Invoke( ) method (Class)

Dynamically invokes a method whose name and parameters must be set at run time. The Invoke( ) method is one of several reflection methods of the Progress.Lang.Class class that provide type information about a class or interface at run time.

Return type: Any data type

Access: PUBLIC

Applies to: Progress.Lang.Class class

Four overloaded versions are supported. The first version is used to invoke a method that does not take any parameters.

Syntax

[ return-value = ] class-reference:Invoke( object-reference, method-name ).

The second overloaded version is used to invoke a method that takes zero or more parameters. Since parameterlist-object can be built with zero or more parameters, this version of the Invoke( ) method can be used to invoke any method, even those that do not take any arguments.

Syntax

[ return-value = ] class-reference:Invoke   ( object-reference, method-name, parameterlist-object ).

The third overloaded version is used when invoking a static method that does not take any parameters.

Syntax

[ return-value = ] class-reference:Invoke( method-name ).

The fourth overloaded version is used when invoking a static method that takes zero or more parameters. Since parameterlist-object can be built with zero or more parameters, this version of the Invoke( ) method can be used to invoke any static method, even those that do not take any arguments.

Syntax

[ return-value = ] class-reference:Invoke   ( method-name, parameterlist-object ).

Element descriptions for the syntax diagrams follow:

return-value

An optional data element which is assigned the return value from the invoked, non-void method. This data element can be any data type. The AVM checks return-value at run time for data type compatibility with what is actually returned by the method.

class-reference

An object reference for the Progress.Lang.Class instance containing the type information.

object-reference

A reference to the object that contains the method you want to invoke, and whose type is compatible with the class-reference object. When invoking a static method, the Unknown value (?) is passed for this parameter.

method-name

A CHARACTER expression that evaluates at run time to the name of the method to be invoked.

parameterlist-object

An instance of the Progress.Lang.ParameterList class.
Notes: The Invoke( ) method allows for I/O blocking. The method to run must be VOID and the Invoke( ) method must be used as a stand-alone statement and not part of an expression.

The DYNAMIC-INVOKE function provides similar functionality to the Invoke( ) method. The advantage of the former is that it has a fixed, compile-time parameter list and does not require the creation of a Progress.Lang.ParameterList object at run time.

See also: DYNAMIC-INVOKE function, DYNAMIC-NEW statement, New( ) method, NumParameters property, Progress.Lang.ParameterList class, SetParameter( ) method (Class)

OpenEdge Release 10.2B

Copyright © 2009 Progress Software Corporation