Package org.jgroups

Class Membership

  • public class Membership
extends java.lang.Object
    Represents a membership of a cluster group. Membership is not exposed to clients and is used by JGroups internally. The membership object holds a list of Address objects that are in the same membership. Each unique address can only exist once.
    Since:
    2.0
    Author:
    Bela Ban

    • Field Detail

      • members

        protected final java.util.List<Address> members

    • Constructor Detail

      • Membership

        public Membership()
        Creates a member ship object with zero members

      • Membership

        public Membership​(java.util.Collection<Address> initial_members)
        Creates a Membership with a given initial members. The Address references are copied out of the list, so that the list passed in as parameters is not the same reference as the list that the membership class uses
        Parameters:
        initial_members - a list of members that belong to this membership

      • Membership

        public Membership​(Address... initial_members)

    • Method Detail

      • getMembers

        public java.util.List<Address> getMembers()
        Returns a copy (clone) of the members in this membership. The vector returned is immutable in reference to this object. ie, modifying the vector that is being returned in this method will not modify this membership object.
        Returns:
        a list of members

      • add

        public Membership add​(Address new_member)
        Adds a new member to this membership. If the member already exist (Address.equals(Object) returns true then the member will not be added to the membership

      • add

        public Membership add​(java.util.Collection<Address> v)
        Adds a list of members to this membership
        Parameters:
        v - - a listof addresses
        Throws:
        java.lang.ClassCastException - if v contains objects that don't implement the Address interface

      • remove

        public Membership remove​(Address old_member)
        Removes a member from the membership. If this member doesn't exist, no action will be performed on the existing membership
        Parameters:
        old_member - The member to be removed

      • remove

        public Membership remove​(java.util.Collection<Address> v)
        Removes all the members contained in v from this membership
        Parameters:
        v - a list of all the members to be removed

      • clear

        public Membership clear()
        Removes all the members from this membership

      • set

        public Membership set​(java.util.Collection<Address> v)
        Clears the membership and adds all members of v This method will clear out all the old members of this membership by invoking the Clear method. Then it will add all the all members provided in the vector v
        Parameters:
        v - List containing all the members this membership will contain

      • set

        public Membership set​(Membership m)
        Clears the membership and adds all members of a given membership parameter. Prior to setting membership this method will clear out all the old members of this membership by invoking the clear method.
        Parameters:
        m - a membership containing all the members this membership will contain

      • merge

        public Membership merge​(java.util.Collection<Address> new_mems,
                        java.util.Collection<Address> suspects)
        Merges membership with the new members and removes suspects. The Merge method will remove all the suspects and add in the new members. It will do it in the order 1. Remove suspects 2. Add new members the order is very important to notice.
        Parameters:
        new_mems - - a vector containing a list of members (Address) to be added to this membership
        suspects - - a vector containing a list of members (Address) to be removed from this membership

      • contains

        public boolean contains​(Address member)
        Returns true if the provided member belongs to this membership
        Parameters:
        member -
        Returns:
        true if the member belongs to this membership

      • copy

        public Membership copy()
        Returns a copy of this membership
        Returns:
        an exact copy of this membership

      • size

        public int size()
        Returns the number of addresses in this membership

      • isEmpty

        public boolean isEmpty()

      • elementAt

        public Address elementAt​(int index)
        Returns the component at the specified index
        Parameters:
        index - 0..size()-1
        Throws:
        java.lang.ArrayIndexOutOfBoundsException - If the index is negative or not less than the current size of this object

      • getFirst

        public Address getFirst()

      • isCoord

        public boolean isCoord​(Address mbr)

      • getPrevious

        public Address getPrevious​(Address mbr)
        Returns the members to the left of mbr
        Parameters:
        mbr - The member whose neighbor to the left should be returned
        Returns:
        The neighbor to the left, or null if mbr is null, or the size is less than 2.

      • getNext

        public Address getNext​(Address mbr)
        Returns the members next to mbr.
        Parameters:
        mbr - The member whose neighbor to the right should be returned
        Returns:
        The neighbor to the right, or null if mbr is null, or the size is less than 2.

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object