Abstract: An art distribution system for distributing art to multiple display devices within an environment. The art distribution system provides a technique for specifying images to be displayed in an environment. The art distribution system provides a hierarchical representation of spaces within the environment. Each space may be further subdivided into subspaces. The art distribution system allows a user to select a space within the hierarchy and then to select an image that is to be displayed at the display devices within the selected space. The art distribution system then displays the selected image within the space including within all subspaces of the selected space. The art distribution system may allow a subsequent assignment of the image to a subspace to override within that subspace the previous selection of an image for the space.

Abstract: A method and system for implementing functions in a class that inherits an interface and that inherits an implementing class which implements the interface. A forwarding system adds to the class for each virtual function a forwarding implementation of that virtual function. The forwarding implementation forwards its invocation to the implementation of that the virtual function in the implementing class. The forwarding system implements a special forwarding instruction that specifies the interface and implementing class. A developer of a class that inherits the interface and the implementing class inserts the forwarding instruction into the class definition. When the forwarding system encounters such an instruction during compilation of the class definition, the forwarding system provides an implementation of each virtual function of the interface that forwards its invocation to a corresponding virtual function in the implementing class.

Abstract: A method system for tracking the state of an entity (e.g., an object) on behalf of a client (e.g., an application program). The states of an entity include up and down. The tracking system of the present invention receives a request from a client to track the state of an entity. The tracking system then watches the state of the entity to detect when the entity enters the up state. When the entity enters the up state, the tracking system performs a behavior that is specified by the client to be performed when the entity enters the up state. When the entity is in the up state, the tracking system monitors the state of the entity to detect when the entity enters the down state. When the entity enters the down state, the tracking system performs a behavior that is specified by the client to be performed when the entity enters the down state.

Abstract: An art distribution system for distributing art to multiple display devices within an environment. The art distribution system provides a technique for specifying images to be displayed in an environment. The art distribution system provides a hierarchical representation of spaces within the environment. Each space may be further subdivided into subspaces. The art distribution system allows a user to select a space within the hierarchy and then to select an image that is to be displayed at the display devices within the selected space. The art distribution system then displays the selected image within the space including within all subspaces of the selected space. The art distribution system may allow a subsequent assignment of the image to a subspace to override within that subspace the previous selection of an image for the space.

Abstract: A method system for tracking the state of an entity (e.g., an object) on behalf of a client (e.g., an application program). The states of an entity include up and down. The tracking system of the present invention receives a request from a client to track the state of an entity. The tracking system then watches the state of the entity to detect when the entity enters the up state. When the entity enters the up state, the tracking system performs a behavior that is specified by the client to be performed when the entity enters the up state. When the entity, is in the up state, the tracking system monitors the state of the entity to detect when the entity enters the down state. When the entity enters the down state, the tracking system performs a behavior that is specified by the client to be performed when the entity enters the down state.

Abstract: A method system for tracking the state of an entity (e.g., an object) on behalf of a client (e.g., an application program). The states of an entity include up and down. The tracking system of the present invention receives a request from a client to track the state of an entity. The tracking system then watches the state of the entity to detect when the entity enters the up state. When the entity enters the up state, the tracking system performs a behavior that is specified by the client to be performed when the entity enters the up state. When the entity, is in the up state, the tracking system monitors the state of the entity to detect when the entity enters the down state. When the entity enters the down state, the tracking system performs a behavior that is specified by the client to be performed when the entity enters the down state.