src/java/org/apache/cassandra/net/RequestCallback.java

/*
 * 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.cassandra.net;

import org.apache.cassandra.exceptions.RequestFailureReason;
import org.apache.cassandra.locator.InetAddressAndPort;

/**
 * implementors of {@link RequestCallback} need to make sure that any public methods
 * are threadsafe with respect to {@link #onResponse} being called from the message
 * service.  In particular, if any shared state is referenced, making
 * response alone synchronized will not suffice.
 */
public interface RequestCallback<T>
{
    /**
     * @param msg response received.
     */
    void onResponse(Message<T> msg);

    /**
     * Called when there is an exception on the remote node or timeout happens
     */
    default void onFailure(InetAddressAndPort from, RequestFailureReason failureReason)
    {
    }

    /**
     * @return true if the callback should be invoked on failure
     */
    default boolean invokeOnFailure()
    {
        return false;
    }

    /**
     * @return true if this callback is on the read path and its latency should be
     * given as input to the dynamic snitch.
     */
    default boolean trackLatencyForSnitch()
    {
        return false;
    }
}