package org.apache.commons.jcs.auxiliary.remote.http.server;
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*/
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.OutputStream;
import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.jcs.access.exception.CacheException;
import org.apache.commons.jcs.auxiliary.AuxiliaryCacheConfigurator;
import org.apache.commons.jcs.auxiliary.remote.http.behavior.IRemoteHttpCacheConstants;
import org.apache.commons.jcs.auxiliary.remote.value.RemoteCacheRequest;
import org.apache.commons.jcs.auxiliary.remote.value.RemoteCacheResponse;
import org.apache.commons.jcs.engine.behavior.ICacheElement;
import org.apache.commons.jcs.engine.behavior.ICacheServiceNonLocal;
import org.apache.commons.jcs.engine.behavior.ICompositeCacheManager;
import org.apache.commons.jcs.engine.control.CompositeCacheManager;
import org.apache.commons.jcs.engine.logging.behavior.ICacheEventLogger;
import org.apache.commons.jcs.io.ObjectInputStreamClassLoaderAware;
import org.apache.commons.jcs.utils.config.PropertySetter;
import org.apache.commons.jcs.utils.serialization.StandardSerializer;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* This servlet simply reads and writes objects. The requests are packaged in a general wrapper. The
* processor works on the wrapper object and returns a response wrapper.
*/
public class RemoteHttpCacheServlet
extends HttpServlet
{
/** Don't change. */
private static final long serialVersionUID = 8752849397531933346L;
/** The Logger. */
private static final Log log = LogFactory.getLog( RemoteHttpCacheServlet.class );
/** The cache manager */
private static CompositeCacheManager cacheMgr;
/** The service that does the work. */
private static ICacheServiceNonLocal<Serializable, Serializable> remoteCacheService;
/** This needs to be standard, since the other side is standard */
private final StandardSerializer serializer = new StandardSerializer();
/** Number of service calls. */
private int serviceCalls = 0;
/** The interval at which we will log the count. */
private final int logInterval = 100;
/**
* Initializes the cache.
* <p>
* This provides an easy extension point. Simply extend this servlet and override the init
* method to change the way the properties are loaded.
* @param config
* @throws ServletException
*/
@Override
public void init( ServletConfig config )
throws ServletException
{
try
{
cacheMgr = CompositeCacheManager.getInstance();
}
catch (CacheException e)
{
throw new ServletException(e);
}
remoteCacheService = createRemoteHttpCacheService( cacheMgr );
super.init( config );
}
/**
* Read the request, call the processor, write the response.
* <p>
* @param request
* @param response
* @throws ServletException
* @throws IOException
*/
@Override
public void service( HttpServletRequest request, HttpServletResponse response )
throws ServletException, IOException
{
incrementServiceCallCount();
if ( log.isDebugEnabled() )
{
log.debug( "Servicing a request. " + request );
}
RemoteCacheRequest<Serializable, Serializable> remoteRequest = readRequest( request );
RemoteCacheResponse<Object> cacheResponse = processRequest( remoteRequest );
writeResponse( response, cacheResponse );
}
/**
* Read the request from the input stream.
* <p>
* @param request
* @return RemoteHttpCacheRequest
*/
protected RemoteCacheRequest<Serializable, Serializable> readRequest( HttpServletRequest request )
{
RemoteCacheRequest<Serializable, Serializable> remoteRequest = null;
try
{
InputStream inputStream = request.getInputStream();
if ( log.isDebugEnabled() )
{
log.debug( "After getting input stream and before reading it" );
}
remoteRequest = readRequestFromStream( inputStream );
}
catch ( Exception e )
{
log.error( "Could not get a RemoteHttpCacheRequest object from the input stream.", e );
}
return remoteRequest;
}
/**
* Reads the response from the stream and then closes it.
* <p>
* @param inputStream
* @return RemoteHttpCacheRequest
* @throws IOException
* @throws ClassNotFoundException
*/
protected RemoteCacheRequest<Serializable, Serializable> readRequestFromStream( InputStream inputStream )
throws IOException, ClassNotFoundException
{
ObjectInputStream ois = new ObjectInputStreamClassLoaderAware( inputStream, null );
@SuppressWarnings("unchecked") // Need to cast from Object
RemoteCacheRequest<Serializable, Serializable> remoteRequest
= (RemoteCacheRequest<Serializable, Serializable>) ois.readObject();
ois.close();
return remoteRequest;
}
/**
* Write the response to the output stream.
* <p>
* @param response
* @param cacheResponse
*/
protected void writeResponse( HttpServletResponse response, RemoteCacheResponse<Object> cacheResponse )
{
try
{
response.setContentType( "application/octet-stream" );
byte[] responseAsByteAray = serializer.serialize( cacheResponse );
response.setContentLength( responseAsByteAray.length );
OutputStream outputStream = response.getOutputStream();
if ( log.isDebugEnabled() )
{
log.debug( "Opened output stream. Response size: " + responseAsByteAray.length );
}
// WRITE
outputStream.write( responseAsByteAray );
outputStream.flush();
outputStream.close();
}
catch ( IOException e )
{
log.error( "Problem writing response. " + cacheResponse, e );
}
}
/**
* Processes the request. It will call the appropriate method on the service
* <p>
* @param request
* @return RemoteHttpCacheResponse, never null
*/
protected RemoteCacheResponse<Object> processRequest( RemoteCacheRequest<Serializable, Serializable> request )
{
RemoteCacheResponse<Object> response = new RemoteCacheResponse<Object>();
if ( request == null )
{
String message = "The request is null. Cannot process";
log.warn( message );
response.setSuccess( false );
response.setErrorMessage( message );
}
else
{
try
{
switch ( request.getRequestType() )
{
case GET:
ICacheElement<Serializable, Serializable> element =
remoteCacheService.get( request.getCacheName(), request.getKey(), request.getRequesterId() );
response.setPayload(element);
break;
case GET_MULTIPLE:
Map<Serializable, ICacheElement<Serializable, Serializable>> elementMap =
remoteCacheService.getMultiple( request.getCacheName(), request.getKeySet(), request.getRequesterId() );
if ( elementMap != null )
{
Map<Serializable, ICacheElement<Serializable, Serializable>> map = new HashMap<Serializable, ICacheElement<Serializable, Serializable>>();
map.putAll(elementMap);
response.setPayload(map);
}
break;
case GET_MATCHING:
Map<Serializable, ICacheElement<Serializable, Serializable>> elementMapMatching =
remoteCacheService.getMatching( request.getCacheName(), request.getPattern(), request.getRequesterId() );
if ( elementMapMatching != null )
{
Map<Serializable, ICacheElement<Serializable, Serializable>> map = new HashMap<Serializable, ICacheElement<Serializable, Serializable>>();
map.putAll(elementMapMatching);
response.setPayload(map);
}
break;
case REMOVE:
remoteCacheService.remove( request.getCacheName(), request.getKey(), request.getRequesterId() );
break;
case REMOVE_ALL:
remoteCacheService.removeAll( request.getCacheName(), request.getRequesterId() );
break;
case UPDATE:
remoteCacheService.update( request.getCacheElement(), request.getRequesterId() );
break;
case ALIVE_CHECK:
case DISPOSE:
response.setSuccess( true );
// DO NOTHING
break;
case GET_KEYSET:
Set<Serializable> keys = remoteCacheService.getKeySet( request.getCacheName() );
response.setPayload( keys );
break;
default:
String message = "Unknown event type. Cannot process " + request;
log.warn( message );
response.setSuccess( false );
response.setErrorMessage( message );
break;
}
}
catch ( IOException e )
{
String message = "Problem processing request. " + request + " Error: " + e.getMessage();
log.error( message, e );
response.setSuccess( false );
response.setErrorMessage( message );
}
}
return response;
}
/**
* Configures the attributes and the event logger and constructs a service.
* <p>
* @param cacheManager
* @return RemoteHttpCacheService
*/
protected <K, V> RemoteHttpCacheService<K, V> createRemoteHttpCacheService( ICompositeCacheManager cacheManager )
{
Properties props = cacheManager.getConfigurationProperties();
ICacheEventLogger cacheEventLogger = configureCacheEventLogger( props );
RemoteHttpCacheServerAttributes attributes = configureRemoteHttpCacheServerAttributes( props );
RemoteHttpCacheService<K, V> service = new RemoteHttpCacheService<K, V>( cacheManager, attributes, cacheEventLogger );
if ( log.isInfoEnabled() )
{
log.info( "Created new RemoteHttpCacheService " + service );
}
return service;
}
/**
* Tries to get the event logger.
* <p>
* @param props
* @return ICacheEventLogger
*/
protected ICacheEventLogger configureCacheEventLogger( Properties props )
{
ICacheEventLogger cacheEventLogger = AuxiliaryCacheConfigurator
.parseCacheEventLogger( props, IRemoteHttpCacheConstants.HTTP_CACHE_SERVER_PREFIX );
return cacheEventLogger;
}
/**
* Configure.
* <p>
* jcs.remotehttpcache.serverattributes.ATTRIBUTENAME=ATTRIBUTEVALUE
* <p>
* @param prop
* @return RemoteCacheServerAttributesconfigureRemoteCacheServerAttributes
*/
protected RemoteHttpCacheServerAttributes configureRemoteHttpCacheServerAttributes( Properties prop )
{
RemoteHttpCacheServerAttributes rcsa = new RemoteHttpCacheServerAttributes();
// configure automatically
PropertySetter.setProperties( rcsa, prop,
IRemoteHttpCacheConstants.HTTP_CACHE_SERVER_ATTRIBUTES_PROPERTY_PREFIX + "." );
return rcsa;
}
/**
* @param rcs the remoteCacheService to set
*/
protected void setRemoteCacheService(ICacheServiceNonLocal<Serializable, Serializable> rcs)
{
remoteCacheService = rcs;
}
/**
* Log some details.
*/
private void incrementServiceCallCount()
{
// not thread safe, but it doesn't have to be accurate
serviceCalls++;
if ( log.isInfoEnabled() )
{
if ( serviceCalls % logInterval == 0 )
{
log.info( "serviceCalls = " + serviceCalls );
}
}
}
/** Release the cache manager. */
@Override
public void destroy()
{
if ( log.isInfoEnabled() )
{
log.info( "Servlet Destroyed, shutting down JCS." );
}
cacheMgr.shutDown();
}
/**
* Get servlet information
* <p>
* @return basic info
*/
@Override
public String getServletInfo()
{
return "RemoteHttpCacheServlet";
}
}