以下的demo引入装饰器模式对Service进行日志的扩展

demo:

Provider

student-manage/Activator.java

package com.demo.service;

import java.util.Dictionary;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.Map;

import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;

import com.demo.service.impl.StudentManage;

public class Activator implements BundleActivator {

	public void start(BundleContext context) throws Exception {
		System.out.println("register service start...");
		Dictionary<String, String> prop=new Hashtable<String, String>();
		prop.put("action", "student_action");
		context.registerService(IStudentManage.class.getName(), new StudentManage(), prop);
		System.out.println("register service end...");
	}

	public void stop(BundleContext context) throws Exception {

	}

}

Consumer

student-action/Activator.java

package com.demo.action;

import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;

import com.demo.action.log.LogStudentManager;
import com.demo.action.tracker.StudentManagerTracker;
import com.demo.service.IStudentManage;

public class Activator implements BundleActivator{
	StudentManagerTracker managerTracker ;
	public void start(BundleContext context) throws Exception {
		System.out.println("action start begin...");
		managerTracker=new StudentManagerTracker(context);
		//开启
		managerTracker.open();
		//获取服务
		IStudentManage service=(IStudentManage)managerTracker.getService();
		service.add();
		System.out.println("action start end...");
	}

	public void stop(BundleContext context) throws Exception {
		//关闭
		managerTracker.close();
	}

}

student-action/StudentManagerTracker.java

package com.demo.action.tracker;

import org.omg.PortableInterceptor.INACTIVE;
import org.osgi.framework.BundleContext;
import org.osgi.framework.Filter;
import org.osgi.framework.ServiceReference;
import org.osgi.util.tracker.ServiceTracker;
import org.osgi.util.tracker.ServiceTrackerCustomizer;

import com.demo.action.log.LogStudentManager;
import com.demo.service.IStudentManage;

public class StudentManagerTracker extends ServiceTracker {
	
	public StudentManagerTracker(BundleContext context) {
		super(context, IStudentManage.class.getName(), null);
	}

	@Override
	public Object addingService(ServiceReference reference) {
		IStudentManage manage=new LogStudentManager(context, reference);
		return manage;
	}

	@Override
	public void open() {
		super.open();
	}
	
}

student-action/LogStudentManager.java

package com.demo.action.log;

import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceReference;

import com.demo.service.IStudentManage;

public class LogStudentManager implements IStudentManage {
	IStudentManage studentManage;
	BundleContext context;
	ServiceReference reference;
	
	public LogStudentManager(BundleContext context, ServiceReference reference) {
		this.context = context;
		this.reference = reference;
	}

	public void add() {
		studentManage=(IStudentManage) context.getService(reference);
		System.out.println("log start...");
		studentManage.add();
		System.out.println("log end...");
	}

}

结果: