/**
*
* 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.hadoop.hbase.mapred;
import java.io.IOException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.filter.Filter;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.hbase.regionserver.HRegion;
import org.apache.hadoop.mapred.InputFormat;
import org.apache.hadoop.mapred.InputSplit;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.RecordReader;
import org.apache.hadoop.mapred.Reporter;
/**
* A Base for {@link TableInputFormat}s. Receives a {@link HTable}, a
* byte[] of input columns and optionally a {@link Filter}.
* Subclasses may use other TableRecordReader implementations.
* <p>
* An example of a subclass:
* <pre>
* class ExampleTIF extends TableInputFormatBase implements JobConfigurable {
*
* public void configure(JobConf job) {
* HTable exampleTable = new HTable(HBaseConfiguration.create(job),
* Bytes.toBytes("exampleTable"));
* // mandatory
* setHTable(exampleTable);
* Text[] inputColumns = new byte [][] { Bytes.toBytes("columnA"),
* Bytes.toBytes("columnB") };
* // mandatory
* setInputColumns(inputColumns);
* RowFilterInterface exampleFilter = new RegExpRowFilter("keyPrefix.*");
* // optional
* setRowFilter(exampleFilter);
* }
*
* public void validateInput(JobConf job) throws IOException {
* }
* }
* </pre>
*/
@Deprecated
public abstract class TableInputFormatBase
implements InputFormat<ImmutableBytesWritable, Result> {
final Log LOG = LogFactory.getLog(TableInputFormatBase.class);
private byte [][] inputColumns;
private HTable table;
private TableRecordReader tableRecordReader;
private Filter rowFilter;
/**
* Builds a TableRecordReader. If no TableRecordReader was provided, uses
* the default.
*
* @see org.apache.hadoop.mapred.InputFormat#getRecordReader(InputSplit,
* JobConf, Reporter)
*/
public RecordReader<ImmutableBytesWritable, Result> getRecordReader(
InputSplit split, JobConf job, Reporter reporter)
throws IOException {
TableSplit tSplit = (TableSplit) split;
TableRecordReader trr = this.tableRecordReader;
// if no table record reader was provided use default
if (trr == null) {
trr = new TableRecordReader();
}
trr.setStartRow(tSplit.getStartRow());
trr.setEndRow(tSplit.getEndRow());
trr.setHTable(this.table);
trr.setInputColumns(this.inputColumns);
trr.setRowFilter(this.rowFilter);
trr.init();
return trr;
}
/**
* Calculates the splits that will serve as input for the map tasks.
* <ul>
* Splits are created in number equal to the smallest between numSplits and
* the number of {@link HRegion}s in the table. If the number of splits is
* smaller than the number of {@link HRegion}s then splits are spanned across
* multiple {@link HRegion}s and are grouped the most evenly possible. In the
* case splits are uneven the bigger splits are placed first in the
* {@link InputSplit} array.
*
* @param job the map task {@link JobConf}
* @param numSplits a hint to calculate the number of splits (mapred.map.tasks).
*
* @return the input splits
*
* @see org.apache.hadoop.mapred.InputFormat#getSplits(org.apache.hadoop.mapred.JobConf, int)
*/
public InputSplit[] getSplits(JobConf job, int numSplits) throws IOException {
if (this.table == null) {
throw new IOException("No table was provided");
}
byte [][] startKeys = this.table.getStartKeys();
if (startKeys == null || startKeys.length == 0) {
throw new IOException("Expecting at least one region");
}
if (this.inputColumns == null || this.inputColumns.length == 0) {
throw new IOException("Expecting at least one column");
}
int realNumSplits = numSplits > startKeys.length? startKeys.length:
numSplits;
InputSplit[] splits = new InputSplit[realNumSplits];
int middle = startKeys.length / realNumSplits;
int startPos = 0;
for (int i = 0; i < realNumSplits; i++) {
int lastPos = startPos + middle;
lastPos = startKeys.length % realNumSplits > i ? lastPos + 1 : lastPos;
String regionLocation = table.getRegionLocation(startKeys[startPos]).
getHostname();
splits[i] = new TableSplit(this.table.getTableName(),
startKeys[startPos], ((i + 1) < realNumSplits) ? startKeys[lastPos]:
HConstants.EMPTY_START_ROW, regionLocation);
LOG.info("split: " + i + "->" + splits[i]);
startPos = lastPos;
}
return splits;
}
/**
* @param inputColumns to be passed in {@link Result} to the map task.
*/
protected void setInputColumns(byte [][] inputColumns) {
this.inputColumns = inputColumns;
}
/**
* Allows subclasses to get the {@link HTable}.
*/
protected HTable getHTable() {
return this.table;
}
/**
* Allows subclasses to set the {@link HTable}.
*
* @param table to get the data from
*/
protected void setHTable(HTable table) {
this.table = table;
}
/**
* Allows subclasses to set the {@link TableRecordReader}.
*
* @param tableRecordReader
* to provide other {@link TableRecordReader} implementations.
*/
protected void setTableRecordReader(TableRecordReader tableRecordReader) {
this.tableRecordReader = tableRecordReader;
}
/**
* Allows subclasses to set the {@link Filter} to be used.
*
* @param rowFilter
*/
protected void setRowFilter(Filter rowFilter) {
this.rowFilter = rowFilter;
}
}