What is Apache Maven ?- Definition from Trenovision

What is Maven?

Maven is a software management and comprehension tool based on the concept of Project Object Model (POM) which can manage project build, reporting, and documentation from a central piece of information.

What is POM?

“As a fundamental unit of work in Maven, POM is an XML file that contains information about project and configuration details used by Maven to build the project”
History: Jakarta Turbine Project

Objectives and Characteristics of MAVEN

• Maven is more than just Build Tool
• It was built considering certain objectives
• It Provides:
  • Easy Build Process
  • Uniform Build System
  • Quality Project Information
  • Guidelines for Best Practices Development
• Achieved Characteristics:
  • Visibility
  • Reusability
  • Maintainability
  • Comprehensibility “Accumulator of Knowledge”

Comparison with ANT

1. One level above ANT
2. Higher level of reusability between builds
3. Faster turn around time to set up a powerful build
4. Project website generation
5. Less maintenance
6. Greater momentum
7. Repository management
8. Automatic downloads

Main Features of MAVEN

• Build-Tool
• Dependency Management Tool
• Documentation Tool

Overview of Simple Architecture

Project Creation in MAVEN

mvn archetype:generate
-DgroupId = com.mycompany.app
-DartifactId = my-app
-DarchetypeArtifactId = maven-archetype-quickstart
-DinteractiveMode = false
 

Contents of the Created Project

• POM
• source tree for your application’s sources
• source tree for your test sources

POM.XML

<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/xsd/maven-4.0.0.xsd”>
<modelVersion> 4.0.0 </modelVersion>
<groupId> com.mycompany.app </groupId>
<artifactId> my-app </artifactId>
<packaging> jar </packaging>
<version> 1.0-SNAPSHOT </version>
<name> Maven Quick Start Archetype </name>
<url> http://maven.apache.org </url>
<dependencies>
<dependency>
<groupId> junit </groupId>
<artifactId> junit </artifactId>
<version> 4.8.2 </version>
<scope> test </scope>
</dependency>
</dependencies>
</project>
 

BUILD.XML

<project default = “compile”>
<property name = “classesdir = ” ” value = “…”/>
<property name = “libdir” value = “…”/>
<target name = “compile”>
<mkdir dir = “${classesdir}”/>
<javac destdir = “${classesdir}”>
<src>
<pathelement location = “src/main/java”/>
</src>
<classpath>
<fileset dir = “${libdir}”>
<include name = “*.jar”/>
</fileset>
</classpath>
</javac>
</target>
</project>
 

Project Object Model (POM)

• Metadata: Location of Directories, Developers/Contributors, Dependencies, Repositories
• Dependencies (Transitive Dependencies), Inheritance, and Aggregation
• Key Elements
  • Project
  • Model Version
  • Group ID
  • Packaging
  • Artifact ID
  • Version
  • Name
  • URL
  • Description

Standard Directory Layout

src/main/java	Application/Library sources
src/main/resources	Application/Library resources
src/main/filters	Resource filter files
src/main/assembly	Assembly descriptors
src/main/config	Configuration files
src/main/scripts	Application/Library scripts
src/main/webapp	Web application sources
src/test/java	Test sources
src/test/resources	Test resources
src/test/filters	Test resource filter files
src/site	Site
LICENSE.txt	Project’s license
NOTICE.txt	Notices and attributions required by libraries that the project depends on
README.txt	Project’s readme

 

Documentation – Building Own Site

• mvn site
• pom.xml

<project> …
<distributionManagement>
<site>
<id>website</id>
<url>scp://www.mycompany.com/www/docs/project/</url>
</site>
</distributionManagement> …
</project>

• mvn site-deploy