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.HConstants;
23 import org.apache.hadoop.hbase.util.Bytes;
24
25 import org.apache.commons.logging.Log;
26 import org.apache.commons.logging.LogFactory;
27
28 import java.io.DataInput;
29 import java.io.DataOutput;
30 import java.io.IOException;
31 import java.nio.charset.Charset;
32 import java.nio.charset.IllegalCharsetNameException;
33 import java.util.regex.Pattern;
34
35 /**
36 * This comparator is for use with {@link CompareFilter} implementations, such
37 * as {@link RowFilter}, {@link QualifierFilter}, and {@link ValueFilter}, for
38 * filtering based on the value of a given column. Use it to test if a given
39 * regular expression matches a cell value in the column.
40 * <p>
41 * Only EQUAL or NOT_EQUAL comparisons are valid with this comparator.
42 * <p>
43 * For example:
44 * <p>
45 * <pre>
46 * ValueFilter vf = new ValueFilter(CompareOp.EQUAL,
47 * new RegexStringComparator(
48 * // v4 IP address
49 * "(((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3,3}" +
50 * "(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?))(\\/[0-9]+)?" +
51 * "|" +
52 * // v6 IP address
53 * "((([\\dA-Fa-f]{1,4}:){7}[\\dA-Fa-f]{1,4})(:([\\d]{1,3}.)" +
54 * "{3}[\\d]{1,3})?)(\\/[0-9]+)?"));
55 * </pre>
56 */
57 public class RegexStringComparator extends WritableByteArrayComparable {
58
59 private static final Log LOG = LogFactory.getLog(RegexStringComparator.class);
60
61 private Charset charset = Charset.forName(HConstants.UTF8_ENCODING);
62
63 private Pattern pattern;
64
65 /** Nullary constructor for Writable, do not use */
66 public RegexStringComparator() { }
67
68 /**
69 * Constructor
70 * @param expr a valid regular expression
71 */
72 public RegexStringComparator(String expr) {
73 super(Bytes.toBytes(expr));
74 this.pattern = Pattern.compile(expr, Pattern.DOTALL);
75 }
76
77 /**
78 * Specifies the {@link Charset} to use to convert the row key to a String.
79 * <p>
80 * The row key needs to be converted to a String in order to be matched
81 * against the regular expression. This method controls which charset is
82 * used to do this conversion.
83 * <p>
84 * If the row key is made of arbitrary bytes, the charset {@code ISO-8859-1}
85 * is recommended.
86 * @param charset The charset to use.
87 */
88 public void setCharset(final Charset charset) {
89 this.charset = charset;
90 }
91
92 @Override
93 public int compareTo(byte[] value) {
94 // Use find() for subsequence match instead of matches() (full sequence
95 // match) to adhere to the principle of least surprise.
96 return pattern.matcher(new String(value, charset)).find() ? 0 : 1;
97 }
98
99 @Override
100 public void readFields(DataInput in) throws IOException {
101 final String expr = in.readUTF();
102 this.value = Bytes.toBytes(expr);
103 this.pattern = Pattern.compile(expr);
104 final String charset = in.readUTF();
105 if (charset.length() > 0) {
106 try {
107 this.charset = Charset.forName(charset);
108 } catch (IllegalCharsetNameException e) {
109 LOG.error("invalid charset", e);
110 }
111 }
112 }
113
114 @Override
115 public void write(DataOutput out) throws IOException {
116 out.writeUTF(pattern.toString());
117 out.writeUTF(charset.name());
118 }
119
120 }