A reactivex-based class to represent a mutable property of an object

ObservableProperty.java

import rx.Observable;
import rx.functions.Action1;
import rx.subjects.BehaviorSubject;

public class ObservableProperty<T> implements Action1<T> {
  private final BehaviorSubject<T> valueSubject;
  private T value;

  public ObservableProperty() {
    valueSubject = BehaviorSubject.create();
  }

  public ObservableProperty(T defaultValue) {
    this.value = defaultValue;
    valueSubject = BehaviorSubject.create(defaultValue);
  }

  public T getValue() {
    return value;
  }

  public void setValue(T value) {
    this.value = value;
    valueSubject.onNext(value);
  }

  public boolean hasValue() {
    return value != null;
  }

  public Observable<T> observe() {
    return valueSubject;
  }

  @Override
  public void call(T value) {
    setValue(value);
  }
}

usage.md

public class TextItem {
  private final ObservableProperty<String> text = new ObservableProperty<>();
  private final ObservableProperty<String> fontPath = new ObservableProperty<>("fonts/Anton.ttf");

  public ObservableProperty<String> text() {
    return text;
  }

  public ObservableProperty<String> fontPath() {
    return fontPath;
  }
}

    textItem.text().observe().subscribe(new Action1<CharSequence>() {
      @Override
      public void call(CharSequence text) {
        // Update the view.
        setText(text);
      }
    });