RWDBStatus Class Reference
[Utilities and Diagnostics]

Encapsulates the error state of an object or operation. More...

#include <rw/db/status.h>

Inherits RWDBFuture.

List of all members.

Public Types
enum	ErrorCode {   ok, noMem, notInitialized, typeConversion,   dbNotFound, serverError, serverMessage, vendorLib,   notConnected, endOfFetch, invalidUsage, columnNotFound,   invalidPosition, notSupported, nullReference, notFound,   missing, noMultiReaders, noDeleter, noInserter,   noUpdater, noReader, noIndex, noDrop,   wrongConnection, noPrivilege, noCursor, cantOpen,   applicationError, notReady }
typedef void(*	ErrorHandler )(const RWDBStatus &status)
Public Member Functions
	RWDBStatus ()
	RWDBStatus (const RWDBStatus &status)
RWDBStatus &	operator= (const RWDBStatus &status)
void	setErrorHandler (ErrorHandler handler)
void	raise () const
ErrorCode	errorCode () const
ErrorHandler	errorHandler () const
long	vendorError1 () const
long	vendorError2 () const
bool	isValid () const
bool	isTerminal () const
RWCString	message () const
RWCString	vendorMessage1 () const
RWCString	vendorMessage2 () const

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Detailed Description

RWDBStatus encapsulates the error state of an object or operation. A valid object or a successful operation is represented by RWDBStatus::ok. An RWDBStatus that is not valid contains an error code, an error message, and often some supplemental information provided by a database vendor's API.

Each RWDBStatus object contains a callback routine that can be changed by an application. If an RWDBStatus changes state to anything but RWDBStatus::ok, the installed handler is called with self as an argument.

In the error model of the DB Interface Module, the use of exceptions is optional, and is under the application's control. The raise() method of RWDBStatus throws an exception of type RWExternalErr. Thus, an application may choose to enforce a terminating or nonterminating model of error handling by installing an appropriate error handler.

When objects of the DB Interface Module are produced by other objects, the produced object's status is copied from the producer. Consequently, an application can control error handling at any level it chooses. A handler installed in the RWDBManager is propagated to every object of The DB Interface Module in the application; one installed in an RWDBDatabase is propagated to each object produced by that RWDBDatabase, and so on down to the level of individual objects.

RWDBStatus is designed around the Interface/Implementation paradigm. An RWDBStatus instance is an interface to a reference-counted implementation; copy constructors and assignment operators produce additional references to a shared implementation.

Synopsis

 #include <rw/db/status.h>

 RWDBStatus status = myDbase.status();    //status of object
 RWDBStatus status = myDbase.createTable("tableName",myschema);
                                          //status of function

Examples

An application that requires C++ exceptions throughout would proceed this way:

 void throwStatus(const RWDBStatus& status)
 {
     status.raise();
 }
 RWDBManager::setErrorHandler(throwStatus);

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Member Typedef Documentation

typedef void(* RWDBStatus::ErrorHandler)(const RWDBStatus &status)

A typedef for the error handling function.

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Member Enumeration Documentation

enum RWDBStatus::ErrorCode

Possible RWDBStatus error codes.

Enumerator:

ok	No error.
noMem	Out of Memory.
notInitialized	Object never initialized.
typeConversion	Type conversion error.
dbNotFound	Database not registered.
serverError	Error reported by server.
serverMessage	Message from server.
vendorLib	Error in vendor's library.
notConnected	Lost connection.
endOfFetch	End of fetch.
invalidUsage	Invalid usage of object.
columnNotFound	Column does not exist.
invalidPosition	Invalid positioning within object, i.e. bounds error.
notSupported	Unsupported feature.
nullReference	Null reference parameter.
notFound	Database Object not found.
missing	Required piece of information is missing.
noMultiReaders	This object cannot support multiple readers.
noDeleter	This object cannot support deletions.
noInserter	This object cannot support insertions.
noUpdater	This object cannot support updates.
noReader	This object cannot support readers.
noIndex	This object cannot support indices.
noDrop	This object cannot be dropped.
wrongConnection	Incorrect connection was supplied.
noPrivilege	This object cannot support privileges.
noCursor	This object cannot support cursors.
cantOpen	Unable to open.
applicationError	For errors produced at the application level.
notReady	For future use.

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Constructor & Destructor Documentation

RWDBStatus::RWDBStatus

(

)

The default constructor creates an RWDBStatus of notInitialized. Data members are set to default values of 0 or the empty string, and the error handler is set to rwnil.

RWDBStatus::RWDBStatus

(

const RWDBStatus &

status

)

Copy constructor. The created RWDBStatus shares an implementation with status.

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Member Function Documentation

ErrorCode RWDBStatus::errorCode

(

)

const

Returns self's error code. The code errorCode() != ok can be interpreted as an abnormal condition.

ErrorHandler RWDBStatus::errorHandler

(

)

const

Returns self's installed error handler, if any.

bool RWDBStatus::isTerminal

(

)

const

Returns true if the error that occurred will terminate the application.

bool RWDBStatus::isValid

(

)

const

Returns true if errorCode() == ok, otherwise returns false.

RWCString RWDBStatus::message

(

)

const

Returns the error message associated with the current error code. Returns an empty string if the current error code is ok.

RWDBStatus& RWDBStatus::operator=

(

const RWDBStatus &

status

)

Assignment operator. Self shares an implementation with status. Returns a reference to self.

void RWDBStatus::raise

(

)

const

If exceptions are not supported according to the Essential Tools Module macro RW_NO_EXCEPTIONS, aborts via a call to exit(ok). Otherwise raises an exception via an invocation of the Essential Tools Module macro RWTHROW(), passing the error message associated with self.

void RWDBStatus::setErrorHandler

(

ErrorHandler

handler

)

Installs handler as self's error handler. The supplied handler is inherited by all objects produced by self. By default, an RWDBStatus::ErrorHandler is inherited from the object that produced it; this method overrides the default.

long RWDBStatus::vendorError1

(

)

const

Returns a code supplied by the database vendor, or 0 if not relevant.

long RWDBStatus::vendorError2

(

)

const

Returns a code supplied by the database vendor, or 0 if not relevant.

RWCString RWDBStatus::vendorMessage1

(

)

const

Returns a string supplied by the database vendor, or an empty string if not relevant.

RWCString RWDBStatus::vendorMessage2

(

)

const

Returns a string supplied by the database vendor, or an empty string if not relevant.