1 /**
2 * Copyright 2007 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 package org.apache.hadoop.hbase.mapreduce;
21
22 import java.io.DataInput;
23 import java.io.DataOutput;
24 import java.io.IOException;
25
26 import org.apache.hadoop.hbase.HConstants;
27 import org.apache.hadoop.hbase.util.Bytes;
28 import org.apache.hadoop.io.Writable;
29 import org.apache.hadoop.mapreduce.InputSplit;
30
31 /**
32 * A table split corresponds to a key range (low, high). All references to row
33 * below refer to the key of the row.
34 */
35 public class TableSplit extends InputSplit
36 implements Writable, Comparable<TableSplit> {
37
38 private byte [] tableName;
39 private byte [] startRow;
40 private byte [] endRow;
41 private String regionLocation;
42
43 /** Default constructor. */
44 public TableSplit() {
45 this(HConstants.EMPTY_BYTE_ARRAY, HConstants.EMPTY_BYTE_ARRAY,
46 HConstants.EMPTY_BYTE_ARRAY, "");
47 }
48
49 /**
50 * Creates a new instance while assigning all variables.
51 *
52 * @param tableName The name of the current table.
53 * @param startRow The start row of the split.
54 * @param endRow The end row of the split.
55 * @param location The location of the region.
56 */
57 public TableSplit(byte [] tableName, byte [] startRow, byte [] endRow,
58 final String location) {
59 this.tableName = tableName;
60 this.startRow = startRow;
61 this.endRow = endRow;
62 this.regionLocation = location;
63 }
64
65 /**
66 * Returns the table name.
67 *
68 * @return The table name.
69 */
70 public byte [] getTableName() {
71 return tableName;
72 }
73
74 /**
75 * Returns the start row.
76 *
77 * @return The start row.
78 */
79 public byte [] getStartRow() {
80 return startRow;
81 }
82
83 /**
84 * Returns the end row.
85 *
86 * @return The end row.
87 */
88 public byte [] getEndRow() {
89 return endRow;
90 }
91
92 /**
93 * Returns the region location.
94 *
95 * @return The region's location.
96 */
97 public String getRegionLocation() {
98 return regionLocation;
99 }
100
101 /**
102 * Returns the region's location as an array.
103 *
104 * @return The array containing the region location.
105 * @see org.apache.hadoop.mapreduce.InputSplit#getLocations()
106 */
107 @Override
108 public String[] getLocations() {
109 return new String[] {regionLocation};
110 }
111
112 /**
113 * Returns the length of the split.
114 *
115 * @return The length of the split.
116 * @see org.apache.hadoop.mapreduce.InputSplit#getLength()
117 */
118 @Override
119 public long getLength() {
120 // Not clear how to obtain this... seems to be used only for sorting splits
121 return 0;
122 }
123
124 /**
125 * Reads the values of each field.
126 *
127 * @param in The input to read from.
128 * @throws IOException When reading the input fails.
129 */
130 @Override
131 public void readFields(DataInput in) throws IOException {
132 tableName = Bytes.readByteArray(in);
133 startRow = Bytes.readByteArray(in);
134 endRow = Bytes.readByteArray(in);
135 regionLocation = Bytes.toString(Bytes.readByteArray(in));
136 }
137
138 /**
139 * Writes the field values to the output.
140 *
141 * @param out The output to write to.
142 * @throws IOException When writing the values to the output fails.
143 */
144 @Override
145 public void write(DataOutput out) throws IOException {
146 Bytes.writeByteArray(out, tableName);
147 Bytes.writeByteArray(out, startRow);
148 Bytes.writeByteArray(out, endRow);
149 Bytes.writeByteArray(out, Bytes.toBytes(regionLocation));
150 }
151
152 /**
153 * Returns the details about this instance as a string.
154 *
155 * @return The values of this instance as a string.
156 * @see java.lang.Object#toString()
157 */
158 @Override
159 public String toString() {
160 return regionLocation + ":" +
161 Bytes.toStringBinary(startRow) + "," + Bytes.toStringBinary(endRow);
162 }
163
164 /**
165 * Compares this split against the given one.
166 *
167 * @param split The split to compare to.
168 * @return The result of the comparison.
169 * @see java.lang.Comparable#compareTo(java.lang.Object)
170 */
171 @Override
172 public int compareTo(TableSplit split) {
173 return Bytes.compareTo(getStartRow(), split.getStartRow());
174 }
175
176 @Override
177 public boolean equals(Object o) {
178 if (o == null || !(o instanceof TableSplit)) {
179 return false;
180 }
181 return Bytes.equals(tableName, ((TableSplit)o).tableName) &&
182 Bytes.equals(startRow, ((TableSplit)o).startRow) &&
183 Bytes.equals(endRow, ((TableSplit)o).endRow) &&
184 regionLocation.equals(((TableSplit)o).regionLocation);
185 }
186 }