Package org.apache.catalina.tribes.group

Class ChannelInterceptorBase

java.lang.Object

org.apache.catalina.tribes.group.ChannelInterceptorBase

All Implemented Interfaces:

ChannelInterceptor, Heartbeat, MembershipListener

Direct Known Subclasses:

ChannelCoordinator, DomainFilterInterceptor, EncryptInterceptor, FragmentationInterceptor, GroupChannel, GzipInterceptor, MessageDispatchInterceptor, NonBlockingCoordinator, OrderInterceptor, SimpleCoordinator, StaticMembershipInterceptor, TcpFailureDetector, TcpPingInterceptor, ThroughputInterceptor, TwoPhaseCommitInterceptor

public abstract class ChannelInterceptorBase
extends Object
implements ChannelInterceptor

Abstract class for the interceptor base class.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.catalina.tribes.ChannelInterceptor

ChannelInterceptor.InterceptorEvent

Field Summary

Fields

Modifier and Type	Field	Description
protected int	optionFlag

Constructor Summary

Constructors

Constructor	Description
ChannelInterceptorBase()

Method Summary

Modifier and Type	Method	Description
void	fireInterceptorEvent(ChannelInterceptor.InterceptorEvent event)	Fire an event.
Channel	getChannel()	Return the channel that is related to this interceptor
Member	getLocalMember(boolean incAlive)	Intercepts the Channel.getLocalMember(boolean) method
Member	getMember(Member mbr)	Intercepts the Channel.getMember(Member) method
Member[]	getMembers()	Intercepts the Channel.getMembers() method
final ChannelInterceptor	getNext()	Retrieve the next interceptor in the list
int	getOptionFlag()	An interceptor can react to a message based on a set bit on the message options.
final ChannelInterceptor	getPrevious()	Retrieve the previous interceptor in the list
boolean	hasMembers()	Intercepts the Channel.hasMembers() method
void	heartbeat()	The heartbeat() method gets invoked periodically to allow interceptors to clean up resources, time out object and perform actions that are unrelated to sending/receiving data.
void	memberAdded(Member member)	A member was added to the group
void	memberDisappeared(Member member)	A member was removed from the group If the member left voluntarily, the Member.getCommand will contain the Member.SHUTDOWN_PAYLOAD data
void	messageReceived(ChannelMessage msg)	The messageReceived is invoked when a message is received.
boolean	okToProcess(int messageFlags)
void	sendMessage(Member[] destination, ChannelMessage msg, InterceptorPayload payload)	The sendMessage method is called when a message is being sent to one more destinations.
void	setChannel(Channel channel)	Set the channel that is related to this interceptor
final void	setNext(ChannelInterceptor next)	Set the next interceptor in the list of interceptors
void	setOptionFlag(int optionFlag)	Sets the option flag
final void	setPrevious(ChannelInterceptor previous)	Set the previous interceptor in the list
void	start(int svc)	Starts up the channel.
void	stop(int svc)	Shuts down the channel.

Methods inherited from class java.lang.Object

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

Field Details

optionFlag

protected int optionFlag

Constructor Details

ChannelInterceptorBase

public ChannelInterceptorBase()

Method Details

okToProcess

public boolean okToProcess(int messageFlags)

setNext

public final void setNext(ChannelInterceptor next)

Description copied from interface: ChannelInterceptor

Set the next interceptor in the list of interceptors

Specified by:

setNext in interface ChannelInterceptor

Parameters:

next - ChannelInterceptor

getNext

public final ChannelInterceptor getNext()

Description copied from interface: ChannelInterceptor

Retrieve the next interceptor in the list

Specified by:

getNext in interface ChannelInterceptor

Returns:

ChannelInterceptor - returns the next interceptor in the list or null if no more interceptors exist

setPrevious

public final void setPrevious(ChannelInterceptor previous)

Description copied from interface: ChannelInterceptor

Set the previous interceptor in the list

Specified by:

setPrevious in interface ChannelInterceptor

Parameters:

previous - ChannelInterceptor

setOptionFlag

public void setOptionFlag(int optionFlag)

Description copied from interface: ChannelInterceptor

Sets the option flag

Specified by:

setOptionFlag in interface ChannelInterceptor

Parameters:

optionFlag - int

See Also:

• ChannelInterceptor.getOptionFlag()

getPrevious

public final ChannelInterceptor getPrevious()

Description copied from interface: ChannelInterceptor

Retrieve the previous interceptor in the list

Specified by:

getPrevious in interface ChannelInterceptor

Returns:

ChannelInterceptor - returns the previous interceptor in the list or null if no more interceptors exist

getOptionFlag

public int getOptionFlag()

Description copied from interface: ChannelInterceptor

An interceptor can react to a message based on a set bit on the message options. When a message is sent, the options can be retrieved from ChannelMessage.getOptions() and if the bit is set, this interceptor will react to it.

A simple evaluation if an interceptor should react to the message would be:
boolean react = (getOptionFlag() == (getOptionFlag() & ChannelMessage.getOptions()));
The default option is 0, meaning there is no way for the application to trigger the interceptor. The interceptor itself will decide.

Specified by:

getOptionFlag in interface ChannelInterceptor

Returns:

int

See Also:

• ChannelMessage.getOptions()

sendMessage

public void sendMessage(Member[] destination,
 ChannelMessage msg,
 InterceptorPayload payload)
                 throws ChannelException

Description copied from interface: ChannelInterceptor

The sendMessage method is called when a message is being sent to one more destinations. The interceptor can modify any of the parameters and then pass on the message down the stack by invoking getNext().sendMessage(destination,msg,payload).

Alternatively the interceptor can stop the message from being sent by not invoking getNext().sendMessage(destination,msg,payload).

If the message is to be sent asynchronous the application can be notified of completion and errors by passing in an error handler attached to a payload object.

The ChannelMessage.getAddress contains Channel.getLocalMember, and can be overwritten to simulate a message sent from another node.

Specified by:

sendMessage in interface ChannelInterceptor

Parameters:

destination - Member[] - the destination for this message

msg - ChannelMessage - the message to be sent

payload - InterceptorPayload - the payload, carrying an error handler and future useful data, can be null

Throws:

ChannelException - if a serialization error happens.

See Also:

• ErrorHandler
• InterceptorPayload

messageReceived

public void messageReceived(ChannelMessage msg)

Description copied from interface: ChannelInterceptor

The messageReceived is invoked when a message is received. ChannelMessage.getAddress() is the sender, or the reply-to address if it has been overwritten.

Specified by:

messageReceived in interface ChannelInterceptor

Parameters:

msg - ChannelMessage

memberAdded

public void memberAdded(Member member)

Description copied from interface: MembershipListener

A member was added to the group

Specified by:

memberAdded in interface MembershipListener

Parameters:

member - Member - the member that was added

memberDisappeared

public void memberDisappeared(Member member)

Description copied from interface: MembershipListener

A member was removed from the group
If the member left voluntarily, the Member.getCommand will contain the Member.SHUTDOWN_PAYLOAD data

Specified by:

memberDisappeared in interface MembershipListener

Parameters:

member - Member

See Also:

• Member.SHUTDOWN_PAYLOAD

heartbeat

public void heartbeat()

Description copied from interface: ChannelInterceptor

The heartbeat() method gets invoked periodically to allow interceptors to clean up resources, time out object and perform actions that are unrelated to sending/receiving data.

Specified by:

heartbeat in interface ChannelInterceptor

Specified by:

heartbeat in interface Heartbeat

hasMembers

public boolean hasMembers()

Description copied from interface: ChannelInterceptor

Intercepts the Channel.hasMembers() method

Specified by:

hasMembers in interface ChannelInterceptor

Returns:

boolean - if the channel has members in its membership group

See Also:

• Channel.hasMembers()

getMembers

public Member[] getMembers()

Description copied from interface: ChannelInterceptor

Intercepts the Channel.getMembers() method

Specified by:

getMembers in interface ChannelInterceptor

Returns:

the members

See Also:

• Channel.getMembers()

getMember

public Member getMember(Member mbr)

Description copied from interface: ChannelInterceptor

Intercepts the Channel.getMember(Member) method

Specified by:

getMember in interface ChannelInterceptor

Parameters:

mbr - Member

Returns:

Member - the actual member information, including stay alive

See Also:

• Channel.getMember(Member)

getLocalMember

public Member getLocalMember(boolean incAlive)

Description copied from interface: ChannelInterceptor

Intercepts the Channel.getLocalMember(boolean) method

Specified by:

getLocalMember in interface ChannelInterceptor

Parameters:

incAlive - boolean

Returns:

the member that represents this node

See Also:

• Channel.getLocalMember(boolean)

start

public void start(int svc)
           throws ChannelException

Description copied from interface: ChannelInterceptor

Starts up the channel. This can be called multiple times for individual services to start The svc parameter can be the logical or value of any constants

Specified by:

start in interface ChannelInterceptor

Parameters:

svc - one of:

• Channel.DEFAULT - will start all services
• Channel.MBR_RX_SEQ - starts the membership receiver
• Channel.MBR_TX_SEQ - starts the membership broadcaster
• Channel.SND_TX_SEQ - starts the replication transmitter
• Channel.SND_RX_SEQ - starts the replication receiver

Throws:

ChannelException - if a startup error occurs or the service is already started.

See Also:

• Channel

stop

public void stop(int svc)
          throws ChannelException

Description copied from interface: ChannelInterceptor

Shuts down the channel. This can be called multiple times for individual services to shutdown The svc parameter can be the logical or value of any constants

Specified by:

stop in interface ChannelInterceptor

Parameters:

svc - one of:

• Channel.DEFAULT - will shutdown all services
• Channel.MBR_RX_SEQ - stops the membership receiver
• Channel.MBR_TX_SEQ - stops the membership broadcaster
• Channel.SND_TX_SEQ - stops the replication transmitter
• Channel.SND_RX_SEQ - stops the replication receiver

Throws:

ChannelException - if a startup error occurs or the service is already started.

See Also:

• Channel

fireInterceptorEvent

public void fireInterceptorEvent(ChannelInterceptor.InterceptorEvent event)

Description copied from interface: ChannelInterceptor

Fire an event.

Specified by:

fireInterceptorEvent in interface ChannelInterceptor

Parameters:

event - the event

getChannel

public Channel getChannel()

Description copied from interface: ChannelInterceptor

Return the channel that is related to this interceptor

Specified by:

getChannel in interface ChannelInterceptor

Returns:

Channel

setChannel

public void setChannel(Channel channel)

Description copied from interface: ChannelInterceptor

Set the channel that is related to this interceptor

Specified by:

setChannel in interface ChannelInterceptor

Parameters:

channel - The channel