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1   /**
2    * Copyright 2010 The Apache Software Foundation
3    *
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *     http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing, software
15   * distributed under the License is distributed on an "AS IS" BASIS,
16   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17   * See the License for the specific language governing permissions and
18   * limitations under the License.
19   */
20  package org.apache.hadoop.hbase.ipc;
21  
22  /**
23   * All custom RPC protocols to be exported by Coprocessors must extend this interface.
24   *
25   * <p>
26   * <strong>Note that all callable methods must have a return type handled by
27   * {@link org.apache.hadoop.hbase.io.HbaseObjectWritable#writeObject(java.io.DataOutput, Object, Class, org.apache.hadoop.conf.Configuration)}.</strong>
28   * That is:
29   * <ul>
30   *   <li>a Java primitive type ({@code int}, {@code float}, etc)</li>
31   *   <li>a Java {@code String}</li>
32   *   <li>a {@link org.apache.hadoop.io.Writable}</li>
33   *   <li>an array or {@code java.util.List} of one of the above</li>
34   * </ul>
35   * </p>
36   */
37  public interface CoprocessorProtocol extends VersionedProtocol {
38    public static final long VERSION = 1L;
39  }