Object Characteristics

Objects, whether real-world or computer representations, have certain characteristics that help us understand what they are and how they behave. The following concepts describe the aspects and characteristics of computer representations:

• Properties — Objects have certain characteristics or attributes, called properties, that define their appearance or state — for example, color, size, and modification date. Properties are not limited to the external or visible traits of an object. They may reflect the internal or operational state of an object, such as an option in a spelling check utility that automatically suggests alternative spellings.
• Operations — Things that can be done with or to an object are considered its operations. Moving or copying an object are examples of operations. You can expose operations in the interface through a variety of mechanisms, including commands and direct manipulation.
• Relationships — Objects always exist within the context of other objects. The context, or relationships, that an object may have often affects the way the object appears or behaves. Common kinds of relationships include collections, constraints, and composites.