package com.liuzhen.twenty_three_interpreter;

import java.util.StringTokenizer;

public class Context {
    StringTokenizer tokenizer;
    String token;
    
    public Context(String text){
        setContext(text);
    }
    
    public void setContext(String text){
        tokenizer = new StringTokenizer(text);
    }
    
    String nextToken(){
        if(tokenizer.hasMoreTokens())
            token = tokenizer.nextToken();
        else
            token = "";
        return token;
    }
}

package com.liuzhen.twenty_three_interpreter;

public class Twenty_threeApplication {
    
    public static void main(String[] args){
        String text = "He beat tiger";
        Context context = new Context(text);
        Node node = new SentenceNode();
        node.parse(context);
        node.execute();
        text = "You eat apple";
        context.setContext(text);
        System.out.println();
        node.parse(context);
        node.execute();
    }
    
}

他打老虎
你吃苹果