| 1 | /* |
| 2 | |
| 3 | Derby - Class org.apache.derby.impl.services.reflect.UpdateLoader |
| 4 | |
| 5 | Copyright 1998, 2004 The Apache Software Foundation or its licensors, as applicable. |
| 6 | |
| 7 | Licensed under the Apache License, Version 2.0 (the "License"); |
| 8 | you may not use this file except in compliance with the License. |
| 9 | You may obtain a copy of the License at |
| 10 | |
| 11 | http://www.apache.org/licenses/LICENSE-2.0 |
| 12 | |
| 13 | Unless required by applicable law or agreed to in writing, software |
| 14 | distributed under the License is distributed on an "AS IS" BASIS, |
| 15 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 16 | See the License for the specific language governing permissions and |
| 17 | limitations under the License. |
| 18 | |
| 19 | */ |
| 20 | |
| 21 | package org.apache.derby.impl.services.reflect; |
| 22 | |
| 23 | import org.apache.derby.iapi.services.context.ContextService; |
| 24 | import org.apache.derby.iapi.services.monitor.Monitor; |
| 25 | import org.apache.derby.iapi.services.monitor.Monitor; |
| 26 | import org.apache.derby.iapi.services.stream.HeaderPrintWriter; |
| 27 | import org.apache.derby.iapi.util.IdUtil; |
| 28 | import org.apache.derby.iapi.error.StandardException; |
| 29 | import org.apache.derby.iapi.services.locks.ShExLockable; |
| 30 | import org.apache.derby.iapi.services.locks.ShExQual; |
| 31 | import org.apache.derby.iapi.services.locks.LockFactory; |
| 32 | import org.apache.derby.iapi.services.locks.Latch; |
| 33 | import org.apache.derby.iapi.services.locks.C_LockFactory; |
| 34 | import org.apache.derby.iapi.services.loader.ClassFactoryContext; |
| 35 | import org.apache.derby.iapi.services.loader.JarReader; |
| 36 | import org.apache.derby.iapi.services.property.PersistentSet; |
| 37 | |
| 38 | import org.apache.derby.iapi.services.property.PropertyUtil; |
| 39 | import org.apache.derby.iapi.reference.Property; |
| 40 | |
| 41 | import java.io.InputStream; |
| 42 | |
| 43 | import org.apache.derby.iapi.reference.MessageId; |
| 44 | import org.apache.derby.iapi.reference.Module; |
| 45 | import org.apache.derby.iapi.services.i18n.MessageService; |
| 46 | |
| 47 | public class UpdateLoader { |
| 48 | |
| 49 | private JarLoader[] jarList; |
| 50 | private HeaderPrintWriter vs; |
| 51 | private final ClassLoader myLoader; |
| 52 | private boolean initDone; |
| 53 | private String thisClasspath; |
| 54 | private final LockFactory lf; |
| 55 | private final ShExLockable classLoaderLock; |
| 56 | private int version; |
| 57 | private boolean normalizeToUpper; |
| 58 | private DatabaseClasses parent; |
| 59 | |
| 60 | private boolean needReload; |
| 61 | private JarReader jarReader; |
| 62 | |
| 63 | public UpdateLoader(String classpath, DatabaseClasses parent, boolean verbose, boolean normalizeToUpper) |
| 64 | throws StandardException { |
| 65 | |
| 66 | this.normalizeToUpper = normalizeToUpper; |
| 67 | this.parent = parent; |
| 68 | lf = (LockFactory) Monitor.getServiceModule(parent, Module.LockFactory); |
| 69 | |
| 70 | if (verbose) { |
| 71 | vs = Monitor.getStream(); |
| 72 | } |
| 73 | |
| 74 | myLoader = getClass().getClassLoader(); |
| 75 | |
| 76 | this.classLoaderLock = new ClassLoaderLock(this); |
| 77 | |
| 78 | initializeFromClassPath(classpath); |
| 79 | } |
| 80 | |
| 81 | private void initializeFromClassPath(String classpath) throws StandardException { |
| 82 | |
| 83 | String[][] elements = IdUtil.parseDbClassPath(classpath, normalizeToUpper); |
| 84 | |
| 85 | int jarCount = elements.length; |
| 86 | jarList = new JarLoader[jarCount]; |
| 87 | |
| 88 | for (int i = 0; i < jarCount; i++) { |
| 89 | jarList[i] = new JarLoader(this, elements[i], vs); |
| 90 | } |
| 91 | |
| 92 | if (vs != null) { |
| 93 | vs.println(MessageService.getTextMessage(MessageId.CM_CLASS_LOADER_START, classpath)); |
| 94 | } |
| 95 | |
| 96 | thisClasspath = classpath; |
| 97 | initDone = false; |
| 98 | } |
| 99 | |
| 100 | /** |
| 101 | Load the class from the class path. |
| 102 | |
| 103 | @exception ClassNotFoundException Class can not be found |
| 104 | */ |
| 105 | public Class loadClass(String className, boolean resolve) |
| 106 | throws ClassNotFoundException { |
| 107 | |
| 108 | |
| 109 | JarLoader jl = null; |
| 110 | |
| 111 | boolean unlockLoader = false; |
| 112 | try { |
| 113 | unlockLoader = lockClassLoader(ShExQual.SH); |
| 114 | |
| 115 | synchronized (this) { |
| 116 | |
| 117 | if (needReload) { |
| 118 | reload(); |
| 119 | } |
| 120 | |
| 121 | Class clazz = checkLoaded(className, resolve); |
| 122 | if (clazz != null) |
| 123 | return clazz; |
| 124 | |
| 125 | String jvmClassName = className.replace('.', '/').concat(".class"); |
| 126 | |
| 127 | if (!initDone) |
| 128 | initLoaders(); |
| 129 | |
| 130 | for (int i = 0; i < jarList.length; i++) { |
| 131 | |
| 132 | jl = jarList[i]; |
| 133 | |
| 134 | Class c = jl.loadClassData(className, jvmClassName, resolve); |
| 135 | if (c != null) { |
| 136 | if (vs != null) |
| 137 | vs.println(MessageService.getTextMessage(MessageId.CM_CLASS_LOAD, className, jl.getJarName())); |
| 138 | |
| 139 | return c; |
| 140 | } |
| 141 | } |
| 142 | } |
| 143 | |
| 144 | return null; |
| 145 | |
| 146 | |
| 147 | } catch (StandardException se) { |
| 148 | throw new ClassNotFoundException(MessageService.getTextMessage(MessageId.CM_CLASS_LOAD_EXCEPTION, className, jl == null ? null : jl.getJarName(), se)); |
| 149 | } finally { |
| 150 | if (unlockLoader) { |
| 151 | lf.unlock(this, this, classLoaderLock, ShExQual.SH); |
| 152 | } |
| 153 | } |
| 154 | } |
| 155 | |
| 156 | public InputStream getResourceAsStream(String name) { |
| 157 | |
| 158 | InputStream is = (myLoader == null) ? |
| 159 | ClassLoader.getSystemResourceAsStream(name) : |
| 160 | myLoader.getResourceAsStream(name); |
| 161 | |
| 162 | if (is != null) |
| 163 | return is; |
| 164 | |
| 165 | // match behaviour of standard class loaders. |
| 166 | if (name.endsWith(".class")) |
| 167 | return null; |
| 168 | |
| 169 | boolean unlockLoader = false; |
| 170 | try { |
| 171 | unlockLoader = lockClassLoader(ShExQual.SH); |
| 172 | |
| 173 | synchronized (this) { |
| 174 | |
| 175 | if (needReload) { |
| 176 | reload(); |
| 177 | } |
| 178 | |
| 179 | if (!initDone) |
| 180 | initLoaders(); |
| 181 | |
| 182 | for (int i = 0; i < jarList.length; i++) { |
| 183 | |
| 184 | JarLoader jl = jarList[i]; |
| 185 | |
| 186 | is = jl.getStream(name); |
| 187 | if (is != null) { |
| 188 | return is; |
| 189 | } |
| 190 | } |
| 191 | } |
| 192 | return null; |
| 193 | |
| 194 | } catch (StandardException se) { |
| 195 | return null; |
| 196 | } finally { |
| 197 | if (unlockLoader) { |
| 198 | lf.unlock(this, this, classLoaderLock, ShExQual.SH); |
| 199 | } |
| 200 | } |
| 201 | } |
| 202 | |
| 203 | public synchronized void modifyClasspath(String classpath) |
| 204 | throws StandardException { |
| 205 | |
| 206 | // lock transaction classloader exclusively |
| 207 | lockClassLoader(ShExQual.EX); |
| 208 | version++; |
| 209 | |
| 210 | |
| 211 | modifyJar(false); |
| 212 | initializeFromClassPath(classpath); |
| 213 | } |
| 214 | |
| 215 | |
| 216 | public synchronized void modifyJar(boolean reload) throws StandardException { |
| 217 | |
| 218 | // lock transaction classloader exclusively |
| 219 | lockClassLoader(ShExQual.EX); |
| 220 | version++; |
| 221 | |
| 222 | if (!initDone) |
| 223 | return; |
| 224 | |
| 225 | if (reload) { |
| 226 | //first close the existing jar file opens |
| 227 | close(); |
| 228 | initializeFromClassPath(thisClasspath); |
| 229 | return; |
| 230 | } |
| 231 | |
| 232 | // first thing to do is to remove all Class entries |
| 233 | // and then get a complete set of loaders ... |
| 234 | synchronized (this) { |
| 235 | |
| 236 | for (int i = 0; i < jarList.length; i++) { |
| 237 | |
| 238 | JarLoader jl = jarList[i]; |
| 239 | |
| 240 | JarFile newJarFile = jl.setInvalid(reload); |
| 241 | } |
| 242 | } |
| 243 | } |
| 244 | |
| 245 | private boolean lockClassLoader(ShExQual qualifier) |
| 246 | throws StandardException { |
| 247 | |
| 248 | if (lf == null) |
| 249 | return false; |
| 250 | |
| 251 | ClassFactoryContext cfc = (ClassFactoryContext) ContextService.getContextOrNull(ClassFactoryContext.CONTEXT_ID); |
| 252 | |
| 253 | // This method can be called from outside of the database |
| 254 | // engine, in which case tc will be null. In that case |
| 255 | // we lock the class loader only for the duration of |
| 256 | // the loadClass(). |
| 257 | Object lockSpace = null; |
| 258 | |
| 259 | if (cfc != null) { |
| 260 | lockSpace = cfc.getLockSpace(); |
| 261 | } |
| 262 | if (lockSpace == null) |
| 263 | lockSpace = this; |
| 264 | |
| 265 | lf.lockObject(lockSpace, lockSpace, classLoaderLock, qualifier, C_LockFactory.TIMED_WAIT); |
| 266 | |
| 267 | return (lockSpace == this); |
| 268 | } |
| 269 | |
| 270 | Class checkLoaded(String className, boolean resolve) { |
| 271 | |
| 272 | for (int i = 0; i < jarList.length; i++) { |
| 273 | Class c = jarList[i].checkLoaded(className, resolve); |
| 274 | if (c != null) |
| 275 | return c; |
| 276 | } |
| 277 | return null; |
| 278 | } |
| 279 | |
| 280 | public void close() { |
| 281 | |
| 282 | for (int i = 0; i < jarList.length; i++) { |
| 283 | jarList[i].setInvalid(false); |
| 284 | } |
| 285 | |
| 286 | } |
| 287 | |
| 288 | private void initLoaders() { |
| 289 | |
| 290 | if (initDone) |
| 291 | return; |
| 292 | |
| 293 | for (int i = 0; i < jarList.length; i++) { |
| 294 | jarList[i].initialize(); |
| 295 | } |
| 296 | initDone = true; |
| 297 | } |
| 298 | |
| 299 | public int getClassLoaderVersion() { |
| 300 | return version; |
| 301 | } |
| 302 | |
| 303 | synchronized void needReload() { |
| 304 | version++; |
| 305 | needReload = true; |
| 306 | } |
| 307 | |
| 308 | private void reload() throws StandardException { |
| 309 | thisClasspath = getClasspath(); |
| 310 | // first close the existing jar file opens |
| 311 | close(); |
| 312 | initializeFromClassPath(thisClasspath); |
| 313 | needReload = false; |
| 314 | } |
| 315 | |
| 316 | |
| 317 | private String getClasspath() |
| 318 | throws StandardException { |
| 319 | |
| 320 | ClassFactoryContext cfc = (ClassFactoryContext) ContextService.getContextOrNull(ClassFactoryContext.CONTEXT_ID); |
| 321 | |
| 322 | PersistentSet ps = cfc.getPersistentSet(); |
| 323 | |
| 324 | String classpath = PropertyUtil.getServiceProperty(ps, Property.DATABASE_CLASSPATH); |
| 325 | |
| 326 | // |
| 327 | //In per database mode we must always have a classpath. If we do not |
| 328 | //yet have one we make one up. |
| 329 | if (classpath==null) |
| 330 | classpath=""; |
| 331 | |
| 332 | |
| 333 | return classpath; |
| 334 | } |
| 335 | |
| 336 | JarReader getJarReader() { |
| 337 | if (jarReader == null) { |
| 338 | |
| 339 | ClassFactoryContext cfc = (ClassFactoryContext) ContextService.getContextOrNull(ClassFactoryContext.CONTEXT_ID); |
| 340 | |
| 341 | jarReader = cfc.getJarReader(); |
| 342 | } |
| 343 | return jarReader; |
| 344 | } |
| 345 | } |
| 346 | |
| 347 | |
| 348 | class ClassLoaderLock extends ShExLockable { |
| 349 | |
| 350 | private UpdateLoader myLoader; |
| 351 | |
| 352 | ClassLoaderLock(UpdateLoader myLoader) { |
| 353 | this.myLoader = myLoader; |
| 354 | } |
| 355 | |
| 356 | public void unlockEvent(Latch lockInfo) |
| 357 | { |
| 358 | super.unlockEvent(lockInfo); |
| 359 | |
| 360 | if (lockInfo.getQualifier().equals(ShExQual.EX)) { |
| 361 | // how do we tell if we are reverting or not |
| 362 | myLoader.needReload(); |
| 363 | } |
| 364 | } |
| 365 | } |