org.hbase.async

Class RegexStringComparator

java.lang.Object

org.hbase.async.FilterComparator

org.hbase.async.RegexStringComparator

public final class RegexStringComparator
extends FilterComparator

A regular expression comparator used in comparison filters such as RowFilter, QualifierFilter, and ValueFilter.

Don't use an expensive regular expression, because Java's implementation uses backtracking and matching will happen on the server side, potentially on many many row keys, columns, or values. See Regular Expression Matching Can Be Simple And Fast for more details on regular expression performance (or lack thereof) and what "backtracking" means.

This means you need to be careful about using regular expressions supplied by users as that would allow them to easily DDoS HBase by sending prohibitively expensive regexps that would consume all CPU cycles and cause the entire HBase node to time out.

Only EQUAL and NOT_EQUAL comparisons are valid with this comparator.

Since:

1.6

Constructor Summary

Constructors

Constructor and Description
RegexStringComparator(String expr) Create a regular expression filter with the specified regular expression.
RegexStringComparator(String expr, Charset charset) Create a regular expression filter with the specified regular expression and charset.

Method Summary

Methods

Modifier and Type	Method and Description
Charset	charset()
String	expression()
String	toString()

Methods inherited from class org.hbase.async.FilterComparator

toProtobuf

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

RegexStringComparator

public RegexStringComparator(String expr)

Create a regular expression filter with the specified regular expression.

This is equivalent to calling RegexStringComparator(String, Charset) with the UTF-8 charset in argument.

Parameters:

expr - The regular expression with which to filter.

RegexStringComparator

public RegexStringComparator(String expr,
                     Charset charset)

Create a regular expression filter with the specified regular expression and charset.

Parameters:

expr - The regular expression with which to filter.

Method Detail

expression

public String expression()

charset

public Charset charset()

toString

public String toString()

Overrides:

toString in class Object