Generated observable options

Base.java

class Foo {

  private String bar;
  private int baz;

  public void setBar(String bar) {...}
  public String getBar();

  public void setBaz(int baz) {...}
  public int getBaz();

}

Option1.java

@Generated
class ObservableFoo extends Foo {

  public void addBarListener(...) {...}
  public void removeBarListener(...) {...}
  public void addBazListener(...) {...}
  public void removeBazListener(...) {...}

  interface BarListener { void barChanged(String oldValue, newValue); }
  interface BazListener { void bazChanged(int oldValue, newValue); }

}

Option2.java

@Generated
class ObservableFoo extends Foo {

  public void addListener(...) {...}
  public void removeListener(...) {...}

  interface FooListener {
    void barChanged(String oldValue, newValue);
    void bazChanged(int oldValue, newValue);
  }

}

Option3.java

interface ObservableListener<T> {
    void memberChanged(T source, String memberName, Object oldValue, Object value);
}

@Generated
class ObservableFoo extends Foo {

  // Makes strings a bit less icky
  public static final String MEMBER_NAME_BAR = "bar";
  public static final String MEMBER_NAME_BAZ = "bar";

  public void addListener(ObservableListener<ObservableFoo> listener) {...}
  public void removeListener(...) {...}

}

Option4.java

interface ObservableListener<T> {
    <V> void memberChanged(T source, Observable<V> member, V oldValue, V value);
}

@Generated
class ObservableFoo extends Foo {

  public static final Observable<String> MEMBER_BAR = ...;
  public static final Observable<Integer> MEMBER_BAZ = ...;

  public void addListener(ObservableListener<ObservableFoo> listener) {...}
  public void removeListener(...) {...}

}