Files
briar/briar-api/src/org/briarproject/api/clients/MessageQueueManager.java

70 lines
2.3 KiB
Java

package org.briarproject.api.clients;
import org.briarproject.api.db.DbException;
import org.briarproject.api.db.Metadata;
import org.briarproject.api.db.Transaction;
import org.briarproject.api.nullsafety.NotNullByDefault;
import org.briarproject.api.sync.ClientId;
import org.briarproject.api.sync.Group;
import org.briarproject.api.sync.InvalidMessageException;
import org.briarproject.api.sync.MessageContext;
@NotNullByDefault
public interface MessageQueueManager {
/**
* The key used for storing the queue's state in the group metadata.
*/
String QUEUE_STATE_KEY = "queueState";
/**
* Sends a message using the given queue.
*/
QueueMessage sendMessage(Transaction txn, Group queue, long timestamp,
byte[] body, Metadata meta) throws DbException;
/**
* Sets the message validator for the given client.
*/
void registerMessageValidator(ClientId c, QueueMessageValidator v);
/**
* Sets the incoming message hook for the given client. The hook will be
* called once for each incoming message that passes validation. Messages
* are passed to the hook in order.
*/
void registerIncomingMessageHook(ClientId c, IncomingQueueMessageHook hook);
interface QueueMessageValidator {
/**
* Validates the given message and returns its metadata and
* dependencies.
*/
MessageContext validateMessage(QueueMessage q, Group g)
throws InvalidMessageException;
}
interface IncomingQueueMessageHook {
/**
* Called once for each incoming message that passes validation.
* Messages are passed to the hook in order.
*
* @throws DbException Should only be used for real database errors.
* If this is thrown, delivery will be attempted again at next startup,
* whereas if an InvalidMessageException is thrown,
* the message will be permanently invalidated.
* @throws InvalidMessageException for any non-database error
* that occurs while handling remotely created data.
* This includes errors that occur while handling locally created data
* in a context controlled by remotely created data
* (for example, parsing the metadata of a dependency
* of an incoming message).
* Never rethrow DbException as InvalidMessageException!
*/
void incomingMessage(Transaction txn, QueueMessage q, Metadata meta)
throws DbException, InvalidMessageException;
}
}