| package org.apache.jcs.access; |
| |
| /* |
| * The Apache Software License, Version 1.1 |
| * |
| * Copyright (c) 2001 The Apache Software Foundation. All rights |
| * reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * 3. The end-user documentation included with the redistribution, if |
| * any, must include the following acknowlegement: |
| * "This product includes software developed by the |
| * Apache Software Foundation (http://www.apache.org/)." |
| * Alternately, this acknowlegement may appear in the software itself, |
| * if and wherever such third-party acknowlegements normally appear. |
| * |
| * 4. The names "The Jakarta Project", "Velocity", and "Apache Software |
| * Foundation" must not be used to endorse or promote products derived |
| * from this software without prior written permission. For written |
| * permission, please contact apache@apache.org. |
| * |
| * 5. Products derived from this software may not be called "Apache" |
| * nor may "Apache" appear in their names without prior written |
| * permission of the Apache Group. |
| * |
| * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED |
| * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR |
| * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF |
| * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
| * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
| * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| * ==================================================================== |
| * |
| * This software consists of voluntary contributions made by many |
| * individuals on behalf of the Apache Software Foundation. For more |
| * information on the Apache Software Foundation, please see |
| * <http://www.apache.org/>. |
| */ |
| import java.io.IOException; |
| import java.io.Serializable; |
| |
| import org.apache.jcs.access.behavior.ICacheAccess; |
| |
| import org.apache.jcs.access.exception.CacheException; |
| import org.apache.jcs.access.exception.InvalidHandleException; |
| |
| import org.apache.jcs.engine.behavior.IElementAttributes; |
| import org.apache.jcs.engine.CompositeCacheAttributes; |
| |
| import org.apache.jcs.engine.behavior.ICache; |
| import org.apache.jcs.engine.behavior.ICompositeCacheAttributes; |
| |
| import org.apache.jcs.engine.control.Cache; |
| import org.apache.jcs.engine.control.CacheManagerFactory; |
| import org.apache.jcs.engine.control.CompositeCacheManager; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| |
| /** |
| * Class which provides interface for all access to the cache. An instance of |
| * this class is tied to a specific cache region. Static methods are provided to |
| * get such instances. |
| * |
| * @author <a href="mailto:asmuts@yahoo.com">Aaron Smuts</a> |
| * @created February 13, 2002 |
| * @version $Id$ |
| */ |
| public class CacheAccess implements ICacheAccess |
| { |
| private final static Log log = |
| LogFactory.getLog( CacheAccess.class ); |
| |
| /** |
| * Cache manager use by the various forms of defineRegion and getAccess |
| */ |
| private static CompositeCacheManager cacheMgr; |
| |
| /** |
| * Cache that a given instance of this class provides access to. Should this |
| * be the inteface? |
| */ |
| protected Cache cacheControl; |
| |
| /** |
| * Constructor for the CacheAccess object. |
| * |
| * @param cacheControl The cache which the created instance accesses |
| */ |
| protected CacheAccess( Cache cacheControl ) |
| { |
| this.cacheControl = cacheControl; |
| } |
| |
| // ----------------------------- static methods for access to cache regions |
| |
| /** |
| * Define a new cache region with the given name. In the oracle |
| * specification, these attributes are global and not region specific, |
| * regional overirdes is a value add each region should be able to house |
| * both cache and element attribute sets. It is more efficient to define a |
| * cache in the props file and then strictly use the get access method. Use |
| * of the define region outside of an initialization block should be |
| * avoided. |
| * |
| * @param name Name that will identify the region |
| * @return CacheAccess instance for the new region |
| * @exception CacheException |
| */ |
| public static CacheAccess defineRegion( String name ) |
| throws CacheException |
| { |
| ensureCacheManager(); |
| |
| return new CacheAccess( ( Cache ) cacheMgr.getCache( name ) ); |
| } |
| |
| /** |
| * Define a new cache region with the specified name and attributes. |
| * |
| * @param name Name that will identify the region |
| * @param cattr CompositeCacheAttributes for the region |
| * @return CacheAccess instance for the new region |
| * @exception CacheException |
| */ |
| public static CacheAccess defineRegion( String name, |
| CompositeCacheAttributes cattr ) |
| throws CacheException |
| { |
| ensureCacheManager(); |
| |
| return new CacheAccess( ( Cache ) cacheMgr.getCache( name, cattr ) ); |
| } |
| |
| /** |
| * Define a new cache region with the specified name and attributes and |
| * return a CacheAccess to it. |
| * |
| * @param name Name that will identify the region |
| * @param cattr CompositeCacheAttributes for the region |
| * @param attr Attributes for the region |
| * @return CacheAccess instance for the new region |
| * @exception CacheException |
| */ |
| public static CacheAccess defineRegion( String name, |
| CompositeCacheAttributes cattr, |
| IElementAttributes attr ) |
| throws CacheException |
| { |
| ensureCacheManager(); |
| |
| return new CacheAccess( |
| ( Cache ) cacheMgr.getCache( name, cattr, attr ) ); |
| } |
| |
| /** |
| * Get a CacheAccess instance for the given region. |
| * |
| * @param region Name that identifies the region |
| * @return CacheAccess instance for region |
| * @exception CacheException |
| */ |
| public static CacheAccess getAccess( String region ) |
| throws CacheException |
| { |
| ensureCacheManager(); |
| |
| return new CacheAccess( ( Cache ) cacheMgr.getCache( region ) ); |
| } |
| |
| /** |
| * Get a CacheAccess instance for the given region with the given |
| * attributes. |
| * |
| * @param region Name that identifies the region |
| * @param icca |
| * @return CacheAccess instance for region |
| * @exception CacheException |
| */ |
| public static CacheAccess getAccess( String region, |
| ICompositeCacheAttributes icca ) |
| throws CacheException |
| { |
| ensureCacheManager(); |
| |
| return new CacheAccess( ( Cache ) cacheMgr.getCache( region, icca ) ); |
| } |
| |
| /** |
| * Helper method which checks to make sure the cacheMgr class field is set, |
| * and if not requests an instance from CacheManagerFactory. |
| */ |
| protected static void ensureCacheManager() |
| { |
| if ( cacheMgr == null ) |
| { |
| synchronized ( CacheAccess.class ) |
| { |
| if ( cacheMgr == null ) |
| { |
| cacheMgr = CacheManagerFactory.getInstance(); |
| } |
| } |
| } |
| } |
| |
| // ------------------------------------------------------- instance methods |
| |
| /** |
| * Retrieve an object from the cache region this instance provides access |
| * to. |
| * |
| * @param name Key the object is stored as |
| * @return The object if found or null |
| */ |
| public Object get( Object name ) |
| { |
| return ( Object ) cacheControl.get( ( Serializable ) name ); |
| } |
| |
| /** |
| * Place a new object in the cache, associated with key name. If there is |
| * currently an object associated with name in the region an |
| * ObjectExistsException is thrown. Names are scoped to a region so they |
| * must be unique within the region they are placed. |
| * |
| * @param name Key object will be stored with |
| * @param obj Object to store |
| * @exception CacheException |
| */ |
| public void putSafe( Object name, Object obj ) |
| throws CacheException |
| { |
| try |
| { |
| cacheControl.putSafe( ( Serializable ) name, ( Serializable ) obj ); |
| } |
| catch ( Exception e ) |
| { |
| throw new CacheException( e ); |
| } |
| } |
| |
| |
| /** |
| * Place a new object in the cache, associated with key name. If there is |
| * currently an object associated with name in the region it is replaced. |
| * Names are scoped to a region so they must be unique within the region |
| * they are placed. |
| * |
| * @param name Key object will be stored with |
| * @param obj Object to store |
| * @exception CacheException |
| */ |
| public void put( Object name, Object obj ) |
| throws CacheException |
| { |
| try |
| { |
| cacheControl.put( ( Serializable ) name, ( Serializable ) obj ); |
| } |
| catch ( Exception e ) |
| { |
| throw new CacheException( e ); |
| } |
| } |
| |
| /** |
| * Place a new object in the cache. This form allows attributes to associate |
| * with the object may be specified with attr. |
| * |
| * @param name Key object will be stored with |
| * @param obj Object to store |
| * @param attr Attributes to store object with |
| * @exception CacheException |
| */ |
| public void put( Object name, Object obj, IElementAttributes attr ) |
| throws CacheException |
| { |
| try |
| { |
| cacheControl.put( ( Serializable ) name, |
| ( Serializable ) obj, |
| attr ); |
| } |
| catch ( Exception e ) |
| { |
| throw new CacheException( e ); |
| } |
| } |
| |
| /** |
| * Destory the region and all objects within it. After calling this method, |
| * the Cache object can no longer be used as it will be closed. |
| * |
| * @exception CacheException |
| */ |
| public void destroy() |
| throws CacheException |
| { |
| cacheControl.removeAll(); |
| } |
| |
| /** Description of the Method */ |
| public void remove() |
| throws CacheException |
| { |
| cacheControl.removeAll(); |
| } |
| |
| /** |
| * Invalidate all objects associated with key name, removing all references |
| * to the objects from the cache. |
| * |
| * @param name Key that specifies object to invalidate |
| * @exception CacheException |
| */ |
| public void destroy( Object name ) |
| throws CacheException |
| { |
| cacheControl.remove( ( Serializable ) name ); |
| } |
| |
| /** Description of the Method */ |
| public void remove( Object name ) |
| throws CacheException |
| { |
| cacheControl.remove( ( Serializable ) name ); |
| } |
| |
| |
| // TODO: rethink the point of these methods |
| // /** |
| // * Remove the entire region of elements from other caches specified in the |
| // * cache.properties file as lateral caches. |
| // */ |
| // public void removeLateralDirect() |
| // { |
| // cacheControl.removeLateralDirect( "ALL" ); |
| // } |
| // /** |
| // * Remove the specified element from other caches specified in in the |
| // * cache.properties file as lateral caches. |
| // * |
| // * @param key Key identifying object to remove |
| // */ |
| // public void removeLateralDirect( Serializable key ) |
| // { |
| // cacheControl.removeLateralDirect( key ); |
| // } |
| |
| /** |
| * If there are any auxiliary caches associated with this cache, save all |
| * objects to them. |
| */ |
| public void save() |
| { |
| cacheControl.save(); |
| } |
| |
| /** |
| * ResetAttributes allows for some of the attributes of a region to be reset |
| * in particular expiration time attriubtes, time to live, default time to |
| * live and idle time, and event handlers. Changing default settings on |
| * groups and regions will not affect existing objects. Only object loaded |
| * after the reset will use the new defaults. If no name argument is |
| * provided, the reset is applied to the region. NOTE: this method is |
| * currently not implemented. |
| * |
| * @param attr New attributes for this region. |
| * @exception CacheException |
| * @exception InvalidHandleException |
| */ |
| public void resetElementAttributes( IElementAttributes attr ) |
| throws CacheException, InvalidHandleException |
| { |
| // Not implemented |
| } |
| |
| /** |
| * Reset attributes for a particular element in the cache. NOTE: this method |
| * is currently not implemented. |
| * |
| * @param name Key of object to reset attributes for |
| * @param attr New attributes for the object |
| * @exception CacheException |
| * @exception InvalidHandleException |
| */ |
| public void resetElementAttributes( Object name, IElementAttributes attr ) |
| throws CacheException, InvalidHandleException |
| { |
| // Not implemented |
| } |
| |
| /** |
| * GetElementAttributes will return an attribute object describing the current |
| * attributes associated with the object name. |
| * |
| * @return Attributes for this region |
| * @exception CacheException |
| */ |
| public IElementAttributes getElementAttributes() |
| throws CacheException |
| { |
| return cacheControl.attr; |
| } |
| |
| /** |
| * GetElementAttributes will return an attribute object describing the current |
| * attributes associated with the object name. The name object must override |
| * the Object.equals and Object.hashCode methods. |
| * |
| * @param name Key of object to get attributes for |
| * @return Attributes for the object, null if object not in cache |
| * @exception CacheException |
| */ |
| public IElementAttributes getElementAttributes( Object name ) |
| throws CacheException |
| { |
| IElementAttributes attr = null; |
| |
| try |
| { |
| attr = cacheControl.getElementAttributes( ( Serializable ) name ); |
| } |
| catch ( IOException ioe ) |
| { |
| log.error( "Failure getting element attributes", ioe ); |
| } |
| |
| return attr; |
| } |
| |
| /** |
| * Dispose this region. Flushes objects to and closes auxiliary caches. |
| */ |
| protected void dispose() |
| { |
| cacheControl.dispose(); |
| } |
| |
| /** |
| * Return statistics for the region. |
| * |
| * @return HTML formatted string containing region statistics |
| */ |
| protected String getStats() |
| { |
| return cacheControl.getStats(); |
| } |
| |
| |
| /** |
| * Gets the ICompositeCacheAttributes of the cache region |
| * |
| * @return |
| */ |
| public ICompositeCacheAttributes getCacheAttributes() |
| { |
| return cacheControl.getCacheAttributes(); |
| } |
| |
| /** |
| * Sets the ICompositeCacheAttributes of the cache region. |
| * |
| * @param cattr The new ICompositeCacheAttribute value |
| */ |
| public void setCacheAttributes( ICompositeCacheAttributes cattr ) |
| { |
| cacheControl.setCacheAttributes( cattr ); |
| } |
| |
| // -------------------------------- methods for testing and error reporting |
| |
| // protected void dumpMap() |
| // { |
| // cache_control.dumpMap(); |
| // } |
| // protected void dumpCacheEntries() |
| // { |
| // cache_control.dumpCacheEntries(); |
| // } |
| } |
