llhash.java

CMM编译器词法分析及语法分析代码

package try_sw;
import java.util.*;
import java.util.regex.*;

public class LLhash {

	/**
	 * @param args
	 */
	private Hashtable<String,String> llhash= new Hashtable<String,String>();
	//内部的哈西表
	
	public void put(String nt,String t,String[] reg ){//其值t需要解析
		String input =nt+"@"+t;
		String input2="";
		for(String tmp : reg)input2+= (tmp+"@");
		input2=input2.substring(0,input2.length()-1);//去掉尾巴上的＠
		
		llhash.put(input, input2);
		//nt non-terminal t-terminal reg-算式
		
	}
	
	public boolean containsKey(String nt,String t){
		
		String search=nt+"@"+t;
		return llhash.containsKey(search);
			
		}
	
	public String[] get(String nt,String t){
		String input = nt+"@"+t;
		if(llhash.containsKey(input))
		{String output=llhash.get(input);
		
		return output.split("@");
		}
		else return null;
		
	}
	
	public void clear(){
		
		llhash.clear();
	}
	
	
	public static void main(String[] args) {
		// TODO Auto-generated method stub

		String [] st = {""};
		LLhash ll= new LLhash();
		ll.put("a", "b",st );
		String[] al=(String[])ll.get("a","b");
	for(String c:al)
		System.out.println(al.length);
	}

}