1 /*
2 * Copyright 2008-2010 smartics, Kronseder & Reiner GmbH
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 de.smartics.maven.issues.cache;
18
19 import java.io.File;
20 import java.io.InputStream;
21 import java.io.OutputStream;
22
23 import javax.xml.stream.XMLInputFactory;
24 import javax.xml.stream.XMLOutputFactory;
25 import javax.xml.stream.XMLStreamException;
26 import javax.xml.stream.XMLStreamReader;
27 import javax.xml.stream.XMLStreamWriter;
28
29 import org.apache.commons.logging.Log;
30 import org.apache.commons.logging.LogFactory;
31 import org.eclipse.mylyn.tasks.core.data.TaskData;
32
33 /**
34 * Implementation of the data store that writes task data to XML files.
35 *
36 * @author <a href="mailto:robert.reiner@smartics.de">Robert Reiner</a>
37 * @version $Revision:591 $
38 */
39 public class XmlTaskDataStore extends AbstractFileTaskDataStore
40 {
41 // ********************************* Fields *********************************
42
43 // --- constants ------------------------------------------------------------
44
45 /**
46 * Reference to the logger for this class.
47 */
48 private static final Log LOG = LogFactory.getLog(XmlTaskDataStore.class);
49
50 // --- members --------------------------------------------------------------
51
52 // ****************************** Initializer *******************************
53
54 // ****************************** Constructors ******************************
55
56 /**
57 * Default constructor.
58 *
59 * @param persistentStoreDirectory the reference to the directory to store the
60 * individual task files.
61 */
62 public XmlTaskDataStore(final File persistentStoreDirectory)
63 {
64 super(persistentStoreDirectory, ".xml");
65 }
66
67 // ****************************** Inner Classes *****************************
68
69 // ********************************* Methods ********************************
70
71 // --- init -----------------------------------------------------------------
72
73 // --- get&set --------------------------------------------------------------
74
75 // --- business -------------------------------------------------------------
76
77 /**
78 * Reads the task from the given input stream.
79 *
80 * @param inputStream the input stream to read from.
81 * @return the task information read from the given input stream.
82 * @throws PersistenceException if the task data cannot be read from the given
83 * input stream.
84 */
85 protected TaskData readTask(final InputStream inputStream)
86 throws PersistenceException
87 {
88 final XMLInputFactory factory = XMLInputFactory.newInstance();
89 XMLStreamReader xmlReader = null;
90 try
91 {
92 xmlReader = factory.createXMLStreamReader(inputStream);
93 final XmlTaskReader taskReader = new XmlTaskReader(xmlReader);
94 return taskReader.readTask();
95 }
96 catch (final XMLStreamException e)
97 {
98 throw new PersistenceException("Cannot read task from XML stream.", e);
99 }
100 finally
101 {
102 if (xmlReader != null)
103 {
104 try
105 {
106 xmlReader.close();
107 }
108 catch (final XMLStreamException e)
109 {
110 // Ignore
111 if (LOG.isErrorEnabled())
112 {
113 LOG.error("Cannot close input stream. Continue...", e);
114 }
115 }
116 }
117 }
118 }
119
120 /**
121 * Persists the task to the given output stream. This method takes
122 * responsibility of closing the stream.
123 *
124 * @param outputStream the output stream to write to.
125 * @param task the task data to store.
126 * @throws PersistenceException if the task data cannot be written to the
127 * given output stream.
128 */
129 protected void writeTask(final OutputStream outputStream, final TaskData task)
130 throws PersistenceException
131 {
132 final XMLOutputFactory factory = XMLOutputFactory.newInstance();
133 XMLStreamWriter xmlWriter = null;
134 try
135 {
136 xmlWriter = factory.createXMLStreamWriter(outputStream);
137 xmlWriter.writeStartDocument();
138 final XmlTaskWriter taskWriter = new XmlTaskWriter(xmlWriter);
139 taskWriter.writeTask(task);
140 xmlWriter.writeEndDocument();
141 }
142 catch (final XMLStreamException e)
143 {
144 final String message =
145 "Cannot persist task data with ID '" + task.getTaskId() + "'.";
146 LOG.warn(message, e);
147 throw new PersistenceException(message, e);
148 }
149 finally
150 {
151 if (xmlWriter != null)
152 {
153 try
154 {
155 xmlWriter.close();
156 }
157 catch (final XMLStreamException e)
158 {
159 // Ignore
160 if (LOG.isErrorEnabled())
161 {
162 LOG.error("Cannot close output stream. Continue...", e);
163 }
164 }
165 }
166 }
167 }
168
169 // --- object basics --------------------------------------------------------
170
171 }