Relationships Between Objects

Abstract

As you saw in Chapter 4, any two objects can have a “fleeting relationship” based on the fact that they invoke methods on each other, in the same way that two strangers passing on the street might say “Hello!” to one another. We call such relationships between objects behavioral relationships because they arise out of the behaviors, or actions, taken by one object X relative to another object Y. With behavioral relationships, object X is either temporarily handed a reference to object Y as an argument in a method call or temporarily requests a reference to Y from another object Z. However, the emphasis is on temporary; when X is finished communicating with Y, object X often discards the reference to Y.