/*
 * ====================================================================
 *
 *  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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */
package org.apache.http.client;

import org.apache.http.HttpResponse;

/**
 * When managing a dynamic number of connections for a given route, this
 * strategy assesses whether a given request execution outcome should
 * result in a backoff signal or not, based on either examining the
 * <code>Throwable</code> that resulted or by examining the resulting
 * response (e.g. for its status code).
 *
 * @since 4.2
 *
 */
public interface ConnectionBackoffStrategy {

    /**
     * Determines whether seeing the given <code>Throwable</code> as
     * a result of request execution should result in a backoff
     * signal.
     * @param t the <code>Throwable</code> that happened
     * @return <code>true</code> if a backoff signal should be
     *   given
     */
    boolean shouldBackoff(Throwable t);

    /**
     * Determines whether receiving the given {@link HttpResponse} as
     * a result of request execution should result in a backoff
     * signal. Implementations MUST restrict themselves to examining
     * the response header and MUST NOT consume any of the response
     * body, if any.
     * @param resp the <code>HttpResponse</code> that was received
     * @return <code>true</code> if a backoff signal should be
     *   given
     */
    boolean shouldBackoff(HttpResponse resp);
}