Reminder About JavaBeans Design Patterns

JavaBeans have the following main design patterns:

Properties

Properties can be defined with a pair of get/set methods. Their names are derived from the method names. The following class contains the "severity" property:

public class Alarm {
  public int getSeverity() {...}
  public void setSeverity(int severity) {...}
}

If the getSeverity method is specified without the setSeverity method, the property is readable only.

Bound properties

Each time the value of a bound property changes, other objects are notified accordingly. A PropertyChange event is fired specifying the property name, the old value, and the new value. The IlpBeansObject class takes advantage of this process, so that each time a bound property changes, its new value is reflected in all the graphic components displaying it.

Mandatory default constructor or serialized instance

A constructor with no parameters should be available on the Bean or a serialized instance should be provided. For more information, see the instantiate method of the class java.beans.Beans.

Following is an example of a Java class that conforms to the JavaBeans design pattern.

How to Write a Java Class that Conforms to the JavaBeans Design Pattern

public static class MO {
  String name;
  int state = 0;
  PropertyChangeSupport support = new PropertyChangeSupport(this);
  public MO() {
  }
  public MO(String name) {
   this.name = name;
  }
  public String getName() {
   return name;
  }
  public void setName(String name) {
   String oldName = this.name;
   this.name = name;
   support.firePropertyChange("name",oldName,name);
  }
  public int getState() {
   return state;
  }
  public void setState(int state) {
   int oldState = this.state;
   this.state = state;
   support.firePropertyChange("state",oldState,state);
  }
  public void addPropertyChangeListener(PropertyChangeListener listener) {
   support.addPropertyChangeListener(listener);
  }
  public void removePropertyChangeListener(PropertyChangeListener
listener) {
  support.removePropertyChangeListener(listener);
  }
}

To retrieve the corresponding IlpClass, execute the following (assuming that you have a class manager):

IlpClass moAsIlpClass = classManager.get(MO.getClass().getName());

For details, see Business Class Manager API.

For an example of how to use this class in a data source, see Adding Business Objects from JavaBeans.

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Defining the Business Model from JavaBeans Classes