cmsflexcache.java

cms是开源的框架

            case I_CmsEventListener.EVENT_PUBLISH_PROJECT:
            case I_CmsEventListener.EVENT_CLEAR_CACHES:
                if (LOG.isDebugEnabled()) {
                    LOG.debug(Messages.get().getBundle().key(Messages.LOG_FLEXCACHE_RECEIVED_EVENT_CLEAR_CACHE_0));
                }
                clear();
                break;
            case I_CmsEventListener.EVENT_FLEX_PURGE_JSP_REPOSITORY:
                if (LOG.isDebugEnabled()) {
                    LOG.debug(Messages.get().getBundle().key(Messages.LOG_FLEXCACHE_RECEIVED_EVENT_PURGE_REPOSITORY_0));
                }
                purgeJspRepository();
                break;
            case I_CmsEventListener.EVENT_FLEX_CACHE_CLEAR:
                if (LOG.isDebugEnabled()) {
                    LOG.debug(Messages.get().getBundle().key(
                        Messages.LOG_FLEXCACHE_RECEIVED_EVENT_CLEAR_CACHE_PARTIALLY_0));
                }
                Map m = event.getData();
                if (m == null) {
                    break;
                }
                Integer it = null;
                try {
                    it = (Integer)m.get("action");
                } catch (Exception e) {
                    // it will be null
                }
                if (it == null) {
                    break;
                }
                int i = it.intValue();
                switch (i) {
                    case CLEAR_ALL:
                        clear();
                        break;
                    case CLEAR_ENTRIES:
                        clearEntries();
                        break;
                    case CLEAR_ONLINE_ALL:
                        clearOnline();
                        break;
                    case CLEAR_ONLINE_ENTRIES:
                        clearOnlineEntries();
                        break;
                    case CLEAR_OFFLINE_ALL:
                        clearOffline();
                        break;
                    case CLEAR_OFFLINE_ENTRIES:
                        clearOfflineEntries();
                        break;
                    default:
                // no operation
                }
            default:
        // no operation
        }
    }

    /**
     * Returns the CmsFlexCacheKey data structure for a given
     * key (i.e. resource name).<p>
     * 
     * Usefull if you want to show the cache key for a resources,
     * like on the FlexCache administration page.<p>
     *
     * Only users with administrator permissions are allowed
     * to perform this operation.<p>
     *
     * @param key the resource name for which to look up the variation for
     * @param cms the CmsObject used for user authorization
     * @return the CmsFlexCacheKey data structure found for the resource
     */
    public CmsFlexCacheKey getCachedKey(String key, CmsObject cms) {

        if (!isEnabled() || !cms.hasRole(CmsRole.WORKPLACE_MANAGER)) {
            return null;
        }
        Object o = m_keyCache.get(key);
        if (o != null) {
            return ((CmsFlexCacheVariation)o).m_key;
        }
        return null;
    }

    /**
     * Returns a set of all cached resource names.
     * Usefull if you want to show a list of all cached resources,
     * like on the FlexCache administration page.<p>
     *
     * Only users with administrator permissions are allowed
     * to perform this operation.<p>
     *
     * @param cms the CmsObject used for user authorization
     * @return a Set of cached resource names (which are of type String)
     */
    public Set getCachedResources(CmsObject cms) {

        if (!isEnabled() || !cms.hasRole(CmsRole.WORKPLACE_MANAGER)) {
            return null;
        }
        return m_keyCache.keySet();
    }

    /**
     * Returns all variations in the cache for a given resource name.
     * The variations are of type String.<p>
     * 
     * Usefull if you want to show a list of all cached entry - variations,
     * like on the FlexCache administration page.<p>
     *
     * Only users with administrator permissions are allowed
     * to perform this operation.<p>
     *
     * @param key the resource name for which to look up the variations for
     * @param cms the CmsObject used for user authorization
     * @return a Set of cached variations (which are of type String)
     */
    public Set getCachedVariations(String key, CmsObject cms) {

        if (!isEnabled() || !cms.hasRole(CmsRole.WORKPLACE_MANAGER)) {
            return null;
        }
        Object o = m_keyCache.get(key);
        if (o != null) {
            return ((CmsFlexCacheVariation)o).m_map.keySet();
        }
        return null;
    }

    /**
     * Returns the LRU cache where the CacheEntries are cached.<p>
     *
     * @return the LRU cache where the CacheEntries are cached
     */
    public CmsLruCache getEntryLruCache() {

        return m_variationCache;
    }

    /**
     * Indicates if the cache is enabled (i.e. actually
     * caching entries) or not.<p>
     *
     * @return true if the cache is enabled, false if not
     */
    public boolean isEnabled() {

        return m_enabled;
    }

    /**
     * Returns the total number of cached resource keys.
     *
     * @return the number of resource keys in the cache
     */
    public int keySize() {

        if (!isEnabled()) {
            return 0;
        }
        return m_keyCache.size();
    }

    /**
     * Returns the total number of entries in the cache.<p>
     *
     * @return the number of entries in the cache
     */
    public int size() {

        return m_variationCache.size();
    }

    /**
     * Clears the cache for finalization.<p>
     * @throws Throwable if something goes wrong
     */
    protected void finalize() throws Throwable {

        try {
            clear();
            m_variationCache = null;
            m_keyCache = null;
        } catch (Throwable t) {
            // ignore
        }
        super.finalize();
    }

    /**
     * Looks up a specific entry in the cache.<p>
     * 
     * In case a found entry has a timeout set, it will be checked upon lookup.
     * In case the timeout of the entry has been reached, it will be removed from
     * the cache (and null will be returned in this case).<p>
     *
     * @param key The key to look for in the cache
     * @return the entry found for the key, or null if key is not in the cache
     */
    CmsFlexCacheEntry get(CmsFlexRequestKey key) {

        if (!isEnabled()) {
            // cache is disabled
            return null;
        }
        Object o = m_keyCache.get(key.getResource());
        if (o != null) {
            // found a matching key in the cache
            CmsFlexCacheVariation v = (CmsFlexCacheVariation)o;
            String variation = v.m_key.matchRequestKey(key);

            if (CmsStringUtil.isEmpty(variation)) {
                // requested resource is not cacheable
                return null;
            }
            CmsFlexCacheEntry entry = (CmsFlexCacheEntry)v.m_map.get(variation);
            if (entry == null) {
                // no cache entry available for variation
                return null;
            }
            if (entry.getDateExpires() < System.currentTimeMillis()) {
                // cache entry avaiable but expired, remove entry
                m_variationCache.remove(entry);
                return null;
            }
            // return the found cache entry
            return entry;
        } else {
            return null;
        }
    }

    /**
     * Returns the CmsFlexCacheKey data structure for a given resource name.<p>
     *
     * @param resource the resource name for which to look up the key for
     * @return the CmsFlexCacheKey data structure found for the resource
     */
    CmsFlexCacheKey getKey(String resource) {

        if (!isEnabled()) {
            return null;
        }
        Object o = m_keyCache.get(resource);
        if (o != null) {
            if (LOG.isDebugEnabled()) {
                LOG.debug(Messages.get().getBundle().key(Messages.LOG_FLEXCACHEKEY_FOUND_1, resource));
            }
            return ((CmsFlexCacheVariation)o).m_key;
        } else {
            if (LOG.isDebugEnabled()) {
                LOG.debug(Messages.get().getBundle().key(Messages.LOG_FLEXCACHEKEY_NOT_FOUND_1, resource));
            }
            return null;
        }
    }

    /**
     * Checks if the cache is empty or if at last one element is contained.<p>
     *
     * @return true if the cache is empty, false otherwise
     */
    boolean isEmpty() {

        if (!isEnabled()) {
            return true;
        }
        return m_keyCache.isEmpty();
    }

    /**
     * This method adds new entries to the cache.<p>
     *
     * The key describes the conditions under which the value can be cached.
     * Usually the key belongs to the response.
     * The variation describes the conditions under which the
     * entry was created. This is usually calculated from the request.
     * If the variation is != null, the entry is cachable.<p>
     *
     * @param key the key for the new value entry
     * @param entry the CmsFlexCacheEntry to store in the cache
     * @param variation the pre-calculated variation for the entry
     * @return true if the value was added to the cache, false otherwise
     */
    boolean put(CmsFlexCacheKey key, CmsFlexCacheEntry entry, String variation) {

        if (!isEnabled()) {
            return false;
        }
        if (LOG.isDebugEnabled()) {
            LOG.debug(Messages.get().getBundle().key(Messages.LOG_FLEXCACHE_ADD_ENTRY_1, key.getResource()));
        }
        if (variation != null) {
            // This is a cachable result
            key.setVariation(variation);
            if (LOG.isDebugEnabled()) {
                LOG.debug(Messages.get().getBundle().key(
                    Messages.LOG_FLEXCACHE_ADD_ENTRY_WITH_VARIATION_2,
                    key.getResource(),
                    key.getVariation()));
            }
            put(key, entry);
            // Note that duplicates are NOT checked, it it assumed that this is done beforehand,
            // while checking if the entry is already in the cache or not.
            return true;
        } else {
            // Result is not cachable
            if (LOG.isDebugEnabled()) {