oracle.javatools.db.execute

Class ConnectionWrapper

java.lang.Object

oracle.javatools.db.execute.ConnectionWrapper

public class ConnectionWrapper
extends java.lang.Object

Class to wrap a process that uses a Database connection and can execute that process while recovering from a closed connection (by reconnecting). This is automatically used by the StatementWrapper and QueryWrapper so does not need to be used in addition to them.

Example usage 1: Retrieving the user name for the Connection

 final Database db = ...
 try
 {
   final ConnectionWrapper wrapper =
     new ConnectionWrapper( db, "Query username from connection metadata" ); // description should be translated
   final String userName = wrapper.call(
     wrapper.new SQLCallable()
     {
       public String call() throws SQLException
       {
         return getConnection().getMetaData().getUserName();
       }
     } );
 }
 catch( SQLException sqe )
 {
   // process the exception
 }
 

Example usage 2: Setting the autocommit flag on the connection

 final Database db = ...
 try
 {
   final ConnectionWrapper wrapper =
     new ConnectionWrapper( db, "Set the auto commit flag on the Connection" ); // description should be translated
   final String userName = wrapper.run(
     wrapper.new SQLRunnable()
     {
       public void run() throws SQLException
       {
         getConnection().setAutoCommit( true );
       }
     } );
 }
 catch( SQLException sqe )
 {
   // process the exception
 }
 

Since:

11.1.1.4.0

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	ConnectionWrapper.SQLCallable<T> Callable class that can throw a SQLException from its call method.
class	ConnectionWrapper.SQLRunnable Runnable class that can throw a SQLException from its run method.

Constructor Summary

Constructors

Constructor and Description
ConnectionWrapper(Database db, java.lang.String desc) Creates a ConnectionWrapper using the given Database.

Method Summary

Methods

Modifier and Type	Method and Description
<T> T	call(ConnectionWrapper.SQLCallable<T> c) Calls the given SQLCallable.
void	run(ConnectionWrapper.SQLRunnable r) Runs the given SQLRunnable.

Methods inherited from class java.lang.Object

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

Constructor Detail

ConnectionWrapper

public ConnectionWrapper(Database db,
                 java.lang.String desc)

Creates a ConnectionWrapper using the given Database.

Parameters:

db - the database to use the Connection from

desc - a translatable description of the nature of the process being executed. This will be wrapped into any DBException thrown if the process fails to indicate to the user what failed.

Method Detail

run

public void run(ConnectionWrapper.SQLRunnable r)
         throws DBException

Runs the given SQLRunnable. If a SQLException is encountered that is identifiable as a "closed connection" exception then the connection will be reconnected and the runnable re-run.

Parameters:

r - the runnable to run as a unit of work on the Connection

Throws:

DBException - if an error with the database occurs

call

public <T> T call(ConnectionWrapper.SQLCallable<T> c)
       throws DBException

Calls the given SQLCallable. If a SQLException is encountered that is identifiable as a "closed connection" exception then the connection will be reconnected and the callable re-called.

Parameters:

c - the callable to run as a unit of work on the Connection

Returns:

the result of the SQLCallable if no exception was encountered

Throws:

DBException - if an error with the database occurs