Class TwoPhaseCommitInterceptor

java.lang.Object

org.apache.catalina.tribes.group.ChannelInterceptorBase

org.apache.catalina.tribes.group.interceptors.TwoPhaseCommitInterceptor

All Implemented Interfaces:

ChannelInterceptor, Heartbeat, MembershipListener

public class TwoPhaseCommitInterceptor
extends ChannelInterceptorBase

Two-phase commit interceptor. The sender transmits a confirmation message after each message. The receiver stores each message and only passes it on when the matching confirmation message is received. There is no retransmission, so a message whose confirmation is lost, or that arrives out of order, is dropped after the expiration time.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	TwoPhaseCommitInterceptor.MapEntry

Nested classes/interfaces inherited from interface ChannelInterceptor

ChannelInterceptor.InterceptorEvent

Field Summary

Fields

Modifier and Type	Field	Description
protected boolean	deepclone	Whether the confirmation message is deep cloned (true) or shallow cloned (false) before it is sent.
protected long	expire	Message expiration time in milliseconds.
protected final Map<UniqueId, TwoPhaseCommitInterceptor.MapEntry>	messages	Map of pending messages keyed by their unique ID.
protected static final StringManager	sm	The string manager for this package.

Fields inherited from class ChannelInterceptorBase

optionFlag

Constructor Summary

Constructors

Constructor	Description
TwoPhaseCommitInterceptor()	Constructs a new TwoPhaseCommitInterceptor.

Method Summary

Modifier and Type	Method	Description
boolean	getDeepclone()	Returns whether deep cloning is enabled.
long	getExpire()	Returns the message expiration time in milliseconds.
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	messageReceived(ChannelMessage msg)	The messageReceived is invoked when a message is received.
void	sendMessage(Member[] destination, ChannelMessage msg, InterceptorPayload payload)	The sendMessage method is called when a message is being sent to one more destinations.
void	setDeepclone(boolean deepclone)	Sets whether deep cloning should be used.
void	setExpire(long expire)	Sets the message expiration time in milliseconds.

Methods inherited from class ChannelInterceptorBase

fireInterceptorEvent, getChannel, getLocalMember, getMember, getMembers, getNext, getOptionFlag, getPrevious, hasMembers, memberAdded, memberDisappeared, okToProcess, setChannel, setNext, setOptionFlag, setPrevious, start, stop

Methods inherited from class Object

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

Field Details

sm

protected static final StringManager sm

The string manager for this package.

messages

protected final Map<UniqueId, TwoPhaseCommitInterceptor.MapEntry> messages

Map of pending messages keyed by their unique ID.

expire

protected long expire

Message expiration time in milliseconds.

deepclone

protected boolean deepclone

Whether the confirmation message is deep cloned (true) or shallow cloned (false) before it is sent. Messages that are stored for later delivery are always deep cloned.

Constructor Details

TwoPhaseCommitInterceptor

public TwoPhaseCommitInterceptor()

Constructs a new TwoPhaseCommitInterceptor.

Method Details

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

Overrides:

sendMessage in class ChannelInterceptorBase

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

Overrides:

messageReceived in class ChannelInterceptorBase

Parameters:

msg - ChannelMessage

getDeepclone

public boolean getDeepclone()

Returns whether deep cloning is enabled.

Returns:

true if deep cloning is enabled

getExpire

public long getExpire()

Returns the message expiration time in milliseconds.

Returns:

the expiration time

setDeepclone

public void setDeepclone(boolean deepclone)

Sets whether deep cloning should be used.

Parameters:

deepclone - true to enable deep cloning

setExpire

public void setExpire(long expire)

Sets the message expiration time in milliseconds.

Parameters:

expire - the expiration time

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

Overrides:

heartbeat in class ChannelInterceptorBase