| /* |
| * 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 org.apache.pig.Algebraic; |
| import org.apache.pig.EvalFunc; |
| import org.apache.pig.PigException; |
| import org.apache.pig.backend.executionengine.ExecException; |
| import org.apache.pig.data.DataBag; |
| import org.apache.pig.data.Tuple; |
| import org.apache.pig.data.TupleFactory; |
| |
| /** |
| * The purpose of this class is to hold some of the common code shared among |
| * the typed Basic*Funcs (BasicDoubleFunc, BasicIntegerFunc, etc). |
| */ |
| abstract class AlgebraicMathBase<T> extends EvalFunc<T> implements Algebraic { |
| |
| protected static enum KNOWN_OP { |
| SUM, MIN, MAX; |
| } |
| |
| protected interface KnownOpProvider { |
| public KNOWN_OP getOp(); |
| } |
| |
| protected KnownOpProvider opProvider; |
| |
| protected void setOp(final KNOWN_OP op) { |
| opProvider = new KnownOpProvider() { |
| @Override |
| public KNOWN_OP getOp() { |
| return op; |
| }}; |
| } |
| |
| @Override |
| public String getInitial() { |
| return Initial.class.getName(); |
| } |
| |
| |
| static public class Initial extends EvalFunc<Tuple> { |
| private static TupleFactory tfact = TupleFactory.getInstance(); |
| |
| @Override |
| public Tuple exec(Tuple input) throws IOException { |
| // Initial is called in the map. |
| // we just send the tuple down |
| try { |
| // input is a bag with one tuple containing |
| // the column we are trying to operate on |
| DataBag bg = (DataBag) input.get(0); |
| if (bg.iterator().hasNext()) { |
| return bg.iterator().next(); |
| } else { |
| // make sure that we call the object constructor, not the list constructor |
| return tfact.newTuple((Object) null); |
| } |
| } catch (ExecException e) { |
| throw e; |
| } catch (Exception e) { |
| int errCode = 2106; |
| throw new ExecException("Error executing an algebraic function", errCode, PigException.BUG, e); |
| } |
| } |
| } |
| |
| @Override |
| public String getIntermed() { |
| for (@SuppressWarnings("rawtypes") |
| Class c : this.getClass().getDeclaredClasses()) { |
| if (Intermediate.class.isAssignableFrom(c)) { |
| return c.getName(); |
| } |
| } |
| // Try inheritance |
| for (@SuppressWarnings("rawtypes") |
| Class c : this.getClass().getClasses()) { |
| if (Intermediate.class.isAssignableFrom(c)) { |
| return c.getName(); |
| } |
| } |
| return null; |
| } |
| |
| @Override |
| public String getFinal() { |
| for (@SuppressWarnings("rawtypes") |
| Class c : this.getClass().getDeclaredClasses()) { |
| if (Final.class.isAssignableFrom(c)) { |
| return c.getName(); |
| } |
| } |
| for (@SuppressWarnings("rawtypes") |
| Class c : this.getClass().getClasses()) { |
| if (Final.class.isAssignableFrom(c)) { |
| return c.getName(); |
| } |
| } |
| return null; |
| } |
| |
| static public abstract class Intermediate extends EvalFunc<Tuple> implements KnownOpProvider { |
| } |
| static public abstract class Final<T> extends EvalFunc<T> implements KnownOpProvider { |
| } |
| |
| } |