2012 NEWS 2012-05-05 - UIZE Adds Support for Singletons
UIZE has added support for singletons in the form of the new Uize.Class.singleton static method implemented in the Uize.Class base class and inherited by all Uize.Class subclasses.
The Uize.Class.singleton static method returns a singleton for the class for the optionally specified scope (default is empty scope).
DIFFERENT USAGES
singletonOBJ = MyClass.singleton ();
Get a Singleton for a Class for a Specific Scope
singletonOBJ = MyClass.singleton (scopeSTR);
Get a Singleton for a Class for a Specific Scope, Specifying Initial State
singletonOBJ = MyClass.singleton (scopeSTR,propertiesOBJ);
1. Get a Singleton for a Class
When no parameters are specified, this method will return a singleton for the class in the default scope.
SYNTAX
singletonOBJ = MyClass.singleton ();
When the Uize.Class.singleton static method is called on a class, if a singleton instance has already been created for the default scope, then that instance will be returned. Otherwise, a singleton instance will be created for the default scope and then returned.
2. Get a Singleton for a Class for a Specific Scope
When the optional scopeSTR parameter is specified, this method will return a singleton for the class in the specified scope.
SYNTAX
singletonOBJ = MyClass.singleton (scopeSTR);
When the Uize.Class.singleton static method is called on a class, if a singleton instance has already been created for the specified scope, then that instance will be returned. Otherwise, a singleton instance will be created for the specified scope and then returned.
3. Get a Singleton for a Class for a Specific Scope, Specifying Initial State
When the optional propertiesOBJ parameter is specified, then this method will return a singleton for the class in the specified scope, and with the state of its state properties set using the propertiesOBJ object.
SYNTAX
singletonOBJ = MyClass.singleton (scopeSTR,propertiesOBJ);
When the Uize.Class.singleton static method is called on a class, if a singleton instance has already been created for the specified scope, then that instance will be set to the state specified by the propertiesOBJ parameter and then returned. Otherwise, a singleton instance will be created for the specified scope, with its state initialized using the propertiesOBJ parameter, and then returned.
4. Singleton Scope
As a convenience, the Uize.Class.singleton static method lets you optionally specify a scope when getting singleton instances, using the scopeSTR parameter.
If no scopeSTR parameter is specified when getting a singleton for a class, then the default scope (an empty string) will be used. Therefore, the statement MyClass.singleton () is equivalent to the statement MyClass.singleton ('').
A scope provides multiple different bits of related but distributed code to get a reference to the same singleton by specifying the same scope, while still allowing other code to share references to a different singleton created using a different scope.