Package org.apache.lucene.replicator

Class ReplicationClient

java.lang.Object

org.apache.lucene.replicator.ReplicationClient

All Implemented Interfaces:

Closeable, AutoCloseable

public class ReplicationClient
extends Object
implements Closeable

A client which monitors and obtains new revisions from a Replicator. It can be used to either periodically check for updates by invoking startUpdateThread(long, java.lang.String), or manually by calling updateNow().

Whenever a new revision is available, the requiredFiles(Map) are copied to the Directory specified by PerSessionDirectoryFactory and a handler is notified.

WARNING: This API is experimental and might change in incompatible ways in the next release.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	ReplicationClient.ReplicationHandler	Handler for revisions obtained by the client.
static interface	ReplicationClient.SourceDirectoryFactory	Resolves a session and source into a Directory to use for copying the session files to.

Field Summary

Fields

Modifier and Type	Field	Description
static String	INFO_STREAM_COMPONENT	The component name to use with InfoStream.isEnabled(String).

Constructor Summary

Constructors

Constructor	Description
ReplicationClient(Replicator replicator, ReplicationClient.ReplicationHandler handler, ReplicationClient.SourceDirectoryFactory factory)	Constructor.

Method Summary

Modifier and Type	Method	Description
void	close()
protected void	ensureOpen()	Throws AlreadyClosedException if the client has already been closed.
protected void	handleUpdateException(Throwable t)	Called when an exception is hit by the replication thread.
boolean	isUpdateThreadAlive()	Returns true if the update thread is alive.
protected Map<String,List<RevisionFile>>	requiredFiles(Map<String,List<RevisionFile>> newRevisionFiles)	Returns the files required for replication.
void	setInfoStream(InfoStream infoStream)	Sets the InfoStream to use for logging messages.
void	startUpdateThread(long intervalMillis, String threadName)	Start the update thread with the specified interval in milliseconds.
void	stopUpdateThread()	Stop the update thread.
String	toString()
void	updateNow()	Executes the update operation immediately, irregardless if an update thread is running or not.

Methods inherited from class java.lang.Object

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

Field Detail

INFO_STREAM_COMPONENT

public static final String INFO_STREAM_COMPONENT

The component name to use with InfoStream.isEnabled(String).

See Also:

Constant Field Values

Constructor Detail

ReplicationClient

public ReplicationClient(Replicator replicator,
                         ReplicationClient.ReplicationHandler handler,
                         ReplicationClient.SourceDirectoryFactory factory)

Constructor.

Parameters:

replicator - the Replicator used for checking for updates

handler - notified when new revisions are ready

factory - returns a Directory for a given source and session

Method Detail

ensureOpen

protected final void ensureOpen()

Throws AlreadyClosedException if the client has already been closed.

handleUpdateException

protected void handleUpdateException(Throwable t)

Called when an exception is hit by the replication thread. The default implementation prints the full stacktrace to the InfoStream set in setInfoStream(InfoStream), or the default one. You can override to log the exception elswhere.

NOTE: if you override this method to throw the exception further, the replication thread will be terminated. The only way to restart it is to call stopUpdateThread() followed by startUpdateThread(long, String).

requiredFiles

protected Map<String,List<RevisionFile>> requiredFiles(Map<String,List<RevisionFile>> newRevisionFiles)

Returns the files required for replication. By default, this method returns all files that exist in the new revision, but not in the handler.

close

public void close()

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

startUpdateThread

public void startUpdateThread(long intervalMillis,
                              String threadName)

Start the update thread with the specified interval in milliseconds. For debugging purposes, you can optionally set the name to set on Thread.setName(String). If you pass null, a default name will be set.

Throws:

IllegalStateException - if the thread has already been started

stopUpdateThread

public void stopUpdateThread()

Stop the update thread. If the update thread is not running, silently does nothing. This method returns after the update thread has stopped.

isUpdateThreadAlive

public boolean isUpdateThreadAlive()

Returns true if the update thread is alive. The update thread is alive if it has been started and not stopped, as well as didn't hit an error which caused it to terminate (i.e. handleUpdateException(Throwable) threw the exception further).

toString

public String toString()

Overrides:

toString in class Object

updateNow

public void updateNow()
               throws IOException

Executes the update operation immediately, irregardless if an update thread is running or not.

Throws:

IOException

setInfoStream

public void setInfoStream(InfoStream infoStream)

Sets the InfoStream to use for logging messages.