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1   /*
2    * Copyright 2010 The Apache Software Foundation
3    *
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *     http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing, software
15   * distributed under the License is distributed on an "AS IS" BASIS,
16   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17   * See the License for the specific language governing permissions and
18   * limitations under the License.
19   */
20  
21  package org.apache.hadoop.hbase.client;
22  
23  import org.apache.hadoop.hbase.HConstants;
24  import org.apache.hadoop.hbase.KeyValue;
25  import org.apache.hadoop.hbase.util.Bytes;
26  import org.apache.hadoop.io.Writable;
27  
28  import java.io.DataInput;
29  import java.io.DataOutput;
30  import java.io.IOException;
31  import java.util.ArrayList;
32  import java.util.List;
33  import java.util.Map;
34  
35  /**
36   * Used to perform Delete operations on a single row.
37   * <p>
38   * To delete an entire row, instantiate a Delete object with the row
39   * to delete.  To further define the scope of what to delete, perform
40   * additional methods as outlined below.
41   * <p>
42   * To delete specific families, execute {@link #deleteFamily(byte[]) deleteFamily}
43   * for each family to delete.
44   * <p>
45   * To delete multiple versions of specific columns, execute
46   * {@link #deleteColumns(byte[], byte[]) deleteColumns}
47   * for each column to delete.
48   * <p>
49   * To delete specific versions of specific columns, execute
50   * {@link #deleteColumn(byte[], byte[], long) deleteColumn}
51   * for each column version to delete.
52   * <p>
53   * Specifying timestamps, deleteFamily and deleteColumns will delete all
54   * versions with a timestamp less than or equal to that passed.  If no
55   * timestamp is specified, an entry is added with a timestamp of 'now'
56   * where 'now' is the servers's System.currentTimeMillis().
57   * Specifying a timestamp to the deleteColumn method will
58   * delete versions only with a timestamp equal to that specified.
59   * If no timestamp is passed to deleteColumn, internally, it figures the
60   * most recent cell's timestamp and adds a delete at that timestamp; i.e.
61   * it deletes the most recently added cell.
62   * <p>The timestamp passed to the constructor is used ONLY for delete of
63   * rows.  For anything less -- a deleteColumn, deleteColumns or
64   * deleteFamily -- then you need to use the method overrides that take a
65   * timestamp.  The constructor timestamp is not referenced.
66   */
67  public class Delete extends Mutation
68    implements Writable, Row, Comparable<Row> {
69    private static final byte DELETE_VERSION = (byte)3;
70  
71    /** Constructor for Writable.  DO NOT USE */
72    public Delete() {
73      this((byte [])null);
74    }
75  
76    /**
77     * Create a Delete operation for the specified row.
78     * <p>
79     * If no further operations are done, this will delete everything
80     * associated with the specified row (all versions of all columns in all
81     * families).
82     * @param row row key
83     */
84    public Delete(byte [] row) {
85      this(row, HConstants.LATEST_TIMESTAMP, null);
86    }
87  
88    /**
89     * Create a Delete operation for the specified row and timestamp, using
90     * an optional row lock.<p>
91     *
92     * If no further operations are done, this will delete all columns in all
93     * families of the specified row with a timestamp less than or equal to the
94     * specified timestamp.<p>
95     *
96     * This timestamp is ONLY used for a delete row operation.  If specifying
97     * families or columns, you must specify each timestamp individually.
98     * @param row row key
99     * @param timestamp maximum version timestamp (only for delete row)
100    * @param rowLock previously acquired row lock, or null
101    */
102   public Delete(byte [] row, long timestamp, RowLock rowLock) {
103     this.row = row;
104     this.ts = timestamp;
105     if (rowLock != null) {
106     	this.lockId = rowLock.getLockId();
107     }
108   }
109 
110   /**
111    * @param d Delete to clone.
112    */
113   public Delete(final Delete d) {
114     this.row = d.getRow();
115     this.ts = d.getTimeStamp();
116     this.lockId = d.getLockId();
117     this.familyMap.putAll(d.getFamilyMap());
118     this.writeToWAL = d.writeToWAL;
119   }
120 
121   /**
122    * Delete all versions of all columns of the specified family.
123    * <p>
124    * Overrides previous calls to deleteColumn and deleteColumns for the
125    * specified family.
126    * @param family family name
127    * @return this for invocation chaining
128    */
129   public Delete deleteFamily(byte [] family) {
130     this.deleteFamily(family, HConstants.LATEST_TIMESTAMP);
131     return this;
132   }
133 
134   /**
135    * Delete all columns of the specified family with a timestamp less than
136    * or equal to the specified timestamp.
137    * <p>
138    * Overrides previous calls to deleteColumn and deleteColumns for the
139    * specified family.
140    * @param family family name
141    * @param timestamp maximum version timestamp
142    * @return this for invocation chaining
143    */
144   public Delete deleteFamily(byte [] family, long timestamp) {
145     List<KeyValue> list = familyMap.get(family);
146     if(list == null) {
147       list = new ArrayList<KeyValue>();
148     } else if(!list.isEmpty()) {
149       list.clear();
150     }
151     list.add(new KeyValue(row, family, null, timestamp, KeyValue.Type.DeleteFamily));
152     familyMap.put(family, list);
153     return this;
154   }
155 
156   /**
157    * Delete all versions of the specified column.
158    * @param family family name
159    * @param qualifier column qualifier
160    * @return this for invocation chaining
161    */
162   public Delete deleteColumns(byte [] family, byte [] qualifier) {
163     this.deleteColumns(family, qualifier, HConstants.LATEST_TIMESTAMP);
164     return this;
165   }
166 
167   /**
168    * Delete all versions of the specified column with a timestamp less than
169    * or equal to the specified timestamp.
170    * @param family family name
171    * @param qualifier column qualifier
172    * @param timestamp maximum version timestamp
173    * @return this for invocation chaining
174    */
175   public Delete deleteColumns(byte [] family, byte [] qualifier, long timestamp) {
176     List<KeyValue> list = familyMap.get(family);
177     if (list == null) {
178       list = new ArrayList<KeyValue>();
179     }
180     list.add(new KeyValue(this.row, family, qualifier, timestamp,
181       KeyValue.Type.DeleteColumn));
182     familyMap.put(family, list);
183     return this;
184   }
185 
186   /**
187    * Delete the latest version of the specified column.
188    * This is an expensive call in that on the server-side, it first does a
189    * get to find the latest versions timestamp.  Then it adds a delete using
190    * the fetched cells timestamp.
191    * @param family family name
192    * @param qualifier column qualifier
193    * @return this for invocation chaining
194    */
195   public Delete deleteColumn(byte [] family, byte [] qualifier) {
196     this.deleteColumn(family, qualifier, HConstants.LATEST_TIMESTAMP);
197     return this;
198   }
199 
200   /**
201    * Delete the specified version of the specified column.
202    * @param family family name
203    * @param qualifier column qualifier
204    * @param timestamp version timestamp
205    * @return this for invocation chaining
206    */
207   public Delete deleteColumn(byte [] family, byte [] qualifier, long timestamp) {
208     List<KeyValue> list = familyMap.get(family);
209     if(list == null) {
210       list = new ArrayList<KeyValue>();
211     }
212     list.add(new KeyValue(
213         this.row, family, qualifier, timestamp, KeyValue.Type.Delete));
214     familyMap.put(family, list);
215     return this;
216   }
217 
218   /**
219    * Set the timestamp of the delete.
220    * 
221    * @param timestamp
222    */
223   public void setTimestamp(long timestamp) {
224     this.ts = timestamp;
225   }
226 
227   @Override
228   public Map<String, Object> toMap(int maxCols) {
229     // we start with the fingerprint map and build on top of it.
230     Map<String, Object> map = super.toMap(maxCols);
231     // why is put not doing this?
232     map.put("ts", this.ts);
233     return map;
234   }
235 
236   //Writable
237   public void readFields(final DataInput in) throws IOException {
238     int version = in.readByte();
239     if (version > DELETE_VERSION) {
240       throw new IOException("version not supported");
241     }
242     this.row = Bytes.readByteArray(in);
243     this.ts = in.readLong();
244     this.lockId = in.readLong();
245     if (version > 2) {
246       this.writeToWAL = in.readBoolean();
247     }
248     this.familyMap.clear();
249     int numFamilies = in.readInt();
250     for(int i=0;i<numFamilies;i++) {
251       byte [] family = Bytes.readByteArray(in);
252       int numColumns = in.readInt();
253       List<KeyValue> list = new ArrayList<KeyValue>(numColumns);
254       for(int j=0;j<numColumns;j++) {
255     	KeyValue kv = new KeyValue();
256     	kv.readFields(in);
257     	list.add(kv);
258       }
259       this.familyMap.put(family, list);
260     }
261     if (version > 1) {
262       readAttributes(in);
263     }
264   }
265 
266   public void write(final DataOutput out) throws IOException {
267     out.writeByte(DELETE_VERSION);
268     Bytes.writeByteArray(out, this.row);
269     out.writeLong(this.ts);
270     out.writeLong(this.lockId);
271     out.writeBoolean(this.writeToWAL);
272     out.writeInt(familyMap.size());
273     for(Map.Entry<byte [], List<KeyValue>> entry : familyMap.entrySet()) {
274       Bytes.writeByteArray(out, entry.getKey());
275       List<KeyValue> list = entry.getValue();
276       out.writeInt(list.size());
277       for(KeyValue kv : list) {
278         kv.write(out);
279       }
280     }
281     writeAttributes(out);
282   }
283 }