/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.camel.spi;

import org.apache.camel.Exchange;
import org.apache.camel.Route;

/**
 * Policy for a {@link Route} which allows controlling the route at runtime.
 * <p/>
 * For example using the {@link org.apache.camel.impl.ThrottlingInflightRoutePolicy} to throttle the {@link Route}
 * at runtime where it suspends and resume the {@link org.apache.camel.Route#getConsumer()}.
 *
 * @version $Revision$
 */
public interface RoutePolicy {

    /**
     * Callback invoked when the {@link Route} is being initialized
     *
     * @param route     the route being initialized
     */
    void onInit(Route route);

    /**
     * Callback invoked when an {@link Exchange} is started being routed on the given {@link Route}
     *
     * @param route     the route where the exchange started from
     * @param exchange  the created exchange
     */
    void onExchangeBegin(Route route, Exchange exchange);

    /**
     * Callback invoked when an {@link Exchange} is done being routed, where it started from the given {@link Route}
     * <p/>
     * Notice this callback is invoked when the <b>Exchange</b> is done and the {@link Route} is the route where
     * the {@link Exchange} was started. Most often its also the route where the exchange is done. However its
     * possible to route an {@link Exchange} to other routes using endpoints such as
     * <b>direct</b> or <b>seda</b>. Bottom line is that the {@link Route} parameter may not be the endpoint
     * route and thus why we state its the starting route.
     *
     * @param route     the route where the exchange started from
     * @param exchange  the created exchange
     */
    void onExchangeDone(Route route, Exchange exchange);
}
