d20-charsheet/src/org/leumasjaffe/charsheet/observer/ObservableController.java

package org.leumasjaffe.charsheet.observer;

import java.util.Objects;
import java.util.function.Consumer;
import java.util.function.Function;

import javax.swing.text.JTextComponent;

import org.leumasjaffe.charsheet.observer.helper.Helper;
import org.leumasjaffe.event.AnyActionDocumentListener;

import lombok.experimental.FieldDefaults;
import lombok.AccessLevel;

@FieldDefaults(level=AccessLevel.PRIVATE, makeFinal=true)
public class ObservableController<T extends Observable> extends ObservableListener<T> {
	Helper<T> func;

	public ObservableController(final JTextComponent text, final Helper<T> func,
			final Function<? super T, String> stringify) {
		super(text, stringify);
		this.func = func;
		AnyActionDocumentListener.skipEmpty(text, evt -> accept( ) );
	}
	
	public ObservableController(final JTextComponent text, final Helper<T> func,
			final Function<? super T, String> stringify, final Consumer<T> onEmpty) {
		super(text, stringify);
		this.func = func;
		AnyActionDocumentListener.emptyOrText( text, 
				e -> onEmpty.accept( model ), 
				evt -> accept( ) );
	}

	private boolean update() {
		return func.apply( text.getText( ), model );
	}

	private void accept() {
		Objects.requireNonNull( model );
		if ( update( ) ) {
			ObserverDispatch.notifySubscribers( model, this );
		}
	}
}