hbase-server/src/main/java/org/apache/hadoop/hbase/mapred/TableRecordReader.java

/**
 *
 * 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.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.classification.InterfaceStability;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.Table;
import org.apache.hadoop.hbase.filter.Filter;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.mapred.RecordReader;


/**
 * Iterate over an HBase table data, return (Text, RowResult) pairs
 */
@InterfaceAudience.Public
@InterfaceStability.Stable
public class TableRecordReader
implements RecordReader<ImmutableBytesWritable, Result> {

  private TableRecordReaderImpl recordReaderImpl = new TableRecordReaderImpl();

  /**
   * Restart from survivable exceptions by creating a new scanner.
   *
   * @param firstRow
   * @throws IOException
   */
  public void restart(byte[] firstRow) throws IOException {
    this.recordReaderImpl.restart(firstRow);
  }

  /**
   * Build the scanner. Not done in constructor to allow for extension.
   *
   * @throws IOException
   */
  public void init() throws IOException {
    this.recordReaderImpl.restart(this.recordReaderImpl.getStartRow());
  }

  /**
   * @param htable the {@link org.apache.hadoop.hbase.HTableDescriptor} to scan.
   */
  public void setHTable(Table htable) {
    this.recordReaderImpl.setHTable(htable);
  }

  /**
   * @param inputColumns the columns to be placed in {@link Result}.
   */
  public void setInputColumns(final byte [][] inputColumns) {
    this.recordReaderImpl.setInputColumns(inputColumns);
  }

  /**
   * @param startRow the first row in the split
   */
  public void setStartRow(final byte [] startRow) {
    this.recordReaderImpl.setStartRow(startRow);
  }

  /**
   *
   * @param endRow the last row in the split
   */
  public void setEndRow(final byte [] endRow) {
    this.recordReaderImpl.setEndRow(endRow);
  }

  /**
   * @param rowFilter the {@link Filter} to be used.
   */
  public void setRowFilter(Filter rowFilter) {
    this.recordReaderImpl.setRowFilter(rowFilter);
  }

  public void close() {
    this.recordReaderImpl.close();
  }

  /**
   * @return ImmutableBytesWritable
   *
   * @see org.apache.hadoop.mapred.RecordReader#createKey()
   */
  public ImmutableBytesWritable createKey() {
    return this.recordReaderImpl.createKey();
  }

  /**
   * @return RowResult
   *
   * @see org.apache.hadoop.mapred.RecordReader#createValue()
   */
  public Result createValue() {
    return this.recordReaderImpl.createValue();
  }

  public long getPos() {

    // This should be the ordinal tuple in the range;
    // not clear how to calculate...
    return this.recordReaderImpl.getPos();
  }

  public float getProgress() {
    // Depends on the total number of tuples and getPos
    return this.recordReaderImpl.getPos();
  }

  /**
   * @param key HStoreKey as input key.
   * @param value MapWritable as input value
   * @return true if there was more data
   * @throws IOException
   */
  public boolean next(ImmutableBytesWritable key, Result value)
  throws IOException {
    return this.recordReaderImpl.next(key, value);
  }
}