Membership

java.lang.Object
- org.jgroups.Membership

```
public class Membership
extends java.lang.Object
```
Represents a membership of a cluster group. Class 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

Constructor Summary

Constructors
Constructor and Description
`Membership()` Creates a member ship object with zero members
`Membership(java.util.Collection<Address> initial_members)` Creates a Membership with a given initial members.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`Membership`	`add(Address... mbrs)`
`Membership`	`add(Address new_member)` Adds a new member to this membership.
`Membership`	`add(java.util.Collection<Address> v)` Adds a list of members to this membership
`Membership`	`clear()` Removes all the members from this membership
`boolean`	`contains(Address member)` Returns true if the provided member belongs to this membership
`Membership`	`copy()` Returns a copy of this membership
`Address`	`elementAt(int index)` Returns the component at the specified index
`java.util.List<Address>`	`getMembers()` Returns a copy (clone) of the members in this membership.
`Membership`	`merge(java.util.Collection<Address> new_mems, java.util.Collection<Address> suspects)` Merges membership with the new members and removes suspects.
`Membership`	`remove(Address old_member)` Removes an member from the membership.
`Membership`	`remove(java.util.Collection<Address> v)` Removes all the members contained in v from this membership
`Membership`	`retainAll(java.util.Collection<Address> v)`
`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.
`Membership`	`set(Membership m)` Clears the membership and adds all members of a given membership parameter.
`int`	`size()` Returns the number of addresses in this membership
`Membership`	`sort()`
`java.lang.String`	`toString()`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- 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 vector, so that the vector passed in as parameters is not the same reference as the vector that the membership class is using
    
    Parameters:
    
    initial_members - - a list of members that belong to this membership
- 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(Address... mbrs)
```
  - add
```
public Membership add(java.util.Collection<Address> v)
```
    Adds a list of members to this membership
    
    Parameters:
    
    v - - a vector containing Address objects
    
    Throws:
    
    java.lang.ClassCastException - if v contains objects that don't implement the Address interface
  - remove
```
public Membership remove(Address old_member)
```
    Removes an 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
  - retainAll
```
public Membership retainAll(java.util.Collection<Address> v)
```
  - 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 - - a vector 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
  - sort
```
public Membership sort()
```
  - 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
    
    Returns:
    
    the number of addresses in this membership
  - 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 Membership object.
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object

Class Membership

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Membership

Membership

Method Detail

getMembers

add

add

add

remove

remove

retainAll

clear

set

set

merge

contains

sort

copy

size

elementAt

toString