Difference between revisions of "RecordLockingConflict class"

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<!-- RecordLockingConflict class -->
 
<!-- RecordLockingConflict class -->
 
The <var>RecordLockingConflict</var> exception class catches record locking conflict errors thrown by file object operations; that is from methods in the <var>[[File_classes|file]]</var> (that is: <var>[[Record_class|Record]]</var>, <var>[[Recordset_class|Recordset]]</var>, <var>[[SortedRecordset_class|SortedRecordset]]</var>, and <var>[[RecordsetCursor_class|RecordsetCursor]]</var>) classes.
 
The <var>RecordLockingConflict</var> exception class catches record locking conflict errors thrown by file object operations; that is from methods in the <var>[[File_classes|file]]</var> (that is: <var>[[Record_class|Record]]</var>, <var>[[Recordset_class|Recordset]]</var>, <var>[[SortedRecordset_class|SortedRecordset]]</var>, and <var>[[RecordsetCursor_class|RecordsetCursor]]</var>) classes.
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==Summary==
 
==Summary==
 
A RecordLockingConflict exception is thrown only if there is a Catcher for the exception. This allows <code>On record Locking Conflict</code> and <code>On Find Conflict</code> units to trap record locking conflicts if there is no Catch block for the exception.
 
A RecordLockingConflict exception is thrown only if there is a Catcher for the exception. This allows <code>On record Locking Conflict</code> and <code>On Find Conflict</code> units to trap record locking conflicts if there is no Catch block for the exception.

Revision as of 01:49, 30 August 2012

The RecordLockingConflict exception class catches record locking conflict errors thrown by file object operations; that is from methods in the file (that is: Record, Recordset, SortedRecordset, and RecordsetCursor) classes.

Summary

A RecordLockingConflict exception is thrown only if there is a Catcher for the exception. This allows On record Locking Conflict and On Find Conflict units to trap record locking conflicts if there is no Catch block for the exception.

There is no distinction between a Find conflict and a record locking conflict. For example, you can use the following:

try fd to %foo ... end find catch recordLockingConflict ... end try

And you can also use:

try %rec = new(%recnum, exclusive) for record %rec ... end for catch recordLockingConflict ... end try

You can even catch record locking conflicts caused by LoopLockStrength promotions during a loop:

%rec = new(%recnum, none, loopLockStrength=share) ... try for record %rec ... end for catch recordLockingConflict ... end try

Or as in the following:

%curser = new(%recset, loopLockStrength=none) ... try for record at cursor %curser ... end for catch recordLockingConflict .. end try

Or as in this example:

fdwol to %recset = new(loopLockStrength=exclusive) ... end find ... try for each record in %recset ... end for catch recordLockingConflict ... end try

In the latter example, note that any iteration of the For loop can throw an exception, and there is no way of picking up where you left off (at the next record, say) if you get a RecordLockingConflict exception in such a case. So, unless you always want to lose the whole loop on a record locking conflict, such a case is almost always better structured with a cursor on the recordset and with Try around the For Record At Cursor loop:

fdwol to %recset = new(loopLockStrength=exclusive) ... end find ... %curser = new(%recset, loopLockStrength=exclusive) repeat while %curser:state eq hasRecord try for record at cursor %curser ... end for catch recordLockingConflict ... end try %curser:next end repeat

Note: The For statement can be on the same line as the Try, or it can be inside the Try block.


The RecordLockingConflict methods

The following are the available RecordLockingConflict class methods.

MethodDescription
ConflictTimeMillisecondsTime that the conflict occurred
ConflictingLockStrengthLock strength of conflicting lock
ConflictingRecordLockTypeLock type of conflicting lock
CopyCopy the RecordLockingConflict object
DeepCopyDeep copy the RecordLockingConflict object
FilenameName of the file in which last record locking conflict occurred
LockTimeMillisecondsTime that the conflicting record was locked
LockingUserNumberUser number of the user that locked the conflicting record
NewCreate a new RecordLockingConflict object
NewFromLastConflictCreate object from current conflict information
RecordNumberRecord number of the record that has the conflict
UserIDUser ID (login name) of the user that has the conflict
UserNumberUser number of the user that has the conflict

The methods in the class are described in the subsections that follow. In addition:


Filename property

Name of the file in which last record locking conflict occurred (RecordLockingConflict class)

This ReadOnly property returns a Longstring that contains the name of the file in which the last record locking conflict occurred.

Syntax

%string = recordLockingConflict:Filename

Syntax terms

%string A longstring to receive the file name.
recordLockingConflict A reference to an instance of a RecordLockingConflict object.


New constructor

Create a new RecordLockingConflict object (RecordLockingConflict class)

This Constructor generates an instance of an RecordLockingConflict exception. As shown in the syntax that follows, the New method arguments set the values of the class properties having the corresponding names. Each argument to New sets the value of the corresponding property of the newly constructed RecordLockingConflict object.

Syntax

%recordLockingConflict = [%(RecordLockingConflict):]New( Filename= string, - RecordNumber= number, - UserNumber= number, - UserID= string, - [LockingUserNumber= number], - [LockTimeMilliseconds= number], - [ConflictTimeMilliseconds= number], - [ConflictingLockStrength= lockStrength], - [ConflictingRecordLockType= recordLockType])

Syntax terms

%recordLockingConflict A reference to an instance of a RecordLockingConflict object.
[%(RecordLockingConflict):] The class name in parentheses denotes a Constructor.
Filename This name required parameter specifies the Longstring value (string) to be assigned to the object's Filename property. Its default value is a null string.
RecordNumber This name required parameter specifies the numeric value (number) to be assigned to the object's RecordNumber property. Its default value is 0.
UserNumber This name required parameter specifies the numeric value (number) to be assigned to the exception object's UserNumber property. Its default value is 0.
UserID This name required parameter specifies the longstring value (string) to be assigned to the object's UserID property. Its default value is a null string.

RecordNumber property

Record number of the record that has the conflict (RecordLockingConflict class)

This ReadOnly property returns the numeric value of the Model 204 internal record number of the record that has the conflict.


Syntax

%number = recordLockingConflict:RecordNumber

Syntax terms

%number A numeric variable to receive the record number.
recordLockingConflict A reference to an instance of a RecordLockingConflict object.

Example

The following example shows all the properties of the RecordLockingConflict class. While the standard record locking conflict information is available for retrieval via the User Language functions $rlcfile, $rlcrec, $rlcuid, and $rlcusr, that information is also set in the exception object and retrievable via that object:

%rlc is object RecordLockingConflict ... %rec = new(%recnum, none, loopLockStrength=share) ... try for record %rec ... end for catch recordLockingConflict to %rlc auditText Conflict on record {%rlc:recordNumber} - in file {%rlc:filename} auditText Conflicting user was userid {%rlc:userid}, - with user number:{%rlc:userNumber} end try


UserID property

User ID (login name) of the user that has the conflict (RecordLockingConflict class)

This ReadOnly property returns the Model 204 userid (login name) of the user that has the conflict.

Syntax

%string = recordLockingConflict:UserID

Syntax terms

%string A longstring to receive the userid value.
recordLockingConflict A reference to an instance of a RecordLockingConflict object.


UserNumber property

User number of the user that has the conflict (RecordLockingConflict class)

This ReadOnly property returns the user number (unique per session) of the user that has the conflict.

Syntax

%number = recordLockingConflict:UserNumber

Syntax terms

%number A numeric variable to receive the user number.
recordLockingConflict A reference to an instance of a RecordLockingConflict object.