001/*
002 *
003 * Licensed to the Apache Software Foundation (ASF) under one
004 * or more contributor license agreements.  See the NOTICE file
005 * distributed with this work for additional information
006 * regarding copyright ownership.  The ASF licenses this file
007 * to you under the Apache License, Version 2.0 (the
008 * "License"); you may not use this file except in compliance
009 * with the License.  You may obtain a copy of the License at
010 *
011 *     http://www.apache.org/licenses/LICENSE-2.0
012 *
013 * Unless required by applicable law or agreed to in writing, software
014 * distributed under the License is distributed on an "AS IS" BASIS,
015 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
016 * See the License for the specific language governing permissions and
017 * limitations under the License.
018 */
019
020package org.apache.hadoop.hbase.client.coprocessor;
021
022import java.io.IOException;
023
024import org.apache.yetus.audience.InterfaceAudience;
025
026/**
027 * A collection of interfaces and utilities used for interacting with custom RPC
028 * interfaces exposed by Coprocessors.
029 */
030@InterfaceAudience.Public
031public abstract class Batch {
032  /**
033   * Defines a unit of work to be executed.
034   *
035   * <p>
036   * When used with
037   * {@link org.apache.hadoop.hbase.client.Table#coprocessorService(Class, byte[], byte[],
038   * org.apache.hadoop.hbase.client.coprocessor.Batch.Call)}
039   * the implementations {@link Batch.Call#call(Object)} method will be invoked
040   * with a proxy to each region's coprocessor {@link com.google.protobuf.Service} implementation.
041   * </p>
042   * @see org.apache.hadoop.hbase.client.coprocessor.Batch
043   * @see org.apache.hadoop.hbase.client.Table#coprocessorService(byte[])
044   * @see org.apache.hadoop.hbase.client.Table#coprocessorService(Class, byte[], byte[],
045   * org.apache.hadoop.hbase.client.coprocessor.Batch.Call)
046   * @param <T> the instance type to be passed to
047   * {@link Batch.Call#call(Object)}
048   * @param <R> the return type from {@link Batch.Call#call(Object)}
049   */
050  @InterfaceAudience.Public
051  public interface Call<T,R> {
052    R call(T instance) throws IOException;
053  }
054
055  /**
056   * Defines a generic callback to be triggered for each {@link Batch.Call#call(Object)}
057   * result.
058   *
059   * <p>
060   * When used with
061   * {@link org.apache.hadoop.hbase.client.Table#coprocessorService(Class, byte[], byte[],
062   * org.apache.hadoop.hbase.client.coprocessor.Batch.Call)}
063   * the implementation's {@link Batch.Callback#update(byte[], byte[], Object)}
064   * method will be called with the {@link Batch.Call#call(Object)} return value
065   * from each region in the selected range.
066   * </p>
067   * @param <R> the return type from the associated {@link Batch.Call#call(Object)}
068   * @see org.apache.hadoop.hbase.client.Table#coprocessorService(Class, byte[], byte[],
069   * org.apache.hadoop.hbase.client.coprocessor.Batch.Call)
070   */
071  @InterfaceAudience.Public
072  public interface Callback<R> {
073    void update(byte[] region, byte[] row, R result);
074  }
075}