| /* |
| * 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.impl.builtin; |
| |
| import java.io.IOException; |
| import java.text.MessageFormat; |
| import java.util.Random; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.pig.EvalFunc; |
| import org.apache.pig.backend.executionengine.ExecException; |
| import org.apache.pig.data.BagFactory; |
| import org.apache.pig.data.DataBag; |
| import org.apache.pig.data.Tuple; |
| import org.apache.pig.data.TupleFactory; |
| import org.apache.pig.impl.PigImplConstants; |
| import org.apache.pig.impl.util.UDFContext; |
| |
| |
| public class GFCross extends EvalFunc<DataBag> { |
| |
| private static final Log LOG = LogFactory.getLog(GFCross.class); |
| |
| private int numInputs, myNumber, numGroupsPerInput, numGroupsGoingTo; |
| private BagFactory mBagFactory = BagFactory.getInstance(); |
| private TupleFactory mTupleFactory = TupleFactory.getInstance(); |
| private int parallelism = 0; |
| private Random r = new Random(); |
| private String crossKey; |
| |
| static private final int DEFAULT_PARALLELISM = 96; |
| |
| public GFCross(String key) { |
| crossKey = key; |
| } |
| |
| public String getCrossKey() { |
| return crossKey; |
| } |
| |
| @Override |
| public DataBag exec(Tuple input) throws IOException { |
| if (parallelism == 0) { |
| parallelism = DEFAULT_PARALLELISM; |
| Configuration cfg = UDFContext.getUDFContext().getJobConf(); |
| if (cfg != null) { |
| String s = cfg.get(PigImplConstants.PIG_CROSS_PARALLELISM + "." + crossKey); |
| if (s == null) { |
| throw new IOException("Unable to get parallelism hint from job conf"); |
| } |
| parallelism = Integer.valueOf(s); |
| if (parallelism < 0) { |
| throw new IOException(PigImplConstants.PIG_CROSS_PARALLELISM + "." + crossKey + " was " + parallelism); |
| } |
| } |
| |
| numInputs = (Integer)input.get(0); |
| myNumber = (Integer)input.get(1); |
| |
| numGroupsPerInput = (int) Math.ceil(Math.pow(parallelism, 1.0/numInputs)); |
| numGroupsGoingTo = (int) Math.pow(numGroupsPerInput,numInputs - 1); |
| |
| LOG.info(MessageFormat.format("Parallelism = {0}, numInputs = {1}, myNumber = {2}," |
| + " numGroupsPerInput = {3}, numGroupsGoingTo = {4}", |
| parallelism, numInputs, myNumber, |
| numGroupsPerInput, numGroupsGoingTo)); |
| |
| } |
| |
| DataBag output = mBagFactory.newDefaultBag(); |
| |
| try{ |
| |
| int[] digits = new int[numInputs]; |
| digits[myNumber] = r.nextInt(numGroupsPerInput); |
| |
| for (int i=0; i<numGroupsGoingTo; i++){ |
| output.add(toTuple(digits)); |
| next(digits); |
| } |
| |
| return output; |
| }catch(ExecException e){ |
| throw e; |
| } |
| } |
| |
| private Tuple toTuple(int[] digits) throws IOException, ExecException{ |
| Tuple t = mTupleFactory.newTuple(numInputs); |
| for (int i=0; i<numInputs; i++){ |
| t.set(i, digits[i]); |
| } |
| return t; |
| } |
| |
| private void next(int[] digits){ |
| for (int i=0; i<numInputs; i++){ |
| if (i== myNumber) |
| continue; |
| else{ |
| if (digits[i] == numGroupsPerInput - 1){ |
| digits[i] = 0; |
| }else{ |
| digits[i]++; |
| break; |
| } |
| } |
| } |
| } |
| |
| } |