SetObject (System function): Difference between revisions
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<tr><th>%gen</th><td>The new generation number associated with name. This is a positive integer (set to 1 the first time the method succeeds) that increases by one each time the name object is updated. <var class="term">gen</var> is set to 0 if the method encounters a problem or if <var class="term">testGen</var> differs from the current generation number of name. | <tr><th>%gen</th><td>The new generation number associated with name. This is a positive integer (set to 1 the first time the method succeeds) that increases by one each time the name object is updated. <var class="term">gen</var> is set to 0 if the method encounters a problem or if <var class="term">testGen</var> differs from the current generation number of name. | ||
<p>All other errors result in request cancellation.</p></td></tr> | <p>All other errors result in request cancellation.</p></td></tr> | ||
<tr><th>%(System)</th> | <tr><th><var>%(System)</var></th> | ||
<td>The class name in parentheses denotes a shared method. <var>SetObject</var> can also be invoked via a <var>[[System_class|System]]</var> object variable, which may be <var>null</var>.</td></tr> | <td>The class name in parentheses denotes a shared method. <var>SetObject</var> can also be invoked via a <var>[[System_class|System]]</var> object variable, which may be <var>null</var>.</td></tr> | ||
<tr><th>name</th> | <tr><th>name</th> | ||
Revision as of 01:16, 3 May 2011
Set a system-wide object (System class)
SetObject sets a "system-wide object".
Syntax
[%gen =] %(System):SetObject( name, object, [testGen])
Syntax terms
| %gen | The new generation number associated with name. This is a positive integer (set to 1 the first time the method succeeds) that increases by one each time the name object is updated. gen is set to 0 if the method encounters a problem or if testGen differs from the current generation number of name.
All other errors result in request cancellation. |
|---|---|
| %(System) | The class name in parentheses denotes a shared method. SetObject can also be invoked via a System object variable, which may be null. |
| name | The string name by which the system-wide object is identified. |
| object | The object variable that becomes the current system-wide object. The object referenced by object must be "deep copyable"). |
| testGen | An optional argument, this is an integer that is compared to the current generation number of name. If the values differ, SetObject fails to replace %obj, and it returns a 0 value. |
Examples
- The following example shows how the generation number can be used to make sure that you do not update an object that someone else updated after you got your copy.
%myObj is object myClass ... retry: %gen = %(system):getObject('FOO', %myObj) ... fiddle with the object * Now try to update it if not %(system):setObject('FOO', %myObj, %gen) then * Someone else changed it, let's see what they did jump to retry end if
In this case, when you try to update FOO, FOO's generation is compared with %gen. If the generation number changed, the SetObject call does not succeed, and 0 is returned.