Module io.github.mmm.bean

Provides advanced Java beans based on mmm-property.

Bean


Writing regular Java Beans is painful. You have to write a lot of boilerplate code and implement getters, setters, equals, hashCode, and toString.
The WritableBean API provided here saves you from all this pain and makes your life a lot easier.

Class implementation


To implement a bean you only need to extend from Bean: 
 public class TestBean extends Bean {

   public final StringProperty Name;

   public final IntegerProperty Age;

   public TestBean() {

     this(null, true);
   }

   public TestBean(AbstractBean writable, boolean dynamic) {

     super(writable, dynamic);
     this.Name = add(new StringProperty("Name"));
     this.Age = add(new IntegerProperty("Age"));
   }
 }
Now you can do things like this: 
 TestBean bean = new TestBean();
 bean.Name.set("John Doe");
 bean.Age.set(42);
 // Read-Only views
 TestBean readonly = WritableBean.getReadOnly(bean);
 assertThat(readonly.Age.get()).isEqualTo(42);
 bean.Age.set(43);
 assertThat(readonly.Age.get()).isEqualTo(43);
 try {
   readonly.Age.set(44);
   fail("Exception expected");
 } catch (IllegalStateException e) {
 }
 // Change listener...
 bean.Age.addListener((e) -> {
   System.out.println(e.getOldValue() + "-->" + e.getValue());
 });
 bean.Age.set(44); // prints: 43 --> 44
 // Copy and compare
 TestBean bean2 = new TestBean();
 for (WritableProperty<?> property : bean.getProperties()) {
   bean2.set(property.getName(), property.getValue());
 }
 assertThat(bean.isEqualTo(bean2)).isTrue();

Interface only


If you want to have no boilerplate code at all, like to have multi-inheritance and do not fear magic, you can even define your beans as interfaces only. Then you can instantiate them using BeanFactory from the module io.github.mmm.bean.factory of mmm-bean-factory.