org.drools.jsr94.rules.RuleServiceProviderImpl Maven / Gradle / Ivy

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Implements the JSR-94 API with Drools.
There is a newer version: 7.2.0.Final
/*
 * Copyright 2010 Red Hat, Inc. and/or its affiliates.
 *
 * 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.drools.jsr94.rules;

import javax.rules.ConfigurationException;
import javax.rules.RuleRuntime;
import javax.rules.RuleServiceProvider;
import javax.rules.RuleServiceProviderManager;
import javax.rules.admin.RuleAdministrator;

import org.drools.jsr94.rules.admin.RuleAdministratorImpl;
import org.drools.jsr94.rules.repository.RuleExecutionSetRepository;
import org.drools.jsr94.rules.repository.RuleExecutionSetRepositoryLoader;

/**
 * This class provides access to the RuleRuntime and
 * RuleAdministrator implementation supplied by Drools when
 * running under J2SE.  This class should be used in environments without a
 * JNDI provider - typically when writing standalone J2SE clients. Within the
 * J2EE environment the RuleServiceProvider implementation class
 * provided by Drools should be retrieved using a JNDI lookup.  This class
 * should be constructed using the
 * RuleServiceProviderManager.getRuleServiceProvider method.
 * This class is automatically registered to "http://drools.org/" on startup, 
 * via the static block.
 * 
 * @see RuleRuntimeImpl
 * @see RuleAdministratorImpl
 * @see RuleServiceProvider
 * @see javax.rules.RuleServiceProviderManager#getRuleServiceProvider(String)
 */
public class RuleServiceProviderImpl extends RuleServiceProvider implements java.io.Serializable {
    public static final String         RULE_SERVICE_PROVIDER = "http://drools.org/";

    /** An instance of RuleRuntimeImpl. */
    private RuleRuntime                ruleRuntime;

    /** An instance of RuleAdministratorImpl. */
    private RuleAdministrator          ruleAdministrator;

    private RuleExecutionSetRepository repository;

    static {
        try {
            RuleServiceProviderManager.registerRuleServiceProvider( RULE_SERVICE_PROVIDER,
                                                                    RuleServiceProviderImpl.class );
        } catch ( ConfigurationException e ) {
            System.err.println( "Unable to regiser Rule Service  Provider " + RULE_SERVICE_PROVIDER );
        }
    }

    /**
     * Create a new RuleServiceProviderImpl.
     */
    public RuleServiceProviderImpl() {
        // no special initialization required
    }

    /**
     * Returns the RuleExecutionSetRepository
     * @return
     */
    public synchronized RuleExecutionSetRepository getRepository() {
        // Lazy loaded
        if ( this.repository == null ) {
            this.repository = createRuleExecutionSetRepository();
        }
        return this.repository;
    }

    /**
     * Returns a class instance of RuleRuntime. Specifically an
     * instance of the Drools RuleRuntimeImpl is returned.
     * 
     * @return an instance of RuleRuntime
     */
    public synchronized RuleRuntime getRuleRuntime() {
        if ( this.ruleRuntime == null ) {
            this.ruleRuntime = new RuleRuntimeImpl( getRepository() );
        }
        
        return this.ruleRuntime;
    }

    /**
     * Returns a class instance of RuleAdministrator.
     * Specifically an instance of the Drools RuleAdministratorImpl
     * is returned.
     * 
     * @return an instance of RuleAdministrator
     */
    public synchronized RuleAdministrator getRuleAdministrator() {
        // Lazy instantiate
        if ( this.ruleAdministrator == null ) {
            this.ruleAdministrator = new RuleAdministratorImpl( getRepository() );
        }
        return this.ruleAdministrator;
    }
    
    /**
     * Creates the RuleExecutionSetRepository.
     * 
     * @return
     */
    protected RuleExecutionSetRepository createRuleExecutionSetRepository() {
        String defaultFactoryName = "org.drools.jsr94.rules.repository.DefaultRuleExecutionSetRepository";
        return RuleExecutionSetRepositoryLoader.loadRuleExecutionSetRepository(defaultFactoryName);
    }
}