Difference between revisions of "M2E/Extension Development"

Revision as of 09:21, 22 June 2011

Prerequisites

Some OSGi bundle development and PDE knowledge is assumed. TODO link to some PDE documentation and tutorials

Java code generation overview

Although there are no strict rules, usually maven java code generation plugins like antlr3-maven-plugin or maven-jaxb-plugin take one or more input files from project source tree and generate a number java source files in a subdirectory of target/generated-sources/ directory. These generated sources are usually required to compile and/or run project tests.

To properly support code generation inside Eclipse IDE workspace, the IDE generally needs to perform some configuration (semi) statically during project import and then do actually code generation either on request or automatically as part of workspace build.

m2e extension that provides support for generation will typically need to

implement a subclass of org.eclipse.m2e.jdt.AbstractJavaProjectConfigurator to perform necessary project configuration
implement subclass of MojoExecutionBuildParticipant to delegate actual code generation to underlying maven plugin goal
provide metadata to metadata to register the project configurator with m2e and to map maven plugin execution to the project configurator

m2e/antlr3 code generation support explained

As an example, here is explanation of how different parts of [m2e/antlr] fit together

On command line, [antlr3-maven-plugin], reads ANTLR grammar files from directory specified by ${sourceDirectory} plugin configuration parameter (defaults to src/main/antlr3) and generates output files in directory specified by ${outputDirectory} plugin configuration parameter (defaults to target/generated-sources/antlr3).

AntlrProjectConfigurator and corresponding metadata

[AbstractJavaProjectConfigurator] is a convenience abstract implementation of AbstractProjectConfigurator that provides default behaviour common to many java code generation m2e extensions. AbstractJavaProjectConfigurator assumes single additional java source folder needs to be configured for the project and the source folder location is defined by ${outputDirectory} maven plugin configuration parameter. This allows very simple ANTLR project configurator implementation

   public class AntlrProjectConfigurator
       extends AbstractJavaProjectConfigurator
   {
       @Override
       public AbstractBuildParticipant getBuildParticipant( IMavenProjectFacade projectFacade,
                                                            MojoExecution execution,
                                                            IPluginExecutionMetadata executionMetadata )
       {
           return new AntlrBuildParticipant( execution );
       }
   }

Project directory structure overview

 org.somecatchyname/                   <= project basedir, all project files are under this directory
   org.somecatchyname.m2e/             <= main bundle project
     src/
     pom.xml
   org.somecatchyname.m2e.tests/       <= automated tests (optional, but highly recommended)
     src/
     pom.xml
   org.somecatchyname.m2e.feature/     <= eclipse feature project
     feature.xml
     pom.xml
   pom.xml                             <= aggregator pom.xml

Submitting M2E marketplace entries

M2E extension development environment

@@ Line 8: / Line 8: @@
 Although there are no strict rules, usually maven java code generation plugins like antlr3-maven-plugin or maven-jaxb-plugin take one or more input files from project source tree and generate a number java source files in a subdirectory of target/generated-sources/ directory. These generated sources are usually required to compile and/or run project tests.
 To properly support code generation inside Eclipse IDE workspace, the IDE generally needs to perform some configuration (semi) statically during project import and then do actually code generation either on request or automatically as part of workspace build.
+m2e extension that provides support for generation will typically need to
+* implement a subclass of org.eclipse.m2e.jdt.AbstractJavaProjectConfigurator to perform necessary project configuration
+* implement subclass of MojoExecutionBuildParticipant to delegate actual code generation to underlying maven plugin goal
+* provide metadata to metadata to register the project configurator with m2e and to map maven plugin execution to the project configurator
+=== m2e/antlr3 code generation support explained ===
+As an example, here is explanation of how different parts of [[https://github.com/sonatype/m2eclipse-extras/tree/0.13.0.20110622-1538/org.sonatype.m2e.antlr m2e/antlr]] fit together
+On command line, [[http://www.antlr.org/antlr3-maven-plugin/usage.html antlr3-maven-plugin]], reads ANTLR grammar files from directory specified by ${sourceDirectory} plugin configuration parameter (defaults to src/main/antlr3) and generates output files in directory specified by ${outputDirectory} plugin configuration parameter (defaults to target/generated-sources/antlr3).
+==== AntlrProjectConfigurator and corresponding metadata ====
+[[http://git.eclipse.org/c/m2e/m2e-core.git/tree/org.eclipse.m2e.jdt/src/org/eclipse/m2e/jdt/AbstractJavaProjectConfigurator.java?id=releases/1.0/1.0.0.20110607-2117 AbstractJavaProjectConfigurator]] is a convenience abstract implementation of AbstractProjectConfigurator that provides default behaviour common to many java code generation m2e extensions. AbstractJavaProjectConfigurator assumes single additional java source folder needs to be configured for the project and the source folder location is defined by ${outputDirectory} maven plugin configuration parameter. This allows very simple ANTLR project configurator implementation
+    public class AntlrProjectConfigurator
+        extends AbstractJavaProjectConfigurator
+    {
+        @Override
+        public AbstractBuildParticipant getBuildParticipant( IMavenProjectFacade projectFacade,
+                                                             MojoExecution execution,
+                                                             IPluginExecutionMetadata executionMetadata )
+        {
+            return new AntlrBuildParticipant( execution );
+        }
+    }
 == Project directory structure overview ==
@@ Line 24: / Line 54: @@
      pom.xml                             <= aggregator pom.xml
-This wiki assumes project basedir is /var/tmp/somecatchyname, but this can obviously be any other directory.
-== Create test bundle project ==
-  org.somecatchyname.m2e.tests/
-    src/
-    projects/
-      basic/                     <= test maven project used to verify m2e extension behaviour
-        pom.xml
-    pom.xml
-Use Plug-In Project new project wizard to create main bundle project. This is regular PDE stuff.
-== Create main bundle project ==

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