| /* |
| * 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.pig.builtin; |
| |
| import java.io.IOException; |
| import java.util.List; |
| import java.util.ArrayList; |
| import java.math.BigDecimal; |
| import java.math.RoundingMode; |
| |
| import org.apache.pig.EvalFunc; |
| import org.apache.pig.FuncSpec; |
| import org.apache.pig.data.Tuple; |
| import org.apache.pig.impl.logicalLayer.schema.Schema; |
| import org.apache.pig.data.DataType; |
| import org.apache.pig.impl.logicalLayer.FrontendException; |
| |
| /** |
| * |
| * ROUND_TO safely rounds a number to a given precision by using an intermediate |
| * BigDecimal. The too-often seen trick of doing (1000.0 * ROUND(x/1000)) is not |
| * only hard to read but also fails to produce numerically accurate results. |
| * |
| * Given a single data atom and number of digits, it returns a double extending to the |
| * given number of decimal places. |
| * |
| * The result is a multiple of ten to the power given by the digits argument: a |
| * negative value zeros out correspondingly many places to the left of the |
| * decimal point: ROUND_TO(0.9876543, 3) is 0.988; ROUND_TO(0.9876543, 0) is |
| * 1.0; and ROUND_TO(1234.56, -2) is 1200.0. |
| * |
| * The optional mode argument specifies the {@link java.math.RoundingMode rounding mode}; |
| * by default, {@link java.math.RoundingMode#HALF_EVEN HALF_EVEN} is used. |
| * |
| */ |
| public class ROUND_TO extends EvalFunc<Double>{ |
| /** |
| * java level API |
| * @param input expects a numeric value to round, a number of digits to keep, and an optional rounding mode. |
| * @return output returns a single numeric value, the number with only those digits retained |
| */ |
| @Override |
| public Double exec(Tuple input) throws IOException { |
| if (input == null || input.size() < 2) |
| return null; |
| |
| try { |
| Double num = DataType.toDouble(input.get(0)); |
| Integer digits = DataType.toInteger(input.get(1)); |
| RoundingMode mode = (input.size() >= 3) ? |
| RoundingMode.valueOf(DataType.toInteger(input.get(2))) : RoundingMode.HALF_EVEN; |
| if (num == null) return null; |
| |
| BigDecimal bdnum = BigDecimal.valueOf(num); |
| bdnum = bdnum.setScale(digits, mode); |
| return bdnum.doubleValue(); |
| } catch (NumberFormatException nfe){ |
| System.err.println("Failed to process input; error - " + nfe.getMessage()); |
| return null; |
| } catch (Exception e){ |
| throw new IOException("Caught exception processing input row ", e); |
| } |
| } |
| |
| @Override |
| public Schema outputSchema(Schema input) { |
| return new Schema(new Schema.FieldSchema( |
| getSchemaName(this.getClass().getName().toLowerCase(), input), DataType.DOUBLE)); |
| } |
| |
| /* (non-Javadoc) |
| * @see org.apache.pig.EvalFunc#getArgToFuncMapping() |
| */ |
| @Override |
| public List<FuncSpec> getArgToFuncMapping() throws FrontendException { |
| List<FuncSpec> funcList = new ArrayList<FuncSpec>(); |
| |
| Schema s_bty_2 = new Schema(); |
| s_bty_2.add(new Schema.FieldSchema(null, DataType.BYTEARRAY)); |
| s_bty_2.add(new Schema.FieldSchema(null, DataType.BYTEARRAY)); |
| Schema s_bty_3 = new Schema(); |
| s_bty_3.add(new Schema.FieldSchema(null, DataType.BYTEARRAY)); |
| s_bty_3.add(new Schema.FieldSchema(null, DataType.BYTEARRAY)); |
| s_bty_3.add(new Schema.FieldSchema(null, DataType.INTEGER)); |
| |
| Schema s_dbl_2 = new Schema(); |
| s_dbl_2.add(new Schema.FieldSchema(null, DataType.DOUBLE)); |
| s_dbl_2.add(new Schema.FieldSchema(null, DataType.INTEGER)); |
| Schema s_dbl_3 = new Schema(); |
| s_dbl_3.add(new Schema.FieldSchema(null, DataType.DOUBLE)); |
| s_dbl_3.add(new Schema.FieldSchema(null, DataType.INTEGER)); |
| s_dbl_3.add(new Schema.FieldSchema(null, DataType.INTEGER)); |
| |
| Schema s_flt_2 = new Schema(); |
| s_flt_2.add(new Schema.FieldSchema(null, DataType.FLOAT)); |
| s_flt_2.add(new Schema.FieldSchema(null, DataType.INTEGER)); |
| Schema s_flt_3 = new Schema(); |
| s_flt_3.add(new Schema.FieldSchema(null, DataType.FLOAT)); |
| s_flt_3.add(new Schema.FieldSchema(null, DataType.INTEGER)); |
| s_flt_3.add(new Schema.FieldSchema(null, DataType.INTEGER)); |
| |
| funcList.add(new FuncSpec(this.getClass().getName(), s_bty_2)); |
| funcList.add(new FuncSpec(this.getClass().getName(), s_bty_3)); |
| funcList.add(new FuncSpec(DoubleRoundTo.class.getName(), s_dbl_2)); |
| funcList.add(new FuncSpec(DoubleRoundTo.class.getName(), s_dbl_3)); |
| funcList.add(new FuncSpec(FloatRoundTo.class.getName(), s_flt_2)); |
| funcList.add(new FuncSpec(FloatRoundTo.class.getName(), s_flt_3)); |
| |
| return funcList; |
| } |
| |
| @Override |
| public boolean allowCompileTimeCalculation() { |
| return true; |
| } |
| } |