1. Introduction
2. Composition of an MhSnapper

• MhSnapperShape
• MhBehavior

MhSnapper

Introduction

MhSnapper is the primary Snapper within the abstract. This class follows the composition over inheritance pattern and as such should not be overridden. Instead, the behavior of the Snapper is determined by the MhSnapperShape and MhBehaviors that compose it.

Composition of an MhSnapper

MhSnapper contains the minimum amount of state required for it to exist in the drawing. This includes things like position, rotation, and family relationships with other Snappers. State and functionality are provided by the MhSnapper's MhBehaviors and MhSnapperShape.

MhSnapperShape

THe MhSnapperShape on MhSnapper contains the majority of the MhSnapper's state, such as category, dimensions, Connectors, and other required fields. The MhSnapperShape is responsible for determining the identity of the MhSnapper and is provided to the MhSnapper by the MhSnapperSpawner that creates it. The MhSnapperShape is stored in the shape field on MhSnapper.

MhBehavior

The MhBehavior class holds a specific piece of functionality for an MhSnapper such as graphics, snapping, parts, or any other functionality usually contained within the Snapper class. There are many pre-defined behavior classes in the abstract which are used to isolate specific functionality. For example, the MhGenericGfxBehavior should be used for behaviors relating to Snapper graphics. Behaviors are added to an MhSnapper by the MhSnapperSpawner that creates it.

Creating MhSnappers

The MhSnapperSpawner is responsible for creating and configuring MhSnappers. MhSnapperSpawner is used by the both the library, for a user to insert an MhSnapper as well as by the MhEngine and its MhSystemEngineFunctions to generate MhSnappers automatically. MhSnapperSpawners populate the snapper spawned with the appropriate MhSnapperShape and MhBehaviors to spawn the object that the spawner inserts.

Child Snappers

The abstract uses child snappers, which are snappers that are stored on other snappers, to represent objects in a material handling system which are composed of many separate objects. MhSnapper may have many child snappers representing the objects that compose it. The SnapperRelationship class is used to determine the functionality of child snappers and their relationship to their parent snapper. The SnapperRelationship is provided to the MhSnapper by the MhSnapperSpawner that creates it. The SnapperRelationship is used to determine the specifics of Snapper adoption.