OSGi and AspectJ integration

Introduction
The Model of Tutorial
Project target-runtime
Project "osgi-define-aspectj"
Project "affected-osgi"

1. Introduction

This document base on:

Eclipse 4.7, 4.6 (OXYGEN, NEON)

You should check your Eclipse was installed Ajdt Plugin, If it hasn't been installed, you should refer this following document :
Install AspectJ development tools for Eclipse

2. The Model of Tutorial

These examples are models which include 3 projects :

target-runtime
osgi-define-aspectj
affected-osgi

osgi-define-aspectj
- is an osgi project as well as an aspectj project. This is also the definition of aspectj SumAspectj.aj
affected-osgi
- is an osgi project, but it's not an aspectj project. It relies on osgi and is affected by aspectj which has definition as above.

3. Project target-runtime

Create a java project, with the name "target-runtime":

File/New/Other

Copy:

http://download.eclipse.org/tools/ajdt/47/dev/update/ (Eclipse 4.7 OXYGEN)
http://download.eclipse.org/tools/ajdt/46/dev/update/ (Eclipse 4.6 NEON)

Finally click "Set As Target Runtime" to the runtime library affect to all project in the workspace

4. Project "osgi-define-aspectj"

Create project "osgi-define-aspectj":

File/New/Other..

org.o7planning.tutorial.osgidefineaspectj.Activator

Convert this project into aspectj project:

Result:

We will create some classes and an AspectJ to get a result as following pictures:

First, add aspectj "SumAspecj" and click on Eclipse:

File/New/Others...

Package: org.o7planning.tutorial.osgidefineaspectj
Name: SumAspectj

SumAspectj.aj

package org.o7planning.tutorial.osgidefineaspectj;

public aspect SumAspectj {
 
  before() : execution(* *.sum(..)) {
      System.out.println("Before execution sum");
  }
 
}

MathUtils.java

package org.o7planning.tutorial.osgidefineaspectj;

public class MathUtils {
   
   public static int sum(int a, int b) {
       return a + b;
   }
}

TestSumInternal.java

package org.o7planning.tutorial.osgidefineaspectj;

public class TestSumInternal {
   
   public static void main(String[] args) {
       
       int value= MathUtils.sum(10,20);
       System.out.println("Value ="+value);

   }

}

Run class TestSumInternal, As a result. when the method with name of "sum" runs, aspectj SumAspectj will work and have text "Before execution sum"

Next, we declare export package and aspectj in order to use the other osgi.

Until now, we can create an osgi project with aspectj, and it can completely run in this internal osgi.

However, every osgi bundle use its own ClassLoader, so aspectj can only use in this internal osgi. It need to have some configurations to affect the other osgi bundle. Work on a different project to be affected by aspectj which is declared on the project as above.

5. Project "affected-osgi"

Similarly, you can create the other osgi project with the name "affected-osgi".

Declare it to rely on osgi as "osgi-define-aspectj". Two bundles:

org.eclipse.equinox.console
org.apache.felix.gogo.shell

Math2Utils.java

package org.o7planning.tutorial.affectedosgi;

public class Math2Utils {
   
   
   public static float sum(float a,float b)  {
       return a+b;
   }
   
   public static int sum(int a, int b)  {
       return a+b;
   }  
   
}

Activator.java

package org.o7planning.tutorial.affectedosgi;

import org.o7planning.tutorial.osgidefineaspectj.MathUtils;
import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;

public class Activator implements BundleActivator {

   private static BundleContext context;

   static BundleContext getContext() {
       return context;
   }

   public void start(BundleContext bundleContext) throws Exception {
       Activator.context = bundleContext;

       this.testSumAspectj();
   }

   private void testSumAspectj() {
       System.out.println("-----------------------");
       int value1 = MathUtils.sum(100, 100);
       System.out.println("Value =" + value1);

       System.out.println("-----------------------");
       int value2 = Math2Utils.sum(100, 100);
       System.out.println("Value =" + value2);

       System.out.println("-----------------------");
       float value3 = Math2Utils.sum(100f, 100f);
       System.out.println("Value =" + value3);
   }

   public void stop(BundleContext bundleContext) throws Exception {
       Activator.context = null;
   }

}

Now we will configure to run OSGi "affected-osgi".

Name the configured application "Run affected-osgi project".
Check your two projects.
Skip check all Target Platform
Click on "Add Required Bundles" ,and Eclise can automatically calculates dependent bundles.
Click Apply

After running osgi project "affected-osgi", we have a result:

As a result, aspectj "SumAspectj" which is comfimedin osgi "osgi-define-aspectj" hasn't affected the other osgi.
Next, we configure to ensure that "SumAspectj" can affect the other osgi "affected-osgi".

Declare more bundles which required for osgi "affected-osgi".