sp_rununit.java

JAVA编程实现用于处理表达式的简单编译器

import  java.util.*;
import  java.text.*; 

/**
 * 变量实体描述 
 *      属于语法分析包
 * @author  林玉东.烟台
 * @version 1.0 11/01 2003 
 */ 
public class SP_RunUnit  implements SP_Const
{
	//
	public double value1;  //保存(所有)数字量 
	public String value2;  //保存字符串 null
	public int    type;    //类型 :整数/浮点/字符串

	public SP_RunUnit()
	{
		value1=0;
		value2=null;
		type=WT_NULL;
	}
	//赋值
	public void set(String value,int type)
	{
		this.type=type;
		value2=value;
		try{
			value1=Double.parseDouble(value); //无论字符串/数字
		}
		catch(Exception e){
			value1=0.0;
		}
	}
	//取值
	public String getValue()
	{
		String rs="";

		if(type==WT_IntegerConst)
			rs= String.valueOf((int)value1);
		else if(type==WT_FloatConst)
			rs= numf.format(value1);
		else if(type==WT_StringConst)
			rs= value2;
		return rs;
	}
	/*********/
	//
	public void plus(SP_RunUnit another)
	{
		//处理字符串的+操作
		if(type==WT_StringConst || another.type==WT_StringConst ){ //字符串只有+操作
			value2=getValue()+another.getValue();
			type=WT_StringConst;
		}
		//处理数字型的+操作
		else{
			//System.out.println("plus======="+value1+":"+another.value1);
			value1=value1+another.value1;     
			type=Math.max(type,another.type); //类型向上造型
		}
	}
	//
	public void minus(SP_RunUnit another)
	{
		value1=value1-another.value1;     
		type=Math.max(type,another.type);
	}
	//
	public void times(SP_RunUnit another)
	{
		value1=value1*another.value1;     
		type=Math.max(type,another.type);
	}
	//
	public void divide(SP_RunUnit another)
	{
		value1=value1/another.value1;     
		type=Math.max(type,another.type);
	}
	//
	public void mod(SP_RunUnit another)
	{
		value1=((int)value1)%((int)another.value1);     
		type=WT_IntegerConst;
	}

	//
	public void band(SP_RunUnit another)
	{
		value1=((int)value1)&((int)another.value1);     
		type=WT_IntegerConst;
	}
	//
	public void bor(SP_RunUnit another)
	{
		value1=((int)value1)|((int)another.value1);     
		type=WT_IntegerConst;
	}
	//
	public void and(SP_RunUnit another)
	{
		value1=(((int)value1)==1 && ((int)another.value1)==1) ? 1:0;     
		type=WT_IntegerConst;
	}
	//
	public void or(SP_RunUnit another)
	{
		value1=(((int)value1)==1 || ((int)another.value1)==1) ? 1:0;     
		type=WT_IntegerConst;
	}

	//
	public void eql(SP_RunUnit another)
	{
		value1=(value1==another.value1)?1:0;     
		type=WT_IntegerConst;
	}
	//
	public void neq(SP_RunUnit another)
	{
		value1=(value1!=another.value1)?1:0;     
		type=WT_IntegerConst;
	}
	//
	public void grt(SP_RunUnit another)
	{
		value1=(value1>another.value1)?1:0;     
		type=WT_IntegerConst;
	}
	//
	public void geq(SP_RunUnit another)
	{
		value1=(value1>=another.value1)?1:0;     
		type=WT_IntegerConst;
	}
	//
	public void lss(SP_RunUnit another)
	{
		value1=(value1<another.value1)?1:0;     
		type=WT_IntegerConst;
	}
	//
	public void leq(SP_RunUnit another)
	{
		value1=(value1<=another.value1)?1:0;     
		type=WT_IntegerConst;
	}
	public void set(SP_RunUnit another)
	{
		value1=another.value1;     
		value2=another.value2;     
		type=another.type;     
	}
	/*********/
	//
	static NumberFormat numf=NumberFormat.getNumberInstance();
    static {
		numf.setMaximumFractionDigits(3);
		numf.setMinimumFractionDigits(3);
	}
}