| /* |
| * 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.io; |
| |
| import java.io.IOException; |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.mapreduce.InputFormat; |
| import org.apache.hadoop.mapreduce.InputSplit; |
| import org.apache.hadoop.mapreduce.Job; |
| import org.apache.hadoop.mapreduce.JobContext; |
| import org.apache.hadoop.mapreduce.JobID; |
| import org.apache.hadoop.mapreduce.RecordReader; |
| import org.apache.hadoop.mapreduce.TaskAttemptContext; |
| import org.apache.hadoop.mapreduce.TaskAttemptID; |
| import org.apache.pig.Expression; |
| import org.apache.pig.LoadCaster; |
| import org.apache.pig.LoadFunc; |
| import org.apache.pig.LoadMetadata; |
| import org.apache.pig.ResourceSchema; |
| import org.apache.pig.ResourceStatistics; |
| import org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigSplit; |
| import org.apache.pig.backend.hadoop.executionengine.shims.HadoopShims; |
| import org.apache.pig.data.SchemaTupleBackend; |
| import org.apache.pig.data.Tuple; |
| import org.apache.pig.impl.plan.OperatorKey; |
| |
| /** |
| * This is wrapper Loader which wraps a real LoadFunc underneath and allows |
| * to read a file completely starting a given split (indicated by a split index |
| * which is used to look in the List<InputSplit> returned by the underlying |
| * InputFormat's getSplits() method). So if the supplied split index is 0, this |
| * loader will read the entire file. If it is non zero it will read the partial |
| * file beginning from that split to the last split. |
| * |
| * The call sequence to use this is: |
| * 1) construct an object using the constructor |
| * 2) Call getNext() in a loop till it returns null |
| */ |
| public class ReadToEndLoader extends LoadFunc implements LoadMetadata { |
| |
| /** |
| * the wrapped LoadFunc which will do the actual reading |
| */ |
| private LoadFunc wrappedLoadFunc; |
| |
| /** |
| * the Configuration object used to locate the input location - this will |
| * be used to call {@link LoadFunc#setLocation(String, Job)} on |
| * the wrappedLoadFunc |
| */ |
| private Configuration conf; |
| |
| /** |
| * the input location string (typically input file/dir name ) |
| */ |
| private String inputLocation; |
| |
| /** |
| * If the splits to be read are not in increasing sequence of integers |
| * this array can be used |
| */ |
| private int[] toReadSplits = null; |
| |
| /** |
| * index into toReadSplits |
| */ |
| private int toReadSplitsIdx = 0; |
| |
| /** |
| * the index of the split the loader is currently reading from |
| */ |
| private int curSplitIndex; |
| |
| /** |
| * the input splits returned by underlying {@link InputFormat#getSplits(JobContext)} |
| */ |
| private List<InputSplit> inpSplits = null; |
| |
| /** |
| * underlying RecordReader |
| */ |
| private RecordReader reader = null; |
| |
| /** |
| * underlying InputFormat |
| */ |
| private InputFormat inputFormat = null; |
| |
| private String udfContextSignature = null; |
| |
| /** |
| * @param wrappedLoadFunc |
| * @param conf |
| * @param inputLocation |
| * @param splitIndex |
| * @throws IOException |
| * @throws InterruptedException |
| */ |
| public ReadToEndLoader(LoadFunc wrappedLoadFunc, Configuration conf, |
| String inputLocation, int splitIndex) throws IOException { |
| this.wrappedLoadFunc = wrappedLoadFunc; |
| this.inputLocation = inputLocation; |
| this.conf = conf; |
| this.curSplitIndex = splitIndex; |
| init(); |
| } |
| |
| public ReadToEndLoader(LoadFunc wrappedLoadFunc, Configuration conf, |
| String inputLocation, int splitIndex, String signature) throws IOException { |
| this.udfContextSignature = signature; |
| this.wrappedLoadFunc = wrappedLoadFunc; |
| this.inputLocation = inputLocation; |
| this.conf = conf; |
| this.curSplitIndex = splitIndex; |
| init(); |
| } |
| |
| /** |
| * This constructor takes an array of split indexes (toReadSplitIdxs) of the |
| * splits to be read. |
| * @param wrappedLoadFunc |
| * @param conf |
| * @param inputLocation |
| * @param toReadSplitIdxs |
| * @throws IOException |
| * @throws InterruptedException |
| */ |
| public ReadToEndLoader(LoadFunc wrappedLoadFunc, Configuration conf, |
| String inputLocation, int[] toReadSplitIdxs) throws IOException { |
| this.wrappedLoadFunc = wrappedLoadFunc; |
| this.inputLocation = inputLocation; |
| this.toReadSplits = toReadSplitIdxs; |
| this.conf = conf; |
| this.curSplitIndex = |
| toReadSplitIdxs.length > 0 ? toReadSplitIdxs[0] : Integer.MAX_VALUE; |
| init(); |
| } |
| |
| @SuppressWarnings("unchecked") |
| private void init() throws IOException { |
| if (conf != null) { |
| SchemaTupleBackend.initialize(conf, true); |
| } |
| |
| // make a copy so that if the underlying InputFormat writes to the |
| // conf, we don't affect the caller's copy |
| conf = new Configuration(conf); |
| |
| // let's initialize the wrappedLoadFunc |
| Job job = new Job(conf); |
| wrappedLoadFunc.setUDFContextSignature(this.udfContextSignature); |
| wrappedLoadFunc.setLocation(inputLocation, |
| job); |
| // The above setLocation call could write to the conf within |
| // the job - get a hold of the modified conf |
| conf = job.getConfiguration(); |
| inputFormat = wrappedLoadFunc.getInputFormat(); |
| try { |
| inpSplits = inputFormat.getSplits(HadoopShims.createJobContext(conf, |
| new JobID())); |
| } catch (InterruptedException e) { |
| throw new IOException(e); |
| } |
| } |
| |
| private boolean initializeReader() throws IOException, |
| InterruptedException { |
| // Close the previous reader first |
| if(reader != null) { |
| reader.close(); |
| reader = null; |
| } |
| if(curSplitIndex > inpSplits.size() - 1) { |
| // past the last split, we are done |
| return false; |
| } |
| InputSplit curSplit = inpSplits.get(curSplitIndex); |
| TaskAttemptContext tAContext = HadoopShims.createTaskAttemptContext(conf, |
| new TaskAttemptID()); |
| reader = inputFormat.createRecordReader(curSplit, tAContext); |
| reader.initialize(curSplit, tAContext); |
| // create a dummy pigsplit - other than the actual split, the other |
| // params are really not needed here where we are just reading the |
| // input completely |
| PigSplit pigSplit = new PigSplit(new InputSplit[] {curSplit}, -1, |
| new ArrayList<OperatorKey>(), -1); |
| // Set the conf object so that if the wrappedLoadFunc uses it, |
| // it won't be null |
| pigSplit.setConf(conf); |
| wrappedLoadFunc.prepareToRead(reader, pigSplit); |
| return true; |
| } |
| |
| @Override |
| public Tuple getNext() throws IOException { |
| try { |
| Tuple t = null; |
| if(reader == null) { |
| // first call |
| return getNextHelper(); |
| } else { |
| // we already have a reader initialized |
| t = wrappedLoadFunc.getNext(); |
| if(t != null) { |
| return t; |
| } |
| // if loadfunc returned null, we need to read next split |
| // if there is one |
| updateCurSplitIndex(); |
| return getNextHelper(); |
| } |
| } catch (InterruptedException e) { |
| throw new IOException(e); |
| } |
| } |
| |
| private Tuple getNextHelper() throws IOException, InterruptedException { |
| Tuple t = null; |
| while(initializeReader()) { |
| t = wrappedLoadFunc.getNext(); |
| if(t == null) { |
| // try next split |
| updateCurSplitIndex(); |
| } else { |
| return t; |
| } |
| } |
| return null; |
| } |
| |
| |
| /** |
| * Updates curSplitIndex , just increment if splitIndexes is null, |
| * else get next split in splitIndexes |
| */ |
| private void updateCurSplitIndex() { |
| if(toReadSplits == null){ |
| ++curSplitIndex; |
| }else{ |
| ++toReadSplitsIdx; |
| if(toReadSplitsIdx >= toReadSplits.length){ |
| // finished all the splits in splitIndexes array |
| curSplitIndex = Integer.MAX_VALUE; |
| }else{ |
| curSplitIndex = toReadSplits[toReadSplitsIdx]; |
| } |
| } |
| } |
| |
| @Override |
| public InputFormat getInputFormat() throws IOException { |
| throw new UnsupportedOperationException(); |
| } |
| |
| @Override |
| public LoadCaster getLoadCaster() throws IOException { |
| throw new UnsupportedOperationException(); |
| } |
| |
| @Override |
| public void prepareToRead(RecordReader reader, PigSplit split) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| @Override |
| public void setLocation(String location, Job job) throws IOException { |
| wrappedLoadFunc.setLocation(location, job); |
| } |
| |
| @Override |
| public ResourceSchema getSchema(String location, Job job) throws IOException { |
| if (wrappedLoadFunc instanceof LoadMetadata) { |
| return ((LoadMetadata) wrappedLoadFunc).getSchema(location, job); |
| } else { |
| return null; |
| } |
| } |
| |
| @Override |
| public ResourceStatistics getStatistics(String location, Job job) throws IOException { |
| if (wrappedLoadFunc instanceof LoadMetadata) { |
| return ((LoadMetadata) wrappedLoadFunc).getStatistics(location, job); |
| } else { |
| return null; |
| } |
| } |
| |
| @Override |
| public String[] getPartitionKeys(String location, Job job) throws IOException { |
| if (wrappedLoadFunc instanceof LoadMetadata) { |
| return ((LoadMetadata) wrappedLoadFunc).getPartitionKeys(location, job); |
| } else { |
| return null; |
| } |
| } |
| |
| @Override |
| public void setPartitionFilter(Expression partitionFilter) throws IOException { |
| if (wrappedLoadFunc instanceof LoadMetadata) { |
| ((LoadMetadata) wrappedLoadFunc).setPartitionFilter(partitionFilter); |
| } |
| } |
| |
| @Override |
| public void setUDFContextSignature(String signature) { |
| this.udfContextSignature = signature; |
| } |
| } |