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1 package org.columba.core.io;
2
3 import java.io.File  ;
4 import java.io.FileInputStream ;
5 import java.io.FileNotFoundException ;
6 import java.io.FileOutputStream ;
7 import java.io.IOException ;
8 import java.io.InputStream ;
9 import java.io.ObjectInputStream ;
10 import java.io.ObjectOutputStream ;
11 import java.io.Serializable ;
12 import java.util.ArrayList ;
13 import java.util.Collections ;
14 import java.util.Comparator ;
15 import java.util.Date ;
16 import java.util.Iterator ;
17 import java.util.List ;
18
19 public class StreamCache {
20
21 public static final long DEFAULT_SIZE = 10 * 1024 * 1024;
23 public static final String FIFO_FILE = ".fifo";
24
25 private File dir;
26
27 private List <CacheEntry> fifo;
28
29 private long actSize;
30
31 private long maxSize;
32
33 public StreamCache(File directory) {
34 this(directory, DEFAULT_SIZE);
35 }
36
37 public StreamCache(File directory, long maxSize) {
38 dir = directory;
39 if (!dir.exists()) {
40 if (!dir.mkdirs()) {
41 throw new RuntimeException (dir.toString()
42 + " could not be created!");
43 }
44 } else {
45 try {
47 restore();
48 } catch (IOException e) {
49 }
51 }
52 actSize = 0;
53
54 if (fifo == null) {
56 fifo = new ArrayList <CacheEntry>(100);
57 }
58
59 this.maxSize = maxSize;
60 }
61
62 public InputStream passiveAdd(Object key, InputStream in)
63 throws IOException {
64 File streamFile = new File (dir.getAbsoluteFile() + File.separator
65 + key.toString() + ".cache");
66 return new StreamCacheCopyStream(in, key, streamFile, this);
67 }
68
69 public void activeAdd(Object key, InputStream in) throws IOException {
70 File streamFile = new File (dir.getAbsoluteFile() + File.separator
71 + key.toString() + ".cache");
72 StreamUtils.streamCopy(in, new FileOutputStream (streamFile));
73 add(key, streamFile);
74 }
75
76 void add(Object key, File out) {
77 fifo.add(new CacheEntry(key, out));
78
79 actSize += out.length();
80
81 Comparator _myComperator = new Comparator () {
82
83 public int compare(Object arg0, Object arg1) {
84 Date a = ((CacheEntry) arg0).lastAccess;
85 Date b = ((CacheEntry) arg1).lastAccess;
86
87 if (a.before(b))
88 return 1;
89 if (a.after(b))
90 return -1;
91 return 0;
92 }
93
94 };
95 Collections.sort(fifo, _myComperator);
96
97 ensureMaxSize();
98 }
99
100 private void ensureMaxSize() {
101 while (actSize > maxSize) {
102 CacheEntry entry = fifo.remove(fifo.size() - 1);
103 actSize -= entry.file.length();
104 entry.file.delete();
105 }
106 }
107
108 public InputStream get(Object key) {
109 Iterator it = fifo.iterator();
110
111 while (it.hasNext()) {
112 CacheEntry c = (CacheEntry) it.next();
113 if (c.key.equals(key)) {
114 try {
115 return c.createStream();
116 } catch (FileNotFoundException e) {
117 it.remove();
118 actSize -= c.file.length();
119 }
120 }
121 }
122
123 return null;
124 }
125
126 public long getActSize() {
127 return actSize;
128 }
129
130 public void clear() {
131 Iterator it = fifo.iterator();
132
133 while (it.hasNext()) {
134 CacheEntry c = (CacheEntry) it.next();
135 if (!c.file.delete()) {
136 c.file.deleteOnExit();
138 }
139 it.remove();
140 }
141
142 actSize = 0;
143 }
144
145 public void persist() throws IOException {
146 File file = new File (dir.getAbsoluteFile() + File.separator + FIFO_FILE);
147 ObjectOutputStream out = new ObjectOutputStream (new FileOutputStream (
148 file));
149 out.writeObject(fifo);
150 out.close();
151 }
152
153 public void restore() throws IOException {
154 File file = new File (dir.getAbsoluteFile() + File.separator + FIFO_FILE);
155 try {
156 fifo = (List <CacheEntry>) new ObjectInputStream (new FileInputStream (file))
157 .readObject();
158 } catch (ClassNotFoundException e) {
159 }
161 }
162
163 public long getMaxSize() {
164 return maxSize;
165 }
166
167 public void setMaxSize(long maxSize) {
168 this.maxSize = maxSize;
169 ensureMaxSize();
170 }
171 }
172
173 @SuppressWarnings ({"serial","serial"}) class CacheEntry implements Serializable {
174 Date lastAccess;
175
176 Object key;
177
178 File file;
179
180 public CacheEntry(Object key, File file) {
181 this.key = key;
182 this.file = file;
183 this.lastAccess = new Date ();
184 }
185
186 public InputStream createStream() throws FileNotFoundException {
187 this.lastAccess = new Date ();
188 return new FileInputStream (file);
189 }
190
191
194 public File getFile() {
195 return file;
196 }
197
198
202 public void setFile(File file) {
203 this.file = file;
204 }
205
206
209 public Object getKey() {
210 return key;
211 }
212
213
217 public void setKey(Object key) {
218 this.key = key;
219 }
220
221
224 public Date getLastAccess() {
225 return lastAccess;
226 }
227
228
232 public void setLastAccess(Date lastAccess) {
233 this.lastAccess = lastAccess;
234 }
235 } |
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