java-design-patterns/command/src/main/java/com/iluwatar/Wizard.java

package com.iluwatar;

import java.util.Deque;
import java.util.LinkedList;

public class Wizard extends Target {

	private Deque<Command> undoStack = new LinkedList<>();
	private Deque<Command> redoStack = new LinkedList<>();

	public Wizard() {
		setSize(Size.NORMAL);
		setVisibility(Visibility.VISIBLE);
	}

	public void castSpell(Command command, Target target) {
		System.out.println(this + " casts " + command + " at " + target);
		command.execute(target);
		undoStack.offerLast(command);
	}

	public void undoLastSpell() {
		if (!undoStack.isEmpty()) {
			Command previousSpell = undoStack.pollLast();
			redoStack.offerLast(previousSpell);
			System.out.println(this + " undoes " + previousSpell);
			previousSpell.undo();
		}
	}

	public void redoLastSpell() {
		if (!redoStack.isEmpty()) {
			Command previousSpell = redoStack.pollLast();
			undoStack.offerLast(previousSpell);
			System.out.println(this + " redoes " + previousSpell);
			previousSpell.redo();
		}
	}

	@Override
	public String toString() {
		return "Wizard";
	}

}