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1
24
25 package com.mckoi.database;
26
27 import com.mckoi.store.*;
28 import com.mckoi.debug.Lvl;
29 import java.io.File  ;
30 import java.io.FileOutputStream ;
31 import java.io.IOException ;
32
33
41
42 class V1FileStoreSystem implements StoreSystem {
43
44
47 private static final String FLOCK_EXT = ".lock";
48
49
53 private TransactionSystem system;
54
55
58 private File path;
59
60
63 private boolean read_only;
64
65
68 private FileOutputStream lock_file;
69
70
73 public V1FileStoreSystem(TransactionSystem system, File path,
74 boolean read_only) {
75 this.system = system;
76 this.path = path;
77 this.read_only = read_only;
78 if (!read_only && !path.exists()) {
80 path.mkdirs();
81 }
82 }
83
84
87 private JournalledFileStore createFileStore(String file_name)
88 throws IOException {
89 LoggingBufferManager buffer_manager = system.getBufferManager();
90 return new JournalledFileStore(file_name, buffer_manager, read_only);
91 }
92
93
95 public boolean storeExists(String name) {
96 try {
97 JournalledFileStore store = createFileStore(name);
98 return store.exists();
99 }
100 catch (IOException e) {
101 system.Debug().writeException(e);
102 throw new RuntimeException ("IO Error: " + e.getMessage());
103 }
104 }
105
106 public Store createStore(String name) {
107 LoggingBufferManager buffer_manager = system.getBufferManager();
108 if (read_only) {
109 throw new RuntimeException (
110 "Can not create store because system is read-only.");
111 }
112 try {
113 buffer_manager.lockForWrite();
114
115 JournalledFileStore store = createFileStore(name);
116 if (!store.exists()) {
117 store.open();
118 return store;
119 }
120 else {
121 throw new RuntimeException ("Can not create - store with name " + name +
122 " already exists.");
123 }
124 }
125 catch (IOException e) {
126 system.Debug().writeException(e);
127 throw new RuntimeException ("IO Error: " + e.getMessage());
128 }
129 catch (InterruptedException e) {
130 throw new Error ("Interrupted: " + e.getMessage());
131 }
132 finally {
133 buffer_manager.unlockForWrite();
134 }
135
136 }
137
138 public Store openStore(String name) {
139 LoggingBufferManager buffer_manager = system.getBufferManager();
140 try {
141 buffer_manager.lockForWrite();
142
143 JournalledFileStore store = createFileStore(name);
144 if (store.exists()) {
145 store.open();
146 return store;
147 }
148 else {
149 throw new RuntimeException ("Can not open - store with name " + name +
150 " does not exist.");
151 }
152 }
153 catch (IOException e) {
154 system.Debug().writeException(e);
155 throw new RuntimeException ("IO Error: " + e.getMessage());
156 }
157 catch (InterruptedException e) {
158 throw new Error ("Interrupted: " + e.getMessage());
159 }
160 finally {
161 buffer_manager.unlockForWrite();
162 }
163
164 }
165
166 public boolean closeStore(Store store) {
167 LoggingBufferManager buffer_manager = system.getBufferManager();
168 try {
169 buffer_manager.lockForWrite();
170
171 ((JournalledFileStore) store).close();
172 return true;
173 }
174 catch (IOException e) {
175 system.Debug().writeException(e);
176 throw new RuntimeException ("IO Error: " + e.getMessage());
177 }
178 catch (InterruptedException e) {
179 throw new Error ("Interrupted: " + e.getMessage());
180 }
181 finally {
182 buffer_manager.unlockForWrite();
183 }
184
185 }
186
187 public boolean deleteStore(Store store) {
188 LoggingBufferManager buffer_manager = system.getBufferManager();
189 try {
190 buffer_manager.lockForWrite();
191
192 return ((JournalledFileStore) store).delete();
193 }
194 catch (IOException e) {
195 system.Debug().writeException(e);
196 throw new RuntimeException ("IO Error: " + e.getMessage());
197 }
198 catch (InterruptedException e) {
199 throw new Error ("Interrupted: " + e.getMessage());
200 }
201 finally {
202 buffer_manager.unlockForWrite();
203 }
204
205 }
206
207 public void setCheckPoint() {
208 try {
209 LoggingBufferManager buffer_manager = system.getBufferManager();
210 buffer_manager.setCheckPoint(false);
211 }
212 catch (IOException e) {
213 system.Debug().writeException(e);
214 throw new RuntimeException ("IO Error: " + e.getMessage());
215 }
216 catch (InterruptedException e) {
217 system.Debug().writeException(e);
218 throw new RuntimeException ("Interrupted Error: " + e.getMessage());
219 }
220 }
221
222 public void lock(String name) throws IOException {
223 File flock_fn = new File (path, name + FLOCK_EXT);
224 if (flock_fn.exists()) {
225 system.Debug().write(Lvl.WARNING, this,
229 "File lock file exists: " + flock_fn);
230 boolean deleted = false;
231 deleted = flock_fn.delete();
232 if (!deleted) {
233 System.err.println("\n" +
235 "I couldn't delete the file lock for Database '" + name + "'.\n" +
236 "This most likely means the database is open and being used by\n" +
237 "another process.\n" +
238 "The lock file is: " + flock_fn + "\n\n");
239 throw new IOException ("Couldn't delete conglomerate file lock.");
240 }
241 }
242 flock_fn.createNewFile();
245 flock_fn.deleteOnExit();
247 lock_file = new FileOutputStream (flock_fn);
250 }
251
252 public void unlock(String name) throws IOException {
253 if (lock_file != null) {
255 lock_file.close();
256 }
257 File flock_fn = new File (path, name + FLOCK_EXT);
259 flock_fn.delete();
260 }
261
262 }
263
264 |
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