exampleruleenginefacade.java

rule engine drools-2.0-beta-18

package org.drools.jsr94.rules;

/*
 * $Id: ExampleRuleEngineFacade.java,v 1.5 2004/11/17 03:09:50 dbarnett Exp $
 *
 * Copyright 2002-2004 (C) The Werken Company. All Rights Reserved.
 *
 * Redistribution and use of this software and associated documentation
 * ("Software"), with or without modification, are permitted provided that the
 * following conditions are met:
 *
 * 1. Redistributions of source code must retain copyright statements and
 * notices. Redistributions must also contain a copy of this document.
 *
 * 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 name "drools" must not be used to endorse or promote products derived
 * from this Software without prior written permission of The Werken Company.
 * For written permission, please contact [e-mail].
 *
 * 4. Products derived from this Software may not be called "drools" nor may
 * "drools" appear in their names without prior written permission of The Werken
 * Company. "drools" is a registered trademark of The Werken Company.
 *
 * 5. Due credit should be given to The Werken Company.
 * (http://drools.werken.com/).
 *
 * THIS SOFTWARE IS PROVIDED BY THE WERKEN COMPANY AND CONTRIBUTORS ``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 WERKEN COMPANY 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.
 *
 */

import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;

import javax.rules.RuleRuntime;
import javax.rules.RuleServiceProvider;
import javax.rules.RuleServiceProviderManager;
import javax.rules.StatefulRuleSession;
import javax.rules.StatelessRuleSession;
import javax.rules.admin.LocalRuleExecutionSetProvider;
import javax.rules.admin.RuleAdministrator;
import javax.rules.admin.RuleExecutionSet;

/**
 * Builds up the JSR94 object structure. It'll simplify the task of building a
 * <code>RuleExecutionSet</code> and associated <code>RuntimeSession</code>
 * objects from a given <code>InputStream</code>.
 *
 * @author N. Alex Rupp (n_alex <at>codehaus.org)
 */
public class ExampleRuleEngineFacade
{

    public static final String RULE_SERVICE_PROVIDER = "http://drools.org/";

    private RuleAdministrator ruleAdministrator;

    private RuleServiceProvider ruleServiceProvider;

    private LocalRuleExecutionSetProvider ruleSetProvider;

    private RuleRuntime ruleRuntime;

    // configuration parameters
    String ruleFilesDirectory;

    String ruleFilesIncludes;

    public ExampleRuleEngineFacade( ) throws Exception
    {
        RuleServiceProviderManager.registerRuleServiceProvider(
            RULE_SERVICE_PROVIDER, RuleServiceProviderImpl.class );

        ruleServiceProvider = RuleServiceProviderManager.getRuleServiceProvider(
            RULE_SERVICE_PROVIDER );

        ruleAdministrator = ruleServiceProvider.getRuleAdministrator( );

        ruleSetProvider =
            ruleAdministrator.getLocalRuleExecutionSetProvider( null );
    }

    public void addRuleExecutionSet(
        String bindUri, InputStream resourceAsStream ) throws Exception
    {
        Reader ruleReader = new InputStreamReader( resourceAsStream );

        RuleExecutionSet ruleExecutionSet =
            ruleSetProvider.createRuleExecutionSet( ruleReader, null );

        ruleAdministrator.registerRuleExecutionSet(
            bindUri, ruleExecutionSet, null );
    }

    /**
     * Returns a named <code>StatelessRuleSession</code>.
     *
     * @param key
     * @return StatelessRuleSession
     * @throws Exception
     */
    public StatelessRuleSession getStatelessRuleSession( String key)
        throws Exception
    {
        ruleRuntime = ruleServiceProvider.getRuleRuntime( );

        return ( StatelessRuleSession ) ruleRuntime.createRuleSession(
            key, null, RuleRuntime.STATELESS_SESSION_TYPE );
    }

    public StatefulRuleSession getStatefulRuleSession( String key )
        throws Exception
    {
        ruleRuntime = ruleServiceProvider.getRuleRuntime( );

        return ( StatefulRuleSession ) ruleRuntime.createRuleSession(
            key, null, RuleRuntime.STATEFUL_SESSION_TYPE );
    }

    public RuleServiceProvider getRuleServiceProvider( )
    {
        return this.ruleServiceProvider;
    }
}