1 /*
2 * Copyright 2008-2013 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 package de.smartics.maven.issues.cache;
17
18 import java.io.File;
19 import java.io.InputStream;
20 import java.io.OutputStream;
21
22 import javax.xml.stream.XMLInputFactory;
23 import javax.xml.stream.XMLOutputFactory;
24 import javax.xml.stream.XMLStreamException;
25 import javax.xml.stream.XMLStreamReader;
26 import javax.xml.stream.XMLStreamWriter;
27
28 import org.apache.commons.logging.Log;
29 import org.apache.commons.logging.LogFactory;
30 import org.eclipse.mylyn.tasks.core.data.TaskData;
31
32 /**
33 * Implementation of the data store that writes task data to XML files.
34 */
35 public class XmlTaskDataStore extends AbstractFileTaskDataStore
36 {
37 // ********************************* Fields *********************************
38
39 // --- constants ------------------------------------------------------------
40
41 /**
42 * Reference to the logger for this class.
43 */
44 private static final Log LOG = LogFactory.getLog(XmlTaskDataStore.class);
45
46 // --- members --------------------------------------------------------------
47
48 /**
49 * The character encoding to read and write files.
50 */
51 private final String encoding;
52
53 // ****************************** Initializer *******************************
54
55 // ****************************** Constructors ******************************
56
57 /**
58 * Default constructor.
59 *
60 * @param encoding the character encoding to read and write files.
61 * @param persistentStoreDirectory the reference to the directory to store the
62 * individual task files.
63 */
64 public XmlTaskDataStore(final String encoding,
65 final File persistentStoreDirectory)
66 {
67 super(persistentStoreDirectory, ".xml");
68 this.encoding = encoding;
69 }
70
71 // ****************************** Inner Classes *****************************
72
73 // ********************************* Methods ********************************
74
75 // --- init -----------------------------------------------------------------
76
77 // --- get&set --------------------------------------------------------------
78
79 // --- business -------------------------------------------------------------
80
81 /**
82 * Reads the task from the given input stream.
83 *
84 * @param inputStream the input stream to read from.
85 * @return the task information read from the given input stream.
86 * @throws PersistenceException if the task data cannot be read from the given
87 * input stream.
88 */
89 protected TaskData readTask(final InputStream inputStream)
90 throws PersistenceException
91 {
92 final XMLInputFactory factory = XMLInputFactory.newInstance();
93 XmlTaskReader taskReader = null;
94 ;
95 try
96 {
97 final XMLStreamReader xmlReader =
98 factory.createXMLStreamReader(inputStream, encoding);
99 taskReader = new XmlTaskReader(xmlReader);
100 return taskReader.readTask();
101 }
102 catch (final XMLStreamException e)
103 {
104 throw new PersistenceException("Cannot read task from XML stream.", e);
105 }
106 finally
107 {
108 if (taskReader != null)
109 {
110 taskReader.close();
111 }
112 }
113 }
114
115 /**
116 * Persists the task to the given output stream. This method takes
117 * responsibility of closing the stream.
118 *
119 * @param outputStream the output stream to write to.
120 * @param task the task data to store.
121 * @throws PersistenceException if the task data cannot be written to the
122 * given output stream.
123 */
124 protected void writeTask(final OutputStream outputStream, final TaskData task)
125 throws PersistenceException
126 {
127 final XMLOutputFactory factory = XMLOutputFactory.newInstance();
128 XmlTaskWriter taskWriter = null;
129 try
130 {
131 final XMLStreamWriter xmlWriter =
132 factory.createXMLStreamWriter(outputStream, encoding);
133 xmlWriter.writeStartDocument(encoding, "1.0");
134 taskWriter = new XmlTaskWriter(xmlWriter);
135 taskWriter.writeTask(task);
136 xmlWriter.writeEndDocument();
137 }
138 catch (final XMLStreamException e)
139 {
140 final String message =
141 "Cannot persist task data with ID '" + task.getTaskId() + "'.";
142 LOG.warn(message, e);
143 throw new PersistenceException(message, e);
144 }
145 finally
146 {
147 if (taskWriter != null)
148 {
149 taskWriter.close();
150 }
151 }
152 }
153
154 // --- object basics --------------------------------------------------------
155
156 }