/*
* Copyright 2005 Tim Telcik, Werner Guttmann, Ralf Joachim
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.castor.cache.distributed;
import java.lang.reflect.Method;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.castor.cache.AbstractBaseCache;
import org.castor.cache.CacheAcquireException;
/**
* JCS (Java Caching System) implementation of Castor JDO Cache.
*
* For more details of JCS, see http://jakarta.apache.org/jcs
*
* @see <a href="http://jakarta.apache.org/jcs">The JCS Home Page</a>
* @author <a href="mailto:ttelcik AT hbf DOT com DOT au">Tim Telcik</a>
* @author <a href="mailto:werner DOT guttmann AT gmx DOT net">Werner Guttmann</a>
* @author <a href="mailto:ralf DOT joachim AT syscon DOT eu">Ralf Joachim</a>
* @version $Revision: 7950 $ $Date: 2006-04-25 16:09:10 -0600 (Tue, 25 Apr 2006) $
* @since 1.0
*/
public final class JcsCache extends AbstractBaseCache {
//--------------------------------------------------------------------------
/** The <a href="http://jakarta.apache.org/commons/logging/">Jakarta Commons
* Logging </a> instance used for all logging. */
private static final Log LOG = LogFactory.getLog(JcsCache.class);
/** The type of the cache. */
public static final String TYPE = "jcs";
/** The classname of the implementations factory class. */
public static final String IMPLEMENTATION = "org.apache.jcs.JCS";
/** Parameter types for calling getInstance() method on IMPLEMENTATION. */
private static final Class < ? > [] TYPES_GET_INSTANCE = new Class[] {String.class};
/** Parameter types for calling get() method on cache instance. */
private static final Class < ? > [] TYPES_GET = new Class[] {Object.class};
/** Parameter types for calling put() method on cache instance. */
private static final Class < ? > [] TYPES_PUT = new Class[] {Object.class, Object.class};
/** Parameter types for calling remove() method on cache instance. */
private static final Class < ? > [] TYPES_REMOVE = TYPES_GET;
/** The cache instance. */
private Object _cache;
/** The method to invoke on cache instead of calling get() directly. */
private Method _getMethod;
/** The method to invoke on cache instead of calling put() directly. */
private Method _putMethod;
/** The method to invoke on cache instead of calling remove() directly. */
private Method _removeMethod;
/** The method to invoke on cache instead of calling clear() directly. */
private Method _clearMethod;
//--------------------------------------------------------------------------
// operations for life-cycle management of cache
/**
* {@inheritDoc}
*/
public void initialize(final Properties params) throws CacheAcquireException {
initialize(IMPLEMENTATION, params);
}
/**
* Normally called to initialize JcsCache. To be able to test the method
* without having <code>org.apache.jcs.JCS</code> implementation, it can also
* be called with a test implementations classname.
*
* @param implementation Cache implementation classname to initialize.
* @param params Parameters to initialize the cache (e.g. name, capacity).
* @throws CacheAcquireException If cache can not be initialized.
*/
public void initialize(final String implementation, final Properties params)
throws CacheAcquireException {
super.initialize(params);
try {
ClassLoader ldr = this.getClass().getClassLoader();
Class < ? > cls = ldr.loadClass(implementation);
Method method = cls.getMethod("getInstance", TYPES_GET_INSTANCE);
_cache = method.invoke(null, new Object[] {getName()});
cls = _cache.getClass();
_getMethod = cls.getMethod("get", TYPES_GET);
_putMethod = cls.getMethod("put", TYPES_PUT);
_removeMethod = cls.getMethod("remove", TYPES_REMOVE);
_clearMethod = cls.getMethod("clear", (Class[]) null);
} catch (Exception e) {
String msg = "Error creating JCS cache: " + e.getMessage();
LOG.error(msg, e);
throw new CacheAcquireException(msg, e);
}
}
//--------------------------------------------------------------------------
// getters/setters for cache configuration
/**
* {@inheritDoc}
*/
public String getType() { return TYPE; }
//--------------------------------------------------------------------------
// query operations of map interface
/**
* {@inheritDoc}
*/
public int size() {
throw new UnsupportedOperationException("size()");
}
/**
* {@inheritDoc}
*/
public boolean isEmpty() {
throw new UnsupportedOperationException("isEmpty()");
}
/**
* {@inheritDoc}
*/
public boolean containsKey(final Object key) {
return (get(key) != null);
}
/**
* {@inheritDoc}
*/
public boolean containsValue(final Object value) {
throw new UnsupportedOperationException("containsValue(Object)");
}
/**
* {@inheritDoc}
*/
public Object get(final Object key) {
return invokeCacheMethod(_getMethod, new Object[] {key});
}
//--------------------------------------------------------------------------
// modification operations of map interface
/**
* {@inheritDoc}
*/
public Object put(final Object key, final Object value) {
Object oldValue = get(key);
invokeCacheMethod(_putMethod, new Object[] {key, value});
return oldValue;
}
/**
* {@inheritDoc}
*/
public Object remove(final Object key) {
Object oldValue = get(key);
invokeCacheMethod(_removeMethod, new Object[] {key});
return oldValue;
}
//--------------------------------------------------------------------------
// bulk operations of map interface
/**
* {@inheritDoc}
*/
public void putAll(final Map < ? extends Object, ? extends Object > map) {
Iterator < ? extends Entry < ? extends Object, ? extends Object > > iter;
iter = map.entrySet().iterator();
while (iter.hasNext()) {
Entry < ? extends Object, ? extends Object > entry = iter.next();
Object[] params = new Object[] {entry.getKey(), entry.getValue()};
invokeCacheMethod(_putMethod, params);
}
}
/**
* {@inheritDoc}
*/
public void clear() {
invokeCacheMethod(_clearMethod, null);
}
//--------------------------------------------------------------------------
// view operations of map interface
/**
* {@inheritDoc}
*/
public Set < Object > keySet() {
throw new UnsupportedOperationException("keySet()");
}
/**
* {@inheritDoc}
*/
public Collection < Object > values() {
throw new UnsupportedOperationException("values()");
}
/**
* {@inheritDoc}
*/
public Set < Entry < Object, Object > > entrySet() {
throw new UnsupportedOperationException("entrySet()");
}
//--------------------------------------------------------------------------
// helper methods
/**
* Invoke given method on cache with given arguments. Any possible exception will
* be catched and IllegalStateException will be thrown instead.
*
* @param method The method to call on cache.
* @param arguments The parameters.
* @return The result of the method invocation.
*/
private Object invokeCacheMethod(final Method method, final Object[] arguments) {
try {
return method.invoke(_cache, arguments);
} catch (Exception e) {
String msg = "Failed to call method on JCS instance: " + e.getMessage();
LOG.error(msg, e);
throw new IllegalStateException(e.getMessage());
}
}
//--------------------------------------------------------------------------
}