Tip: How to use Intellij IDEA and Maven 2 together for debugging and context help

Latest version of Intellij IDEA has excellent integration with Maven 2. I want to explain one tip that could help you to gain productivity.

When you debug with IDEA, it's nice to have sources and javadocs for each used library registered with IDEA. If you have registered additional sources, you can debug deeper, going inside those sources. If you have registered additional javadocs, you can get context help for used classes from that libraries.

Unfortunately, this process is manual and tedious. Usually you have to do the following actions:

1. Find out on Internet sources for given library and unzip them locally.


2. Find out on Internet javadocs for given library and unzip it locally.


3. With the help of Intellij IDEA you have to register unzipped sources and javadocs.

This should be done for each external library in the project. If you have a lot of dependencies,
it'll take a lot of time.

Even if your project is dependent on other your own libraries, you still won't get sources and context helps
for them automatically. To have this support, you will do same things as what you did for external libraries -
IDEA should know where your dependent sources/javadocs are located.

Is it possible to make this process less time consuming, less painful? And the answer is: Yes.

When your project is equipped with maven's pom.xml file, you can do the following trick. Close your current
project and next time, when you try to open this project again, use pom.xml file as the project file (use "Open Project" functionality) instead of regular IDEA project file.

What happens here, IDEA is trying to resolve dependencies, defined inside maven project file and populates them back into IDEA's project (synch up). After such synchronization, IDEA is looking for sources and javadocs inside maven reopsitory. They should be located in same folder as your jar file and should have name built by special scheme. For example, my example library is located here:


${maven.local.repository}/org/google/code/maven-archetypes/1.0.0/maven-archetypes-1.0.0.jar


My sources and javadocs should be layed out in this way


${maven.local.repository}/org/google/code/maven-archetypes/1.0.0/maven-archetypes-1.0.0-sources.jar
${maven.local.repository}/org/google/code/maven-archetypes/1.0.0/maven-archetypes-1.0.0-javadoc.jar


As you can see, maven has "classifier" notion that helps us to differentiate "jar" artifact from "sources" and
"javadocs" artifacts.

Good thing is that most of new artifacts to be deployed recently into maven repositories (or at least everybody who understand it and wants to benefit from it), follow this pattern.

Now, what we have to do for our project components to be "in synch" with this pattern? Follow these steps:

1. Generate sources and javadocs with the help of "maven-source-plugin" and "maven-javadoc-plugin"
plugins:


>mvn source:jar
                                                                              
>mvn javadoc:jar


After the execution of these commands, 2 new files will be created. By default, you will see these files in "target" folder:


maven-archetypes-1.0.0-javadoc.jar
maven-archetypes-1.0.0-sources.jar


2. Install sources into maven repository:


mvn install:install-file ^
  -Dfile=target/yourArtifactId-yourVersion-sources.jar ^
  -DgroupId=yourGroupId ^
  -DartifactId=yourArtifactId ^
  -Dversion=yourVersion ^
  -Dpackaging=jar ^
  -Dclassifier=sources ^
  -DgeneratePom=false


3. Install javadocs into maven repository:


mvn install:install-file ^
  -Dfile=target/yourArtifactId-yourVersion-javadoc.jar ^
  -DgroupId=yourGroupId ^
  -DartifactId=yourArtifactId ^
  -Dversion=yourVersion ^
  -Dpackaging=jar ^
  -Dclassifier=javadoc ^
  -DgeneratePom=false


You can use this batch script to do all commands in one step:


rem install-jar-javadoc-sources.bat

rem 1. generate sources jar file

call mvn source:jar

rem 2. generate javadoc jar file

call mvn javadoc:jar

SET GROUP_ID=org.google.code
SET ARTIFACT_ID=maven-archetypes
SET VERSION=1.0.0

SET SOURCES_CLASSIFIER=sources
SET JAVADOC_CLASSIFIER=javadoc

rem 3. install sources jar file

call mvn install:install-file ^
  "-Dfile=target/%ARTIFACT_ID%-%VERSION%-%SOURCES_CLASSIFIER%.jar" ^
  "-DgroupId=%GROUP_ID%" ^
  "-DartifactId=%ARTIFACT_ID%" ^
  "-Dversion=%VERSION%" ^
  "-Dpackaging=jar" ^
  "-Dclassifier=%SOURCES_CLASSIFIER%" ^
  "-DgeneratePom=false"

rem 4. install javadoc jar file

call mvn install:install-file ^
  "-Dfile=target/%ARTIFACT_ID%-%VERSION%-%JAVADOC_CLASSIFIER%.jar" ^
  "-DgroupId=%GROUP_ID%" ^
  "-DartifactId=%ARTIFACT_ID%" ^
  "-Dversion=%VERSION%" ^
  "-Dpackaging=jar" ^
  "-Dclassifier=%JAVADOC_CLASSIFIER%" ^
  "-DgeneratePom=false"


You also can run these commands as Beanshell script:


// installSourcesJavadocs.bsh

import org.sf.pomreader.PomReader;
import org.apache.maven.bootstrap.model.Model;
import org.sf.scriptlandia.MavenHelper;

MavenHelper.executeMaven(null, new String[] { "source:jar" });
MavenHelper.executeMaven(null, new String[] { "javadoc:jar" });

PomReader pomReader = new PomReader();
pomReader.init();

Model model = pomReader.readModel(new File("pom.xml"));

void installArtifact(Model model, String classifier) {
  System.setProperty("file", "target/" + model.getArtifactId() + "-" + classifier + ".jar");
  System.setProperty("groupId", model.getGroupId());
  System.setProperty("artifactId", model.getArtifactId());
  System.setProperty("version", model.getVersion());
  System.setProperty("packaging", model.getPackaging());
  System.setProperty("classifier", classifier);
  System.setProperty("generatePom", "false");

  MavenHelper.executeMaven(null, new String[] { "install:install-file" });
}

installArtifact(model, "sources");
installArtifact(model, "javadoc");


In order to run this script, you have to install Scriptlandia
launcher on your computer. It will take care of downloading all required dependencies, installing them locally on your computer and then executing Beanshell script.