CHAPTER 14 Ensuring Correct Implementation of the Proxy Pattern


  • Common uses of the Proxy Pattern
  • Using a pre-fetching proxy to improve the responsiveness of a web page
  • Using test-driven development to create a proxy
  • Deducing the internal workings of a proxy without breaking data encapsulation


You can find the code downloads for this chapter at on the Download Code tab. The files are in the Chapter 14 download and individually named according to the filenames noted throughout this chapter.

If you are an American, your entire life is literally governed by the Proxy Pattern. Although we live in a democracy, it is a representative democracy: We do not make laws directly but elect people who create laws on our behalf. We believe (rightly or wrongly) that our proxies in Congress and the White House can manage the lawmaking process better than we could. They have the time to become experts in national defense, healthcare, and other areas. We don’t. If every little issue were decided by plebiscite, we would accomplish nothing else.

When the time comes to interpret those laws, we usually hire another proxy: an attorney who is an expert in the interpretation and navigation of the relevant laws.

In software design, it is sometimes useful to create a proxy object to manage access to an underlying object (called the real subject). It acts as an expert attorney, allowing ...

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