# Object Design ### Design principles * Commands down the stack, notifications up the stack ### Where to put a method? Take a feature statement and put the initiating method in the corresponding class. ` the a ` Example: `calculate the anticipated total of an RFQ.` We put the initiating method in the RFQ class. Source: Java Modeling in Color with UML (pg 41) ### Resources * [East-oriented](http://jamesladdcode.com/2011/08/10/east-example-code/) * [Tell, Don't Ask](https://pragprog.com/articles/tell-dont-ask) --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://civilcode.gitbook.io/playbook/education/trails/object-design.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.