View (JGroups 2.12.3.Final API)

java.lang.Object
- org.jgroups.View

All Implemented Interfaces:

Externalizable, Serializable, Cloneable, Streamable

Direct Known Subclasses:

MergeView
```
public class View
extends Object
implements Externalizable, Cloneable, Streamable
```
A view is a local representation of the current membership of a group. Only one view is installed in a channel at a time. Views contain the address of its creator, an ID and a list of member addresses. These addresses are ordered, and the first address is always the coordinator of the view. This way, each member of the group knows who the new coordinator will be if the current one crashes or leaves the group. The views are sent between members using the VIEW_CHANGE event

Author:

Bela Ban

See Also:

Serialized Form

Field Summary

Fields
Modifier and Type	Field and Description
`protected Vector<Address>`	`members` A list containing all the members of the view This list is always ordered, with the coordinator being the first member.
`protected Map<String,Object>`	`payload` Deprecated.
`protected ViewId`	`vid`

Constructor Summary

Constructors
Constructor and Description
`View()` creates an empty view, should not be used
`View(Address creator, long id, Collection<Address> members)` Creates a new view
`View(ViewId vid, Collection<Address> members)`
`View(ViewId vid, Vector<Address> members)` Creates a new view

Method Summary

All Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`void`	`addPayload(String key, Object value)` Deprecated. Will be removed in 3.0
`Object`	`clone()` creates a copy of this view
`boolean`	`containsMember(Address mbr)` returns true, if this view contains a certain member
`View`	`copy()`
`boolean`	`equals(Object obj)`
`Address`	`getCreator()` returns the creator of this view if this view was created with the empty constructur, null will be returned
`Vector<Address>`	`getMembers()` Returns a reference to the List of members (ordered) Do NOT change this list, hence your will invalidate the view Make a copy if you have to modify it.
`Object`	`getPayload(String key)` Deprecated. Will be removed in 3.0
`ViewId`	`getVid()` returns the view ID of this view if this view was created with the empty constructur, null will be returned
`ViewId`	`getViewId()`
`int`	`hashCode()`
`String`	`printDetails()` debug only
`void`	`readExternal(ObjectInput in)`
`void`	`readFrom(DataInputStream in)` Read the state of the current object (including superclasses) from instream Note that the input stream must not be closed
`Object`	`removePayload(String key)` Deprecated. Will be removed in 3.0
`int`	`serializedSize()`
`int`	`size()` returns the number of members in this view
`String`	`toString()`
`void`	`writeExternal(ObjectOutput out)`
`void`	`writeTo(DataOutputStream out)` Write the entire state of the current object (including superclasses) to outstream.

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

- Field Detail
  - vid
```
protected ViewId vid
```
  - members
```
protected Vector<Address> members
```
    A list containing all the members of the view This list is always ordered, with the coordinator being the first member. the second member will be the new coordinator if the current one disappears or leaves the group.
  - payload
```
@Deprecated
protected Map<String,Object> payload
```
    Deprecated.
- Constructor Detail
  - View
```
public View()
```
    creates an empty view, should not be used
  - View
```
public View(ViewId vid,
            Vector<Address> members)
```
    Creates a new view
    
    Parameters:
    
    vid - The view id of this view (can not be null)
    
    members - Contains a list of all the members in the view, can be empty but not null.
  - View
```
public View(ViewId vid,
            Collection<Address> members)
```
  - View
```
public View(Address creator,
            long id,
            Collection<Address> members)
```
    Creates a new view
    
    Parameters:
    
    creator - The creator of this view (can not be null)
    
    id - The lamport timestamp of this view
    
    members - Contains a list of all the members in the view, can be empty but not null.
- Method Detail
  - getVid
```
public ViewId getVid()
```
    returns the view ID of this view if this view was created with the empty constructur, null will be returned
    
    Returns:
    
    the view ID of this view
  - getViewId
```
public ViewId getViewId()
```
  - getCreator
```
public Address getCreator()
```
    returns the creator of this view if this view was created with the empty constructur, null will be returned
    
    Returns:
    
    the creator of this view in form of an Address object
  - getMembers
```
public Vector<Address> getMembers()
```
    Returns a reference to the List of members (ordered) Do NOT change this list, hence your will invalidate the view Make a copy if you have to modify it.
    
    Returns:
    
    a reference to the ordered list of members in this view
  - containsMember
```
public boolean containsMember(Address mbr)
```
    returns true, if this view contains a certain member
    
    Parameters:
    
    mbr - - the address of the member,
    
    Returns:
    
    true if this view contains the member, false if it doesn't if the argument mbr is null, this operation returns false
  - equals
```
public boolean equals(Object obj)
```
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - size
```
public int size()
```
    returns the number of members in this view
    
    Returns:
    
    the number of members in this view 0..n
  - copy
```
public View copy()
```
  - clone
```
public Object clone()
```
    creates a copy of this view
    
    Overrides:
    
    clone in class Object
    
    Returns:
    
    a copy of this view
  - printDetails
```
public String printDetails()
```
    debug only
  - addPayload
```
public void addPayload(String key,
                       Object value)
```
    Deprecated. Will be removed in 3.0
    
    Adds a key and value to the view. Since the payloads will be shipped around *with* the view, so the keys and values need to be serializable. Note that the total serialized size of all keys and values cannot exceed 65000 bytes !
    
    Parameters:
    
    key -
    
    value -
  - removePayload
```
public Object removePayload(String key)
```
    Deprecated. Will be removed in 3.0
    
    Parameters:
    
    key -
    
    Returns:
  - getPayload
```
public Object getPayload(String key)
```
    Deprecated. Will be removed in 3.0
    
    Parameters:
    
    key -
    
    Returns:
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - writeExternal
```
public void writeExternal(ObjectOutput out)
                   throws IOException
```
    Specified by:
    
    writeExternal in interface Externalizable
    
    Throws:
    
    IOException
  - readExternal
```
public void readExternal(ObjectInput in)
                  throws IOException,
                         ClassNotFoundException
```
    Specified by:
    
    readExternal in interface Externalizable
    
    Throws:
    
    IOException
    
    ClassNotFoundException
  - writeTo
```
public void writeTo(DataOutputStream out)
             throws IOException
```
    Description copied from interface: Streamable
    
    Write the entire state of the current object (including superclasses) to outstream. Note that the output stream must not be closed
    
    Specified by:
    
    writeTo in interface Streamable
    
    Throws:
    
    IOException
  - readFrom
```
public void readFrom(DataInputStream in)
              throws IOException,
                     IllegalAccessException,
                     InstantiationException
```
    Description copied from interface: Streamable
    
    Read the state of the current object (including superclasses) from instream Note that the input stream must not be closed
    
    Specified by:
    
    readFrom in interface Streamable
    
    Throws:
    
    IOException
    
    IllegalAccessException
    
    InstantiationException
  - serializedSize
```
public int serializedSize()
```

Class View

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

vid

members

payload

Constructor Detail

View

View

View

View

Method Detail

getVid

getViewId

getCreator

getMembers

containsMember

equals

hashCode

size

copy

clone

printDetails

addPayload

removePayload

getPayload

toString

writeExternal

readExternal

writeTo

readFrom

serializedSize