In the previous chapter, you learned about a generic pattern for representing business objects. The pattern assumed that the business object was a stand- alone object. This scenario is not realistic in business applications. Collections of business objects are far more common than stand-alone business objects. In fact, it is challenging to think of a simple business object that has value in a business application. Nonetheless, Chapter 6, "Exploring the Business Object Pattern" provided you with both a learning experience and a solid foundation for the Business Object Collection pattern.
Consider just about any scenario or common business concept, and it is very likely that you would use a collection to manage it. Sales orders, customers, and products are all business objects that you collect. In fact, the P.T. Monday Coffee Company application is full of collections; you will have collections of products for a product catalog, collections of products in your inventory, and collections of sales orders to keep track of your sales. Many of these collections will become Web Services to allow at least the querying of data by business partners . More often, applications place additional logic on top of the collection. For example, a browser-based interface would locate a particular order using the collection Web Service and then render the status of the order to the user .
Using the Business Object pattern as a foundation for collections of objects, you can easily establish a common pattern for building collections and subsequently representing the collections as Web Services. In addition to introducing business object collections, the sample content and code changes as well. Rather than spending time discussing Apache Axis and its deployment facilities and tools, I will assume you have enough knowledge and details about the environment and focus on the patterns.