/*
* Copyright 2010 JBoss Inc
*
* 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.
*/
/*
* 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.
* under the License.
*/
package org.drools.camel.component;
import org.apache.camel.Endpoint;
import org.apache.camel.Exchange;
import org.apache.camel.impl.DefaultProducer;
import org.drools.grid.GridNode;
import org.drools.runtime.CommandExecutor;
import org.drools.runtime.StatefulKnowledgeSession;
import org.drools.runtime.StatelessKnowledgeSession;
import org.drools.runtime.rule.WorkingMemoryEntryPoint;
/**
* A producer that inserts incoming messages as facts into the
* Drools session.
*
* It can be configured to insert the message body only, or the
* whole message (that includes headers) or even the whole Exchange
* object.
*/
public class DroolsInsertProducer extends DefaultProducer {
// the corresponding endpoint
private DroolsEndpoint de;
// the actual insert is executed by a worker class that
// implements the GoF strategy pattern to avoid conditionals
// at insert time and hopefully improve performance
private InsertWorker worker;
public DroolsInsertProducer(Endpoint endpoint,
GridNode node) {
super( endpoint );
de = (DroolsEndpoint) endpoint;
// Configures this Producer with the proper action
// by composing strategy objects
DroolsEndpoint.Action action = de.getAction();
Unwrapper unwrapper = null;
switch ( action ) {
case INSERT_BODY :
unwrapper = BodyUnwrapper.INSTANCE;
break;
case INSERT_MESSAGE :
unwrapper = MessageUnwrapper.INSTANCE;
break;
case INSERT_EXCHANGE :
unwrapper = ExchangeUnwrapper.INSTANCE;
break;
}
// Creates the actual worker
CommandExecutor exec = de.getExecutor();
if ( exec instanceof StatefulKnowledgeSession ) {
WorkingMemoryEntryPoint wmep;
String ep = de.getEntryPoint();
if ( ep != null ) {
wmep = ((StatefulKnowledgeSession) exec).getWorkingMemoryEntryPoint( ep );
} else {
wmep = (WorkingMemoryEntryPoint) exec;
}
worker = new StatefulSessionInsertWorker( wmep,
unwrapper );
} else {
worker = new StatelessSessionInsertWorker( (StatelessKnowledgeSession) exec,
unwrapper );
}
}
public void process(Exchange exchange) throws Exception {
worker.process( exchange );
}
/**
* An interface for the worker strategy
*/
private static interface InsertWorker {
public void process(Exchange exchange) throws Exception;
}
/**
* A stateful implementation for the worker
*/
private static class StatefulSessionInsertWorker
implements
InsertWorker {
private WorkingMemoryEntryPoint wmep;
private Unwrapper unwrapper;
public StatefulSessionInsertWorker(WorkingMemoryEntryPoint wmep,
Unwrapper unwrapper) {
this.wmep = wmep;
this.unwrapper = unwrapper;
}
public void process(Exchange exchange) throws Exception {
this.wmep.insert( unwrapper.getObject( exchange ) );
}
}
/**
* A stateless implementation for the worker
*/
private static class StatelessSessionInsertWorker
implements
InsertWorker {
private StatelessKnowledgeSession ksession;
private Unwrapper unwrapper;
public StatelessSessionInsertWorker(StatelessKnowledgeSession ksession,
Unwrapper unwrapper) {
this.ksession = ksession;
this.unwrapper = unwrapper;
}
public void process(Exchange exchange) throws Exception {
this.ksession.execute( unwrapper.getObject( exchange ) );
}
}
/**
* Another strategy interface to properly process incoming objects
* selecting between body, message or exchange
*/
private static interface Unwrapper {
public Object getObject(Exchange exchange);
}
private static class BodyUnwrapper
implements
Unwrapper {
public static final BodyUnwrapper INSTANCE = new BodyUnwrapper();
public Object getObject(Exchange exchange) {
return exchange.getIn().getBody();
}
}
private static class MessageUnwrapper
implements
Unwrapper {
public static final MessageUnwrapper INSTANCE = new MessageUnwrapper();
public Object getObject(Exchange exchange) {
return exchange.getIn();
}
}
private static class ExchangeUnwrapper
implements
Unwrapper {
public static final ExchangeUnwrapper INSTANCE = new ExchangeUnwrapper();
public Object getObject(Exchange exchange) {
return exchange;
}
}
}