001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.client.coprocessor;
019
020import com.google.protobuf.ByteString;
021import com.google.protobuf.Message;
022
023import java.io.IOException;
024import java.lang.reflect.InvocationTargetException;
025import java.lang.reflect.Method;
026import java.lang.reflect.ParameterizedType;
027import java.lang.reflect.Type;
028
029import org.apache.hadoop.hbase.HConstants;
030import org.apache.hadoop.hbase.client.Scan;
031import org.apache.hadoop.hbase.coprocessor.ColumnInterpreter;
032import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
033import org.apache.hadoop.hbase.protobuf.generated.AggregateProtos.AggregateRequest;
034import org.apache.hadoop.hbase.util.Bytes;
035import org.apache.yetus.audience.InterfaceAudience;
036
037/**
038 * Helper class for constructing aggregation request and response.
039 */
040@InterfaceAudience.Private
041public final class AggregationHelper {
042  private AggregationHelper() {}
043
044  /**
045   * @param scan the HBase scan object to use to read data from HBase
046   * @param canFamilyBeAbsent whether column family can be absent in familyMap of scan
047   */
048  private static void validateParameters(Scan scan, boolean canFamilyBeAbsent) throws IOException {
049    if (scan == null
050        || (Bytes.equals(scan.getStartRow(), scan.getStopRow())
051            && !Bytes.equals(scan.getStartRow(), HConstants.EMPTY_START_ROW))
052        || ((Bytes.compareTo(scan.getStartRow(), scan.getStopRow()) > 0)
053            && !Bytes.equals(scan.getStopRow(), HConstants.EMPTY_END_ROW))) {
054      throw new IOException("Agg client Exception: Startrow should be smaller than Stoprow");
055    } else if (!canFamilyBeAbsent) {
056      if (scan.getFamilyMap().size() != 1) {
057        throw new IOException("There must be only one family.");
058      }
059    }
060  }
061
062  static <R, S, P extends Message, Q extends Message, T extends Message> AggregateRequest
063      validateArgAndGetPB(Scan scan, ColumnInterpreter<R, S, P, Q, T> ci, boolean canFamilyBeAbsent)
064          throws IOException {
065    validateParameters(scan, canFamilyBeAbsent);
066    final AggregateRequest.Builder requestBuilder = AggregateRequest.newBuilder();
067    requestBuilder.setInterpreterClassName(ci.getClass().getCanonicalName());
068    P columnInterpreterSpecificData = ci.getRequestData();
069    if (columnInterpreterSpecificData != null) {
070      requestBuilder.setInterpreterSpecificBytes(columnInterpreterSpecificData.toByteString());
071    }
072    requestBuilder.setScan(ProtobufUtil.toScan(scan));
073    return requestBuilder.build();
074  }
075
076  /**
077   * Get an instance of the argument type declared in a class's signature. The argument type is
078   * assumed to be a PB Message subclass, and the instance is created using parseFrom method on the
079   * passed ByteString.
080   * @param runtimeClass the runtime type of the class
081   * @param position the position of the argument in the class declaration
082   * @param b the ByteString which should be parsed to get the instance created
083   * @return the instance
084   * @throws IOException Either we couldn't instantiate the method object, or "parseFrom" failed.
085   */
086  @SuppressWarnings("unchecked")
087  // Used server-side too by Aggregation Coprocesor Endpoint. Undo this interdependence. TODO.
088  public static <T extends Message> T getParsedGenericInstance(Class<?> runtimeClass, int position,
089      ByteString b) throws IOException {
090    Type type = runtimeClass.getGenericSuperclass();
091    Type argType = ((ParameterizedType) type).getActualTypeArguments()[position];
092    Class<T> classType = (Class<T>) argType;
093    T inst;
094    try {
095      Method m = classType.getMethod("parseFrom", ByteString.class);
096      inst = (T) m.invoke(null, b);
097      return inst;
098    } catch (SecurityException e) {
099      throw new IOException(e);
100    } catch (NoSuchMethodException e) {
101      throw new IOException(e);
102    } catch (IllegalArgumentException e) {
103      throw new IOException(e);
104    } catch (InvocationTargetException e) {
105      throw new IOException(e);
106    } catch (IllegalAccessException e) {
107      throw new IOException(e);
108    }
109  }
110}