Push.java

public class Push extends Action{

    private String pushFrom;
    private String pushTo;
    public Push(String to, String from){
        this.operatorName = "PUSH";
        this.pushFrom = from;
        this.pushTo = to;
    }

    public boolean checkPreconditions(WorldState worldState) {
        if(!worldState.isMonkeyAt(pushFrom)){
            return false;
        }

        if(!worldState.isMonkeyHeight(WorldState.HEIGHT_LOW)){
            return false;
        }

        return true;
    }

    public WorldState applyPostconditions(WorldState worldState) {
        //create and return a new WorldState
        //with the monkey’s updated location
        return null;
    }
}