Package edu.isi.pegasus.planner.selector.replica

Class 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:
    $Revision$
    Author:
    Karan Vahi

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      private static class  Regex.Rank
      A Data class that allows us to compile a regex expression and associate a rank value with it.

    • Constructor Summary

      Constructors 
      Constructor Description
      Regex​(edu.isi.pegasus.planner.common.PegasusProperties properties)
      The overloaded constructor, that is called by load method.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      java.lang.String description()
      Returns a short description of the replica selector.
      private java.util.SortedSet<Regex.Rank> getRegexSet​(java.util.Properties properties)
      Returns a sorted set containing the various Patterns pre-compiled.
      edu.isi.pegasus.planner.classes.ReplicaLocation selectAndOrderReplicas​(edu.isi.pegasus.planner.classes.ReplicaLocation rl, java.lang.String preferredSite, boolean allowLocalFileURLs)
      This orders amongst all the valid locations returned by the Replica Mechanism.
      edu.isi.pegasus.planner.catalog.replica.ReplicaCatalogEntry selectReplica​(edu.isi.pegasus.planner.classes.ReplicaLocation candidates, java.lang.String preferredSite, boolean allowLocalFileURLs)
      This chooses a location amongst all the locations returned by the replica location service.

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • mDescription

        private static final java.lang.String mDescription
        A short description of the replica selector.
        See Also:
        Constant Field Values

      • PROPERTY_PREFIX

        private static final java.lang.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 java.util.SortedSet<Regex.Rank> mSortedRegexSet
        The Set of regular expressions that orders the regex expressions to use in ascending order.

    • Constructor Detail

      • Regex

        public Regex​(edu.isi.pegasus.planner.common.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

      • selectAndOrderReplicas

        public edu.isi.pegasus.planner.classes.ReplicaLocation selectAndOrderReplicas​(edu.isi.pegasus.planner.classes.ReplicaLocation rl,
                                                                              java.lang.String preferredSite,
                                                                              boolean allowLocalFileURLs)
        This orders amongst all the valid locations returned by the Replica Mechanism. The following ordering mechanism is employed

        - based on the ranks specified in the properties file.

        Specified by:
        selectAndOrderReplicas in interface ReplicaSelector
        Overrides:
        selectAndOrderReplicas 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:
        ReplicaLocation corresponding to the replicas selected

      • selectReplica

        public edu.isi.pegasus.planner.catalog.replica.ReplicaCatalogEntry selectReplica​(edu.isi.pegasus.planner.classes.ReplicaLocation candidates,
                                                                                 java.lang.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:
        candidates - 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:
        ReplicaLocation

      • description

        public java.lang.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 java.util.SortedSet<Regex.Rank> getRegexSet​(java.util.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:
        SortedSet of Rank objects