Properties¶
DragonLib provides a small property system with several specialized property types. In Java you often add many getters and setters for fields that only store or return a value. Properties reduce boilerplate and add useful features like default values and numeric ranges.
Defining Properties¶
Properties are usually declared as public final fields so they remain accessible. Control is handled inside the property object, so exposing the field is fine.
Example:
public final Property<MyType> myProperty =
new Property<MyType>(new MyType(...));
For specialized types the constructor differs:
public final NumberProperty<Integer> myProperty =
new NumberProperty<Integer>(20, 0, 100);
Default Values¶
The value passed to the constructor is the default. Use reset() to restore it, or getDefaultValue() to fetch it without changing the property.
Callbacks¶
Properties can register two callbacks that run before/after a value changes:
<P extends IProperty<T>> P withAfterPropertyChangedCallback(IPropertyAfterUpdateCallback<T> callback);
<P extends IProperty<T>> P withModificationCallback(IPropertyUpdateCallback<T> callback);
Example:
public final Property<ILayoutManager> layout =
new Property<ILayoutManager>(NoLayout.INSTANCE)
.withAfterPropertyChangedCallback((oldValue, newValue) -> newValue.arrangeComponents(this));
!!! tip Callbacks are useful in GUIs. For example, after changing a size property you can update the layout.
Specialized Properties¶
DragonLib includes several specialized property classes for common use cases (numbers, booleans, lists). Use them directly where appropriate.
Use Cases¶
Properties are used heavily in DragonLib's GUI system, where many settings are exposed as properties. They are also used by components like BERLabel.
!!! warning "Please keep in mind!" Properties are not always a replacement for getters/setters. They are best for compactly managing single values and related behaviors.