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.io;
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>, print the value of the
28 * specified Java object to standard output.</p>
29 *
30 * <p><strong>WARNING</strong> - This will probably be
31 * replaced later by a more general purpose input/output mechanism.</p>
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 class DisplayStep extends DescriptorStep {
38
39
40 // ----------------------------------------------------------= Constructors
41
42
43 /**
44 * Construct a default instance of this Step.
45 */
46 public DisplayStep() {
47
48 super();
49
50 }
51
52
53 /**
54 * Construct an instance of this Step with the specified identifier.
55 *
56 * @param id Step identifier
57 */
58 public DisplayStep(String id) {
59
60 super();
61 setId(id);
62
63 }
64
65
66 /**
67 * Construct an instance of this Step with the specified identifier
68 * and associated Descriptor.
69 *
70 * @param id Step identifier
71 * @param descriptor Initial descriptor
72 */
73 public DisplayStep(String id, Descriptor descriptor) {
74
75 super();
76 setId(id);
77 addDescriptor(descriptor);
78
79 }
80
81
82 // --------------------------------------------------------- Public Methods
83
84
85 /**
86 * Perform the executable actions related to this Step, in the context of
87 * the specified Context.
88 *
89 * @param context The Context that is tracking our execution state
90 *
91 * @exception StepException if a processing error has occurred
92 */
93 public void execute(Context context) throws StepException {
94
95 // Process all associated descriptors
96 Descriptor descriptors[] = findDescriptors();
97 for (int i = 0; i < descriptors.length; i++) {
98 Object value = descriptors[i].get(context);
99 if (value == null)
100 throw new StepException
101 ("Cannot retrieve object for " + descriptors[i], this);
102 System.out.println(value);
103 }
104
105 }
106
107
108 }