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Source file | Conditionals | Statements | Methods | TOTAL | |||||||||||||||
AbstractCacheAdministrator.java | 35,7% | 45,6% | 71,4% | 46,4% |
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/*
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* Copyright (c) 2002-2003 by OpenSymphony
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* All rights reserved.
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*/
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package com.opensymphony.oscache.base;
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import com.opensymphony.oscache.base.algorithm.AbstractConcurrentReadCache;
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import com.opensymphony.oscache.base.events.*;
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import com.opensymphony.oscache.base.persistence.PersistenceListener;
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import com.opensymphony.oscache.util.StringUtil;
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import org.apache.commons.logging.Log;
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import org.apache.commons.logging.LogFactory;
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import java.util.*;
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import javax.swing.event.EventListenerList;
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/**
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* An AbstractCacheAdministrator defines an abstract cache administrator, implementing all
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* the basic operations related to the configuration of a cache, including assigning
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* any configured event handlers to cache objects.<p>
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*
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* Extend this class to implement a custom cache administrator.
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*
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* @version $Revision: 1.6 $
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* @author a href="mailto:mike@atlassian.com">Mike Cannon-Brookes</a>
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* @author <a href="mailto:fbeauregard@pyxis-tech.com">Francois Beauregard</a>
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* @author <a href="mailto:abergevin@pyxis-tech.com">Alain Bergevin</a>
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* @author <a href="mailto:fabian.crabus@gurulogic.de">Fabian Crabus</a>
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* @author <a href="mailto:chris@swebtec.com">Chris Miller</a>
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*/
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public abstract class AbstractCacheAdministrator implements java.io.Serializable { |
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private static transient final Log log = LogFactory.getLog(AbstractCacheAdministrator.class); |
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/**
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* A boolean cache configuration property that indicates whether the cache
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* should cache objects in memory. Set this property to <code>false</code>
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* to disable in-memory caching.
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*/
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protected final static String CACHE_MEMORY_KEY = "cache.memory"; |
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/**
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* An integer cache configuration property that specifies the maximum number
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* of objects to hold in the cache. Setting this to a negative value will
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* disable the capacity functionality - there will be no limit to the number
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* of objects that are held in cache.
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*/
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protected final static String CACHE_CAPACITY_KEY = "cache.capacity"; |
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/**
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* A String cache configuration property that specifies the classname of
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* an alternate caching algorithm. This class must extend
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* {@link com.opensymphony.oscache.base.algorithm.AbstractConcurrentReadCache}
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* By default caches will use {@link com.opensymphony.oscache.base.algorithm.LRUCache} as
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* the default algorithm if the cache capacity is set to a postive value, or
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* {@link com.opensymphony.oscache.base.algorithm.UnlimitedCache} if the
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* capacity is negative (ie, disabled).
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*/
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protected final static String CACHE_ALGORITHM_KEY = "cache.algorithm"; |
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/**
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* A boolean cache configuration property that indicates whether the persistent
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* cache should be unlimited in size, or should be restricted to the same size
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* as the in-memory cache. Set this property to <code>true</code> to allow the
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* persistent cache to grow without bound.
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*/
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protected final static String CACHE_DISK_UNLIMITED_KEY = "cache.unlimited.disk"; |
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/**
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* The configuration key that specifies whether we should block waiting for new
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* content to be generated, or just serve the old content instead. The default
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* behaviour is to serve the old content since that provides the best performance
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* (at the cost of serving slightly stale data).
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*/
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protected final static String CACHE_BLOCKING_KEY = "cache.blocking"; |
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/**
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* A String cache configuration property that specifies the classname that will
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* be used to provide cache persistence. This class must extend {@link PersistenceListener}.
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*/
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protected static final String PERSISTENCE_CLASS = "cache.persistence.class"; |
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/**
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* A String cache configuration property that holds a comma-delimited list of
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* classnames. These classes specify the event handlers that are to be applied
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* to the cache.
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*/
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protected static final String CACHE_ENTRY_EVENT_LISTENERS = "cache.event.listeners"; |
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protected Config config = null; |
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/**
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* Holds a list of all the registered event listeners. Event listeners are specified
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* using the {@link #CACHE_ENTRY_EVENT_LISTENERS} configuration key.
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*/
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protected EventListenerList listenerList = new EventListenerList(); |
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/**
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* The algorithm class being used, as specified by the {@link #CACHE_ALGORITHM_KEY}
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* configuration property.
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*/
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protected String algorithmClass = null; |
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/**
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* The cache capacity (number of entries), as specified by the {@link #CACHE_CAPACITY_KEY}
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* configuration property.
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*/
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protected int cacheCapacity = -1; |
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/**
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* Whether the cache blocks waiting for content to be build, or serves stale
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* content instead. This value can be specified using the {@link #CACHE_BLOCKING_KEY}
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* configuration property.
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*/
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private boolean blocking = false; |
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/**
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* Whether or not to store the cache entries in memory. This is configurable using the
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* {@link com.opensymphony.oscache.base.AbstractCacheAdministrator#CACHE_MEMORY_KEY} property.
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*/
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private boolean memoryCaching = true; |
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/**
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* Whether the disk cache should be unlimited in size, or matched 1-1 to the memory cache.
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* This can be set via the {@link #CACHE_DISK_UNLIMITED_KEY} configuration property.
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*/
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private boolean unlimitedDiskCache; |
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/**
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* Create the AbstractCacheAdministrator.
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* This will initialize all values and load the properties from oscache.properties.
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*/
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protected AbstractCacheAdministrator() {
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this(null); |
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} |
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/**
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* Create the AbstractCacheAdministrator.
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*
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* @param p the configuration properties for this cache.
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*/
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protected AbstractCacheAdministrator(Properties p) {
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loadProps(p); |
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initCacheParameters(); |
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if (log.isDebugEnabled()) {
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log.debug("Constructed AbstractCacheAdministrator()");
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} |
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} |
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/**
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* Sets the algorithm to use for the cache.
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*
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* @see com.opensymphony.oscache.base.algorithm.LRUCache
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* @see com.opensymphony.oscache.base.algorithm.FIFOCache
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* @see com.opensymphony.oscache.base.algorithm.UnlimitedCache
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* @param newAlgorithmClass The class to use (eg.
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* <code>"com.opensymphony.oscache.base.algorithm.LRUCache"</code>)
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*/
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public void setAlgorithmClass(String newAlgorithmClass) { |
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algorithmClass = newAlgorithmClass; |
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} |
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/**
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* Indicates whether the cache will block waiting for new content to
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* be built, or serve stale content instead of waiting. Regardless of this
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* setting, the cache will <em>always</em> block if new content is being
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* created, ie, there's no stale content in the cache that can be served.
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*/
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public boolean isBlocking() { |
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return blocking;
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} |
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/**
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* Sets the cache capacity (number of items). Administrator implementations
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* should override this method to ensure that their {@link Cache} objects
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* are updated correctly (by calling {@link AbstractConcurrentReadCache#setMaxEntries(int)}}}.
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*
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* @param newCacheCapacity The new capacity
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*/
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protected void setCacheCapacity(int newCacheCapacity) { |
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cacheCapacity = newCacheCapacity; |
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} |
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/**
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* Whether entries are cached in memory or not.
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* Default is true.
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* Set by the <code>cache.memory</code> property.
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*
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* @return Status whether or not memory caching is used.
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*/
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public boolean isMemoryCaching() { |
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return memoryCaching;
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} |
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/**
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* Retrieves the value of one of the configuration properties.
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*
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* @param key The key assigned to the property
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* @return Property value, or <code>null</code> if the property could not be found.
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*/
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public String getProperty(String key) {
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return config.getProperty(key);
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} |
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/**
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* Indicates whether the unlimited disk cache is enabled or not.
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*/
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public boolean isUnlimitedDiskCache() { |
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return unlimitedDiskCache;
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} |
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/**
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* Retrieves an array containing instances all of the {@link CacheEventListener}
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* classes that are specified in the OSCache configuration file.
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*/
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protected CacheEventListener[] getCacheEventListeners() {
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CacheEventListener[] listeners = null;
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List classes = StringUtil.split(config.getProperty(CACHE_ENTRY_EVENT_LISTENERS), ','); |
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listeners = new CacheEventListener[classes.size()];
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for (int i = 0; i < classes.size(); i++) { |
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String className = (String) classes.get(i); |
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try {
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Class clazz = Class.forName(className); |
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if (!CacheEventListener.class.isAssignableFrom(clazz)) { |
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log.error("Specified listener class '" + className + "' does not implement CacheEventListener. Ignoring this listener."); |
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} else {
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listeners[i] = (CacheEventListener) clazz.newInstance(); |
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} |
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} catch (ClassNotFoundException e) {
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log.error("CacheEventListener class '" + className + "' not found. Ignoring this listener.", e); |
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} catch (InstantiationException e) {
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log.error("CacheEventListener class '" + className + "' could not be instantiated because it is not a concrete class. Ignoring this listener.", e); |
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} catch (IllegalAccessException e) {
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log.error("CacheEventListener class '" + className + "' could not be instantiated because it is not public. Ignoring this listener.", e); |
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} |
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} |
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return listeners;
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} |
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/**
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* If there is a <code>PersistenceListener</code> in the configuration
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* it will be instantiated and applied to the given cache object. If the
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* <code>PersistenceListener</code> cannot be found or instantiated, an
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* error will be logged but the cache will not have a persistence listener
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* applied to it and no exception will be thrown.<p>
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*
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* A cache can only have one <code>PersistenceListener</code>.
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*
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* @param cache the cache to apply the <code>PersistenceListener</code> to.
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*
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* @return the same cache object that was passed in.
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*/
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259 | 34 |
protected Cache setPersistenceListener(Cache cache) {
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260 | 34 |
String persistenceClassname = config.getProperty(PERSISTENCE_CLASS); |
261 |
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262 | 34 |
try {
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263 | 34 |
Class clazz = Class.forName(persistenceClassname); |
264 | 34 |
PersistenceListener persistenceListener = (PersistenceListener) clazz.newInstance(); |
265 |
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cache.setPersistenceListener(persistenceListener.configure(config)); |
267 |
} catch (ClassNotFoundException e) {
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log.error("PersistenceListener class '" + persistenceClassname + "' not found. Check your configuration.", e); |
269 |
} catch (Exception e) {
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270 | 0 |
log.error("Error instantiating class '" + persistenceClassname + "'", e); |
271 |
} |
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273 | 34 |
return cache;
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} |
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/**
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* Applies all of the recognised listener classes to the supplied
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* cache object. Recognised classes are {@link CacheEntryEventListener}
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* and {@link CacheMapAccessEventListener}.<p>
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*
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* @param cache The cache to apply the configuration to.
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* @return cache The configured cache object.
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*/
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284 | 54 |
protected Cache configureStandardListeners(Cache cache) {
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285 | 54 |
if (config.getProperty(PERSISTENCE_CLASS) != null) { |
286 | 34 |
cache = setPersistenceListener(cache); |
287 |
} |
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288 |
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289 | 54 |
if (config.getProperty(CACHE_ENTRY_EVENT_LISTENERS) != null) { |
290 |
// Grab all the specified listeners and add them to the cache's
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// listener list. Note that listeners that implement more than
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// one of the event interfaces will be added multiple times.
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293 | 0 |
CacheEventListener[] listeners = getCacheEventListeners(); |
294 |
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295 | 0 |
for (int i = 0; i < listeners.length; i++) { |
296 |
// Pass through the configuration to those listeners that require it
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297 | 0 |
if (listeners[i] instanceof LifecycleAware) { |
298 | 0 |
try {
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299 | 0 |
((LifecycleAware) listeners[i]).initialize(cache, config); |
300 |
} catch (InitializationException e) {
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301 | 0 |
log.error("Could not initialize listener '" + listeners[i].getClass().getName() + "'. Listener ignored.", e); |
302 |
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303 | 0 |
continue;
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} |
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} |
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307 | 0 |
if (listeners[i] instanceof CacheEntryEventListener) { |
308 | 0 |
cache.addCacheEventListener(listeners[i], CacheEntryEventListener.class);
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} |
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310 |
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311 | 0 |
if (listeners[i] instanceof CacheMapAccessEventListener) { |
312 | 0 |
cache.addCacheEventListener(listeners[i], CacheMapAccessEventListener.class);
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} |
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} |
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} |
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316 |
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317 | 54 |
return cache;
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} |
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319 |
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320 |
/**
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* Finalizes all the listeners that are associated with the given cache object.
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* Any <code>FinalizationException</code>s that are thrown by the listeners will
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* be caught and logged.
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*/
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325 | 3 |
protected void finalizeListeners(Cache cache) { |
326 |
// It's possible for cache to be null if getCache() was never called (CACHE-63)
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327 | 3 |
if (cache == null) { |
328 | 0 |
return;
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} |
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330 |
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331 | 3 |
Object[] listeners = cache.listenerList.getListenerList(); |
332 |
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333 | 3 |
for (int i = listeners.length - 2; i >= 0; i -= 2) { |
334 | 0 |
if (listeners[i + 1] instanceof LifecycleAware) { |
335 | 0 |
try {
|
336 | 0 |
((LifecycleAware) listeners[i + 1]).finialize(); |
337 |
} catch (FinalizationException e) {
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|
338 | 0 |
log.error("Listener could not be finalized", e);
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339 |
} |
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340 |
} |
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341 |
} |
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342 |
} |
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343 |
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344 |
/**
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* Initialize the core cache parameters from the configuration properties.
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346 |
* The parameters that are initialized are:
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347 |
* <ul>
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348 |
* <li>the algorithm class ({@link #CACHE_ALGORITHM_KEY})</li>
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349 |
* <li>the cache size ({@link #CACHE_CAPACITY_KEY})</li>
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350 |
* <li>whether the cache is blocking or non-blocking ({@link #CACHE_BLOCKING_KEY})</li>
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* <li>whether caching to memory is enabled ({@link #CACHE_MEMORY_KEY})</li>
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* <li>whether the persistent cache is unlimited in size ({@link #CACHE_DISK_UNLIMITED_KEY})</li>
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* </ul>
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*/
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355 | 54 |
private void initCacheParameters() { |
356 | 54 |
algorithmClass = getProperty(CACHE_ALGORITHM_KEY); |
357 |
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358 | 54 |
blocking = "true".equalsIgnoreCase(getProperty(CACHE_BLOCKING_KEY));
|
359 |
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|
360 | 54 |
String cacheMemoryStr = getProperty(CACHE_MEMORY_KEY); |
361 |
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|
362 | 54 |
if ((cacheMemoryStr != null) && cacheMemoryStr.equalsIgnoreCase("false")) { |
363 | 17 |
memoryCaching = false;
|
364 |
} |
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365 |
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|
366 | 54 |
unlimitedDiskCache = Boolean.valueOf(config.getProperty(CACHE_DISK_UNLIMITED_KEY)).booleanValue(); |
367 |
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|
368 | 54 |
String cacheSize = getProperty(CACHE_CAPACITY_KEY); |
369 |
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|
370 | 54 |
try {
|
371 | 54 |
if ((cacheSize != null) && (cacheSize.length() > 0)) { |
372 | 34 |
cacheCapacity = Integer.parseInt(cacheSize); |
373 |
} |
|
374 |
} catch (NumberFormatException e) {
|
|
375 | 0 |
log.error("The value supplied for the cache capacity, '" + cacheSize + "', is not a valid number. The cache capacity setting is being ignored."); |
376 |
} |
|
377 |
} |
|
378 |
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|
379 |
/**
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|
380 |
* Load the properties file from the classpath.
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|
381 |
*/
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|
382 | 54 |
private void loadProps(Properties p) { |
383 | 54 |
config = new Config(p);
|
384 |
} |
|
385 |
} |
|
386 |
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