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* 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.
*/
package org.wso2.carbon.rule.engine.drools;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.drools.KnowledgeBase;
import org.drools.KnowledgeBaseFactory;
import org.drools.builder.KnowledgeBuilder;
import org.drools.builder.ResourceType;
import org.drools.definition.KnowledgePackage;
import org.drools.io.ResourceFactory;
import org.drools.runtime.KnowledgeSessionConfiguration;
import org.drools.runtime.StatefulKnowledgeSession;
import org.drools.runtime.StatelessKnowledgeSession;
import org.wso2.carbon.rule.core.LoggedRuntimeException;
import org.wso2.carbon.rule.core.RuleBackendRuntime;
import org.wso2.carbon.rule.core.Session;
import org.wso2.carbon.rulecep.adapters.utils.PropertyDescriptionEvaluator;
import org.wso2.carbon.rulecep.commons.descriptions.rule.RuleSetDescription;
import org.wso2.carbon.rulecep.commons.descriptions.rule.SessionDescription;
import org.wso2.carbon.rulecep.commons.utils.ObjectToStreamConverter;
import java.io.InputStream;
import java.util.Collection;
import java.util.Map;
/**
* The <code>RuleBackendRuntime</code> implemetaion for the Drools native API.
* Implementation is not completed as we uses JSR 94 as the default one
*/
public class DroolsBackendRuntime implements RuleBackendRuntime {
private static Log log = LogFactory.getLog(DroolsBackendRuntime.class);
private KnowledgeBase knowledgeBase;
private KnowledgeBuilder knowledgeBuilder;
public DroolsBackendRuntime(KnowledgeBase knowledgeBase, KnowledgeBuilder knowledgeBuilder) {
this.knowledgeBase = knowledgeBase;
this.knowledgeBuilder = knowledgeBuilder;
}
public String addRuleSet(RuleSetDescription description) {
if (log.isDebugEnabled()) {
log.debug("Creating a Rule Execution Set");
}
Object ruleScript = description.getRuleSource();
Map<String, Object> properties = PropertyDescriptionEvaluator.evaluate(
description.getCreationProperties());
InputStream in = ObjectToStreamConverter.toInputStream(ruleScript, properties);
if (in == null) {
throw new LoggedRuntimeException("The input stream form rule script is null.",
log);
}
ResourceTypeDetectionStrategy strategy = new DefaultResourceTypeDetectionStrategy();
ResourceType resourceType = strategy.getResourceType(properties);
knowledgeBuilder.add(ResourceFactory.newInputStreamResource(in), resourceType);
if (knowledgeBuilder.hasErrors()) {
throw new LoggedRuntimeException("Error during creating rule set: " +
knowledgeBuilder.getErrors(), log);
}
Collection<KnowledgePackage> pkgs = knowledgeBuilder.getKnowledgePackages();
knowledgeBase.addKnowledgePackages(pkgs);
return description.getBindURI();
}
public Session createSession(SessionDescription description) {
boolean stateful = description.isStateful();
String name = description.getRuleSetURI();
final Map<String, Object> properties = PropertyDescriptionEvaluator.evaluate(
description.getSessionProperties());
final KnowledgeSessionConfiguration configuration =
KnowledgeBaseFactory.newKnowledgeSessionConfiguration();
if (stateful) {
if (log.isDebugEnabled()) {
log.debug("Using stateful rule session ");
}
StatefulKnowledgeSession ruleSession = knowledgeBase.newStatefulKnowledgeSession(
configuration, null);
if (ruleSession == null) {
throw new LoggedRuntimeException("The created stateful rule session is null", log);
}
return new DroolsStatefulSession(ruleSession, properties);
} else {
if (log.isDebugEnabled()) {
log.debug("Using stateless rule session");
}
// create stateless rule session
StatelessKnowledgeSession ruleSession =
knowledgeBase.newStatelessKnowledgeSession(configuration);
if (ruleSession == null) {
throw new LoggedRuntimeException("The created stateless rule session is null", log);
}
return new DroolsStatelessSession(ruleSession);
}
}
public void removeRuleSet(RuleSetDescription description) {
String bindUri = description.getBindURI();
if (log.isDebugEnabled()) {
log.debug("Removing the rule execution set" +
" that has been bind to Uri " + bindUri);
}
knowledgeBase.removeKnowledgePackage(bindUri);
}
public void destroy() {
//todo
}
}