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/* 
 * Copyright (C) 2018 V12 Technology Ltd.
 *
 * 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 com.fluxtion.api;

import com.fluxtion.api.annotations.EventHandler;

/**
 * Processes events of any type and dispatches to registered {@link FilteredEventHandler}
 * and methods annotated with {@link EventHandler}. An subclass of a StaticEventProcessor is
 * the product of running the event stream compiler on user input. On receipt of an event
 * the processor selects an execution path that comprises a set of application nodes that
 * have a reference to an incoming {@link EventHandler} for the specific event.
 * 
 * The StaticEventProcessor 
 * has the following functionality:
 * 
 * 

 * StaticEventProcessor process events of multiple type in a predictable order
 * Application classes are nodes managed by StaticEventProcessor and are notified in a predictable manner when an event is processed
 * An execution path is the set of connected nodes to a matching {@link EventHandler} for the incoming event
 * Nodes on the execution path are invoked in topological order, where object reference determine precedence
 * The root of the execution path is an {@link EventHandler}
 * Dispatches events based on type to the correct handler
 * Optional String or int filtering can be supplied to narrow the handler selection in conjunction with event type
 * An execution path that is unique for the Event and filter is invoked when an event is received.
 * All node instances are created and managed by StaticEventProcessor
 * 
 * starting point of event dispatch
 *
 * @author Greg Higgins
 */
public interface StaticEventProcessor {

    StaticEventProcessor NULL_EVENTHANDLER = new StaticEventProcessor() {
        @Override
        public void onEvent(Object e) {
        }

    };

    /**
     * Called when a new event e is ready to be processed.
     *
     * @param e the {@link com.fluxtion.api.event.Event Event} to process.
     */
    void onEvent(Object e);


}