MacApp 2.0 Object And Method Reference

MacApp 2.0 Object and Method Reference This chapter describes the object classes that existed in MacApp 1.1. If you need infonnation on classes and methods not described here. refer to other release notes and to the source code. Each object description in this chapter contains the following elements: • whether you customize the object type. instantiate it. or call its methods • notes about the object type • the chain of ancestors leading to the object type • field declarations and explanations • descriptions of the methods for each object type Important Complete Information about the Implementation of each method Is not given In this chapter. If you need further details ab6ut any method. refer to the MacApp source code. TObject Customize: usually Instantiate: never Call methods: usually TObject is the ultimate ancestor for all objects in MacApp. TObject is documented here primarily for background information. It is an abstract object type that exists so that other object types can inherit characteristics from it, and thus share them. The only TObject methods you might override are Free and Clone. Ancestors: none Fields none MacApp 2.0 Globals 10/3/88 Page 1 Clone FUNCTION TObject .Clone: TObject; The retum value An exact copy of the calling object Purpose To clone dependent objects referred to by the fields of an object as well as cloning the object i~lf. An object is dependent on another object when the second object has the only (or the only important) reference to the first object Dependency is a relatively vague condition; when you override this method, you need to detennine what objects are dependent on SELF. The default version Calls ShallowClone, and thus clones only the object i~lf Override Sometimes Call Sometimes Free PROCEDURE TOb ject:. Free; Purpose To free the calling object and any dependent objects referred to by its fields. An· object is dependent on another object when the second object has the only (or the only important) reference to the first object Dependency is a relatively vague condition; when you override this method, you need to determine what objects are dependent on SELF. Th• default version Calls ShallowFree Override Often. Your version should free any dependent objects you have added for your customization and then call INHERITED Free so that any ancestor methods can free other dependent objects. The chain of INHERI1ED calls leads to TObject.Free, which calls TObjecLShallowFree, which frees SELF. Call Often ShallowClone FUNCTION TObject. ShalloWClone: TObject; The retum value Purpose This is the lowest-level method for copying an object Called by TObject.Oone The default version Calls HandToHand, an Inside Macintosh routine, to copy the object data Override Never Call Rarely MocApp 2.0 Globals 10/3/88 Page 2 Shallow Free PROCEDURE TObject.ShallowFxee; Purpose This is the lowest-level method for freeing an objecL Called by TObjecLFree The default version Frees t…