org.apache.derby.impl.jdbc

Class EmbedConnectionContext

java.lang.Object

org.apache.derby.iapi.services.context.ContextImpl

org.apache.derby.impl.jdbc.EmbedConnectionContext

All Implemented Interfaces:

ConnectionContext, Context

class EmbedConnectionContext
extends ContextImpl
implements ConnectionContext

Field Summary

Fields

Modifier and Type	Field and Description
private java.lang.ref.SoftReference	connRef We hold a soft reference to the connection so that when the application releases its reference to the Connection without closing it, its finalize method will be called, which will then close the connection.

Fields inherited from interface org.apache.derby.iapi.jdbc.ConnectionContext

CONTEXT_ID

Constructor Summary

Constructors

Constructor and Description
EmbedConnectionContext(ContextManager cm, EmbedConnection conn)

Method Summary

Modifier and Type	Method and Description
void	cleanupOnError(java.lang.Throwable error) Contexts will be passed errors that are caught by the outer system when they are serious enough to require corrective action.
java.sql.Connection	getNestedConnection(boolean internal) Get a connection equivalent to the call DriverManager.getConnection("jdbc:default:connection");
java.sql.ResultSet	getResultSet(ResultSet executionResultSet) Get a jdbc ResultSet based on the execution ResultSet.
boolean	processInaccessibleDynamicResult(java.sql.ResultSet resultSet) Process a ResultSet from a procedure to be a dynamic result, but one that will be closed due to it being inaccessible.

Methods inherited from class org.apache.derby.iapi.services.context.ContextImpl

appendErrorInfo, getContextManager, getIdName, isLastHandler, popMe, pushMe

Methods inherited from class java.lang.Object

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

Field Detail

connRef

private java.lang.ref.SoftReference connRef

We hold a soft reference to the connection so that when the application releases its reference to the Connection without closing it, its finalize method will be called, which will then close the connection. If a direct reference is used here, such a Connection will never be closed or garbage collected as modules hold onto the ContextManager and thus there would be a direct reference through this object.

Constructor Detail

EmbedConnectionContext

EmbedConnectionContext(ContextManager cm,
                       EmbedConnection conn)

Method Detail

cleanupOnError

public void cleanupOnError(java.lang.Throwable error)

Description copied from interface: Context

Contexts will be passed errors that are caught by the outer system when they are serious enough to require corrective action. They will be told what the error is, so that they can react appropriately. Most of the time, the contexts will react by either doing nothing or by removing themselves from the context manager. If there are no other references to the context, removing itself from the manager equates to freeing it.
On an exception that is session severity or greater the Context must push itself off the stack. This is to ensure that after a session has been closed there are no Contexts on the stack that potentially hold references to objects, thus delaying their garbage collection.

Contexts must release all their resources before removing themselves from their context manager.

The context manager will "unwind" the contexts during cleanup in the reverse order they were placed on its global stack.

If error is an instance of StandardException then an implementation of this method may throw a new exception if and only if the new exception is an instance of StandardException that is more severe than the original error or the new exception is a not an instance of StandardException (e.g java.lang.NullPointerException).

Specified by:

cleanupOnError in interface Context

getNestedConnection

public java.sql.Connection getNestedConnection(boolean internal)
                                        throws java.sql.SQLException

Get a connection equivalent to the call

                DriverManager.getConnection("jdbc:default:connection");
                

Specified by:

getNestedConnection in interface ConnectionContext

Throws:

java.sql.SQLException - Parent connection has been closed.

getResultSet

public java.sql.ResultSet getResultSet(ResultSet executionResultSet)
                                throws java.sql.SQLException

Get a jdbc ResultSet based on the execution ResultSet.

Specified by:

getResultSet in interface ConnectionContext

Parameters:

executionResultSet - a result set as gotten from execution

Throws:

java.sql.SQLException - on error

processInaccessibleDynamicResult

public boolean processInaccessibleDynamicResult(java.sql.ResultSet resultSet)

Process a ResultSet from a procedure to be a dynamic result, but one that will be closed due to it being inaccessible. We cannot simply close the ResultSet as it the nested connection that created it might be closed, leading to its close method being a no-op. This performs all the conversion (linking the ResultSet to a valid connection) required but does not close the ResultSet.

Specified by:

processInaccessibleDynamicResult in interface ConnectionContext

Parameters:

resultSet - ResultSet to process.

Returns:

True if this ResultSet was created by this connection and the result set is open. False otherwise.

See Also:

EmbedStatement.processDynamicResult(EmbedConnection, java.sql.ResultSet, EmbedStatement)