Class FragmentationInterceptor

java.lang.Object

org.apache.catalina.tribes.group.ChannelInterceptorBase

org.apache.catalina.tribes.group.interceptors.FragmentationInterceptor

All Implemented Interfaces:

ChannelInterceptor, FragmentationInterceptorMBean, Heartbeat, MembershipListener

public class FragmentationInterceptor
extends ChannelInterceptorBase
implements FragmentationInterceptorMBean

The fragmentation interceptor splits up large messages into smaller messages and assembles them on the other end. This is very useful when you don't want large messages hogging the sending sockets and smaller messages can make it through.
Configuration Options
FragmentationInterceptor.expire=<milliseconds> - how long do we keep the fragments in memory and wait for the rest to arrive default=60,000ms -> 60seconds This setting is useful to avoid OutOfMemoryErrors
FragmentationInterceptor.maxSize=<max message size> - message size in bytes default=1024*100 (around a tenth of a MB)

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	FragmentationInterceptor.FragCollection	Collection that holds the fragments of a message for reassembly.
static class	FragmentationInterceptor.FragKey	Key used to identify a set of fragments belonging to the same original message.

Nested classes/interfaces inherited from interface ChannelInterceptor

ChannelInterceptor.InterceptorEvent

Field Summary

Fields

Modifier and Type	Field	Description
protected final boolean	deepclone	Flag indicating whether deep cloning is enabled for fragments.
protected final Map<FragmentationInterceptor.FragKey, FragmentationInterceptor.FragCollection>	fragpieces	Map of fragment keys to their fragment collections for reassembly.
protected static final StringManager	sm	String manager for internationalization support.

Fields inherited from class ChannelInterceptorBase

optionFlag

Constructor Summary

Constructors

Constructor	Description
FragmentationInterceptor()	Creates a new FragmentationInterceptor instance.

Method Summary

Modifier and Type	Method	Description
void	defrag(ChannelMessage msg)	Reassembles a fragmented message from its parts.
void	frag(Member[] destination, ChannelMessage msg, InterceptorPayload payload)	Fragments a large message into smaller pieces and sends them.
long	getExpire()	Returns the expiration time for fragments in milliseconds.
FragmentationInterceptor.FragCollection	getFragCollection(FragmentationInterceptor.FragKey key, ChannelMessage msg)	Gets the fragment collection for the given key, creating one if it does not exist.
int	getMaxSize()	Returns the maximum size of a fragment in bytes.
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	removeFragCollection(FragmentationInterceptor.FragKey key)	Removes the fragment collection for the given key.
void	sendMessage(Member[] destination, ChannelMessage msg, InterceptorPayload payload)	The sendMessage method is called when a message is being sent to one more destinations.
void	setExpire(long expire)	Sets the expiration time for fragments in milliseconds.
void	setMaxSize(int maxSize)	Sets the maximum size of a fragment in bytes.

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

String manager for internationalization support.

fragpieces

protected final Map<FragmentationInterceptor.FragKey, FragmentationInterceptor.FragCollection> fragpieces

Map of fragment keys to their fragment collections for reassembly.

deepclone

protected final boolean deepclone

Flag indicating whether deep cloning is enabled for fragments.

See Also:

• Constant Field Values

Constructor Details

FragmentationInterceptor

public FragmentationInterceptor()

Creates a new FragmentationInterceptor instance.

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

getFragCollection

public FragmentationInterceptor.FragCollection getFragCollection(FragmentationInterceptor.FragKey key,
 ChannelMessage msg)

Gets the fragment collection for the given key, creating one if it does not exist.

Parameters:

key - The fragment key

msg - The channel message used to initialize a new collection if needed

Returns:

The fragment collection for the given key

removeFragCollection

public void removeFragCollection(FragmentationInterceptor.FragKey key)

Removes the fragment collection for the given key.

Parameters:

key - The fragment key to remove

defrag

public void defrag(ChannelMessage msg)

Reassembles a fragmented message from its parts.

Parameters:

msg - The channel message fragment to process

frag

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

Fragments a large message into smaller pieces and sends them.

Parameters:

destination - The destination members

msg - The channel message to fragment

payload - The interceptor payload

Throws:

ChannelException - if an error occurs during fragmentation

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

getMaxSize

public int getMaxSize()

Description copied from interface: FragmentationInterceptorMBean

Returns the maximum size of a fragment in bytes.

Specified by:

getMaxSize in interface FragmentationInterceptorMBean

Returns:

The maximum fragment size

getExpire

public long getExpire()

Description copied from interface: FragmentationInterceptorMBean

Returns the expiration time for fragments in milliseconds.

Specified by:

getExpire in interface FragmentationInterceptorMBean

Returns:

The fragment expiration time

setMaxSize

public void setMaxSize(int maxSize)

Description copied from interface: FragmentationInterceptorMBean

Sets the maximum size of a fragment in bytes.

Specified by:

setMaxSize in interface FragmentationInterceptorMBean

Parameters:

maxSize - The maximum fragment size

setExpire

public void setExpire(long expire)

Description copied from interface: FragmentationInterceptorMBean

Sets the expiration time for fragments in milliseconds.

Specified by:

setExpire in interface FragmentationInterceptorMBean

Parameters:

expire - The fragment expiration time