Token.java

import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Created by Lxx on 2017/4/28.
 */


public class Token {
    public static final List<String> OPERATORS = Arrays.asList("+","-","*","/");
    public static final Map<String,Integer> priorities = new HashMap<>();
    static {
        priorities.put("+",1);
        priorities.put("-",1);
        priorities.put("*",2);
        priorities.put("/",2);
    }
    static final int OPERATOR = 1;
    static final int NUMBER = 2;
    String value;
    int type;
    public Token(int type,String value){
        this.type = type;
        this.value = value;
    }
    public boolean isNumber(){
        return type == NUMBER;
    }
    public boolean isOpretor(){
        return type == OPERATOR;
    }
    public int getIntValue(){
        return Integer.valueOf(value).intValue();
    }
    public String toString(){
        return value;
    }
    public boolean hasHigherPriority(Token t){
        if (!this.isOpretor() && !t.isOpretor()){
            throw new RuntimeException();
        }
        return priorities.get(this.value) - priorities.get(t.value) > 0;
    }
}