 SourcePro® 2022.1 |
SourcePro® API Reference Guide |
Encapsulates the error state of an object or operation. More...
#include <rw/db/status.h>
Inherits RWDBFuture.
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, internalError, cacheWriteError, cacheReadError } |
| typedef void(* | ErrorHandler) (const RWDBStatus &status) |
Public Member Functions | |
| RWDBStatus () | |
| RWDBStatus (const RWDBStatus &status) | |
| ErrorCode | errorCode () const |
| ErrorHandler | errorHandler () const |
| bool | isTerminal () const |
| bool | isValid () const |
| RWCString | message () const |
| RWDBStatus & | operator= (const RWDBStatus &status) |
| void | raise () const |
| void | setErrorHandler (ErrorHandler handler) |
| long | vendorError1 () const |
| long | vendorError2 () const |
| RWCString | vendorMessage1 () const |
| RWCString | vendorMessage2 () const |
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.
An application that requires C++ exceptions throughout would proceed this way:
| typedef void(* RWDBStatus::ErrorHandler) (const RWDBStatus &status) |
A typedef for the error handling function.
Possible RWDBStatus error codes.
| 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.
| 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 |
Throws an exception that contains 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.
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