org.apache.hadoop.ipc.VersionedProtocol.java Source code

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Here is the source code for org.apache.hadoop.ipc.VersionedProtocol.java

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/**
 * 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.hadoop.ipc;

import java.io.IOException;

/**
 * Superclass of all protocols that use Hadoop RPC.
 * Subclasses of this interface are also supposed to have
 * a static final long versionID field.
 */
public interface VersionedProtocol {

    /**
     * Return protocol version corresponding to protocol interface.
     * @param protocol The classname of the protocol interface
     * @param clientVersion The version of the protocol that the client speaks
     * @return the version that the server will speak
     * @throws IOException if any IO error occurs
     */
    public long getProtocolVersion(String protocol, long clientVersion) throws IOException;

    /**
     * Return protocol version corresponding to protocol interface.
     * @param protocol The classname of the protocol interface
     * @param clientVersion The version of the protocol that the client speaks
     * @param clientMethodsHash the hashcode of client protocol methods
     * @return the server protocol signature containing its version and
     *         a list of its supported methods
     * @see ProtocolSignature#getProtocolSignature(VersionedProtocol, String, 
     *                long, int) for a default implementation
     */
    public ProtocolSignature getProtocolSignature(String protocol, long clientVersion, int clientMethodsHash)
            throws IOException;
}