Package com.nimbusds.common.monitor

Class WildCardMetricFilter

java.lang.Object

com.nimbusds.common.monitor.WildCardMetricFilter

All Implemented Interfaces:

com.codahale.metrics.MetricFilter

public class WildCardMetricFilter
extends Object
implements com.codahale.metrics.MetricFilter

Wild card metric filter.

Field Summary

Fields inherited from interface com.codahale.metrics.MetricFilter

ALL

Constructor Summary

Constructors

Constructor	Description
WildCardMetricFilter(List<String> whiteList)	Creates a new wild card metrics filter.

Method Summary

Modifier and Type	Method	Description
static Collection<String>	getMatches(String t, String p)	Simple computation of the longest common extension (LCE) of two given strings, beginning at two given indices.
List<String>	getWhiteList()	Returns the white list.
static int	longestCommonExtension(String t1, int i1, String t2, int i2)	This method takes four parameters: t1 and t2 (the two strings) and two indices i1 and i2 (the index to start at in t1 and t2).
boolean	matches(String name, com.codahale.metrics.Metric metric)
boolean	matchesAny()	Returns true if the filter will match no metric.
boolean	matchesNone()	Returns true if the filter will match any metric.

Methods inherited from class java.lang.Object

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

Constructor Detail

WildCardMetricFilter

public WildCardMetricFilter(List<String> whiteList)

Creates a new wild card metrics filter.

Parameters:

whiteList - The white list entries, null if none.

Method Detail

getWhiteList

public List<String> getWhiteList()

Returns the white list.

Returns:

The white list, null if none.

matchesNone

public boolean matchesNone()

Returns true if the filter will match any metric.

Returns:

true if any metric will be matched, else false.

matchesAny

public boolean matchesAny()

Returns true if the filter will match no metric.

Returns:

true if no metric will be matched, else false.

matches

public boolean matches(String name,
                       com.codahale.metrics.Metric metric)

Specified by:

matches in interface com.codahale.metrics.MetricFilter

longestCommonExtension

public static int longestCommonExtension(String t1,
                                         int i1,
                                         String t2,
                                         int i2)

This method takes four parameters: t1 and t2 (the two strings) and two indices i1 and i2 (the index to start at in t1 and t2). It returns the length of the longest common extension starting at i1 in t1 and at i2 in t2. The method simply iterates over the given strings, starting at the given indices. It compares the characters, counts equal characters and returns that number as soon as the characters differ.

getMatches

public static Collection<String> getMatches(String t,
                                            String p)

Simple computation of the longest common extension (LCE) of two given strings, beginning at two given indices. The LCE computation is part of different algorithms in inexact string matching (Gusfield 1999:196). This simple implementation has a runtime complexity of O(n). Computation in O(1) is possible through constant-time retrieval of Lowest Common Ancestors (LCA) in suffix trees (after linear-time preprocessing). See Gusfield 1999:181 for further reference on constant time LCA retrieval and Gusfield 1999:196 for constant time LCE computation using the LCA.

References: Gusfield, Dan (1999), Algorithms on Strings, Sequences and Trees, Cambridge: University Press.

An implementation of string matching with wildcards, as described in Gusfield 1999:199. When used with a longest common extension computation with suffix trees, it allows for searching a pattern with k wildcards in a text T of length m in O(km) time (Gusfield 1999:199). This implementation uses a simple computation of the longest common extension.