https://jason-grey.com/tags/services/Recent content in Services on jason greyHugoenWed, 01 Oct 2008 00:00:00 +0000https://jason-grey.com/posts/2008/what-makes-a-good-component/Wed, 01 Oct 2008 00:00:00 +0000https://jason-grey.com/posts/2008/what-makes-a-good-component/<p>A few collected thoughts &amp; notes from around the web regarding what makes a good component/service.</p> <ul> <li>Interface - all implementations share this. Should have few methods, use data objects as return values, take primitives as inputs, throw only custom exceptions, and be very, very well documented.</li> <li>Implementations - implement the logic behind the service. May provide extra features such as caching, or such things as optional collaborations.</li> <li>Data - data objects this service deals with. Should be immutable, comparable, cloneable as much as is possible. Should be serializable/XML/Persistance annotated in most languages.</li> <li>Storage - Data (or data.io) package should define storage API, and an in-memory data store. Allow other services/projects/subprojects to define database backed or other kinds of data stores.</li> <li>Cache - Data.Cache packages should define cache API? (or can this be standard per runtime?) Who should be in charge of caching? The service itself, or the user of the service?</li> <li>Use dependency injection for all services/data stores it requires. Use constructor-injection as much as possible.</li> <li>Throw errors early - in constructor if possible.</li> <li>Exceptions - custom exceptions for high level categories of erroneous behavior (try not to do one for every possible condition - classify, and wrap). * Don’t re-throw exceptions from other frameworks - wrap in custom exception.</li> <li>Make behavior configurable via dep injection as much as possible. Use filters or strategies.</li> <li>Inject 1 configuration object instead of many options. Standardize on configuration API/Framework for each runtime/language.</li> <li>Standardize on logging framework/API for each runtime/language, and make sure it’s used (instead of System.out or similar)</li> <li>Provide events/messages and/or hooks for important happenings so others can do things pre/post.</li> </ul>