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16 package org.outerj.daisy.blobstore.impl;
17
18 import org.outerj.daisy.blobstore.BlobStore;
19 import org.outerj.daisy.blobstore.NonExistingBlobException;
20 import org.outerj.daisy.blobstore.BlobIOException;
21 import org.outerj.daisy.configutil.PropertyResolver;
22 import org.apache.avalon.framework.configuration.Configurable;
23 import org.apache.avalon.framework.configuration.Configuration;
24 import org.apache.avalon.framework.configuration.ConfigurationException;
25 import org.apache.avalon.framework.activity.Initializable;
26
27 import java.io.*;
28 import java.security.SecureRandom  ;
29
30 import EDU.oswego.cs.dl.util.concurrent.WriterPreferenceReadWriteLock;
31 import EDU.oswego.cs.dl.util.concurrent.Sync;
32
33
43 public class FSBlobStore implements BlobStore, Configurable, Initializable {
44 private static final int DIRECTORY_DEPTH = 4;
45 private static final int DIRECTORY_NAME_LENGTH = 2;
46 private File directory;
47 private SecureRandom random = null;
48 private int KEYLENGTH = 20;
49 private WriterPreferenceReadWriteLock suspendWritesLock = new WriterPreferenceReadWriteLock();
50
51 public void configure(Configuration configuration) throws ConfigurationException {
52 String directoryName = PropertyResolver.resolveProperties(configuration.getChild("directory").getValue());
53 directory = new File(directoryName);
54 if (!directory.exists())
55 throw new ConfigurationException("The specified directory does not exist: " + directoryName);
56 if (!directory.isDirectory())
57 throw new ConfigurationException("The specified directory is not a directory: " + directoryName);
58 }
59
60 public void initialize() throws Exception {
61 try {
62 random = SecureRandom.getInstance("SHA1PRNG");
63 }
64 catch(java.security.NoSuchAlgorithmException nsae) {
65 random = SecureRandom.getInstance("IBMSecureRandom");
67 }
68 random.setSeed(System.currentTimeMillis());
69 }
70
71 private void checkSuspendWrites() {
72 boolean hasSuspendLock = false;
73 try {
74 hasSuspendLock = suspendWritesLock.readLock().attempt(0);
75 } catch (InterruptedException e) {
76 }
78 if (!hasSuspendLock)
79 throw new RuntimeException ("Write access to the blobstore is currently disabled. Try again later.");
80 }
81
82 public void delete(String name) throws NonExistingBlobException {
83 checkSuspendWrites();
84 try {
85 File file = nameToFile(name);
86 if (!file.exists())
87 throw new NonExistingBlobException(name);
88
89 file.delete();
90 } finally {
91 suspendWritesLock.readLock().release();
92 }
93 }
94
95 public String store(byte[] data) throws BlobIOException {
96 File file = null;
97 FileOutputStream fos = null;
98 checkSuspendWrites();
99 try {
100 try {
101 file = createFile();
102 fos = new FileOutputStream(file);
103 fos.write(data);
104 fos.getFD().sync();
105 } finally {
106 if (fos != null)
107 fos.close();
108 }
109 } catch (IOException e) {
110 throw new BlobIOException("Error storing blob.", e);
111 } finally {
112 suspendWritesLock.readLock().release();
113 }
114 return fileToName(file);
115 }
116
117 private static final int BUFFER_SIZE = 32768;
118
119 public String store(InputStream is) throws BlobIOException {
120 checkSuspendWrites();
121 try {
122 File file = null;
123 FileOutputStream fos = null;
124 byte[] buffer = new byte[BUFFER_SIZE];
125 try {
126 try {
127 file = createFile();
128 fos = new FileOutputStream(file);
129 BufferedOutputStream bos = new BufferedOutputStream(fos);
130 int read;
131 while ((read = is.read(buffer)) != -1) {
132 bos.write(buffer, 0, read);
133 }
134 bos.flush();
135 fos.getFD().sync();
136 } finally {
137 if (fos != null)
138 fos.close();
139 }
140 } catch (IOException e) {
141 throw new BlobIOException("Error storing blob.", e);
142 }
143 return fileToName(file);
144 } finally {
145 suspendWritesLock.readLock().release();
146 try {
147 is.close();
148 } catch (IOException e) {
149 throw new BlobIOException("Error closing input stream.", e);
150 }
151 }
152 }
153
154 public InputStream retrieve(String name) throws BlobIOException, NonExistingBlobException {
155 File file = nameToFile(name);
156 if (!file.exists())
157 throw new NonExistingBlobException(name);
158
159 try {
160 return new FileInputStream(file);
161 } catch (FileNotFoundException e) {
162 throw new BlobIOException("Error retrieving the blob named \"" + name + "\".", e);
163 }
164 }
165
166
173 private File createFile() throws IOException {
174 byte[] bytes = new byte[KEYLENGTH];
175 char[] result = new char[KEYLENGTH * 2];
176
177 while (true) {
178 random.nextBytes(bytes);
179
180 for (int i = 0; i < KEYLENGTH; i++) {
181 byte ch = bytes[i];
182 result[2 * i] = Character.forDigit(Math.abs(ch >> 4), 16);
183 result[2 * i + 1] = Character.forDigit(Math.abs(ch & 0x0f), 16);
184 }
185
186 String id = new String (result);
187 synchronized (this) {
188 File file = nameToFile(id);
189 if (file.createNewFile()) {
190 return file;
191 }
192 }
193 }
194 }
195
196 public boolean suspendWrites(long msecs) throws InterruptedException {
197 return suspendWritesLock.writeLock().attempt(msecs);
198 }
199
200 public void resumeWrites() {
201 suspendWritesLock.writeLock().release();
202 }
203
204 public Sync getAvoidSuspendLock() {
205 return suspendWritesLock.readLock();
206 }
207
208 private File nameToFile(String name) {
209 StringBuffer subdirName = new StringBuffer ((DIRECTORY_NAME_LENGTH+1) * DIRECTORY_DEPTH);
210 int position = 0;
211 for (int i = 0; i < DIRECTORY_DEPTH; i++)
212 subdirName.append(name.substring(position, position+=DIRECTORY_NAME_LENGTH)).append(File.separator);
213
214 File subdir = new File(directory, subdirName.toString());
215 subdir.mkdirs();
216
217 return new File(subdir, name.substring(position));
218 }
219
220 private String fileToName(final File file) throws BlobIOException{
221 File workFile = new File(file, "");
222 String name = file.getName();
223 for (int i = 0; i < DIRECTORY_DEPTH; i++) {
224 workFile = workFile.getParentFile();
225 name = workFile.getName() + name;
226 }
227
228 if (name.length() != KEYLENGTH*2)
229 throw new BlobIOException("Blob '" + file.getPath() + "' does not have the correct id '" + name + "'");
230
231 return name;
232 }
233 }
234 |
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