Package org.jgroups
Class View
java.lang.Object
org.jgroups.View
- All Implemented Interfaces:
Externalizable
,Serializable
,Cloneable
,Streamable
- Direct Known Subclasses:
MergeView
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 adresses 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
- Version:
- $Id: View.java,v 1.18 2007/10/01 07:24:41 belaban Exp $
- Author:
- Bela Ban
- See Also:
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Field Summary
Fields -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionvoid
addPayload
(String key, Object value) Adds a key and value to the view.clone()
creates a copy of this viewboolean
containsMember
(Address mbr) returns true, if this view contains a certain memberboolean
returns the creator of this view if this view was created with the empty constructur, null will be returnedReturns 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.getPayload
(String key) getVid()
returns the view ID of this view if this view was created with the empty constructur, null will be returnedint
hashCode()
debug onlyvoid
void
Read the state of the current object (including superclasses) from instream Note that the input stream must not be closedint
int
size()
returns the number of members in this viewtoString()
void
void
writeTo
(DataOutputStream out) Write the entire state of the current object (including superclasses) to outstream.
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Field Details
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vid
-
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
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Constructor Details
-
View
public View()creates an empty view, should not be used -
View
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
Creates a new view- Parameters:
creator
- The creator of this view (can not be null)id
- The lamport timestamp of this viewmembers
- Contains a list of all the members in the view, can be empty but not null.
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Method Details
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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
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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
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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
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containsMember
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
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equals
-
hashCode
public int hashCode() -
size
public int size()returns the number of members in this view- Returns:
- the number of members in this view 0..n
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clone
creates a copy of this view -
printDetails
debug only -
addPayload
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
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getPayload
-
toString
-
writeExternal
- Specified by:
writeExternal
in interfaceExternalizable
- Throws:
IOException
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readExternal
- Specified by:
readExternal
in interfaceExternalizable
- Throws:
IOException
ClassNotFoundException
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writeTo
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 interfaceStreamable
- Throws:
IOException
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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 interfaceStreamable
- Throws:
IOException
IllegalAccessException
InstantiationException
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serializedSize
public int serializedSize()
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