| /** |
| * 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.mrql; |
| |
| import java.io.*; |
| import java.util.Iterator; |
| import org.apache.hadoop.fs.*; |
| import org.apache.hadoop.io.*; |
| import org.apache.hama.bsp.*; |
| import org.apache.hama.HamaConfiguration; |
| |
| |
| /** A superclass for all MRQL FileInputFormats */ |
| abstract public class BSPMRQLFileInputFormat extends FileInputFormat<MRContainer,MRContainer> implements MRQLFileInputFormat { |
| public BSPMRQLFileInputFormat () {} |
| |
| /** record reader for map-reduce */ |
| abstract public RecordReader<MRContainer,MRContainer> |
| getRecordReader ( InputSplit split, BSPJob job ) throws IOException; |
| |
| /** materialize the input file into a memory Bag */ |
| public Bag materialize ( final Path file ) throws IOException { |
| final BSPJob job = new BSPJob((HamaConfiguration)Plan.conf,MRQLFileInputFormat.class); |
| job.setInputPath(file); |
| final InputSplit[] splits = getSplits(job,1); |
| final RecordReader<MRContainer,MRContainer> rd = getRecordReader(splits[0],job); |
| return new Bag(new BagIterator () { |
| RecordReader<MRContainer,MRContainer> reader = rd; |
| MRContainer key = reader.createKey(); |
| MRContainer value = reader.createKey(); |
| int i = 0; |
| public boolean hasNext () { |
| try { |
| if (reader.next(key,value)) |
| return true; |
| do { |
| if (++i >= splits.length) |
| return false; |
| reader.close(); |
| reader = getRecordReader(splits[i],job); |
| } while (!reader.next(key,value)); |
| return true; |
| } catch (IOException e) { |
| throw new Error("Cannot collect values from an intermediate result"); |
| } |
| } |
| public MRData next () { |
| return value.data(); |
| } |
| }); |
| } |
| |
| /** materialize the entire dataset into a Bag |
| * @param x the DataSet in HDFS to collect values from |
| * @param strip true if you want to stripout the source id (used in BSP sources) |
| * @return the Bag that contains the collected values |
| */ |
| public final Bag collect ( final DataSet x, boolean strip ) throws Exception { |
| Bag res = new Bag(); |
| for ( DataSource s: x.source ) |
| if (s.to_be_merged) |
| res = res.union(Plan.merge(s)); |
| else { |
| Path path = new Path(s.path); |
| final FileSystem fs = path.getFileSystem(Plan.conf); |
| final FileStatus[] ds |
| = fs.listStatus(path, |
| new PathFilter () { |
| public boolean accept ( Path path ) { |
| return !path.getName().startsWith("_"); |
| } |
| }); |
| Bag b = new Bag(); |
| for ( FileStatus st: ds ) |
| b = b.union(s.inputFormat.newInstance().materialize(st.getPath())); |
| if (strip) { |
| // remove source_num |
| final Iterator<MRData> iter = b.iterator(); |
| b = new Bag(new BagIterator() { |
| public boolean hasNext () { |
| return iter.hasNext(); |
| } |
| public MRData next () { |
| return ((Tuple)iter.next()).get(1); |
| } |
| }); |
| }; |
| res = res.union(b); |
| }; |
| return res; |
| } |
| } |