
129 if (next == null)
130 throw new StepException("Cannot find step '" + step + "'",
131 this);
132 context.setNextStep(next);
133 }
134
135 }
136
137
138 }