Chain if responsibility example in java(GoF design pattern)

gistfile1.java

abstract class Animal {
    public Animal successor = null;
    abstract public void processRequest(String request);
}

gistfile2.java

class Cat extends Animal {
	public void processRequest(String request) {
	    Boolean isCat = request.contains("miau") ? true : false;
	    
	    if(isCat){
	        System.out.println("handled by a Cat instance!");
 	    } else if (successor != null){
	        successor.processRequest(request);
	    } else {
	        System.out.println("Cat does not have a successor =/");
	    }
	}
}

gistfile3.java

class Dog extends Animal {
	public void processRequest(String request) {
	    Boolean isDog = request.contains("auau") ? true : false;
	    
	    if(isDog){
	        System.out.println("handled by a Dog instance!");
 	    } else if (successor != null){
	        successor.processRequest(request);
	    } else {
	        System.out.println("Dog does not have a successor =/");
	    }
	}
}

gistfile4.java

class Dispatcher {
    Cat cat = new Cat();
    Dog dog = new Dog();
        
    public void handleForMe(String request) {
        cat.successor = dog;
        cat.processRequest(request);
    }    
}

gistfile5.java

class Run {
	public static void main(String[] args) {
		Dispatcher dispatcher = new Dispatcher();
		dispatcher.handleForMe("the animal who says \"auau\"");
		dispatcher.handleForMe("the animal who says \"miau\"");
		dispatcher.handleForMe("the animal who says \"hakuna matata\"");
	}
}