Class TransactionResourceImpl
TransactionResourceImpl not only serves as a transaction "context", it also takes care of:
- context management: the pushing and popping of the context manager in and out of the global context service
- transaction demarcation: all calls to commit/abort/prepare/close a transaction must route thru the transaction resource.
- error handling
The only connection that have access to the TransactionResource is the root connection, all other nested connections (called proxyConnection) accesses the TransactionResource via the root connection. The root connection may be a plain EmbedConnection, or a DetachableConnection (in case of a XATransaction). A nested connection must be a ProxyConnection. A proxyConnection is not detachable and can itself be a XA connection - although an XATransaction may start nested local (proxy) connections.
this is an example of how all the objects in this package relate to each other. In this example, the connection is nested 3 deep. DetachableConnection.
lcc cm database jdbcDriver ^ ^ ^ ^ | | | | |======================| | TransactionResource | |======================| ^ | | | | | |---------------rootConnection----------| | | | | | | |- rootConnection-| | | | | | | | V V | | |========================| |=================| |=================| | EmbedConnection | | EmbedConnection | | EmbedConnection | | |<-----| |<-----| | | (DetachableConnection) | | ProxyConnection | | ProxyConnection | |========================| |=================| |=================| ^ | ^ ^ ^ | | | | | ---rootConnection-- | | | | | | | | | |======================| |======================| |======================| | ConnectionChild | | ConnectionChild | | ConnectionChild | | | | | | | | (EmbedStatement) | | (EmbedResultSet) | | (...) | |======================| |======================| |======================|
A plain local connection must be attached (doubly linked with) to a TransactionResource at all times. A detachable connection can be without a TransactionResource, and a TransactionResource for an XATransaction (called XATransactionResource) can be without a connection.
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected ContextManager
protected ContextService
protected Database
private String
private String
private InternalDriver
protected LanguageConnectionContext
private String
protected String
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Constructor Summary
ConstructorsConstructorDescriptionTransactionResourceImpl
(InternalDriver driver, String url, Properties info) create a brand new connection for a brand new transaction -
Method Summary
Modifier and TypeMethodDescription(package private) boolean
cleanupOnError
(Throwable e, boolean diagActive) clean up error and print it to derby.log if diagActive is true(package private) void
An error happens in the constructor, pop the context.(package private) void
clearLcc()
Resolve: probably superfluous(package private) void
commit()
local transaction demarcation - note that global or xa transaction cannot commit thru the connection, they can only commit thru the XAResource, which uses the xa_commit or xa_rollback interface as a safeguard.(package private) ContextManager
need to be public because it is in the XATransactionResource interface(package private) ContextService
getCsf()
(package private) Database
(package private) String
(package private) InternalDriver
Return instance variables to EmbedConnection.(package private) LanguageConnectionContext
getLcc()
(package private) String
getUrl()
(package private) String
(package private) final SQLException
handleException
(Throwable thrownException, boolean autoCommit, boolean rollbackOnAutoCommit) clean up the error and wrap the real exception in some SQLException.(package private) boolean
isActive()
(package private) boolean
isIdle()
private boolean
isLoginException
(Throwable thrownException) Determine if the exception thrown is a login exception.(package private) final void
(package private) void
rollback()
(package private) void
setDatabase
(Database db) Called only in EmbedConnection construtor.(package private) final void
(package private) StandardException
(package private) void
static SQLException
wrapInSQLException
(Throwable thrownException) Wrap aThrowable
in anSQLException
.
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Field Details
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cm
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csf
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username
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dbname
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driver
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url
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drdaID
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database
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lcc
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Constructor Details
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TransactionResourceImpl
TransactionResourceImpl(InternalDriver driver, String url, Properties info) throws SQLException create a brand new connection for a brand new transaction- Throws:
SQLException
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Method Details
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setDatabase
Called only in EmbedConnection construtor. The Local Connection sets up the database in its constructor and sets it here. -
startTransaction
- Throws:
StandardException
SQLException
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getDriver
InternalDriver getDriver()Return instance variables to EmbedConnection. RESOLVE: given time, we should perhaps stop giving out reference to these things but instead use the transaction resource itself. -
getCsf
ContextService getCsf() -
getContextManager
ContextManager getContextManager()need to be public because it is in the XATransactionResource interface -
getLcc
LanguageConnectionContext getLcc() -
getDBName
String getDBName() -
getUrl
String getUrl() -
getDatabase
Database getDatabase() -
shutdownDatabaseException
StandardException shutdownDatabaseException() -
commit
local transaction demarcation - note that global or xa transaction cannot commit thru the connection, they can only commit thru the XAResource, which uses the xa_commit or xa_rollback interface as a safeguard.- Throws:
StandardException
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rollback
- Throws:
StandardException
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clearContextInError
void clearContextInError()An error happens in the constructor, pop the context. -
clearLcc
void clearLcc()Resolve: probably superfluous -
setupContextStack
final void setupContextStack() -
restoreContextStack
final void restoreContextStack() -
handleException
final SQLException handleException(Throwable thrownException, boolean autoCommit, boolean rollbackOnAutoCommit) throws SQLException clean up the error and wrap the real exception in some SQLException.- Throws:
SQLException
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isLoginException
Determine if the exception thrown is a login exception. Needed for DERBY-5427 fix to prevent inappropriate thread dumps and javacores. This exception is special because it is SESSION_SEVERITY and database.isActive() is true, but the session hasn't started yet,so it is not an actual crash and should not report extended diagnostics.- Parameters:
thrownException
-- Returns:
- true if this is a login failure exception
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wrapInSQLException
Wrap aThrowable
in anSQLException
.- Parameters:
thrownException
- aThrowable
- Returns:
thrownException
, if it is anSQLException
; otherwise, anSQLException
which wrapsthrownException
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getUserName
String getUserName() -
cleanupOnError
clean up error and print it to derby.log if diagActive is true- Parameters:
e
- the error we want to clean updiagActive
- true if extended diagnostics should be considered, false not interested of extended diagnostic information- Returns:
- true if the context manager is shutdown, false otherwise.
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isIdle
boolean isIdle() -
isActive
boolean isActive()
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