After reading this chapter, we will learn the object interaction. First, we explore the concept of interaction in more detail. In the last chapter we have already analyzed use cases to determine some aspects of the interaction and collaboration between objects involved. 

Then we will learn how to model object interaction using an interaction sequence diagram. An interaction sequence diagram is one of several kinds of UML interaction diagram. It is semantically equivalent to a communication diagram for simple interactions. It also can be drawn at different levels to detail and to meet different purposes at several stages in the development lifestyle. The first part of the sequence diagram uses interaction occurrences which reference the other sequence diagrams list client campaigns and get campaign budget. On occasions it is necessary to represent complex or large interactions using two or more sequence diagrams. A sequence diagram can be labeled to document it in various ways.

Next we learn how to model object interaction using a communication diagram. Communication diagrams are the second kind of interaction diagram in the UML notation set. We will examine the notation for communication diagrams in more detail here. They have many similarities to sequence diagrams.

Last we will know the preparation of sequence and communication diagrams involved the allocation of operations of classes. But to ensure full consistency between a class diagram and a set of related interaction diagrams requires more than the simple syntactic check described above. At this stage it is sufficient to ensure that there is some possible pathway via object links. These are what we will learn in this chapter, it also uses a lot of knowledge in the last chapter, so we must learn every section well, and then we could understand each part.