Clover coverage report -
Coverage timestamp: Fri Jul 2 2004 18:04:44 CEST
file stats: LOC: 381   Methods: 14
NCLOC: 147   Classes: 1
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 Source file Conditionals Statements Methods TOTAL
AbstractCacheAdministrator.java 34.6% 47% 71.4% 47.2%
coverage coverage
 1   
 /*
 2   
  * Copyright (c) 2002-2003 by OpenSymphony
 3   
  * All rights reserved.
 4   
  */
 5   
 package com.opensymphony.oscache.base;
 6   
 
 7   
 import com.opensymphony.oscache.base.algorithm.AbstractConcurrentReadCache;
 8   
 import com.opensymphony.oscache.base.events.*;
 9   
 import com.opensymphony.oscache.base.persistence.PersistenceListener;
 10   
 import com.opensymphony.oscache.util.StringUtil;
 11   
 
 12   
 import org.apache.commons.logging.Log;
 13   
 import org.apache.commons.logging.LogFactory;
 14   
 
 15   
 import java.util.*;
 16   
 
 17   
 import javax.swing.event.EventListenerList;
 18   
 
 19   
 /**
 20   
  * An AbstractCacheAdministrator defines an abstract cache administrator, implementing all
 21   
  * the basic operations related to the configuration of a cache, including assigning
 22   
  * any configured event handlers to cache objects.<p>
 23   
  *
 24   
  * Extend this class to implement a custom cache administrator.
 25   
  *
 26   
  * @version        $Revision: 1.5 $
 27   
  * @author        a href="mailto:mike@atlassian.com">Mike Cannon-Brookes</a>
 28   
  * @author <a href="mailto:fbeauregard@pyxis-tech.com">Francois Beauregard</a>
 29   
  * @author <a href="mailto:abergevin@pyxis-tech.com">Alain Bergevin</a>
 30   
  * @author <a href="mailto:fabian.crabus@gurulogic.de">Fabian Crabus</a>
 31   
  * @author <a href="&#109;a&#105;&#108;&#116;&#111;:chris&#64;swebtec.&#99;&#111;&#109;">Chris Miller</a>
 32   
  */
 33   
 public abstract class AbstractCacheAdministrator implements java.io.Serializable {
 34   
     private static transient final Log log = LogFactory.getLog(AbstractCacheAdministrator.class);
 35   
 
 36   
     /**
 37   
      * A boolean cache configuration property that indicates whether the cache
 38   
      * should cache objects in memory. Set this property to <code>false</code>
 39   
      * to disable in-memory caching.
 40   
      */
 41   
     protected final static String CACHE_MEMORY_KEY = "cache.memory";
 42   
 
 43   
     /**
 44   
      * An integer cache configuration property that specifies the maximum number
 45   
      * of objects to hold in the cache. Setting this to a negative value will
 46   
      * disable the capacity functionality - there will be no limit to the number
 47   
      * of objects that are held in cache.
 48   
      */
 49   
     protected final static String CACHE_CAPACITY_KEY = "cache.capacity";
 50   
 
 51   
     /**
 52   
      * A String cache configuration property that specifies the classname of
 53   
      * an alternate caching algorithm. This class must extend
 54   
      * {@link com.opensymphony.oscache.base.algorithm.AbstractConcurrentReadCache}
 55   
      * By default caches will use {@link com.opensymphony.oscache.base.algorithm.LRUCache} as
 56   
      * the default algorithm if the cache capacity is set to a postive value, or
 57   
      * {@link com.opensymphony.oscache.base.algorithm.UnlimitedCache} if the
 58   
      * capacity is negative (ie, disabled).
 59   
      */
 60   
     protected final static String CACHE_ALGORITHM_KEY = "cache.algorithm";
 61   
 
 62   
     /**
 63   
      * A boolean cache configuration property that indicates whether the persistent
 64   
      * cache should be unlimited in size, or should be restricted to the same size
 65   
      * as the in-memory cache. Set this property to <code>true</code> to allow the
 66   
      * persistent cache to grow without bound.
 67   
      */
 68   
     protected final static String CACHE_DISK_UNLIMITED_KEY = "cache.unlimited.disk";
 69   
 
 70   
     /**
 71   
      * The configuration key that specifies whether we should block waiting for new
 72   
      * content to be generated, or just serve the old content instead. The default
 73   
      * behaviour is to serve the old content since that provides the best performance
 74   
      * (at the cost of serving slightly stale data).
 75   
      */
 76   
     protected final static String CACHE_BLOCKING_KEY = "cache.blocking";
 77   
 
 78   
     /**
 79   
      * A String cache configuration property that specifies the classname that will
 80   
      * be used to provide cache persistence. This class must extend {@link PersistenceListener}.
 81   
      */
 82   
     protected static final String PERSISTENCE_CLASS = "cache.persistence.class";
 83   
 
 84   
     /**
 85   
      * A String cache configuration property that holds a comma-delimited list of
 86   
      * classnames. These classes specify the event handlers that are to be applied
 87   
      * to the cache.
 88   
      */
 89   
     protected static final String CACHE_ENTRY_EVENT_LISTENERS = "cache.event.listeners";
 90   
     protected Config config = null;
 91   
 
 92   
     /**
 93   
      * Holds a list of all the registered event listeners. Event listeners are specified
 94   
      * using the {@link #CACHE_ENTRY_EVENT_LISTENERS} configuration key.
 95   
      */
 96   
     protected EventListenerList listenerList = new EventListenerList();
 97   
 
 98   
     /**
 99   
      * The algorithm class being used, as specified by the {@link #CACHE_ALGORITHM_KEY}
 100   
      * configuration property.
 101   
      */
 102   
     protected String algorithmClass = null;
 103   
 
 104   
     /**
 105   
      * The cache capacity (number of entries), as specified by the {@link #CACHE_CAPACITY_KEY}
 106   
      * configuration property.
 107   
      */
 108   
     protected int cacheCapacity = -1;
 109   
 
 110   
     /**
 111   
      * Whether the cache blocks waiting for content to be build, or serves stale
 112   
      * content instead. This value can be specified using the {@link #CACHE_BLOCKING_KEY}
 113   
      * configuration property.
 114   
      */
 115   
     private boolean blocking = false;
 116   
 
 117   
     /**
 118   
      * Whether or not to store the cache entries in memory. This is configurable using the
 119   
      * {@link com.opensymphony.oscache.base.AbstractCacheAdministrator#CACHE_MEMORY_KEY} property.
 120   
      */
 121   
     private boolean memoryCaching = true;
 122   
 
 123   
     /**
 124   
      * Whether the disk cache should be unlimited in size, or matched 1-1 to the memory cache.
 125   
      * This can be set via the {@link #CACHE_DISK_UNLIMITED_KEY} configuration property.
 126   
      */
 127   
     private boolean unlimitedDiskCache;
 128   
 
 129   
     /**
 130   
      * Create the AbstractCacheAdministrator.
 131   
      * This will initialize all values and load the properties from oscache.properties.
 132   
      */
 133  0
     protected AbstractCacheAdministrator() {
 134  0
         this(null);
 135   
     }
 136   
 
 137   
     /**
 138   
      * Create the AbstractCacheAdministrator.
 139   
      *
 140   
      * @param p the configuration properties for this cache.
 141   
      */
 142  54
     protected AbstractCacheAdministrator(Properties p) {
 143  54
         loadProps(p);
 144  54
         initCacheParameters();
 145   
 
 146  54
         if (log.isDebugEnabled()) {
 147  54
             log.debug("Constructed AbstractCacheAdministrator()");
 148   
         }
 149   
     }
 150   
 
 151   
     /**
 152   
      * Sets the algorithm to use for the cache.
 153   
      *
 154   
      * @see com.opensymphony.oscache.base.algorithm.LRUCache
 155   
      * @see com.opensymphony.oscache.base.algorithm.FIFOCache
 156   
      * @see com.opensymphony.oscache.base.algorithm.UnlimitedCache
 157   
      * @param newAlgorithmClass The class to use (eg.
 158   
      * <code>"com.opensymphony.oscache.base.algorithm.LRUCache"</code>)
 159   
      */
 160  0
     public void setAlgorithmClass(String newAlgorithmClass) {
 161  0
         algorithmClass = newAlgorithmClass;
 162   
     }
 163   
 
 164   
     /**
 165   
      * Indicates whether the cache will block waiting for new content to
 166   
      * be built, or serve stale content instead of waiting. Regardless of this
 167   
      * setting, the cache will <em>always</em> block if new content is being
 168   
      * created, ie, there's no stale content in the cache that can be served.
 169   
      */
 170  51
     public boolean isBlocking() {
 171  51
         return blocking;
 172   
     }
 173   
 
 174   
     /**
 175   
      * Sets the cache capacity (number of items). Administrator implementations
 176   
      * should override this method to ensure that their {@link Cache} objects
 177   
      * are updated correctly (by calling {@link AbstractConcurrentReadCache#setMaxEntries(int)}}}.
 178   
      *
 179   
      * @param newCacheCapacity The new capacity
 180   
      */
 181  0
     protected void setCacheCapacity(int newCacheCapacity) {
 182  0
         cacheCapacity = newCacheCapacity;
 183   
     }
 184   
 
 185   
     /**
 186   
      * Whether entries are cached in memory or not.
 187   
      * Default is true.
 188   
      * Set by the <code>cache.memory</code> property.
 189   
      *
 190   
      * @return Status whether or not memory caching is used.
 191   
      */
 192  54
     public boolean isMemoryCaching() {
 193  54
         return memoryCaching;
 194   
     }
 195   
 
 196   
     /**
 197   
      * Retrieves the value of one of the configuration properties.
 198   
      *
 199   
      * @param key The key assigned to the property
 200   
      * @return Property value, or <code>null</code> if the property could not be found.
 201   
      */
 202  225
     public String getProperty(String key) {
 203  225
         return config.getProperty(key);
 204   
     }
 205   
 
 206   
     /**
 207   
      * Indicates whether the unlimited disk cache is enabled or not.
 208   
      */
 209  54
     public boolean isUnlimitedDiskCache() {
 210  54
         return unlimitedDiskCache;
 211   
     }
 212   
 
 213   
     /**
 214   
      * Retrieves an array containing instances all of the {@link CacheEventListener}
 215   
      * classes that are specified in the OSCache configuration file.
 216   
      */
 217  0
     protected CacheEventListener[] getCacheEventListeners() {
 218  0
         CacheEventListener[] listeners = null;
 219   
 
 220  0
         List classes = StringUtil.split(config.getProperty(CACHE_ENTRY_EVENT_LISTENERS), ',');
 221  0
         listeners = new CacheEventListener[classes.size()];
 222   
 
 223  0
         for (int i = 0; i < classes.size(); i++) {
 224  0
             String className = (String) classes.get(i);
 225   
 
 226  0
             try {
 227  0
                 Class clazz = Class.forName(className);
 228   
 
 229  0
                 if (!CacheEventListener.class.isAssignableFrom(clazz)) {
 230  0
                     log.error("Specified listener class '" + className + "' does not implement CacheEventListener. Ignoring this listener.");
 231   
                 } else {
 232  0
                     listeners[i] = (CacheEventListener) clazz.newInstance();
 233   
                 }
 234   
             } catch (ClassNotFoundException e) {
 235  0
                 log.error("CacheEventListener class '" + className + "' not found. Ignoring this listener.", e);
 236   
             } catch (InstantiationException e) {
 237  0
                 log.error("CacheEventListener class '" + className + "' could not be instantiated because it is not a concrete class. Ignoring this listener.", e);
 238   
             } catch (IllegalAccessException e) {
 239  0
                 log.error("CacheEventListener class '" + className + "' could not be instantiated because it is not public. Ignoring this listener.", e);
 240   
             }
 241   
         }
 242   
 
 243  0
         return listeners;
 244   
     }
 245   
 
 246   
     /**
 247   
      * If there is a <code>PersistenceListener</code> in the configuration
 248   
      * it will be instantiated and applied to the given cache object. If the
 249   
      * <code>PersistenceListener</code> cannot be found or instantiated, an
 250   
      * error will be logged but the cache will not have a persistence listener
 251   
      * applied to it and no exception will be thrown.<p>
 252   
      *
 253   
      * A cache can only have one <code>PersistenceListener</code>.
 254   
      *
 255   
      * @param cache the cache to apply the <code>PersistenceListener</code> to.
 256   
      *
 257   
      * @return the same cache object that was passed in.
 258   
      */
 259  28
     protected Cache setPersistenceListener(Cache cache) {
 260  28
         String persistenceClassname = config.getProperty(PERSISTENCE_CLASS);
 261   
 
 262  28
         try {
 263  28
             Class clazz = Class.forName(persistenceClassname);
 264  28
             PersistenceListener persistenceListener = (PersistenceListener) clazz.newInstance();
 265   
 
 266  28
             cache.setPersistenceListener(persistenceListener.configure(config));
 267   
         } catch (ClassNotFoundException e) {
 268  0
             log.error("PersistenceListener class '" + persistenceClassname + "' not found. Check your configuration.", e);
 269   
         } catch (Exception e) {
 270  0
             log.error("Error instantiating class '" + persistenceClassname + "'", e);
 271   
         }
 272   
 
 273  28
         return cache;
 274   
     }
 275   
 
 276   
     /**
 277   
      * Applies all of the recognised listener classes to the supplied
 278   
      * cache object. Recognised classes are {@link CacheEntryEventListener}
 279   
      * and {@link CacheMapAccessEventListener}.<p>
 280   
      *
 281   
      * @param cache The cache to apply the configuration to.
 282   
      * @return cache The configured cache object.
 283   
      */
 284  45
     protected Cache configureStandardListeners(Cache cache) {
 285  45
         if (config.getProperty(PERSISTENCE_CLASS) != null) {
 286  28
             cache = setPersistenceListener(cache);
 287   
         }
 288   
 
 289  45
         if (config.getProperty(CACHE_ENTRY_EVENT_LISTENERS) != null) {
 290   
             // Grab all the specified listeners and add them to the cache's
 291   
             // listener list. Note that listeners that implement more than
 292   
             // one of the event interfaces will be added multiple times.
 293  0
             CacheEventListener[] listeners = getCacheEventListeners();
 294   
 
 295  0
             for (int i = 0; i < listeners.length; i++) {
 296   
                 // Pass through the configuration to those listeners that require it
 297  0
                 if (listeners[i] instanceof LifecycleAware) {
 298  0
                     try {
 299  0
                         ((LifecycleAware) listeners[i]).initialize(cache, config);
 300   
                     } catch (InitializationException e) {
 301  0
                         log.error("Could not initialize listener '" + listeners[i].getClass().getName() + "'. Listener ignored.", e);
 302   
 
 303  0
                         continue;
 304   
                     }
 305   
                 }
 306   
 
 307  0
                 if (listeners[i] instanceof CacheEntryEventListener) {
 308  0
                     cache.addCacheEventListener(listeners[i], CacheEntryEventListener.class);
 309   
                 }
 310   
 
 311  0
                 if (listeners[i] instanceof CacheMapAccessEventListener) {
 312  0
                     cache.addCacheEventListener(listeners[i], CacheMapAccessEventListener.class);
 313   
                 }
 314   
             }
 315   
         }
 316   
 
 317  45
         return cache;
 318   
     }
 319   
 
 320   
     /**
 321   
      * Finalizes all the listeners that are associated with the given cache object.
 322   
      * Any <code>FinalizationException</code>s that are thrown by the listeners will
 323   
      * be caught and logged.
 324   
      */
 325  3
     protected void finalizeListeners(Cache cache) {
 326  3
         Object[] listeners = cache.listenerList.getListenerList();
 327   
 
 328  3
         for (int i = listeners.length - 2; i >= 0; i -= 2) {
 329  0
             if (listeners[i + 1] instanceof LifecycleAware) {
 330  0
                 try {
 331  0
                     ((LifecycleAware) listeners[i + 1]).finialize();
 332   
                 } catch (FinalizationException e) {
 333  0
                     log.error("Listener could not be finalized", e);
 334   
                 }
 335   
             }
 336   
         }
 337   
     }
 338   
 
 339   
     /**
 340   
      * Initialize the core cache parameters from the configuration properties.
 341   
      * The parameters that are initialized are:
 342   
      * <ul>
 343   
      * <li>the algorithm class ({@link #CACHE_ALGORITHM_KEY})</li>
 344   
      * <li>the cache size ({@link #CACHE_CAPACITY_KEY})</li>
 345   
      * <li>whether the cache is blocking or non-blocking ({@link #CACHE_BLOCKING_KEY})</li>
 346   
      * <li>whether caching to memory is enabled ({@link #CACHE_MEMORY_KEY})</li>
 347   
      * <li>whether the persistent cache is unlimited in size ({@link #CACHE_DISK_UNLIMITED_KEY})</li>
 348   
      * </ul>
 349   
      */
 350  54
     private void initCacheParameters() {
 351  54
         algorithmClass = getProperty(CACHE_ALGORITHM_KEY);
 352   
 
 353  54
         blocking = "true".equalsIgnoreCase(getProperty(CACHE_BLOCKING_KEY));
 354   
 
 355  54
         String cacheMemoryStr = getProperty(CACHE_MEMORY_KEY);
 356   
 
 357  54
         if ((cacheMemoryStr != null) && cacheMemoryStr.equalsIgnoreCase("false")) {
 358  17
             memoryCaching = false;
 359   
         }
 360   
 
 361  54
         unlimitedDiskCache = Boolean.valueOf(config.getProperty(CACHE_DISK_UNLIMITED_KEY)).booleanValue();
 362   
 
 363  54
         String cacheSize = getProperty(CACHE_CAPACITY_KEY);
 364   
 
 365  54
         try {
 366  54
             if ((cacheSize != null) && (cacheSize.length() > 0)) {
 367  34
                 cacheCapacity = Integer.parseInt(cacheSize);
 368   
             }
 369   
         } catch (NumberFormatException e) {
 370  0
             log.error("The value supplied for the cache capacity, '" + cacheSize + "', is not a valid number. The cache capacity setting is being ignored.");
 371   
         }
 372   
     }
 373   
 
 374   
     /**
 375   
      * Load the properties file from the classpath.
 376   
      */
 377  54
     private void loadProps(Properties p) {
 378  54
         config = new Config(p);
 379   
     }
 380   
 }
 381