ruleruntimeimpl.java

rule engine drools-2.0-beta-18

package org.drools.jsr94.rules;

/*
 * $Id: RuleRuntimeImpl.java,v 1.12 2004/11/15 01:12:22 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.util.List;
import java.util.Map;

import javax.rules.RuleExecutionSetNotFoundException;
import javax.rules.RuleRuntime;
import javax.rules.RuleSession;
import javax.rules.RuleSessionTypeUnsupportedException;

import org.drools.jsr94.rules.admin.RuleExecutionSetRepository;

/**
 * The Drools implementation of the <code>RuleRuntime</code> interface which is
 * the access point for runtime execution of <code>RuleExecutionSet</code>s.
 * It provides methods to create <code>RuleSession</code> implementation as well
 * as methods to retrieve <code>RuleExecutionSet</code>s that have been
 * previously registered using the <code>RuleAdministrator</code>.
 * <p/>
 * The <code>RuleRuntime</code> should be accessed through the
 * <code>RuleServiceProvider</code>. An instance of the <code>RuleRuntime</code>
 * can be retrieved by calling:
 * <p/>
 * <code>
 * RuleServiceProvider ruleServiceProvider =
 *     RuleServiceProvider.newInstance();<br/>
 * RuleRuntime ruleRuntime = ruleServiceProvider.getRuleRuntime();
 * </code>
 * <p/>
 * Note: the release method must be called on the <code>RuleSession</code> to
 * clean up all resources used by the <code>RuleSession</code>.
 *
 * @see RuleRuntime
 * @author N. Alex Rupp (n_alex <at>codehaus.org)
 */
public class RuleRuntimeImpl implements RuleRuntime
{
    /**
     * Create a new <code>RuleRuntimeImpl</code>.
     */
    public RuleRuntimeImpl( )
    {
        // no special initialization required
    }

    /**
     * Creates a <code>RuleSession</code> implementation using the supplied
     * Drools-specific rule execution set registration URI.
     *
     * @param uri the URI for the <code>RuleExecutionSet</code>
     * @param properties additional properties used to create the
     *        <code>RuleSession</code> implementation.
     * @param ruleSessionType the type of rule session to create.
     *
     * @throws RuleSessionTypeUnsupportedException if the ruleSessionType is not
     *         supported by Drools or the RuleExecutionSet
     * @throws RuleExecutionSetNotFoundException if the URI could not be
     *         resolved into a <code>RuleExecutionSet</code>
     *
     * @return The created <code>RuleSession</code>.
     */
    public RuleSession createRuleSession(
            String uri, Map properties, int ruleSessionType )
        throws RuleSessionTypeUnsupportedException,
               RuleExecutionSetNotFoundException
    {

        if ( ruleSessionType == RuleRuntime.STATELESS_SESSION_TYPE )
        {
            StatelessRuleSessionImpl session =
                new StatelessRuleSessionImpl( uri, properties );
            return session;
        }

        if ( ruleSessionType == RuleRuntime.STATEFUL_SESSION_TYPE )
        {
            StatefulRuleSessionImpl session =
                new StatefulRuleSessionImpl( uri, properties );
            return session;
        }

        throw new RuleSessionTypeUnsupportedException(
            "invalid session type: " + ruleSessionType );
    }

    /**
     * Retrieves a <code>List</code> of the URIs that currently have
     * <code>RuleExecutionSet</code>s associated with them.
     * An empty list is returned is there are no associations.
     *
     * @return a <code>List</code> of <code>String</code>s (URIs)
     */
    public List getRegistrations( )
    {
        RuleExecutionSetRepository repository =
            RuleExecutionSetRepository.getInstance( );
        return repository.getRegistrations( );
    }
}