org.apache.jackrabbit.core.persistence.bundle.util
Class ConnectionRecoveryManager

java.lang.Object
  org.apache.jackrabbit.core.persistence.bundle.util.ConnectionRecoveryManager

public class ConnectionRecoveryManager
extends Object

This class provides methods to get a database connection and to execute SQL statements. It also contains reconnection logic. If the connection has been closed with the close() method, then a call to any public method except for setAutoReconnect(boolean) will try to reestablish the connection, but only if the autoReconnect equals true.

The reconnection attempt can either be blocking or non-blocking, which is configured during construction. In the latter case a fixed number of reconnection attempts is made. When the reconnection failed an SQLException is thrown.

The methods of this class that execute SQL statements automatically call close() when they encounter an SQLException.

Nested Class Summary

static class

ConnectionRecoveryManager.StreamWrapper A wrapper for a binary stream that includes the size of the stream.

Field Summary

static int

TRIALS Number of reconnection attempts per method call.

Constructor Summary

ConnectionRecoveryManager(boolean block, String driver, String url, String user, String password)
Creates a ConnectionRecoveryManager and establishes a database Connection using the driver, user, password and url arguments.

Method Summary

void	close() Closes all resources held by this ConnectionRecoveryManager.
ResultSet	executeQuery(String sql) Executes the given SQL query.
PreparedStatement	executeStmt(String sql, Object[] params) Executes the given SQL statement with the specified parameters.
PreparedStatement	executeStmt(String sql, Object[] params, boolean returnGeneratedKeys, int maxRows) Executes the given SQL statement with the specified parameters.
Connection	getConnection() Gets the database connection that is managed.
void	setAutoReconnect(boolean autoReconnect) Starts a transaction.

Methods inherited from class java.lang.Object

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

Field Detail

TRIALS

public static final int TRIALS

Number of reconnection attempts per method call. Only used if block == false.

See Also:

Constant Field Values

Constructor Detail

ConnectionRecoveryManager

public ConnectionRecoveryManager(boolean block,
                                 String driver,
                                 String url,
                                 String user,
                                 String password)
                          throws RepositoryException

Creates a ConnectionRecoveryManager and establishes a database Connection using the driver, user, password and url arguments.

By default, the connection is in auto-commit mode, and this manager tries to reconnect if the connection is lost.

Parameters:

block - whether this class should block until the connection can be recovered

driver - the driver to use for the connection

url - the url to use for the connection

user - the user to use for the connection

password - the password to use for the connection

Throws:

RepositoryException - if the database driver could not be loaded

Method Detail

getConnection

public Connection getConnection()
                         throws SQLException,
                                RepositoryException

Gets the database connection that is managed. If the connection has been closed, and autoReconnect==true then an attempt is made to reestablish the connection.

Returns:

the database connection that is managed

Throws:

SQLException - on error

RepositoryException - if the database driver could not be loaded

setAutoReconnect

public void setAutoReconnect(boolean autoReconnect)

Starts a transaction. I.e., the auto-commit is set to false, and the manager does not try to reconnect if the connection is lost. This method call should be followed by a call to endTransaction.

Throws:

SQLException - on error

executeQuery

public ResultSet executeQuery(String sql)
                       throws SQLException,
                              RepositoryException

Executes the given SQL query. Retries once or blocks (when the block parameter has been set to true on construction) if this fails and autoReconnect is enabled.

Parameters:

sql - the SQL query to execute

Returns:

the executed ResultSet

Throws:

SQLException - on error

RepositoryException - if the database driver could not be loaded

executeStmt

public PreparedStatement executeStmt(String sql,
                                     Object[] params)
                              throws SQLException,
                                     RepositoryException

Executes the given SQL statement with the specified parameters.

Parameters:

sql - statement to execute

params - parameters to set

Returns:

the Statement object that had been executed

Throws:

SQLException - if an error occurs

RepositoryException - if the database driver could not be loaded

executeStmt

public PreparedStatement executeStmt(String sql,
                                     Object[] params,
                                     boolean returnGeneratedKeys,
                                     int maxRows)
                              throws SQLException,
                                     RepositoryException

Executes the given SQL statement with the specified parameters.

Parameters:

sql - statement to execute

params - parameters to set

returnGeneratedKeys - if the statement should return auto generated keys

maxRows - the maximum number of rows to return (0 for all rows)

Returns:

the Statement object that had been executed

Throws:

SQLException - if an error occurs

RepositoryException - if the database driver could not be loaded

close

public void close()

Closes all resources held by this ConnectionRecoveryManager. An ongoing transaction is discarded.