| /** |
| * 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.hive.ql.udf.generic; |
| |
| import java.io.DataOutput; |
| import java.io.IOException; |
| |
| import org.apache.hadoop.hive.ql.exec.Description; |
| import org.apache.hadoop.hive.ql.exec.UDFArgumentException; |
| import org.apache.hadoop.hive.ql.metadata.HiveException; |
| import org.apache.hadoop.hive.ql.parse.SemanticException; |
| import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector; |
| import org.apache.hadoop.hive.serde2.objectinspector.primitive.LongObjectInspector; |
| import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory; |
| import org.apache.hadoop.hive.serde2.typeinfo.TypeInfo; |
| import org.apache.hadoop.io.LongWritable; |
| |
| import edu.uci.ics.hivesterix.runtime.evaluator.BufferSerDeUtil; |
| import edu.uci.ics.hivesterix.runtime.evaluator.SerializableBuffer; |
| |
| /** |
| * This class implements the COUNT aggregation function as in SQL. |
| */ |
| @Description(name = "count", value = "_FUNC_(*) - Returns the total number of retrieved rows, including " |
| + "rows containing NULL values.\n" |
| |
| + "_FUNC_(expr) - Returns the number of rows for which the supplied " + "expression is non-NULL.\n" |
| |
| + "_FUNC_(DISTINCT expr[, expr...]) - Returns the number of rows for " |
| + "which the supplied expression(s) are unique and non-NULL.") |
| public class GenericUDAFCount implements GenericUDAFResolver2 { |
| |
| @Override |
| public GenericUDAFEvaluator getEvaluator(TypeInfo[] parameters) throws SemanticException { |
| // This method implementation is preserved for backward compatibility. |
| return new GenericUDAFCountEvaluator(); |
| } |
| |
| @Override |
| public GenericUDAFEvaluator getEvaluator(GenericUDAFParameterInfo paramInfo) throws SemanticException { |
| |
| TypeInfo[] parameters = paramInfo.getParameters(); |
| |
| if (parameters.length == 0) { |
| if (!paramInfo.isAllColumns()) { |
| throw new UDFArgumentException("Argument expected"); |
| } |
| assert !paramInfo.isDistinct() : "DISTINCT not supported with *"; |
| } else { |
| if (parameters.length > 1 && !paramInfo.isDistinct()) { |
| throw new UDFArgumentException("DISTINCT keyword must be specified"); |
| } |
| assert !paramInfo.isAllColumns() : "* not supported in expression list"; |
| } |
| |
| return new GenericUDAFCountEvaluator().setCountAllColumns(paramInfo.isAllColumns()); |
| } |
| |
| /** |
| * GenericUDAFCountEvaluator. |
| */ |
| public static class GenericUDAFCountEvaluator extends GenericUDAFEvaluator { |
| private boolean countAllColumns = false; |
| private LongObjectInspector partialCountAggOI; |
| private LongWritable result; |
| |
| @Override |
| public ObjectInspector init(Mode m, ObjectInspector[] parameters) throws HiveException { |
| super.init(m, parameters); |
| partialCountAggOI = PrimitiveObjectInspectorFactory.writableLongObjectInspector; |
| result = new LongWritable(0); |
| return PrimitiveObjectInspectorFactory.writableLongObjectInspector; |
| } |
| |
| private GenericUDAFCountEvaluator setCountAllColumns(boolean countAllCols) { |
| countAllColumns = countAllCols; |
| return this; |
| } |
| |
| /** class for storing count value. */ |
| static class CountAgg implements SerializableBuffer { |
| long value; |
| |
| @Override |
| public void deSerializeAggBuffer(byte[] data, int start, int len) { |
| value = BufferSerDeUtil.getLong(data, start); |
| } |
| |
| @Override |
| public void serializeAggBuffer(byte[] data, int start, int len) { |
| BufferSerDeUtil.writeLong(value, data, start); |
| } |
| |
| @Override |
| public void serializeAggBuffer(DataOutput output) throws IOException { |
| output.writeLong(value); |
| } |
| } |
| |
| @Override |
| public AggregationBuffer getNewAggregationBuffer() throws HiveException { |
| CountAgg buffer = new CountAgg(); |
| reset(buffer); |
| return buffer; |
| } |
| |
| @Override |
| public void reset(AggregationBuffer agg) throws HiveException { |
| ((CountAgg) agg).value = 0; |
| } |
| |
| @Override |
| public void iterate(AggregationBuffer agg, Object[] parameters) throws HiveException { |
| // parameters == null means the input table/split is empty |
| if (parameters == null) { |
| return; |
| } |
| if (countAllColumns) { |
| assert parameters.length == 0; |
| ((CountAgg) agg).value++; |
| } else { |
| assert parameters.length > 0; |
| boolean countThisRow = true; |
| for (Object nextParam : parameters) { |
| if (nextParam == null) { |
| countThisRow = false; |
| break; |
| } |
| } |
| if (countThisRow) { |
| ((CountAgg) agg).value++; |
| } |
| } |
| } |
| |
| @Override |
| public void merge(AggregationBuffer agg, Object partial) throws HiveException { |
| if (partial != null) { |
| long p = partialCountAggOI.get(partial); |
| ((CountAgg) agg).value += p; |
| } |
| } |
| |
| @Override |
| public Object terminate(AggregationBuffer agg) throws HiveException { |
| result.set(((CountAgg) agg).value); |
| return result; |
| } |
| |
| @Override |
| public Object terminatePartial(AggregationBuffer agg) throws HiveException { |
| return terminate(agg); |
| } |
| } |
| } |