| /* |
| * 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.util.ArrayList; |
| |
| import org.apache.hadoop.fs.Path; |
| import org.apache.hadoop.mapreduce.InputFormat; |
| import org.apache.hadoop.mapreduce.Job; |
| import org.apache.hadoop.mapreduce.RecordReader; |
| import org.apache.pig.LoadCaster; |
| import org.apache.pig.LoadFunc; |
| import org.apache.pig.backend.executionengine.ExecException; |
| import org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigSplit; |
| import org.apache.pig.impl.PigContext; |
| import org.apache.pig.impl.io.FileSpec; |
| import org.apache.pig.impl.util.Pair; |
| |
| /** |
| * Abstract class that specifies the interface for sample loaders |
| * |
| */ |
| public abstract class SampleLoader extends LoadFunc { |
| |
| // number of samples to be sampled |
| protected int numSamples; |
| |
| protected LoadFunc loader; |
| |
| // RecordReader used by the underlying loader |
| private RecordReader<?, ?> recordReader= null; |
| |
| public SampleLoader(String funcSpec) { |
| funcSpec = funcSpec.replaceAll("\\\\'", "'"); |
| loader = (LoadFunc)PigContext.instantiateFuncFromSpec(funcSpec); |
| } |
| |
| public void setNumSamples(int n) { |
| numSamples = n; |
| } |
| |
| public int getNumSamples() { |
| return numSamples; |
| } |
| |
| @Override |
| public InputFormat<?,?> getInputFormat() throws IOException { |
| return loader.getInputFormat(); |
| } |
| |
| public boolean skipNext() throws IOException { |
| try { |
| return recordReader.nextKeyValue(); |
| } catch (InterruptedException e) { |
| throw new IOException("Error getting input",e); |
| } |
| } |
| |
| public void computeSamples(ArrayList<Pair<FileSpec, Boolean>> inputs, |
| PigContext pc) throws ExecException { |
| } |
| |
| @Override |
| public LoadCaster getLoadCaster() throws IOException { |
| return loader.getLoadCaster(); |
| } |
| |
| @Override |
| public String relativeToAbsolutePath(String location, Path curDir) |
| throws IOException { |
| return loader.relativeToAbsolutePath(location, curDir); |
| } |
| |
| @Override |
| public void prepareToRead(RecordReader reader, PigSplit split) throws IOException { |
| loader.prepareToRead(reader, split); |
| this.recordReader = reader; |
| } |
| |
| @Override |
| public void setLocation(String location, Job job) throws IOException { |
| loader.setLocation(location, job); |
| } |
| |
| @Override |
| public void setUDFContextSignature(String signature) { |
| loader.setUDFContextSignature(signature); |
| } |
| } |