org.jgroups.stack

Class ProtocolStack

java.lang.Object

org.jgroups.stack.Protocol

org.jgroups.stack.ProtocolStack

public class ProtocolStack
extends Protocol

A ProtocolStack manages a number of protocols layered above each other. It creates all protocol classes, initializes them and, when ready, starts all of them, beginning with the bottom most protocol. It also dispatches messages received from the stack to registered objects (e.g. channel, GMP) and sends messages sent by those objects down the stack.

The ProtocolStack makes use of the Configurator to setup and initialize stacks, and to destroy them again when not needed anymore

Author:

Bela Ban

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ProtocolStack.RefCounter Keeps track of the number os times init()/destroy() and start()/stop have been called.

Field Summary

Fields

Modifier and Type	Field and Description
static int	ABOVE
static int	BELOW

Fields inherited from class org.jgroups.stack.Protocol

down_prot, ergonomics, id, log, name, stack, stats, up_prot

Constructor Summary

Constructors

Constructor and Description
ProtocolStack() Used for programmatic creation of ProtocolStack
ProtocolStack(JChannel channel)

Method Summary

Methods

Modifier and Type	Method and Description
ProtocolStack	addProtocol(Protocol prot) Adds a protocol at the tail of the protocol list
ProtocolStack	addProtocols(List<Protocol> prots) Adds a list of protocols
ProtocolStack	addProtocols(Protocol... prots) Adds a list of protocols
List<Protocol>	copyProtocols(ProtocolStack targetStack)
protected Protocol	createProtocol(String classname)
void	destroy() This method is called on a Channel.close().
Object	down(Event evt) An event is to be sent down the stack.
Map<String,Object>	dumpStats()
Map<String,Object>	dumpStats(String protocol_name)
Map<String,Object>	dumpStats(String protocol_name, List<String> attrs)
Protocol	findProtocol(Class<?>... classes) Finds the first protocol of a list and returns it.
Protocol	findProtocol(Class<?> clazz)
Protocol	findProtocol(String name) Returns a given protocol or null if not found
Protocol	getBottomProtocol()
JChannel	getChannel()
String	getName() All protocol names have to be unique !
List<Protocol>	getProtocols() Returns all protocols in a list, from top to bottom.
static ConcurrentMap<String,Tuple<TP,ProtocolStack.RefCounter>>	getSingletonTransports()
Protocol	getTopProtocol()
TP	getTransport() Returns the bottom most protocol
void	init() Called after instance has been created (null constructor) and before protocol is started.
void	initProtocolStack()
void	insertProtocol(Protocol prot, int position, Class<? extends Protocol>... neighbor_prots)
void	insertProtocol(Protocol prot, int position, Class<? extends Protocol> neighbor_prot)
void	insertProtocol(Protocol prot, int position, String neighbor_prot) Inserts an already created (and initialized) protocol into the protocol list.
void	insertProtocolAtTop(Protocol prot)
void	insertProtocolInStack(Protocol prot, Protocol neighbor, int position)
String	printProtocolSpec(boolean include_properties) Prints the names of the protocols, from the bottom to top.
String	printProtocolSpecAsPlainString()
String	printProtocolSpecAsXML()
Object	receive(long timeout)
Protocol	removeProtocol(Class... protocols)
Protocol	removeProtocol(Class prot)
Protocol	removeProtocol(String prot_name) Removes a protocol from the stack.
void	replaceProtocol(Protocol existing_prot, Protocol new_prot) Replaces one protocol instance with another.
void	send(Message msg)
void	setChannel(JChannel ch)
void	setup(List<ProtocolConfiguration> configs)
void	setup(ProtocolStack stack)
void	startStack(String cluster_name, Address local_addr) Start all layers.
void	stopStack(String cluster_name) Iterates through all the protocols from top to bottom and does the following: Waits until all messages in the down queue have been flushed (ie., size is 0) Calls stop() on the protocol
Object	up(Event evt) An event was received from the layer below.

Methods inherited from class org.jgroups.stack.Protocol

enableStats, getConfigurableObjects, getDownProtocol, getId, getLevel, getProtocolStack, getSocketFactory, getThreadFactory, getUpProtocol, getValue, isErgonomics, printStats, providedDownServices, providedUpServices, requiredDownServices, requiredUpServices, resetStatistics, resetStats, setDownProtocol, setErgonomics, setId, setLevel, setProtocolStack, setSocketFactory, setUpProtocol, setValue, setValues, start, statsEnabled, stop

Methods inherited from class java.lang.Object

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

Field Detail

ABOVE

public static final int ABOVE

See Also:

Constant Field Values

BELOW

public static final int BELOW

See Also:

Constant Field Values

Constructor Detail

ProtocolStack

public ProtocolStack(JChannel channel)
              throws Exception

Throws:

Exception

ProtocolStack

public ProtocolStack()

Used for programmatic creation of ProtocolStack

Method Detail

getChannel

public JChannel getChannel()

setChannel

public void setChannel(JChannel ch)

getProtocols

public List<Protocol> getProtocols()

Returns all protocols in a list, from top to bottom. These are not copies of protocols, so modifications will affect the actual instances !

copyProtocols

public List<Protocol> copyProtocols(ProtocolStack targetStack)
                             throws IllegalAccessException,
                                    InstantiationException

Throws:

IllegalAccessException

InstantiationException

getTransport

public TP getTransport()

Returns the bottom most protocol

Overrides:

getTransport in class Protocol

getSingletonTransports

public static ConcurrentMap<String,Tuple<TP,ProtocolStack.RefCounter>> getSingletonTransports()

dumpStats

public Map<String,Object> dumpStats()

Overrides:

dumpStats in class Protocol

Returns:

Map>

dumpStats

public Map<String,Object> dumpStats(String protocol_name)

dumpStats

public Map<String,Object> dumpStats(String protocol_name,
                           List<String> attrs)

printProtocolSpec

public String printProtocolSpec(boolean include_properties)

Prints the names of the protocols, from the bottom to top. If include_properties is true, the properties for each protocol will also be printed.

printProtocolSpecAsXML

public String printProtocolSpecAsXML()

printProtocolSpecAsPlainString

public String printProtocolSpecAsPlainString()

setup

public void setup(List<ProtocolConfiguration> configs)
           throws Exception

Throws:

Exception

setup

public void setup(ProtocolStack stack)
           throws Exception

Throws:

Exception

addProtocol

public ProtocolStack addProtocol(Protocol prot)

Adds a protocol at the tail of the protocol list

Parameters:

prot -

Returns:

Since:

2.11

addProtocols

public ProtocolStack addProtocols(Protocol... prots)

Adds a list of protocols

Parameters:

prots -

Returns:

Since:

2.11

addProtocols

public ProtocolStack addProtocols(List<Protocol> prots)

Adds a list of protocols

Parameters:

prots -

Returns:

Since:

2.1

insertProtocol

public void insertProtocol(Protocol prot,
                  int position,
                  String neighbor_prot)
                    throws Exception

Inserts an already created (and initialized) protocol into the protocol list. Sets the links to the protocols above and below correctly and adjusts the linked list of protocols accordingly. Note that this method may change the value of top_prot or bottom_prot.

Parameters:

prot - The protocol to be inserted. Before insertion, a sanity check will ensure that none of the existing protocols have the same name as the new protocol.

position - Where to place the protocol with respect to the neighbor_prot (ABOVE, BELOW)

neighbor_prot - The name of the neighbor protocol. An exception will be thrown if this name is not found

Throws:

Exception - Will be thrown when the new protocol cannot be created, or inserted.

insertProtocolInStack

public void insertProtocolInStack(Protocol prot,
                         Protocol neighbor,
                         int position)

insertProtocol

public void insertProtocol(Protocol prot,
                  int position,
                  Class<? extends Protocol> neighbor_prot)
                    throws Exception

Throws:

Exception

insertProtocol

public void insertProtocol(Protocol prot,
                  int position,
                  Class<? extends Protocol>... neighbor_prots)
                    throws Exception

Throws:

Exception

insertProtocolAtTop

public void insertProtocolAtTop(Protocol prot)

removeProtocol

public Protocol removeProtocol(String prot_name)
                        throws Exception

Removes a protocol from the stack. Stops the protocol and readjusts the linked lists of protocols.

Parameters:

prot_name - The name of the protocol. Since all protocol names in a stack have to be unique (otherwise the stack won't be created), the name refers to just 1 protocol.

Throws:

Exception - Thrown if the protocol cannot be stopped correctly.

removeProtocol

public Protocol removeProtocol(Class... protocols)

removeProtocol

public Protocol removeProtocol(Class prot)

findProtocol

public Protocol findProtocol(String name)

Returns a given protocol or null if not found

getBottomProtocol

public Protocol getBottomProtocol()

getTopProtocol

public Protocol getTopProtocol()

findProtocol

public Protocol findProtocol(Class<?> clazz)

findProtocol

public Protocol findProtocol(Class<?>... classes)

Finds the first protocol of a list and returns it. Returns null if no protocol can be found

Parameters:

classes - A list of protocol classes to find

Returns:

Protocol The protocol found

replaceProtocol

public void replaceProtocol(Protocol existing_prot,
                   Protocol new_prot)
                     throws Exception

Replaces one protocol instance with another. Should be done before the stack is connected

Parameters:

existing_prot -

new_prot -

Throws:

Exception

createProtocol

protected Protocol createProtocol(String classname)
                           throws Exception

Throws:

Exception

init

public void init()
          throws Exception

Description copied from class: Protocol

Called after instance has been created (null constructor) and before protocol is started. Properties are already set. Other protocols are not yet connected and events cannot yet be sent.

Overrides:

init in class Protocol

Throws:

Exception - Thrown if protocol cannot be initialized successfully. This will cause the ProtocolStack to fail, so the channel constructor will throw an exception

initProtocolStack

public void initProtocolStack()
                       throws Exception

Throws:

Exception

destroy

public void destroy()

Description copied from class: Protocol

This method is called on a Channel.close(). Does some cleanup; after the call the VM will terminate

Overrides:

destroy in class Protocol

startStack

public void startStack(String cluster_name,
              Address local_addr)
                throws Exception

Start all layers. The Protocol.start() method is called in each protocol, from top to bottom. Each layer can perform some initialization, e.g. create a multicast socket

Throws:

Exception

stopStack

public void stopStack(String cluster_name)

Iterates through all the protocols from top to bottom and does the following:

1. Waits until all messages in the down queue have been flushed (ie., size is 0)
2. Calls stop() on the protocol

send

public void send(Message msg)
          throws Exception

Throws:

Exception

receive

public Object receive(long timeout)
               throws Exception

Throws:

Exception

getName

public String getName()

Description copied from class: Protocol

All protocol names have to be unique !

Overrides:

getName in class Protocol

up

public Object up(Event evt)

Description copied from class: Protocol

An event was received from the layer below. Usually the current layer will want to examine the event type and - depending on its type - perform some computation (e.g. removing headers from a MSG event type, or updating the internal membership list when receiving a VIEW_CHANGE event). Finally the event is either a) discarded, or b) an event is sent down the stack using down_prot.down() or c) the event (or another event) is sent up the stack using up_prot.up().

Overrides:

up in class Protocol

down

public Object down(Event evt)

Description copied from class: Protocol

An event is to be sent down the stack. The layer may want to examine its type and perform some action on it, depending on the event's type. If the event is a message MSG, then the layer may need to add a header to it (or do nothing at all) before sending it down the stack using down_prot.down(). In case of a GET_ADDRESS event (which tries to retrieve the stack's address from one of the bottom layers), the layer may need to send a new response event back up the stack using up_prot.up().

Overrides:

down in class Protocol