1 /*
2 * Copyright 2011-2013 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.util.io;
17
18 import java.io.ByteArrayInputStream;
19 import java.io.ByteArrayOutputStream;
20 import java.io.FilterOutputStream;
21 import java.io.IOException;
22 import java.io.InputStream;
23 import java.io.OutputStream;
24 import java.util.HashMap;
25 import java.util.Map;
26
27 import javax.annotation.concurrent.NotThreadSafe;
28
29 /**
30 * Handles resources and stores them in-memory.
31 */
32 @NotThreadSafe
33 public final class MemoryStreamHandler implements StreamHandler
34 {
35 // ********************************* Fields *********************************
36
37 // --- constants ------------------------------------------------------------
38
39 // --- members --------------------------------------------------------------
40
41 /**
42 * The in-memory store.
43 */
44 private final Map<String, byte[]> dataStore = new HashMap<String, byte[]>();
45
46 // ****************************** Initializer *******************************
47
48 // ****************************** Constructors ******************************
49
50 /**
51 * Helper to add the streamed information upon closing the stream.
52 */
53 private final class CloseListenerOutputStream extends FilterOutputStream
54 {
55 /**
56 * The identifier of the resource being monitored.
57 */
58 private final String resourceId;
59
60 /**
61 * Reference to the stream whose closing is monitored.
62 */
63 private final ByteArrayOutputStream out;
64
65 private CloseListenerOutputStream(final String resourceId,
66 final ByteArrayOutputStream out)
67 {
68 super(out);
69 this.out = out;
70 this.resourceId = resourceId;
71 }
72
73 @Override
74 public void close() throws IOException
75 {
76 super.close();
77 final byte[] data = out.toByteArray();
78 dataStore.put(resourceId, data);
79 }
80 }
81
82 // ****************************** Inner Classes *****************************
83
84 // ********************************* Methods ********************************
85
86 // --- init -----------------------------------------------------------------
87
88 // --- get&set --------------------------------------------------------------
89
90 // --- business -------------------------------------------------------------
91
92 /**
93 * Allows direct access to the data stored.
94 *
95 * @param resourceId the identifier of the resource requested.
96 * @return the data from the store or <code>null</code> if there is no data
97 * for this key.
98 */
99 public byte[] getData(final String resourceId)
100 {
101 final byte[] data = dataStore.get(resourceId);
102 return data;
103 }
104
105 /**
106 * {@inheritDoc}
107 */
108 @Override
109 public InputStream openToRead(final String resourceId) throws IOException
110 {
111 final byte[] data = dataStore.get(resourceId);
112 if (data == null)
113 {
114 throw new IOException("Resource '" + resourceId + "' cannot be found.");
115 }
116
117 final InputStream in = new ByteArrayInputStream(data);
118 return in;
119 }
120
121 /**
122 * {@inheritDoc}
123 */
124 @Override
125 public OutputStream openToWrite(final String resourceId) throws IOException
126 {
127 final ByteArrayOutputStream out = new ByteArrayOutputStream(4092);
128 final CloseListenerOutputStream clout =
129 new CloseListenerOutputStream(resourceId, out);
130 dataStore.remove(resourceId);
131 return clout;
132 }
133
134 // --- object basics --------------------------------------------------------
135
136 }