cons_list.java

interface ILO {}

class LO<T> implements ILO {
	boolean empty;
	T first;
	LO<T> rest;
	
	// Creates an ILO
	LO(T first, LO<T> rest) {
		this.first = first;
		this.rest = rest;
		this.empty = false;
	}
	
	// Creates an empty ILO
	LO() {
		this.first = null;
		this.rest = null;
		this.empty = true;
	}
	
	public boolean isEmpty() {
		return this.empty;
	}
	
	T getFirst() {
		return this.first;
	}
	
	LO<T> getRest() {
		return this.rest;
	}
	
}

class LOPet extends LO<IPet>{
	LOPet() {
		super();
	}
	
	LOPet(IPet a, LOPet b) {
		super(a, b);
	}
}