ListDefinition.java

import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.function.Supplier;

interface ListDefinition<R> extends Supplier<List<R>>{
	
	default boolean canMutate() {
		return false;
	}

	interface Mutable<R> extends ListDefinition<R> {
		default boolean canMutate() {
			return true;
		}
	}

	static <T> ListDefinition<T> immutable(T... values) {
		return () -> List.of(values);
	}

	static <T> ListDefinition<T> mutable(ArrayList<T> values) {
		return (ListDefinition.Mutable<T>) () -> values;
	}

	static <T> ListDefinition<T> mutable(LinkedList<T> values) {
		return (ListDefinition.Mutable<T>) () -> values;
	}

	public static void main(String[] args) {
		
		ListDefinition<String> immutable = ListDefinition.immutable("1","3","4");
		ListDefinition<String> mutable = ListDefinition.mutable(new ArrayList<>());
		ListDefinition<String> mutable2 = ListDefinition.mutable(new LinkedList<>());
		
		
		System.out.printf("immutable-list: %s is immutable: %s\n",immutable.get(),(!immutable.canMutate()));
		System.out.printf("immutable-list: %s is mutable: %s\n",immutable.get(),(immutable.canMutate()));
		System.out.printf("mutable-list: %s is mutable: %s\n",mutable.get(),(mutable.canMutate()));
		System.out.printf("mutable-list2: %s is mutable: %s\n",mutable2.get(),(mutable2.canMutate()));
		
	}
	
}//END