de.zib.scalaris
Class ReplicatedDHT

java.lang.Object
  de.zib.scalaris.ReplicatedDHT

public class ReplicatedDHT
extends Object

Provides methods to delete all replicas of the given key (from api_rdht.erl).

Instances of this class can be generated using a given connection to a scalaris node using ReplicatedDHT(Connection) or without a connection (ReplicatedDHT()) in which case a new connection is created using ConnectionFactory.createConnection().

Deleting values

 
   String key;
   int timeout;
   DeleteResult result;

   TransactionSingleOp sc = new ReplicatedDHT();
   sc.delete(key);                    // delete(String)
   sc.delete(key, timeout);           // delete(String, int)
   result = sc.getLastDeleteResult(); // getLastDeleteResult()
 
 

Connection errors

Errors when setting up connections or trying to send/receive RPCs will be handed to the ConnectionPolicy that has been set when the connection was created. By default, ConnectionFactory uses DefaultConnectionPolicy which implements automatic connection-retries by classifying nodes as good or bad depending on their previous state. The number of automatic retries is adjustable (default: 3).

Since:

2.6

Version:

3.19

Author:

Nico Kruber, kruber@zib.de

Constructor Summary

ReplicatedDHT()
Constructor, uses the default connection returned by ConnectionFactory.createConnection().

ReplicatedDHT(Connection conn)
Constructor, uses the given connection to an erlang node.

Method Summary

void	closeConnection() Closes the transaction's connection to a scalaris node.
DeleteResult	delete(OtpErlangString key) Tries to delete all replicas of the given key in 2000ms.
DeleteResult	delete(OtpErlangString key, int timeout) Tries to delete all replicas of the given key.
DeleteResult	delete(String key) Tries to delete all replicas of the given key in 2000ms.
DeleteResult	delete(String key, int timeout) Tries to delete all replicas of the given key.
DeleteResult	getLastDeleteResult() Returns the result of the last call to delete(String).

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ReplicatedDHT

public ReplicatedDHT()
              throws ConnectionException

Constructor, uses the default connection returned by ConnectionFactory.createConnection().

Throws:

ConnectionException - if the connection fails

ReplicatedDHT

public ReplicatedDHT(Connection conn)

Constructor, uses the given connection to an erlang node.

Parameters:

conn - connection to use for the transaction

Method Detail

delete

public DeleteResult delete(OtpErlangString key)
                    throws ConnectionException,
                           TimeoutException,
                           UnknownException

Tries to delete all replicas of the given key in 2000ms. WARNING: This function can lead to inconsistent data (e.g. deleted items can re-appear). Also when re-creating an item the version before the delete can re-appear.

Parameters:

key - the key to delete

Returns:

a delete result object

Throws:

ConnectionException - if the connection is not active or a communication error occurs or an exit signal was received or the remote node sends a message containing an invalid cookie

TimeoutException - if a timeout occurred while trying to delete the value

UnknownException - if any other error occurs

Since:

3.19

See Also:

delete(OtpErlangString, int)

delete

public DeleteResult delete(OtpErlangString key,
                           int timeout)
                    throws ConnectionException,
                           TimeoutException,
                           UnknownException

Tries to delete all replicas of the given key. WARNING: This function can lead to inconsistent data (e.g. deleted items can re-appear). Also when re-creating an item the version before the delete can re-appear.

Parameters:

key - the key to delete

timeout - the time (in milliseconds) to wait for results

Returns:

a delete result object

Throws:

ConnectionException - if the connection is not active or a communication error occurs or an exit signal was received or the remote node sends a message containing an invalid cookie

TimeoutException - if a timeout occurred while trying to delete the value

UnknownException - if any other error occurs

Since:

3.19

delete

public DeleteResult delete(String key)
                    throws ConnectionException,
                           TimeoutException,
                           UnknownException

Tries to delete all replicas of the given key in 2000ms.

Parameters:

key - the key to delete

Returns:

a delete result object

Throws:

ConnectionException - if the connection is not active or a communication error occurs or an exit signal was received or the remote node sends a message containing an invalid cookie

TimeoutException - if a timeout occurred while trying to delete the value

UnknownException - if any other error occurs

Since:

3.19

See Also:

delete(String, int)

delete

public DeleteResult delete(String key,
                           int timeout)
                    throws ConnectionException,
                           TimeoutException,
                           UnknownException

Tries to delete all replicas of the given key. WARNING: This function can lead to inconsistent data (e.g. deleted items can re-appear). Also when re-creating an item the version before the delete can re-appear.

Parameters:

key - the key to delete

timeout - the time (in milliseconds) to wait for results

Returns:

a delete result object

Throws:

ConnectionException - if the connection is not active or a communication error occurs or an exit signal was received or the remote node sends a message containing an invalid cookie

TimeoutException - if a timeout occurred while trying to delete the value

UnknownException - if any other error occurs

Since:

3.19

See Also:

delete(OtpErlangString, int)

getLastDeleteResult

public DeleteResult getLastDeleteResult()

Returns the result of the last call to delete(String).

Returns:

the delete result

Throws:

UnknownException - is thrown if an unknown reason was encountered

See Also:

delete(String)

closeConnection

public void closeConnection()

Closes the transaction's connection to a scalaris node. Note: Subsequent calls to the other methods will throw ConnectionExceptions!