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 package org.apache.hadoop.hbase.filter;
21
22 import org.apache.hadoop.hbase.util.Bytes;
23
24 import java.io.DataInput;
25 import java.io.DataOutput;
26 import java.io.IOException;
27
28 /**
29 * This comparator is for use with ColumnValueFilter, for filtering based on
30 * the value of a given column. Use it to test if a given substring appears
31 * in a cell value in the column. The comparison is case insensitive.
32 * <p>
33 * Only EQUAL or NOT_EQUAL tests are valid with this comparator.
34 * <p>
35 * For example:
36 * <p>
37 * <pre>
38 * ColumnValueFilter cvf =
39 * new ColumnValueFilter("col", ColumnValueFilter.CompareOp.EQUAL,
40 * new SubstringComparator("substr"));
41 * </pre>
42 */
43 public class SubstringComparator extends WritableByteArrayComparable {
44
45 private String substr;
46
47 /** Nullary constructor for Writable, do not use */
48 public SubstringComparator() {
49 super();
50 }
51
52 /**
53 * Constructor
54 * @param substr the substring
55 */
56 public SubstringComparator(String substr) {
57 super(Bytes.toBytes(substr.toLowerCase()));
58 this.substr = substr.toLowerCase();
59 }
60
61 @Override
62 public byte[] getValue() {
63 return Bytes.toBytes(substr);
64 }
65
66 @Override
67 public int compareTo(byte[] value) {
68 return Bytes.toString(value).toLowerCase().contains(substr) ? 0 : 1;
69 }
70
71 @Override
72 public void readFields(DataInput in) throws IOException {
73 String substr = in.readUTF();
74 this.value = Bytes.toBytes(substr);
75 this.substr = substr;
76 }
77
78 @Override
79 public void write(DataOutput out) throws IOException {
80 out.writeUTF(substr);
81 }
82
83 }