CachedSupplier.java

CachedSupplier.java

public abstract class CachedSupplier<T> implements Supplier<T>{
	private T cache;

	private boolean cached;

	public CachedSupplier(){
		cache = null;
		cached = false;
	}

	@Override
	public final T get(){
		if(!cached){
			synchronized{
				cache = refresh();
				cacheed = true;
			}
		}
		return cache;
	}

	protected synchronized T refresh();

	public static CachedSupplier<T> of(Supplier<T> supplier){
		return new CachedSupplier<T>(){
			@Override
			public synchronized T refresh(){
				return supplier.get();
			}
		};
	}
}

CachedSupplier<Boolean> checked = new CachedSupplier<Boolean>(){
    @Override
    public Boolean onSupply(){
        return true;
    }
};