org.apache.lucene.replicator
Interface Replicator

All Superinterfaces:

Closeable

All Known Implementing Classes:

HttpReplicator, LocalReplicator

public interface Replicator
extends Closeable

An interface for replicating files. Allows a producer to publish Revisions and consumers to check for updates. When a client needs to be updated, it is given a SessionToken through which it can obtain the files of that revision. After the client has finished obtaining all the files, it should release the given session, so that the files can be reclaimed if they are not needed anymore.

A client is always updated to the newest revision available. That is, if a client is on revision r1 and revisions r2 and r3 were published, then when the cllient will next check for update, it will receive r3.

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

Method Summary

SessionToken	checkForUpdate(String currVersion) Check whether the given version is up-to-date and returns a SessionToken which can be used for fetching the revision files, otherwise returns null.
InputStream	obtainFile(String sessionID, String source, String fileName) Returns an InputStream for the requested file and source in the context of the given session.
void	publish(Revision revision) Publish a new Revision for consumption by clients.
void	release(String sessionID) Notify that the specified SessionToken is no longer needed by the caller.

Methods inherited from interface java.io.Closeable

close

Method Detail

publish

void publish(Revision revision)
             throws IOException

Publish a new Revision for consumption by clients. It is the caller's responsibility to verify that the revision files exist and can be read by clients. When the revision is no longer needed, it will be released by the replicator.

Throws:

IOException

checkForUpdate

SessionToken checkForUpdate(String currVersion)
                            throws IOException

Check whether the given version is up-to-date and returns a SessionToken which can be used for fetching the revision files, otherwise returns null.

NOTE: when the returned session token is no longer needed, you should call release(String) so that the session resources can be reclaimed, including the revision files.

Throws:

IOException

release

void release(String sessionID)
             throws IOException

Notify that the specified SessionToken is no longer needed by the caller.

Throws:

IOException

obtainFile

InputStream obtainFile(String sessionID,
                       String source,
                       String fileName)
                       throws IOException

Returns an InputStream for the requested file and source in the context of the given session.

NOTE: it is the caller's responsibility to close the returned stream.

Throws:

SessionExpiredException - if the specified session has already expired

IOException