EventListener.java

/**
 * 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.
 */

package org.drools.runtime.process;

/**
 * An interface that represents an element that is listening
 * for specific types of events.
 */
public interface EventListener {

    /**
     * Signals that an event has occurred. The type parameter defines
     * which type of event and the event parameter can contain additional information
     * related to the event.
     * 
     * @param type the type of event
     * @param event the data associated with this event
     */
    void signalEvent(String type, 
                     Object event);

    /**
     * Returns the event types this event listener is interested in.
     * May return <code>null</code> if the event types are unknown.
     */
    String[] getEventTypes();

}