private ReplicationState download(
ReplicationDownloaderConfiguration configuration,
ReplicationState serverState,
ReplicationState initialLocalState) {
URL baseUrl;
ReplicationState localState;
Date maximumDownloadTimestamp;
localState = initialLocalState;
// Determine the location of download files.
baseUrl = configuration.getBaseUrl();
// Determine the maximum timestamp that can be downloaded.
maximumDownloadTimestamp =
calculateMaximumTimestamp(
configuration, serverState.getTimestamp(), localState.getTimestamp());
LOG.fine("The maximum timestamp to be downloaded is " + maximumDownloadTimestamp + ".");
// Download all files and send their contents to the sink.
while (localState.getSequenceNumber() < serverState.getSequenceNumber()) {
File replicationFile;
long sequenceNumber;
ReplicationState fileReplicationState;
// Ensure that our current state is within the allowable timestamp range.
if (localState.getTimestamp().compareTo(maximumDownloadTimestamp) >= 0) {
break;
}
// Calculate the next sequence number.
sequenceNumber = localState.getSequenceNumber() + 1;
LOG.finer("Processing replication sequence " + sequenceNumber + ".");
// Get the state associated with the next file.
fileReplicationState = serverStateReader.getServerState(baseUrl, sequenceNumber);
// Download the next replication file to a temporary file.
replicationFile =
downloadReplicationFile(
sequenceFormatter.getFormattedName(sequenceNumber, ".osc.gz"), baseUrl);
// Process the file and send its contents to the sink.
processReplicationFile(replicationFile, fileReplicationState);
// Update the local state to reflect the file state just processed.
localState = fileReplicationState;
}
return localState;
}
private void runImpl() {
try {
ReplicationDownloaderConfiguration configuration;
ReplicationState serverState;
ReplicationState localState;
PropertiesPersister localStatePersistor;
// Instantiate utility objects.
configuration =
new ReplicationDownloaderConfiguration(new File(workingDirectory, CONFIG_FILE));
// Obtain the server state.
LOG.fine("Reading current server state.");
serverState = serverStateReader.getServerState(configuration.getBaseUrl());
// Build the local state persister which is used for both loading and storing local state.
localStatePersistor = new PropertiesPersister(new File(workingDirectory, LOCAL_STATE_FILE));
// Begin processing.
processInitialize(Collections.<String, Object>emptyMap());
// If local state isn't available we need to copy server state to be the initial local state
// then exit.
if (localStatePersistor.exists()) {
localState = new ReplicationState(localStatePersistor.loadMap());
// Download and process the replication files.
localState = download(configuration, serverState, localState);
} else {
localState = serverState;
processInitializeState(localState);
}
// Commit downstream changes.
processComplete();
// Persist the local state.
localStatePersistor.store(localState.store());
} finally {
processRelease();
}
}