pointlistener

A pointlistener is a programming concept, often found in graphical user interface (GUI) development or game development, that allows a piece of code to be notified when a specific point in a coordinate system changes its value. This is a common pattern for event handling.

In essence, a pointlistener is an object or function that "listens" for updates to a point. When the point's coordinates (e.g., x and y values) are modified, the pointlistener is automatically invoked, allowing it to react to the change. This reaction could involve updating a display, triggering an animation, or performing some other action based on the new point location.

The implementation of a pointlistener typically involves a mechanism where the object representing the point maintains a list of registered listeners. When the point's data changes, it iterates through this list and calls a predefined method on each listener. This decouples the point object from the specific actions taken in response to its changes, promoting modularity and flexibility in software design.

This pattern is frequently used in scenarios where user interactions, such as mouse clicks or drags, determine the position of an object on the screen. The mouse event handler would update the point, and any pointlisteners associated with that point would then execute their associated logic. Similarly, in simulations or physics engines, when a simulated object's position is updated, a pointlistener could be used to redraw the object or update related game elements.