EhCacheManagerFactoryBeanExt.java

package com.mtools.core.plugin.ehcache;

import java.io.IOException;
import java.io.InputStream;

import net.sf.ehcache.CacheException;
import net.sf.ehcache.CacheManager;
import net.sf.ehcache.config.Configuration;
import net.sf.ehcache.config.ConfigurationFactory;

import org.springframework.cache.ehcache.EhCacheManagerFactoryBean;
import org.springframework.core.io.Resource;

public class EhCacheManagerFactoryBeanExt extends EhCacheManagerFactoryBean {

	private Resource configLocation;

	private String cacheManagerName;

	private boolean acceptExisting = false;

	private boolean shared = false;

	private CacheManager cacheManager;

	private boolean locallyManaged = true;


	/**
	 * Set the location of the EhCache config file. A typical value is "/WEB-INF/ehcache.xml".
	 * <p>Default is "ehcache.xml" in the root of the class path, or if not found,
	 * "ehcache-failsafe.xml" in the EhCache jar (default EhCache initialization).
	 * @see net.sf.ehcache.CacheManager#create(java.io.InputStream)
	 * @see net.sf.ehcache.CacheManager#CacheManager(java.io.InputStream)
	 */
	public void setConfigLocation(Resource configLocation) {
		this.configLocation = configLocation;
	}

	/**
	 * Set the name of the EhCache CacheManager (if a specific name is desired).
	 * @see net.sf.ehcache.CacheManager#setName(String)
	 */
	public void setCacheManagerName(String cacheManagerName) {
		this.cacheManagerName = cacheManagerName;
	}

	/**
	 * Set whether an existing EhCache CacheManager of the same name will be accepted
	 * for this EhCacheManagerFactoryBean setup. Default is "false".
	 * <p>Typically used in combination with {@link #setCacheManagerName "cacheManagerName"}
	 * but will simply work with the default CacheManager name if none specified.
	 * All references to the same CacheManager name (or the same default) in the
	 * same ClassLoader space will share the specified CacheManager then.
	 * <p><b>NOTE:</b> This feature requires EhCache 2.5 or higher. In contrast to
	 * the {@link #setShared "shared"} flag, it supports controlled shutdown of the
	 * CacheManager by the EhCacheManagerFactoryBean that actually created it.
	 * @see #setCacheManagerName
	 * #see #setShared
	 * @see net.sf.ehcache.CacheManager#getCacheManager(String)
	 * @see net.sf.ehcache.CacheManager#CacheManager()
	 */
	public void setAcceptExisting(boolean acceptExisting) {
		this.acceptExisting = acceptExisting;
	}

	/**
	 * Set whether the EhCache CacheManager should be shared (as a singleton at the
	 * ClassLoader level) or independent (typically local within the application).
	 * Default is "false", creating an independent local instance.
	 * <p><b>NOTE:</b> This feature allows for sharing this EhCacheManagerFactoryBean's
	 * CacheManager with any code calling <code>CacheManager.create()</code> in the same
	 * ClassLoader space, with no need to agree on a specific CacheManager name.
	 * However, it only supports a single EhCacheManagerFactoryBean involved which will
	 * control the lifecycle of the underlying CacheManager (in particular, its shutdown).
	 * <p>This flag overrides {@link #setAcceptExisting "acceptExisting"} if both are set,
	 * since it indicates the 'stronger' mode of sharing.
	 * @see #setCacheManagerName
	 * @see #setAcceptExisting
	 * @see net.sf.ehcache.CacheManager#create()
	 * @see net.sf.ehcache.CacheManager#CacheManager()
	 */
	public void setShared(boolean shared) {
		this.shared = shared;
	}


	@Override
	public void afterPropertiesSet() throws IOException, CacheException {
		logger.info("Initializing EhCache CacheManager");
		InputStream is = (this.configLocation != null ? this.configLocation.getInputStream() : null);
		try {
			Configuration configuration = (is != null ?
					ConfigurationFactory.parseConfiguration(is) : ConfigurationFactory.parseConfiguration());
			if (this.cacheManagerName != null) {
				configuration.setName(this.cacheManagerName);
			}
			if (this.shared) {
				// Old-school EhCache singleton sharing...
				// No way to find out whether we actually created a new CacheManager
				// or just received an existing singleton reference.
				this.cacheManager = CacheManager.create(configuration);
			}
			else if (this.acceptExisting) {
				// EhCache 2.5+: Reusing an existing CacheManager of the same name.
				// Basically the same code as in CacheManager.getInstance(String),
				// just storing whether we're dealing with an existing instance.
				synchronized (CacheManager.class) {
					this.cacheManager = CacheManager.getCacheManager(this.cacheManagerName);
					if (this.cacheManager == null) {
						this.cacheManager = new CacheManager(configuration);
					}
					else {
						this.locallyManaged = false;
					}
				}
			}
			else {
				// Throwing an exception if a CacheManager of the same name exists already...
				this.cacheManager = new CacheManager(configuration);
			}
		}
		finally {
			if (is != null) {
				is.close();
			}
		}
	}


	@Override
	public CacheManager getObject() {
		return this.cacheManager;
	}

	@Override
	public Class<? extends CacheManager> getObjectType() {
		return (this.cacheManager != null ? this.cacheManager.getClass() : CacheManager.class);
	}

	@Override
	public boolean isSingleton() {
		return true;
	}


	@Override
	public void destroy() {
		if (this.locallyManaged) {
			logger.info("Shutting down EhCache CacheManager");
			this.cacheManager.shutdown();
		}
	}
}