Java tutorial
/******************************************************************************* * Copyright (c) 2012 Nikos Papailiou. * All rights reserved. This program and the accompanying materials * are made available under the terms of the GNU Public License v3.0 * which accompanies this distribution, and is available at * http://www.gnu.org/licenses/gpl.html * * Contributors: * Nikos Papailiou - initial API and implementation ******************************************************************************/ package input_format; import java.io.IOException; import java.util.StringTokenizer; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.FileUtil; import org.apache.hadoop.fs.Path; import org.apache.hadoop.hbase.HBaseConfiguration; import org.apache.hadoop.hbase.KeyValue; import org.apache.hadoop.hbase.client.HTable; import org.apache.hadoop.hbase.io.ImmutableBytesWritable; import org.apache.hadoop.hbase.util.Bytes; import org.apache.hadoop.mapreduce.InputSplit; import org.apache.hadoop.mapreduce.RecordReader; import org.apache.hadoop.mapreduce.TaskAttemptContext; import org.apache.hadoop.io.Text; import org.apache.hadoop.hbase.io.hfile.HFile.Reader; import org.apache.hadoop.hbase.io.hfile.CacheConfig; import org.apache.hadoop.hbase.io.hfile.HFile; import org.apache.hadoop.hbase.io.hfile.HFileScanner; import byte_import.MyNewTotalOrderPartitioner; public class HFileRecordReaderNoScan extends RecordReader<ImmutableBytesWritable, Text> { private ImmutableBytesWritable key = null; private Text value = null; private TableColumnSplit tsplit = null; private Reader reader = null; private HFileScanner scanner = null; private KeyValue kv = null; private boolean more; private HBaseConfiguration HBconf = new HBaseConfiguration(); private byte[] stopr; /** * Closes the split. * * @see org.apache.hadoop.mapreduce.RecordReader#close() */ @Override public void close() { try { reader.close(); } catch (IOException e) { e.printStackTrace(); } } /** * Returns the current key. * * @return The current key. * @throws IOException * @throws InterruptedException When the job is aborted. * @see org.apache.hadoop.mapreduce.RecordReader#getCurrentKey() */ @Override public ImmutableBytesWritable getCurrentKey() throws IOException, InterruptedException { return key; } /** * Returns the current value. * * @return The current value. * @throws IOException When the value is faulty. * @throws InterruptedException When the job is aborted. * @see org.apache.hadoop.mapreduce.RecordReader#getCurrentValue() */ @Override public Text getCurrentValue() throws IOException, InterruptedException { return value; } /** * Initializes the reader. * * @param inputsplit The split to work with. * @param context The current task context. * @throws IOException When setting up the reader fails. * @throws InterruptedException When the job is aborted. * @see org.apache.hadoop.mapreduce.RecordReader#initialize( * org.apache.hadoop.mapreduce.InputSplit, * org.apache.hadoop.mapreduce.TaskAttemptContext) */ @Override public void initialize(InputSplit inputsplit, TaskAttemptContext context) throws IOException, InterruptedException { tsplit = (TableColumnSplit) inputsplit; HTable table = new HTable(HBconf, tsplit.getTable()); byte[] rowid = tsplit.getStartRow(); byte[] startr = new byte[19]; stopr = new byte[19]; for (int i = 0; i < rowid.length; i++) { startr[i] = rowid[i]; stopr[i] = rowid[i]; } if (rowid.length == 18) { startr[18] = (byte) 0; stopr[18] = (byte) MyNewTotalOrderPartitioner.MAX_HBASE_BUCKETS; } if (rowid.length == 10) { for (int i = 10; i < startr.length - 1; i++) { startr[i] = (byte) 0; stopr[i] = (byte) 255; } startr[startr.length - 1] = (byte) 0; stopr[startr.length - 1] = (byte) MyNewTotalOrderPartitioner.MAX_HBASE_BUCKETS; } FileSystem fs = FileSystem.get(HBconf); String dir = "/hbase/" + tsplit.getTable() + "/" + table.getRegionLocation(startr).getRegionInfo().getEncodedName() + "/A"; Path regionDir = new Path(dir); Path file = null; Path[] hfiles = FileUtil.stat2Paths(fs.listStatus(regionDir)); for (Path hfile : hfiles) { file = new Path(dir + "/" + hfile.getName()); } reader = HFile.createReader(fs, file, new CacheConfig(HBconf)); //reader = new Reader(fs, file, null, false); // Load up the index. reader.loadFileInfo(); // Get a scanner that caches and that does not use pread. scanner = reader.getScanner(false, true); KeyValue rowKey = KeyValue.createFirstOnRow(startr); scanner.seekBefore(rowKey.getKey()); while (scanner.next()) { kv = scanner.getKeyValue(); if (Bytes.compareTo(kv.getRow(), startr) >= 0) { more = true; return; } } more = false; } /** * Positions the record reader to the next record. * * @return <code>true</code> if there was another record. * @throws IOException When reading the record failed. * @throws InterruptedException When the job was aborted. * @see org.apache.hadoop.mapreduce.RecordReader#nextKeyValue() */ @Override public boolean nextKeyValue() throws IOException, InterruptedException { boolean again = false; if (!more) return more; if (key == null) key = new ImmutableBytesWritable(); if (value == null) value = new Text(); if (Bytes.compareTo(kv.getRow(), stopr) <= 0) { String vars = tsplit.getVars(); StringTokenizer vtok = new StringTokenizer(vars); int i = 0; while (vtok.hasMoreTokens()) { vtok.nextToken(); i++; } if (i == 1) { StringTokenizer vtok2 = new StringTokenizer(vars); String v1 = vtok2.nextToken(); value.set(tsplit.getFname() + "!" + v1 + "#" + Bytes.toLong(kv.getQualifier()) + "_"); //value.set(tsplit.getFname()+"sp"+v1+"$$" // +String.valueOf(Bytes.toChars(kv.getQualifier()))); //value.set(tsplit.getFname()+" "+v1+"$$"+valueToString(kv.getValue())); } else if (i == 2) { StringTokenizer vtok2 = new StringTokenizer(vars); String v1 = vtok2.nextToken(); String v2 = vtok2.nextToken(); byte[] r = kv.getRow(); byte[] r1 = new byte[8]; for (int j = 0; j < r1.length; j++) { r1[j] = r[10 + j]; } value.set(tsplit.getFname() + "!" + v1 + "#" + Bytes.toLong(r1) + "!" + v2 + "#" + Bytes.toLong(kv.getQualifier()) + "_"); //value.set(tsplit.getFname()+"sp"+v1+"$$" // +String.valueOf(Bytes.toChars(r1))+ // "sp"+v2+"$$"+String.valueOf(Bytes.toChars(kv.getQualifier()))); //value.set(tsplit.getFname()+" "+v1+"$$"+valueToString(kv.getQualifier())+ // " "+v2+"$$"+valueToString(kv.getValue())); } more = scanner.next(); if (more) kv = scanner.getKeyValue(); if (again) return nextKeyValue(); return true; } return false; } /** * The current progress of the record reader through its data. * * @return A number between 0.0 and 1.0, the fraction of the data read. * @see org.apache.hadoop.mapreduce.RecordReader#getProgress() */ @Override public float getProgress() { // Depends on the total number of tuples return 0; } }