edu.isi.pegasus.planner.selector.replica
Class Regex

java.lang.Object
  edu.isi.pegasus.planner.selector.replica.Default
      edu.isi.pegasus.planner.selector.replica.Regex

All Implemented Interfaces:

ReplicaSelector

public class Regex
extends Default

A replica selector that allows the user to specific regex expressions that can be used to rank various PFN's returned from the Replica Catalog for a particular LFN. This replica selector selects the highest ranked PFN i.e the replica with the lowest rank value.

The regular expressions are assigned different rank, that determine the order in which the expressions are employed. The rank values for the regex can expressed in user properties using the property. pegasus.selector.replica.regex.rank.[value] The value is an integer value that denotes the rank of an expression with a rank value of 1 being the highest rank.

A thing to note is that before applying any regular expressions on the PFN's, the file URL's that dont match the preferred site are explicitly filtered out.

In order to use the replica selector implemented by this class,

        - the property pegasus.selector.replica.selector must be set to value Regex
 

Version:

$Revision: 2572 $

Author:

Karan Vahi

Nested Class Summary

private class

Regex.Rank A Data class that allows us to compile a regex expression and associate a rank value with it.

Field Summary

private static int	HIGHEST_RANK_VALUE The highest value of rank.
private static int	LOWEST_RANK_VALUE The lowest rank value
private static String	mDescription A short description of the replica selector.
private SortedSet	mSortedRegexSet The Set of regular expressions that orders the regex expressions to use in ascending order.
private static String	PROPERTY_PREFIX The property prefix for all Regex rank property.

Fields inherited from class edu.isi.pegasus.planner.selector.replica.Default

FILE_URL_SCHEME, mLogger, mProps

Fields inherited from interface edu.isi.pegasus.planner.selector.ReplicaSelector

LOCAL_SITE_HANDLE, VERSION

Constructor Summary

Regex(PegasusProperties properties)
The overloaded constructor, that is called by load method.

Method Summary

String	description() Returns a short description of the replica selector.
private SortedSet<Regex.Rank>	getRegexSet(Properties properties) Returns a sorted set containing the various Patterns pre-compiled.
ReplicaCatalogEntry	selectReplica(ReplicaLocation rl, String preferredSite, boolean allowLocalFileURLs) This chooses a location amongst all the locations returned by the replica location service.

Methods inherited from class edu.isi.pegasus.planner.selector.replica.Default

removeFileURL, removeFileURL, selectReplicas

Methods inherited from class java.lang.Object

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

Field Detail

mDescription

private static final String mDescription

A short description of the replica selector.

See Also:

Constant Field Values

PROPERTY_PREFIX

private static final String PROPERTY_PREFIX

The property prefix for all Regex rank property.

See Also:

Constant Field Values

HIGHEST_RANK_VALUE

private static final int HIGHEST_RANK_VALUE

The highest value of rank. In terms of integers , the lower the int higher the rank with 1 being the highest value.

See Also:

Constant Field Values

LOWEST_RANK_VALUE

private static final int LOWEST_RANK_VALUE

The lowest rank value

See Also:

Constant Field Values

mSortedRegexSet

private SortedSet mSortedRegexSet

The Set of regular expressions that orders the regex expressions to use in ascending order.

Constructor Detail

Regex

public Regex(PegasusProperties properties)

The overloaded constructor, that is called by load method.

Parameters:

properties - the PegasusProperties object containing all the properties required by Pegasus.

Method Detail

selectReplica

public ReplicaCatalogEntry selectReplica(ReplicaLocation rl,
                                         String preferredSite,
                                         boolean allowLocalFileURLs)

This chooses a location amongst all the locations returned by the replica location service. If a location is found with re attribute same as the preference pool, it is taken. Else a random location is selected and returned. If more than one location for the lfn is found at the preference pool, then also a random location amongst the ones at the preference pool is selected.

Specified by:

selectReplica in interface ReplicaSelector

Overrides:

selectReplica in class Default

Parameters:

rl - the ReplicaLocation object containing all the pfn's associated with that LFN.

preferredSite - the preffered site for picking up the replicas.

allowLocalFileURLs - indicates whether Replica Selector can select a replica on the local site / submit host.

Returns:

ReplicaCatalogEntry corresponding to the location selected.

See Also:

org.griphyn.cPlanner.classes.ReplicaLocation

description

public String description()

Returns a short description of the replica selector.

Specified by:

description in interface ReplicaSelector

Overrides:

description in class Default

Returns:

string corresponding to the description.

getRegexSet

private SortedSet<Regex.Rank> getRegexSet(Properties properties)

Returns a sorted set containing the various Patterns pre-compiled. The order in the set determines the order in which the patterns are applied on the PFN's

Parameters:

properties - with the key being an integer specifying the rank and value as regex expression to be applied.

Returns:

Sorted