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.StepException;
23 import org.apache.commons.workflow.base.DescriptorStep;
24
25
26 /**
27 * <p>For each associated <code>Descriptor</code>, make a copy of the
28 * specified Java object and push it on to the evaluation stack, in the
29 * order that descriptors are listed.</p>
30 *
31 * @version $Revision: 155475 $ $Date: 2005-02-26 13:31:11 +0000 (Sat, 26 Feb 2005) $
32 * @author Craig R. McClanahan
33 */
34
35 public class GetStep extends DescriptorStep {
36
37
38 // ----------------------------------------------------------= Constructors
39
40
41 /**
42 * Construct a default instance of this Step.
43 */
44 public GetStep() {
45
46 super();
47
48 }
49
50
51 /**
52 * Construct an instance of this Step with the specified identifier.
53 *
54 * @param id Step identifier
55 */
56 public GetStep(String id) {
57
58 super();
59 setId(id);
60
61 }
62
63
64 /**
65 * Construct an instance of this Step with the specified identifier
66 * and associated Descriptor.
67 *
68 * @param id Step identifier
69 * @param descriptor Initial descriptor
70 */
71 public GetStep(String id, Descriptor descriptor) {
72
73 super();
74 setId(id);
75 addDescriptor(descriptor);
76
77 }
78
79
80 // --------------------------------------------------------- Public Methods
81
82
83 /**
84 * Perform the executable actions related to this Step, in the context of
85 * the specified Context.
86 *
87 * @param context The Context that is tracking our execution state
88 *
89 * @exception StepException if a processing error has occurred
90 */
91 public void execute(Context context) throws StepException {
92
93 // Process all associated descriptors
94 Descriptor descriptors[] = findDescriptors();
95 for (int i = 0; i < descriptors.length; i++) {
96 Object value = descriptors[i].get(context);
97 if (value == null)
98 throw new StepException
99 ("Cannot retrieve object for " + descriptors[i], this);
100 context.push(value);
101 }
102
103 }
104
105
106 }