Maven: The Definitive Guide

The Simple Weather Module

The next module we’re going to examine could be considered something of a “service.” The Simple Weather module is the module that contains all of the logic necessary to retrieve and parse the data from the Yahoo! Weather RSS feed. Although Simple Weather contains three Java classes and one JUnit test, it is going to present a single component, WeatherService, to both the Simple Web Application and the Simple Command-line Utility. Very often an enterprise project will contain several API modules that contain critical business logic or logic that interacts with external systems. A banking system might have a module that retrieves and parses data from a third-party data provider, and a system to display sports scores might interact with an XML feed that presents real-time scores for basketball or soccer. In Example 7-5, this module encapsulates all of the network activity and XML parsing that is involved in the interaction with Yahoo! Weather. Other modules can depend on this module and simply call out to the retrieveForecast() method on WeatherService, which takes a zip code as an argument and which returns a Weather object.

Example 7-5. simple-weather module POM

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>org.sonatype.mavenbook.ch07</groupId> ...