The idempotent of program function design

1. idempotent

One of the characteristics of a idempotent operation is that its arbitrary multiple executions have the same effect as one execution. Idempotent operations are "friendly" to proxies and caches, because additional execution of idempotent operations does not have a detrimental effect on both (except bandwidth waste).

In other words, an operation is idempotent, which means that the operation executes once and executes multiple times on the internal state of the system. But we initialized the person object ' Old king ' and then executed the old king. Setage (56) Set the age of the old king, regardless of the old king. Setage (56) executes several times, the effect on the inner state of the object is the same as the old king, so the Setage () method of the person is idempotent.