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A collection of classes that can be used across yestech artifacts/components, but must not be dependant on any yestech component. Most of the code is utility type code. When more than a few classes are found to be in a package or the package start to handle more that a few reposibilities then a new independant component is created and the existing code in yeslib is ported to the new component.

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/*
 * Copyright LGPL3
 * YES Technology Association
 * http://yestech.org
 *
 * http://www.opensource.org/licenses/lgpl-3.0.html
 */

/*
 *
 * Author:  Artie Copeland
 * Last Modified Date: $DateTime: $
 */
package org.yestech.lib.ibatis;

import com.ibatis.sqlmap.engine.cache.CacheModel;
import com.ibatis.sqlmap.engine.cache.CacheController;

import java.net.URL;
import java.util.Properties;

import net.sf.ehcache.Element;
import net.sf.ehcache.CacheManager;
import net.sf.ehcache.Cache;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


/**
 * This is from: http://opensource.atlassian.com/confluence/oss/display/IBATIS/3rd+Party+Contributions
 * 

 * EhCache Implementation of the {@link com.ibatis.sqlmap.engine.cache.CacheController} interface to be able to use
 * EhCache as a cache implementation in iBatis. You can configure your cache model as follows, by example, in your
 * sqlMapping files:
 * <cacheModel id="myCache" type="nl.rabobank.springproject.ibatis.EhCacheController" readOnly="true" serialize="false">
 *   <property name="configFile" value="/path-to-ehcache.xml"/>
 * </cacheModel>
 * Alternatively, you can use a type alias in your type attribute and defining the class with a
 * <TypeAlias> declaration, see iBatis documentation on how to do this.
 */
public class EhCacheController implements CacheController {
    final private static Logger logger = LoggerFactory.getLogger(EhCacheController.class);
    
    /** The EhCache CacheManager. */
    private CacheManager cacheManager;

    /**
     * Flush a cache model.
     * @param cacheModel - the model to flush.
     */
    public void flush(CacheModel cacheModel) {
        getCache(cacheModel).removeAll();
    }

    /**
     * Get an object from a cache model.
     * @param cacheModel - the model.
     * @param key        - the key to the object.
     * @return the object if in the cache, or null(?).
     */
    public Object getObject(CacheModel cacheModel, Object key) {
        Object result = null;
        try {
            Element element = getCache(cacheModel).get(key.toString());
            if (element != null) {
                result = element.getObjectValue();
            }
        }
        catch(Exception e) {
            logger.debug("cache miss, gonna hit ibatis");
        }
        return result;

    }

    /**
     * Put an object into a cache model.
     * @param cacheModel - the model to add the object to.
     * @param key        - the key to the object.
     * @param object     - the object to add.
     */
    public void putObject(CacheModel cacheModel, Object key, Object object) {
        getCache(cacheModel).put(new Element(key.toString(), object));
    }

    /**
     * Remove an object from a cache model.
     * @param cacheModel - the model to remove the object from.
     * @param key        - the key to the object.
     * @return the removed object(?).
     */
    public Object removeObject(CacheModel cacheModel, Object key) {
        Object result = this.getObject(cacheModel, key.toString());
        getCache(cacheModel).remove(key.toString());
        return result;
    }

    /**
     * Configure a cache controller. Initialize the EH Cache Manager as a singleton.
     * @param props - the properties object continaing configuration information.
     */
    public void setProperties(Properties props) {
        URL url = getClass().getResource(props.getProperty("configFile"));
        cacheManager = CacheManager.create(url);
    }

    /**
     * Gets an EH Cache based on an iBatis cache Model.
     * @param cacheModel - the cache model.
     * @return the EH Cache.
     */
    private Cache getCache(CacheModel cacheModel) {
        String cacheName = cacheModel.getId();
        return cacheManager.getCache(cacheName);
    }

    /**
     * Shut down the EH Cache CacheManager.
     */
    public void finalize() {
        if (cacheManager != null) {
            cacheManager.shutdown();
        }
    }
}