001 /*
002 * Copyright 1999-2001,2004 The Apache Software Foundation.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017 package org.apache.commons.workflow.io;
018
019 import java.io.BufferedOutputStream;
020 import java.io.File;
021 import java.io.FileOutputStream;
022 import java.io.IOException;
023 import java.io.OutputStreamWriter;
024 import java.util.EmptyStackException;
025 import org.apache.commons.workflow.Context;
026 import org.apache.commons.workflow.StepException;
027 import org.apache.commons.workflow.base.BaseStep;
028
029
030 /**
031 * <p>Pop the top value from the evaluation stack, and write its contents
032 * as a string to the specified file in the filesystem (replacing any
033 * previous contents in that file).</p>
034 *
035 * <p>Supported Attributes:</p>
036 * <ul>
037 * <li><strong>encoding</strong> - Character encoding in which to write
038 * the characters to the specified file, or omitted for the platform
039 * default encoding.</li>
040 * <li><strong>file</strong> - Relative or absolute operating system pathname
041 * whose contents are to be written.</li>
042 * </ul>
043 *
044 * <strong>DESIGN QUESTION - What about binary content?</strong>
045 *
046 * @version $Revision: 155475 $ $Date: 2005-02-26 13:31:11 +0000 (Sat, 26 Feb 2005) $
047 * @author Craig R. McClanahan
048 */
049
050 public class WriteStep extends BaseStep {
051
052
053 // ----------------------------------------------------------= Constructors
054
055
056 /**
057 * Construct a default instance of this Step.
058 */
059 public WriteStep() {
060
061 super();
062
063 }
064
065
066 /**
067 * Construct an instance of this Step with the specified identifier.
068 *
069 * @param id Step identifier
070 */
071 public WriteStep(String id) {
072
073 super();
074 setId(id);
075
076 }
077
078
079 /**
080 * Construct a fully configured instance of this Step.
081 *
082 * @param id Step identifier
083 * @param encoding Character encoding to use
084 * @param file Relative or absolute pathname
085 */
086 public WriteStep(String id, String encoding, String file) {
087
088 super();
089 setId(id);
090 setEncoding(encoding);
091 setFile(file);
092
093 }
094
095
096 // ------------------------------------------------------------- Properties
097
098
099 /**
100 * The character encoding used to write the contents of this file.
101 */
102 protected String encoding = null;
103
104 public String getEncoding() {
105 return (this.encoding);
106 }
107
108 public void setEncoding(String encoding) {
109 this.encoding = encoding;
110 }
111
112
113 /**
114 * The relative or absolute pathname of the operating system file.
115 */
116 protected String file = null;
117
118 public String getFile() {
119 return (this.file);
120 }
121
122 public void setFile(String file) {
123 this.file = file;
124 }
125
126
127 // --------------------------------------------------------- Public Methods
128
129
130 /**
131 * Perform the executable actions related to this Step, in the context of
132 * the specified Context.
133 *
134 * @param context The Context that is tracking our execution state
135 *
136 * @exception StepException if a processing error has occurred
137 */
138 public void execute(Context context) throws StepException {
139
140 // Pop the top value from the evaluation stack
141 Object value = null;
142 try {
143 value = context.pop();
144 } catch (EmptyStackException e) {
145 throw new StepException("Evaluation stack is empty", e, this);
146 }
147 String string = null;
148 if (value instanceof String)
149 string = (String) value;
150 else
151 string = value.toString();
152
153 // Define variables we will need later
154 FileOutputStream fos = null;
155 BufferedOutputStream bos = null;
156 OutputStreamWriter osw = null;
157 StepException se = null;
158
159 try {
160
161 // Construct a suitable OutputStreamWriter
162 fos = new FileOutputStream(file);
163 bos = new BufferedOutputStream(fos, 2048);
164 if (encoding == null)
165 osw = new OutputStreamWriter(bos);
166 else
167 osw = new OutputStreamWriter(bos, encoding);
168
169 // Copy all characters to this file
170 osw.write(string, 0, string.length());
171
172 // Close the output file
173 osw.flush();
174 osw.close();
175 osw = null;
176 bos = null;
177 fos = null;
178
179 } catch (IOException e) {
180
181 se = new StepException("IOException processing '" + file + "'",
182 e, this);
183
184 } finally {
185
186 if (osw != null) {
187 try {
188 osw.close();
189 } catch (Throwable t) {
190 ;
191 }
192 } else if (bos != null) {
193 try {
194 bos.close();
195 } catch (Throwable t) {
196 ;
197 }
198 } else if (fos != null) {
199 try {
200 fos.close();
201 } catch (Throwable t) {
202 ;
203 }
204 }
205
206 if (se != null)
207 (new File(file)).delete();
208
209 }
210
211 }
212
213
214 }