Delete

/*
 *
 * 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.client;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.KeyValue;
import org.apache.hadoop.hbase.util.Bytes;

/**
 * Used to perform Delete operations on a single row.
 * <p>
 * To delete an entire row, instantiate a Delete object with the row
 * to delete.  To further define the scope of what to delete, perform
 * additional methods as outlined below.
 * <p>
 * To delete specific families, execute {@link #deleteFamily(byte[]) deleteFamily}
 * for each family to delete.
 * <p>
 * To delete multiple versions of specific columns, execute
 * {@link #deleteColumns(byte[], byte[]) deleteColumns}
 * for each column to delete.
 * <p>
 * To delete specific versions of specific columns, execute
 * {@link #deleteColumn(byte[], byte[], long) deleteColumn}
 * for each column version to delete.
 * <p>
 * Specifying timestamps, deleteFamily and deleteColumns will delete all
 * versions with a timestamp less than or equal to that passed.  If no
 * timestamp is specified, an entry is added with a timestamp of 'now'
 * where 'now' is the servers's System.currentTimeMillis().
 * Specifying a timestamp to the deleteColumn method will
 * delete versions only with a timestamp equal to that specified.
 * If no timestamp is passed to deleteColumn, internally, it figures the
 * most recent cell's timestamp and adds a delete at that timestamp; i.e.
 * it deletes the most recently added cell.
 * <p>The timestamp passed to the constructor is used ONLY for delete of
 * rows.  For anything less -- a deleteColumn, deleteColumns or
 * deleteFamily -- then you need to use the method overrides that take a
 * timestamp.  The constructor timestamp is not referenced.
 */
@InterfaceAudience.Public
@InterfaceStability.Stable
public class Delete extends Mutation implements Comparable<Row> {
  /**
   * Create a Delete operation for the specified row.
   * <p>
   * If no further operations are done, this will delete everything
   * associated with the specified row (all versions of all columns in all
   * families).
   * @param row row key
   */
  public Delete(byte [] row) {
    this(row, HConstants.LATEST_TIMESTAMP);
  }

  /**
   * Create a Delete operation for the specified row and timestamp.<p>
   *
   * If no further operations are done, this will delete all columns in all
   * families of the specified row with a timestamp less than or equal to the
   * specified timestamp.<p>
   *
   * This timestamp is ONLY used for a delete row operation.  If specifying
   * families or columns, you must specify each timestamp individually.
   * @param row row key
   * @param timestamp maximum version timestamp (only for delete row)
   */
  public Delete(byte [] row, long timestamp) {
    this(row, 0, row.length, timestamp);
  }

  /**
   * Create a Delete operation for the specified row and timestamp.<p>
   *
   * If no further operations are done, this will delete all columns in all
   * families of the specified row with a timestamp less than or equal to the
   * specified timestamp.<p>
   *
   * This timestamp is ONLY used for a delete row operation.  If specifying
   * families or columns, you must specify each timestamp individually.
   * @param rowArray We make a local copy of this passed in row.
   * @param rowOffset
   * @param rowLength
   * @param ts maximum version timestamp (only for delete row)
   */
  public Delete(final byte [] rowArray, final int rowOffset, final int rowLength, long ts) {
    checkRow(rowArray, rowOffset, rowLength);
    this.row = Bytes.copy(rowArray, rowOffset, rowLength);
    this.ts = ts;
  }

  /**
   * @param d Delete to clone.
   */
  public Delete(final Delete d) {
    this.row = d.getRow();
    this.ts = d.getTimeStamp();
    this.familyMap.putAll(d.getFamilyMap());
    this.durability = d.durability;
  }

  /**
   * Advanced use only.
   * Add an existing delete marker to this Delete object.
   * @param kv An existing KeyValue of type "delete".
   * @return this for invocation chaining
   * @throws IOException
   */
  @SuppressWarnings("unchecked")
  public Delete addDeleteMarker(KeyValue kv) throws IOException {
    // TODO: Deprecate and rename 'add' so it matches how we add KVs to Puts.
    if (!kv.isDelete()) {
      throw new IOException("The recently added KeyValue is not of type "
          + "delete. Rowkey: " + Bytes.toStringBinary(this.row));
    }
    if (Bytes.compareTo(this.row, 0, row.length, kv.getBuffer(),
        kv.getRowOffset(), kv.getRowLength()) != 0) {
      throw new WrongRowIOException("The row in " + kv.toString() +
        " doesn't match the original one " +  Bytes.toStringBinary(this.row));
    }
    byte [] family = kv.getFamily();
    List<? extends Cell> list = familyMap.get(family);
    if (list == null) {
      list = new ArrayList<Cell>();
    }
    // Cast so explicit list type rather than ? extends Cell.  Help the compiler out.  See
    // http://stackoverflow.com/questions/6474784/java-using-generics-with-lists-and-interfaces
    ((List<KeyValue>)list).add(kv);
    familyMap.put(family, list);
    return this;
  }

  /**
   * Delete all versions of all columns of the specified family.
   * <p>
   * Overrides previous calls to deleteColumn and deleteColumns for the
   * specified family.
   * @param family family name
   * @return this for invocation chaining
   */
  public Delete deleteFamily(byte [] family) {
    this.deleteFamily(family, HConstants.LATEST_TIMESTAMP);
    return this;
  }

  /**
   * Delete all columns of the specified family with a timestamp less than
   * or equal to the specified timestamp.
   * <p>
   * Overrides previous calls to deleteColumn and deleteColumns for the
   * specified family.
   * @param family family name
   * @param timestamp maximum version timestamp
   * @return this for invocation chaining
   */
  @SuppressWarnings("unchecked")
  public Delete deleteFamily(byte [] family, long timestamp) {
    List<? extends Cell> list = familyMap.get(family);
    if(list == null) {
      list = new ArrayList<Cell>();
    } else if(!list.isEmpty()) {
      list.clear();
    }
    KeyValue kv = new KeyValue(row, family, null, timestamp, KeyValue.Type.DeleteFamily);
    // Cast so explicit list type rather than ? extends Cell.  Help the compiler out.  See
    // http://stackoverflow.com/questions/6474784/java-using-generics-with-lists-and-interfaces
    ((List<KeyValue>)list).add(kv);
    familyMap.put(family, list);
    return this;
  }

  /**
   * Delete all versions of the specified column.
   * @param family family name
   * @param qualifier column qualifier
   * @return this for invocation chaining
   */
  public Delete deleteColumns(byte [] family, byte [] qualifier) {
    this.deleteColumns(family, qualifier, HConstants.LATEST_TIMESTAMP);
    return this;
  }

  /**
   * Delete all versions of the specified column with a timestamp less than
   * or equal to the specified timestamp.
   * @param family family name
   * @param qualifier column qualifier
   * @param timestamp maximum version timestamp
   * @return this for invocation chaining
   */
  @SuppressWarnings("unchecked")
  public Delete deleteColumns(byte [] family, byte [] qualifier, long timestamp) {
    List<? extends Cell> list = familyMap.get(family);
    if (list == null) {
      list = new ArrayList<Cell>();
    }
    // Cast so explicit list type rather than ? extends Cell.  Help the compiler out.  See
    // http://stackoverflow.com/questions/6474784/java-using-generics-with-lists-and-interfaces
    ((List<KeyValue>)list).add(new KeyValue(this.row, family, qualifier, timestamp,
        KeyValue.Type.DeleteColumn));
    familyMap.put(family, list);
    return this;
  }

  /**
   * Delete the latest version of the specified column.
   * This is an expensive call in that on the server-side, it first does a
   * get to find the latest versions timestamp.  Then it adds a delete using
   * the fetched cells timestamp.
   * @param family family name
   * @param qualifier column qualifier
   * @return this for invocation chaining
   */
  public Delete deleteColumn(byte [] family, byte [] qualifier) {
    this.deleteColumn(family, qualifier, HConstants.LATEST_TIMESTAMP);
    return this;
  }

  /**
   * Delete the specified version of the specified column.
   * @param family family name
   * @param qualifier column qualifier
   * @param timestamp version timestamp
   * @return this for invocation chaining
   */
  @SuppressWarnings("unchecked")
  public Delete deleteColumn(byte [] family, byte [] qualifier, long timestamp) {
    List<? extends Cell> list = familyMap.get(family);
    if(list == null) {
      list = new ArrayList<Cell>();
    }
    // Cast so explicit list type rather than ? extends Cell.  Help the compiler out.  See
    // http://stackoverflow.com/questions/6474784/java-using-generics-with-lists-and-interfaces
    KeyValue kv = new KeyValue(this.row, family, qualifier, timestamp, KeyValue.Type.Delete);
    ((List<KeyValue>)list).add(kv);
    familyMap.put(family, list);
    return this;
  }

  /**
   * Set the timestamp of the delete.
   *
   * @param timestamp
   */
  public void setTimestamp(long timestamp) {
    this.ts = timestamp;
  }

  @Override
  public Map<String, Object> toMap(int maxCols) {
    // we start with the fingerprint map and build on top of it.
    Map<String, Object> map = super.toMap(maxCols);
    // why is put not doing this?
    map.put("ts", this.ts);
    return map;
  }
}