jayanath

public interface Service {
   double calculateServiceCharge();
   String printServiceInfo();
 }

jayanath

public class Internet implements Service {
   private String serviceName;
   	
   @Override
   public double calculateServiceCharge() {
      return 10.19;
   }
 
   @Override
   public String printServiceInfo() {

jayanath

public class Room {
   //this annotation helps spring to identify the constructor
   //argument names when we compile the classes without debug
   //enabled
   @ConstructorProperties({"roomType"})
   public Room(String roomType) {
      this.roomType = roomType;
   }
 
   public double calculateRoomCharge() {

jayanath

 <bean id="propertyLoader"   class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
          <property name="locations" value="classpath:appconfig.properties"/>
 </bean>

jayanath

@PropertySource("classpath:appconfig.properties")
@Autowired Environment env;

jayanath

 <bean id="InternetService" name="InternetService"
          class="com.jayanath.spring.services.impl.Internet">
          <property name="serviceName" value="${internet.service}"/>
 </bean>

jayanath

 @Bean
 public Internet internet() {
   Internet i = new Internet();
   i.setServiceName(env.getProperty("internet.service"));
   return i;
 }

jayanath

# Properties file to keep the frequently changing values

internet.service=Verizon FiOS Internet
telephone.service=Local long distance and international calls
laundry.service=Rapid dry cleaning
food.service=Breakfast and Dinner delivered to the room

jayanath

<util:list id="services" value-type="com.jayanath.spring.services.Service">
     <ref bean="InternetService"/>
     <ref bean="TelephoneService"/>
</util:list>
 
<bean id="Room" name="Room" class="com.jayanath.spring.Room">
     <constructor-arg name="roomType" value="Monte Carlo"/>
     <property name="serviceList" ref="services"/>
</bean>

jayanath

@Bean
public Room room() {
   Room r = new Room("Monte Carlo");
   List<Service> list = new ArrayList<Service>();
   list.add(internet());
   list.add(telephone());
   r.setServiceList(list);
   return r;
}