1010 lines
40 KiB
Java
1010 lines
40 KiB
Java
/*
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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.algorithm.LRUCache;
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import com.opensymphony.oscache.base.algorithm.UnlimitedCache;
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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.FastCronParser;
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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 javax.swing.event.EventListenerList;
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import java.io.Serializable;
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import java.text.ParseException;
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import java.util.*;
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/**
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* Provides an interface to the cache itself. Creating an instance of this class
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* will create a cache that behaves according to its construction parameters.
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* The public API provides methods to manage objects in the cache and configure
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* any cache event listeners.
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*
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* @version $Revision$
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* @author <a href="mailto:mike@atlassian.com">Mike Cannon-Brookes</a>
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* @author <a href="mailto:tgochenour@peregrine.com">Todd Gochenour</a>
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* @author <a href="mailto:fbeauregard@pyxis-tech.com">Francois Beauregard</a>
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* @author <a href="mailto:chris@swebtec.com">Chris Miller</a>
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*/
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public class Cache implements Serializable {
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/**
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* An event that origininated from within another event.
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*/
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public static final String NESTED_EVENT = "NESTED";
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private static transient final Log log = LogFactory.getLog(Cache.class);
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/**
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* A list of all registered event listeners for this cache.
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*/
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protected EventListenerList listenerList = new EventListenerList();
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/**
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* The actual cache map. This is where the cached objects are held.
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*/
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private AbstractConcurrentReadCache cacheMap = null;
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/**
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* Date of last complete cache flush.
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*/
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private Date flushDateTime = null;
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/**
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* A map that holds keys of cache entries that are currently being built, and EntryUpdateState instance as values. This is used to coordinate threads
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* that modify/access a same key in concurrence.
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*
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* The cache checks against this map when a stale entry is requested, or a cache miss is observed.
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*
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* If the requested key is in here, we know the entry is currently being
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* built by another thread and hence we can either block and wait or serve
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* the stale entry (depending on whether cache blocking is enabled or not).
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* <p>
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* To avoid data races, values in this map should remain present during the whole time distinct threads deal with the
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* same key. We implement this using explicit reference counting in the EntryUpdateState instance, to be able to clean up
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* the map once all threads have declared they are done accessing/updating a given key.
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*
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* It is not possible to locate this into the CacheEntry because this would require to have a CacheEntry instance for all cache misses, and
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* may therefore generate a memory leak. More over, the CacheEntry instance may not be hold in memory in the case no
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* memory cache is configured.
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*/
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private Map updateStates = new HashMap();
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/**
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* Indicates whether the cache blocks requests until new content has
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* been generated or just serves stale content instead.
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*/
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private boolean blocking = false;
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/**
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* Create a new Cache
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*
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* @param useMemoryCaching Specify if the memory caching is going to be used
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* @param unlimitedDiskCache Specify if the disk caching is unlimited
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* @param overflowPersistence Specify if the persistent cache is used in overflow only mode
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*/
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public Cache(boolean useMemoryCaching, boolean unlimitedDiskCache, boolean overflowPersistence) {
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this(useMemoryCaching, unlimitedDiskCache, overflowPersistence, false, null, 0);
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}
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/**
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* Create a new Cache.
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*
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* If a valid algorithm class is specified, it will be used for this cache.
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* Otherwise if a capacity is specified, it will use LRUCache.
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* If no algorithm or capacity is specified UnlimitedCache is used.
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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.UnlimitedCache
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* @param useMemoryCaching Specify if the memory caching is going to be used
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* @param unlimitedDiskCache Specify if the disk caching is unlimited
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* @param overflowPersistence Specify if the persistent cache is used in overflow only mode
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* @param blocking This parameter takes effect when a cache entry has
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* just expired and several simultaneous requests try to retrieve it. While
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* one request is rebuilding the content, the other requests will either
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* block and wait for the new content (<code>blocking == true</code>) or
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* instead receive a copy of the stale content so they don't have to wait
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* (<code>blocking == false</code>). the default is <code>false</code>,
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* which provides better performance but at the expense of slightly stale
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* data being served.
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* @param algorithmClass The class implementing the desired algorithm
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* @param capacity The capacity
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*/
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public Cache(boolean useMemoryCaching, boolean unlimitedDiskCache, boolean overflowPersistence, boolean blocking, String algorithmClass, int capacity) {
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// Instantiate the algo class if valid
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if (((algorithmClass != null) && (algorithmClass.length() > 0)) && (capacity > 0)) {
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try {
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cacheMap = (AbstractConcurrentReadCache) Class.forName(algorithmClass).newInstance();
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cacheMap.setMaxEntries(capacity);
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} catch (Exception e) {
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log.error("Invalid class name for cache algorithm class. " + e.toString());
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}
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}
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if (cacheMap == null) {
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// If we have a capacity, use LRU cache otherwise use unlimited Cache
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if (capacity > 0) {
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cacheMap = new LRUCache(capacity);
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} else {
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cacheMap = new UnlimitedCache();
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}
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}
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cacheMap.setUnlimitedDiskCache(unlimitedDiskCache);
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cacheMap.setOverflowPersistence(overflowPersistence);
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cacheMap.setMemoryCaching(useMemoryCaching);
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this.blocking = blocking;
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}
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/**
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* @return the maximum number of items to cache can hold.
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*/
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public int getCapacity() {
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return cacheMap.getMaxEntries();
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}
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/**
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* Allows the capacity of the cache to be altered dynamically. Note that
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* some cache implementations may choose to ignore this setting (eg the
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* {@link UnlimitedCache} ignores this call).
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*
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* @param capacity the maximum number of items to hold in the cache.
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*/
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public void setCapacity(int capacity) {
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cacheMap.setMaxEntries(capacity);
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}
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/**
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* Checks if the cache was flushed more recently than the CacheEntry provided.
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* Used to determine whether to refresh the particular CacheEntry.
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*
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* @param cacheEntry The cache entry which we're seeing whether to refresh
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* @return Whether or not the cache has been flushed more recently than this cache entry was updated.
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*/
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public boolean isFlushed(CacheEntry cacheEntry) {
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if (flushDateTime != null) {
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final long lastUpdate = cacheEntry.getLastUpdate();
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final long flushTime = flushDateTime.getTime();
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// CACHE-241: check flushDateTime with current time also
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return (flushTime <= System.currentTimeMillis()) && (flushTime >= lastUpdate);
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} else {
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return false;
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}
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}
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/**
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* Retrieve an object from the cache specifying its key.
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*
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* @param key Key of the object in the cache.
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*
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* @return The object from cache
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*
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* @throws NeedsRefreshException Thrown when the object either
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* doesn't exist, or exists but is stale. When this exception occurs,
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* the CacheEntry corresponding to the supplied key will be locked
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* and other threads requesting this entry will potentially be blocked
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* until the caller repopulates the cache. If the caller choses not
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* to repopulate the cache, they <em>must</em> instead call
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* {@link #cancelUpdate(String)}.
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*/
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public Object getFromCache(String key) throws NeedsRefreshException {
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return getFromCache(key, CacheEntry.INDEFINITE_EXPIRY, null);
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}
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/**
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* Retrieve an object from the cache specifying its key.
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*
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* @param key Key of the object in the cache.
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* @param refreshPeriod How long before the object needs refresh. To
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* allow the object to stay in the cache indefinitely, supply a value
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* of {@link CacheEntry#INDEFINITE_EXPIRY}.
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*
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* @return The object from cache
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*
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* @throws NeedsRefreshException Thrown when the object either
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* doesn't exist, or exists but is stale. When this exception occurs,
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* the CacheEntry corresponding to the supplied key will be locked
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* and other threads requesting this entry will potentially be blocked
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* until the caller repopulates the cache. If the caller choses not
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* to repopulate the cache, they <em>must</em> instead call
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* {@link #cancelUpdate(String)}.
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*/
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public Object getFromCache(String key, int refreshPeriod) throws NeedsRefreshException {
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return getFromCache(key, refreshPeriod, null);
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}
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/**
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* Retrieve an object from the cache specifying its key.
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*
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* @param key Key of the object in the cache.
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* @param refreshPeriod How long before the object needs refresh. To
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* allow the object to stay in the cache indefinitely, supply a value
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* of {@link CacheEntry#INDEFINITE_EXPIRY}.
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* @param cronExpiry A cron expression that specifies fixed date(s)
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* and/or time(s) that this cache entry should
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* expire on.
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*
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* @return The object from cache
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*
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* @throws NeedsRefreshException Thrown when the object either
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* doesn't exist, or exists but is stale. When this exception occurs,
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* the CacheEntry corresponding to the supplied key will be locked
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* and other threads requesting this entry will potentially be blocked
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* until the caller repopulates the cache. If the caller choses not
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* to repopulate the cache, they <em>must</em> instead call
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* {@link #cancelUpdate(String)}.
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*/
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public Object getFromCache(String key, int refreshPeriod, String cronExpiry) throws NeedsRefreshException {
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CacheEntry cacheEntry = this.getCacheEntry(key, null, null);
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Object content = cacheEntry.getContent();
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CacheMapAccessEventType accessEventType = CacheMapAccessEventType.HIT;
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boolean reload = false;
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// Check if this entry has expired or has not yet been added to the cache. If
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// so, we need to decide whether to block, serve stale content or throw a
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// NeedsRefreshException
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if (this.isStale(cacheEntry, refreshPeriod, cronExpiry)) {
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//Get access to the EntryUpdateState instance and increment the usage count during the potential sleep
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EntryUpdateState updateState = getUpdateState(key);
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try {
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synchronized (updateState) {
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if (updateState.isAwaitingUpdate() || updateState.isCancelled()) {
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// No one else is currently updating this entry - grab ownership
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updateState.startUpdate();
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if (cacheEntry.isNew()) {
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accessEventType = CacheMapAccessEventType.MISS;
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} else {
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accessEventType = CacheMapAccessEventType.STALE_HIT;
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}
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} else if (updateState.isUpdating()) {
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// Another thread is already updating the cache. We block if this
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// is a new entry, or blocking mode is enabled. Either putInCache()
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// or cancelUpdate() can cause this thread to resume.
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if (cacheEntry.isNew() || blocking) {
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do {
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try {
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updateState.wait();
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} catch (InterruptedException e) {
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}
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} while (updateState.isUpdating());
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if (updateState.isCancelled()) {
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// The updating thread canceled the update, let this one have a go.
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// This increments the usage count for this EntryUpdateState instance
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updateState.startUpdate();
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if (cacheEntry.isNew()) {
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accessEventType = CacheMapAccessEventType.MISS;
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} else {
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accessEventType = CacheMapAccessEventType.STALE_HIT;
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}
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} else if (updateState.isComplete()) {
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reload = true;
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} else {
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log.error("Invalid update state for cache entry " + key);
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}
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}
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} else {
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reload = true;
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}
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}
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} finally {
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//Make sure we release the usage count for this EntryUpdateState since we don't use it anymore. If the current thread started the update, then the counter was
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//increased by one in startUpdate()
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releaseUpdateState(updateState, key);
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}
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}
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// If reload is true then another thread must have successfully rebuilt the cache entry
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if (reload) {
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cacheEntry = (CacheEntry) cacheMap.get(key);
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if (cacheEntry != null) {
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content = cacheEntry.getContent();
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} else {
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log.error("Could not reload cache entry after waiting for it to be rebuilt");
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}
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}
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dispatchCacheMapAccessEvent(accessEventType, cacheEntry, null);
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// If we didn't end up getting a hit then we need to throw a NRE
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if (accessEventType != CacheMapAccessEventType.HIT) {
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throw new NeedsRefreshException(content);
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}
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return content;
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}
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/**
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* Set the listener to use for data persistence. Only one
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* <code>PersistenceListener</code> can be configured per cache.
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*
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* @param listener The implementation of a persistance listener
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*/
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public void setPersistenceListener(PersistenceListener listener) {
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cacheMap.setPersistenceListener(listener);
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}
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/**
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* Retrieves the currently configured <code>PersistenceListener</code>.
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*
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* @return the cache's <code>PersistenceListener</code>, or <code>null</code>
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* if no listener is configured.
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*/
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public PersistenceListener getPersistenceListener() {
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return cacheMap.getPersistenceListener();
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}
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/**
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* Register a listener for Cache events. The listener must implement
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* one of the child interfaces of the {@link CacheEventListener} interface.
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*
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* @param listener The object that listens to events.
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* @since 2.4
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*/
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public void addCacheEventListener(CacheEventListener listener) {
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listenerList.add(CacheEventListener.class, listener);
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// listenerList.add(listener.getClass(), listener);
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}
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/**
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* Register a listener for Cache events. The listener must implement
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* one of the child interfaces of the {@link CacheEventListener} interface.
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*
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* @param listener The object that listens to events.
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* @param clazz the type of the listener to be added
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* @deprecated use {@link #addCacheEventListener(CacheEventListener)}
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*/
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public void addCacheEventListener(CacheEventListener listener, Class clazz) {
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if (CacheEventListener.class.isAssignableFrom(clazz)) {
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listenerList.add(clazz, listener);
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} else {
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log.error("The class '" + clazz.getName() + "' is not a CacheEventListener. Ignoring this listener.");
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}
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}
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/**
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* Returns the list of all CacheEventListeners.
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* @return the CacheEventListener's list of the Cache
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*/
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public EventListenerList getCacheEventListenerList() {
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return listenerList;
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}
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/**
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* Cancels any pending update for this cache entry. This should <em>only</em>
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* be called by the thread that is responsible for performing the update ie
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* the thread that received the original {@link NeedsRefreshException}.<p/>
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* If a cache entry is not updated (via {@link #putInCache} and this method is
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* not called to let OSCache know the update will not be forthcoming, subsequent
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* requests for this cache entry will either block indefinitely (if this is a new
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* cache entry or cache.blocking=true), or forever get served stale content. Note
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* however that there is no harm in cancelling an update on a key that either
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* does not exist or is not currently being updated.
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*
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* @param key The key for the cache entry in question.
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* @throws IllegalStateException if the cache entry isn't in the state UPDATE_IN_PROGRESS
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*/
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public void cancelUpdate(String key) {
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EntryUpdateState state;
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if (key != null) {
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synchronized (updateStates) {
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state = (EntryUpdateState) updateStates.get(key);
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if (state != null) {
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synchronized (state) {
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int usageCounter = state.cancelUpdate();
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state.notify();
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checkEntryStateUpdateUsage(key, state, usageCounter);
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}
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} else {
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if (log.isErrorEnabled()) {
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log.error("internal error: expected to get a state from key [" + key + "]");
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}
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}
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}
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}
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}
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/**
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* Utility method to check if the specified usage count is zero, and if so remove the corresponding EntryUpdateState from the updateStates. This is designed to factor common code.
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*
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* Warning: This method should always be called while holding both the updateStates field and the state parameter
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* @throws Exception
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*/
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private void checkEntryStateUpdateUsage(String key, EntryUpdateState state, int usageCounter) {
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//Clean up the updateStates map to avoid a memory leak once no thread is using this EntryUpdateState instance anymore.
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if (usageCounter == 0) {
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EntryUpdateState removedState = (EntryUpdateState) updateStates.remove(key);
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if (state != removedState) {
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if (log.isErrorEnabled()) {
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try {
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throw new Exception("OSCache: internal error: removed state [" + removedState + "] from key [" + key + "] whereas we expected [" + state + "]");
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} catch (Exception e) {
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log.error(e);
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}
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}
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}
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}
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}
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/**
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* Flush all entries in the cache on the given date/time.
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*
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* @param date The date at which all cache entries will be flushed.
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*/
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public void flushAll(Date date) {
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flushAll(date, null);
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}
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/**
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* Flush all entries in the cache on the given date/time.
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*
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* @param date The date at which all cache entries will be flushed.
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* @param origin The origin of this flush request (optional)
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*/
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public void flushAll(Date date, String origin) {
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flushDateTime = date;
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if (listenerList.getListenerCount() > 0) {
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dispatchCachewideEvent(CachewideEventType.CACHE_FLUSHED, date, origin);
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}
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}
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/**
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* Flush the cache entry (if any) that corresponds to the cache key supplied.
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* This call will flush the entry from the cache and remove the references to
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* it from any cache groups that it is a member of. On completion of the flush,
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* a <tt>CacheEntryEventType.ENTRY_FLUSHED</tt> event is fired.
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*
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* @param key The key of the entry to flush
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*/
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public void flushEntry(String key) {
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flushEntry(key, null);
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}
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/**
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* Flush the cache entry (if any) that corresponds to the cache key supplied.
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* This call will mark the cache entry as flushed so that the next access
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* to it will cause a {@link NeedsRefreshException}. On completion of the
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* flush, a <tt>CacheEntryEventType.ENTRY_FLUSHED</tt> event is fired.
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*
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* @param key The key of the entry to flush
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* @param origin The origin of this flush request (optional)
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*/
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public void flushEntry(String key, String origin) {
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flushEntry(getCacheEntry(key, null, origin), origin);
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}
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/**
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* Flushes all objects that belong to the supplied group. On completion
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* this method fires a <tt>CacheEntryEventType.GROUP_FLUSHED</tt> event.
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*
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* @param group The group to flush
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*/
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public void flushGroup(String group) {
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flushGroup(group, null);
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}
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/**
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* Flushes all unexpired objects that belong to the supplied group. On
|
|
* completion this method fires a <tt>CacheEntryEventType.GROUP_FLUSHED</tt>
|
|
* event.
|
|
*
|
|
* @param group The group to flush
|
|
* @param origin The origin of this flush event (optional)
|
|
*/
|
|
public void flushGroup(String group, String origin) {
|
|
// Flush all objects in the group
|
|
Set groupEntries = cacheMap.getGroup(group);
|
|
|
|
if (groupEntries != null) {
|
|
Iterator itr = groupEntries.iterator();
|
|
String key;
|
|
CacheEntry entry;
|
|
|
|
while (itr.hasNext()) {
|
|
key = (String) itr.next();
|
|
entry = (CacheEntry) cacheMap.get(key);
|
|
|
|
if ((entry != null) && !entry.needsRefresh(CacheEntry.INDEFINITE_EXPIRY)) {
|
|
flushEntry(entry, NESTED_EVENT);
|
|
}
|
|
}
|
|
}
|
|
|
|
if (listenerList.getListenerCount() > 0) {
|
|
dispatchCacheGroupEvent(CacheEntryEventType.GROUP_FLUSHED, group, origin);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Flush all entries with keys that match a given pattern
|
|
*
|
|
* @param pattern The key must contain this given value
|
|
* @deprecated For performance and flexibility reasons it is preferable to
|
|
* store cache entries in groups and use the {@link #flushGroup(String)} method
|
|
* instead of relying on pattern flushing.
|
|
*/
|
|
public void flushPattern(String pattern) {
|
|
flushPattern(pattern, null);
|
|
}
|
|
|
|
/**
|
|
* Flush all entries with keys that match a given pattern
|
|
*
|
|
* @param pattern The key must contain this given value
|
|
* @param origin The origin of this flush request
|
|
* @deprecated For performance and flexibility reasons it is preferable to
|
|
* store cache entries in groups and use the {@link #flushGroup(String, String)}
|
|
* method instead of relying on pattern flushing.
|
|
*/
|
|
public void flushPattern(String pattern, String origin) {
|
|
// Check the pattern
|
|
if ((pattern != null) && (pattern.length() > 0)) {
|
|
String key = null;
|
|
CacheEntry entry = null;
|
|
Iterator itr = cacheMap.keySet().iterator();
|
|
|
|
while (itr.hasNext()) {
|
|
key = (String) itr.next();
|
|
|
|
if (key.indexOf(pattern) >= 0) {
|
|
entry = (CacheEntry) cacheMap.get(key);
|
|
|
|
if (entry != null) {
|
|
flushEntry(entry, origin);
|
|
}
|
|
}
|
|
}
|
|
|
|
if (listenerList.getListenerCount() > 0) {
|
|
dispatchCachePatternEvent(CacheEntryEventType.PATTERN_FLUSHED, pattern, origin);
|
|
}
|
|
} else {
|
|
// Empty pattern, nothing to do
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Put an object in the cache specifying the key to use.
|
|
*
|
|
* @param key Key of the object in the cache.
|
|
* @param content The object to cache.
|
|
*/
|
|
public void putInCache(String key, Object content) {
|
|
putInCache(key, content, null, null, null);
|
|
}
|
|
|
|
/**
|
|
* Put an object in the cache specifying the key and refresh policy to use.
|
|
*
|
|
* @param key Key of the object in the cache.
|
|
* @param content The object to cache.
|
|
* @param policy Object that implements refresh policy logic
|
|
*/
|
|
public void putInCache(String key, Object content, EntryRefreshPolicy policy) {
|
|
putInCache(key, content, null, policy, null);
|
|
}
|
|
|
|
/**
|
|
* Put in object into the cache, specifying both the key to use and the
|
|
* cache groups the object belongs to.
|
|
*
|
|
* @param key Key of the object in the cache
|
|
* @param content The object to cache
|
|
* @param groups The cache groups to add the object to
|
|
*/
|
|
public void putInCache(String key, Object content, String[] groups) {
|
|
putInCache(key, content, groups, null, null);
|
|
}
|
|
|
|
/**
|
|
* Put an object into the cache specifying both the key to use and the
|
|
* cache groups the object belongs to.
|
|
*
|
|
* @param key Key of the object in the cache
|
|
* @param groups The cache groups to add the object to
|
|
* @param content The object to cache
|
|
* @param policy Object that implements the refresh policy logic
|
|
*/
|
|
public void putInCache(String key, Object content, String[] groups, EntryRefreshPolicy policy, String origin) {
|
|
CacheEntry cacheEntry = this.getCacheEntry(key, policy, origin);
|
|
boolean isNewEntry = cacheEntry.isNew();
|
|
|
|
// [CACHE-118] If we have an existing entry, create a new CacheEntry so we can still access the old one later
|
|
if (!isNewEntry) {
|
|
cacheEntry = new CacheEntry(key, policy);
|
|
}
|
|
|
|
cacheEntry.setContent(content);
|
|
cacheEntry.setGroups(groups);
|
|
cacheMap.put(key, cacheEntry);
|
|
|
|
// Signal to any threads waiting on this update that it's now ready for them
|
|
// in the cache!
|
|
completeUpdate(key);
|
|
|
|
if (listenerList.getListenerCount() > 0) {
|
|
CacheEntryEvent event = new CacheEntryEvent(this, cacheEntry, origin);
|
|
|
|
if (isNewEntry) {
|
|
dispatchCacheEntryEvent(CacheEntryEventType.ENTRY_ADDED, event);
|
|
} else {
|
|
dispatchCacheEntryEvent(CacheEntryEventType.ENTRY_UPDATED, event);
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Unregister a listener for Cache events.
|
|
*
|
|
* @param listener The object that currently listens to events.
|
|
* @param clazz The registrated class of listening object.
|
|
* @deprecated use instead {@link #removeCacheEventListener(CacheEventListener)}
|
|
*/
|
|
public void removeCacheEventListener(CacheEventListener listener, Class clazz) {
|
|
listenerList.remove(clazz, listener);
|
|
}
|
|
|
|
/**
|
|
* Unregister a listener for Cache events.
|
|
*
|
|
* @param listener The object that currently listens to events.
|
|
* @since 2.4
|
|
*/
|
|
public void removeCacheEventListener(CacheEventListener listener) {
|
|
listenerList.remove(CacheEventListener.class, listener);
|
|
// listenerList.remove(listener.getClass(), listener);
|
|
}
|
|
|
|
/**
|
|
* Get an entry from this cache or create one if it doesn't exist.
|
|
*
|
|
* @param key The key of the cache entry
|
|
* @param policy Object that implements refresh policy logic
|
|
* @param origin The origin of request (optional)
|
|
* @return CacheEntry for the specified key.
|
|
*/
|
|
protected CacheEntry getCacheEntry(String key, EntryRefreshPolicy policy, String origin) {
|
|
CacheEntry cacheEntry = null;
|
|
|
|
// Verify that the key is valid
|
|
if ((key == null) || (key.length() == 0)) {
|
|
throw new IllegalArgumentException("getCacheEntry called with an empty or null key");
|
|
}
|
|
|
|
cacheEntry = (CacheEntry) cacheMap.get(key);
|
|
|
|
// if the cache entry does not exist, create a new one
|
|
if (cacheEntry == null) {
|
|
if (log.isDebugEnabled()) {
|
|
log.debug("No cache entry exists for key='" + key + "', creating");
|
|
}
|
|
|
|
cacheEntry = new CacheEntry(key, policy);
|
|
}
|
|
|
|
return cacheEntry;
|
|
}
|
|
|
|
/**
|
|
* Indicates whether or not the cache entry is stale.
|
|
*
|
|
* @param cacheEntry The cache entry to test the freshness of.
|
|
* @param refreshPeriod The maximum allowable age of the entry, in seconds.
|
|
* @param cronExpiry A cron expression specifying absolute date(s) and/or time(s)
|
|
* that the cache entry should expire at. If the cache entry was refreshed prior to
|
|
* the most recent match for the cron expression, the entry will be considered stale.
|
|
*
|
|
* @return <code>true</code> if the entry is stale, <code>false</code> otherwise.
|
|
*/
|
|
protected boolean isStale(CacheEntry cacheEntry, int refreshPeriod, String cronExpiry) {
|
|
boolean result = cacheEntry.needsRefresh(refreshPeriod) || isFlushed(cacheEntry);
|
|
|
|
if ((!result) && (cronExpiry != null) && (cronExpiry.length() > 0)) {
|
|
try {
|
|
FastCronParser parser = new FastCronParser(cronExpiry);
|
|
result = result || parser.hasMoreRecentMatch(cacheEntry.getLastUpdate());
|
|
} catch (ParseException e) {
|
|
log.warn(e);
|
|
}
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
/**
|
|
* Get the updating cache entry from the update map. If one is not found,
|
|
* create a new one (with state {@link EntryUpdateState#NOT_YET_UPDATING})
|
|
* and add it to the map.
|
|
*
|
|
* @param key The cache key for this entry
|
|
*
|
|
* @return the CacheEntry that was found (or added to) the updatingEntries
|
|
* map.
|
|
*/
|
|
protected EntryUpdateState getUpdateState(String key) {
|
|
EntryUpdateState updateState;
|
|
|
|
synchronized (updateStates) {
|
|
// Try to find the matching state object in the updating entry map.
|
|
updateState = (EntryUpdateState) updateStates.get(key);
|
|
|
|
if (updateState == null) {
|
|
// It's not there so add it.
|
|
updateState = new EntryUpdateState();
|
|
updateStates.put(key, updateState);
|
|
} else {
|
|
//Otherwise indicate that we start using it to prevent its removal until all threads are done with it.
|
|
updateState.incrementUsageCounter();
|
|
}
|
|
}
|
|
|
|
return updateState;
|
|
}
|
|
|
|
/**
|
|
* releases the usage that was made of the specified EntryUpdateState. When this reaches zero, the entry is removed from the map.
|
|
* @param state the state to release the usage of
|
|
* @param key the associated key.
|
|
*/
|
|
protected void releaseUpdateState(EntryUpdateState state, String key) {
|
|
synchronized (updateStates) {
|
|
int usageCounter = state.decrementUsageCounter();
|
|
checkEntryStateUpdateUsage(key, state, usageCounter);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Completely clears the cache.
|
|
*/
|
|
protected void clear() {
|
|
cacheMap.clear();
|
|
}
|
|
|
|
/**
|
|
* Removes the update state for the specified key and notifies any other
|
|
* threads that are waiting on this object. This is called automatically
|
|
* by the {@link #putInCache} method, so it is possible that no EntryUpdateState was hold
|
|
* when this method is called.
|
|
*
|
|
* @param key The cache key that is no longer being updated.
|
|
*/
|
|
protected void completeUpdate(String key) {
|
|
EntryUpdateState state;
|
|
|
|
synchronized (updateStates) {
|
|
state = (EntryUpdateState) updateStates.get(key);
|
|
|
|
if (state != null) {
|
|
synchronized (state) {
|
|
int usageCounter = state.completeUpdate();
|
|
state.notifyAll();
|
|
|
|
checkEntryStateUpdateUsage(key, state, usageCounter);
|
|
|
|
}
|
|
} else {
|
|
//If putInCache() was called directly (i.e. not as a result of a NeedRefreshException) then no EntryUpdateState would be found.
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Completely removes a cache entry from the cache and its associated cache
|
|
* groups.
|
|
*
|
|
* @param key The key of the entry to remove.
|
|
*/
|
|
public void removeEntry(String key) {
|
|
removeEntry(key, null);
|
|
}
|
|
|
|
/**
|
|
* Completely removes a cache entry from the cache and its associated cache
|
|
* groups.
|
|
*
|
|
* @param key The key of the entry to remove.
|
|
* @param origin The origin of this remove request.
|
|
*/
|
|
protected void removeEntry(String key, String origin) {
|
|
CacheEntry cacheEntry = (CacheEntry) cacheMap.get(key);
|
|
cacheMap.remove(key);
|
|
|
|
if (listenerList.getListenerCount() > 0) {
|
|
CacheEntryEvent event = new CacheEntryEvent(this, cacheEntry, origin);
|
|
dispatchCacheEntryEvent(CacheEntryEventType.ENTRY_REMOVED, event);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Dispatch a cache entry event to all registered listeners.
|
|
*
|
|
* @param eventType The type of event (used to branch on the proper method)
|
|
* @param event The event that was fired
|
|
*/
|
|
private void dispatchCacheEntryEvent(CacheEntryEventType eventType, CacheEntryEvent event) {
|
|
// Guaranteed to return a non-null array
|
|
Object[] listeners = listenerList.getListenerList();
|
|
|
|
// Process the listeners last to first, notifying
|
|
// those that are interested in this event
|
|
for (int i = listeners.length - 2; i >= 0; i -= 2) {
|
|
if (listeners[i+1] instanceof CacheEntryEventListener) {
|
|
CacheEntryEventListener listener = (CacheEntryEventListener) listeners[i+1];
|
|
if (eventType.equals(CacheEntryEventType.ENTRY_ADDED)) {
|
|
listener.cacheEntryAdded(event);
|
|
} else if (eventType.equals(CacheEntryEventType.ENTRY_UPDATED)) {
|
|
listener.cacheEntryUpdated(event);
|
|
} else if (eventType.equals(CacheEntryEventType.ENTRY_FLUSHED)) {
|
|
listener.cacheEntryFlushed(event);
|
|
} else if (eventType.equals(CacheEntryEventType.ENTRY_REMOVED)) {
|
|
listener.cacheEntryRemoved(event);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Dispatch a cache group event to all registered listeners.
|
|
*
|
|
* @param eventType The type of event (this is used to branch to the correct method handler)
|
|
* @param group The cache group that the event applies to
|
|
* @param origin The origin of this event (optional)
|
|
*/
|
|
private void dispatchCacheGroupEvent(CacheEntryEventType eventType, String group, String origin) {
|
|
CacheGroupEvent event = new CacheGroupEvent(this, group, origin);
|
|
|
|
// Guaranteed to return a non-null array
|
|
Object[] listeners = listenerList.getListenerList();
|
|
|
|
// Process the listeners last to first, notifying
|
|
// those that are interested in this event
|
|
for (int i = listeners.length - 2; i >= 0; i -= 2) {
|
|
if (listeners[i+1] instanceof CacheEntryEventListener) {
|
|
CacheEntryEventListener listener = (CacheEntryEventListener) listeners[i + 1];
|
|
if (eventType.equals(CacheEntryEventType.GROUP_FLUSHED)) {
|
|
listener.cacheGroupFlushed(event);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Dispatch a cache map access event to all registered listeners.
|
|
*
|
|
* @param eventType The type of event
|
|
* @param entry The entry that was affected.
|
|
* @param origin The origin of this event (optional)
|
|
*/
|
|
private void dispatchCacheMapAccessEvent(CacheMapAccessEventType eventType, CacheEntry entry, String origin) {
|
|
CacheMapAccessEvent event = new CacheMapAccessEvent(eventType, entry, origin);
|
|
|
|
// Guaranteed to return a non-null array
|
|
Object[] listeners = listenerList.getListenerList();
|
|
|
|
// Process the listeners last to first, notifying
|
|
// those that are interested in this event
|
|
for (int i = listeners.length - 2; i >= 0; i -= 2) {
|
|
if (listeners[i+1] instanceof CacheMapAccessEventListener) {
|
|
CacheMapAccessEventListener listener = (CacheMapAccessEventListener) listeners[i + 1];
|
|
listener.accessed(event);
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Dispatch a cache pattern event to all registered listeners.
|
|
*
|
|
* @param eventType The type of event (this is used to branch to the correct method handler)
|
|
* @param pattern The cache pattern that the event applies to
|
|
* @param origin The origin of this event (optional)
|
|
*/
|
|
private void dispatchCachePatternEvent(CacheEntryEventType eventType, String pattern, String origin) {
|
|
CachePatternEvent event = new CachePatternEvent(this, pattern, origin);
|
|
|
|
// Guaranteed to return a non-null array
|
|
Object[] listeners = listenerList.getListenerList();
|
|
|
|
// Process the listeners last to first, notifying
|
|
// those that are interested in this event
|
|
for (int i = listeners.length - 2; i >= 0; i -= 2) {
|
|
if (listeners[i+1] instanceof CacheEntryEventListener) {
|
|
if (eventType.equals(CacheEntryEventType.PATTERN_FLUSHED)) {
|
|
CacheEntryEventListener listener = (CacheEntryEventListener) listeners[i+1];
|
|
listener.cachePatternFlushed(event);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Dispatches a cache-wide event to all registered listeners.
|
|
*
|
|
* @param eventType The type of event (this is used to branch to the correct method handler)
|
|
* @param origin The origin of this event (optional)
|
|
*/
|
|
private void dispatchCachewideEvent(CachewideEventType eventType, Date date, String origin) {
|
|
CachewideEvent event = new CachewideEvent(this, date, origin);
|
|
|
|
// Guaranteed to return a non-null array
|
|
Object[] listeners = listenerList.getListenerList();
|
|
|
|
// Process the listeners last to first, notifying
|
|
// those that are interested in this event
|
|
for (int i = listeners.length - 2; i >= 0; i -= 2) {
|
|
if (listeners[i+1] instanceof CacheEntryEventListener) {
|
|
if (eventType.equals(CachewideEventType.CACHE_FLUSHED)) {
|
|
CacheEntryEventListener listener = (CacheEntryEventListener) listeners[i+1];
|
|
listener.cacheFlushed(event);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Flush a cache entry. On completion of the flush, a
|
|
* <tt>CacheEntryEventType.ENTRY_FLUSHED</tt> event is fired.
|
|
*
|
|
* @param entry The entry to flush
|
|
* @param origin The origin of this flush event (optional)
|
|
*/
|
|
private void flushEntry(CacheEntry entry, String origin) {
|
|
String key = entry.getKey();
|
|
|
|
// Flush the object itself
|
|
entry.flush();
|
|
|
|
if (!entry.isNew()) {
|
|
// Update the entry's state in the map
|
|
cacheMap.put(key, entry);
|
|
}
|
|
|
|
// Trigger an ENTRY_FLUSHED event. [CACHE-107] Do this for all flushes.
|
|
if (listenerList.getListenerCount() > 0) {
|
|
CacheEntryEvent event = new CacheEntryEvent(this, entry, origin);
|
|
dispatchCacheEntryEvent(CacheEntryEventType.ENTRY_FLUSHED, event);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @return the total number of cache entries held in this cache.
|
|
*/
|
|
public int getSize() {
|
|
synchronized(cacheMap) {
|
|
return cacheMap.size();
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Test support only: return the number of EntryUpdateState instances within the updateStates map.
|
|
*/
|
|
protected int getNbUpdateState() {
|
|
synchronized(updateStates) {
|
|
return updateStates.size();
|
|
}
|
|
}
|
|
|
|
|
|
/**
|
|
* Test support only: return the number of entries currently in the cache map
|
|
* @deprecated use getSize()
|
|
*/
|
|
public int getNbEntries() {
|
|
synchronized(cacheMap) {
|
|
return cacheMap.size();
|
|
}
|
|
}
|
|
}
|