cifafenxi.java

一个简单的java词法分析器

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.border.*;
import java.util.regex.*;
public class CiFaFenXi extends JFrame implements ActionListener//主类
{
 private JPanel pA,pB,pC,mainP;//定义容器
 private JButton b1,b2;//定义按钮
 private TextArea textA,textC;//定义文本
 int size;
 char sentenceChar[];//定义转换字符数组
 int senLength = 0;
 int index=0;
 boolean isB=false;//判断标志
 char CHAR;
 String finalAccidence;
 String TOKEN;
 boolean ASTATE = true;
 static CiFaFenXi c;
 public CiFaFenXi(String title)
 { 
  super(title);
  mainPanel();
 }
 public static void main(String[] args)//主函数
 {
  c=new CiFaFenXi("词法分析");
  c.addWindowListener(
    new WindowAdapter() 
    {
     public void windowClosing(WindowEvent e) //关闭
     {
      System.exit(0);
     }
    }
    );
  c.setResizable(false);
 }
    private void mainPanel()//主面板
     { 
      textA=new TextArea("",10,30,TextArea.SCROLLBARS_VERTICAL_ONLY);
      textA.setEditable(true);
      textC=new TextArea("",10,30,TextArea.SCROLLBARS_VERTICAL_ONLY);
      textC.setEditable(false);          
       b1=new JButton("分析");
       b1.addActionListener(this);
       b2=new JButton("清除");
       b2.addActionListener(this);      
       pA=new JPanel();     
       pB=new JPanel();     
       pC=new JPanel();
      mainP=new JPanel();
      pA.setBorder(BorderFactory.createEtchedBorder(EtchedBorder.RAISED)); 
      pC.setBorder(BorderFactory.createEtchedBorder(EtchedBorder.RAISED));      
      pA.setSize(200, 100); 
      pC.setSize(200, 100);          
      pB.setSize(20,100);    
      pA.add(textA);
      pB.add(b1);
      pB.add(b2);     
      pC.add(textC);     
      mainP.setLayout(new BorderLayout());
      mainP.add(pA,BorderLayout.WEST);
      mainP.add(pB,BorderLayout.CENTER);     
      mainP.add(pC,BorderLayout.EAST);    
      mainP.setSize(420, 100);
      getContentPane().add(mainP);
     pack();
     setVisible(true);
     }
    public void actionPerformed(ActionEvent e)//事件捕获
     {
      if (e.getSource()==b1)
      {     
      datainput();
      //toComperEnd();
      //dataoutput();
      }
      else if (e.getSource()==b2){
       dataclear();
      }
     }
 public void dataclear()//清屏
 {
  int i=0;
  textA.setText("");
  textC.setText("");
 }
 public void dataoutput(String data)//结果输出
 { 
  textC.append(data+" ");  
 }
 public String datainput()//数据读入并转换
 {    
      String s=new String(textA.getText()+" ");
      size=s.length();
   sentenceChar = new char[size];
   sentenceChar=s.toCharArray();
   this.senLength = sentenceChar.length;
  int i = 0;
    //分析单词
      while (this.index <= this.senLength) {
      //state0:
      this.TOKEN = "";
      this.CHAR = GETBC(sentenceChar);
     
      //进入状态判断
      switch (this.CHAR) {
        //judge letter
case 'a':case 'b':case 'c':case 'd':case 'e':case 'f':case 'g':case 'h':case 'i':case 'j':case 'k':
case 'l':case 'm':case 'n':case 'o':case 'p':case 'q':case 'r':case 's':case 't':case 'u':case 'v':case 'w':case 'x':case 'y':
case 'z':case 'A':case 'B':case 'C':case 'D':case 'E':case 'F':case 'G':case 'H':case 'I':case 'J':case 'K':case 'L':case 'M':
case 'N':case 'O':case 'P':case 'Q':case 'R':case 'S':case 'T':case 'U':case 'V':case 'W':case 'X':case 'Y':case 'Z':

          //do
          this.TOKEN = this.CONTACT(TOKEN, CHAR);

          //state1
          CHAR = this.GETCHAR(sentenceChar);
          while (this.ISLETTER(CHAR) || this.ISDIGIT(CHAR)) {
            this.TOKEN = this.CONTACT(this.TOKEN, CHAR);
            CHAR = this.GETCHAR(sentenceChar);
          }
          this.RETRACT();

          //state2
          if (keyWord(TOKEN)) {
            textC.append(this.TOKEN+" [关键字]"+'\n');
          }
          else {
            textC.append(this.TOKEN+" [标志符]"+'\n');
          }

          //clear up token
          this.TOKEN = "";
          break;

          //judge ditital
        case '0':case '1':case '2':case '3':case '4':case '5':case '6':case '7':case '8': case '9':

          //do
          this.TOKEN = this.CONTACT(TOKEN, CHAR);

          //state3
          CHAR = this.GETCHAR(sentenceChar);
          while (this.ISDIGIT(CHAR)) {
            this.TOKEN = this.CONTACT(TOKEN, CHAR);
            CHAR = this.GETCHAR(sentenceChar);
          }
          this.RETRACT();

          //state4
			textC.append(this.TOKEN+" [数字]"+'\n');

          //clear up token
          this.TOKEN = "";
          break;

        case '=':

          //state5
          this.TOKEN = this.CONTACT(TOKEN, CHAR);
          textC.append(this.TOKEN+" [等号][运算符]"+'\n');

          //clear up token
          this.TOKEN = "";
          break;

        case '+':

          //state6
          this.TOKEN = this.CONTACT(TOKEN, CHAR);
          textC.append(this.TOKEN+" [加号][运算符]"+'\n');

          //clear up token
          this.TOKEN = "";
          break;

        case '*':

          //state7
          this.TOKEN = this.CONTACT(TOKEN, CHAR);
		  
            textC.append(this.TOKEN+" [乘号][运算符]"+'\n');
          
          //clear up token
          this.TOKEN = "";
          break;

        case ',':

          //state10
          this.TOKEN = this.CONTACT(TOKEN, CHAR);
          textC.append(this.TOKEN+" [逗号][间隔符]"+'\n');

          //clear up token
          this.TOKEN = "";
          break;

        case '(':

          //state11
          this.TOKEN = this.CONTACT(TOKEN, CHAR);
          textC.append(this.TOKEN+" [左括号][间隔符]"+'\n');

          //clear up token
          this.TOKEN = "";
          break;

        case ')':

          //state12
          this.TOKEN = this.CONTACT(TOKEN, CHAR);
          textC.append(this.TOKEN+" [右括号][间隔符]"+'\n');
          //clear up token
          this.TOKEN = "";
          break;

        case '{':

          //state13
          this.TOKEN = this.CONTACT(TOKEN, CHAR);
         textC.append(this.TOKEN+" [左大括号][间隔符]"+'\n');

          //clear up token
          this.TOKEN = "";
          break;

        case '}':

          //state14
          this.TOKEN = this.CONTACT(TOKEN, CHAR);
          textC.append(this.TOKEN+" [右大括号][间隔符]"+'\n');

          //clear up token
          this.TOKEN = "";
          break;

        case '[':

          //state15
          this.TOKEN = this.CONTACT(TOKEN, CHAR);
          textC.append(this.TOKEN+" [左中括号][间隔符]"+'\n');

          //clear up token
          this.TOKEN = "";
          break;

        case ']':

          //state16
          this.TOKEN = this.CONTACT(TOKEN, CHAR);
          textC.append(this.TOKEN+" [右中括号][间隔符]"+'\n');

          //clear up token
          this.TOKEN = "";
          break;

        case '.':

          //state17
          this.TOKEN = this.CONTACT(TOKEN, CHAR);
         textC.append(this.TOKEN+" [点号][间隔符]"+'\n');

          //clear up token
          this.TOKEN = "";
          break;

		

      /*  default:

          //state19
          this.TOKEN = this.CONTACT(this.TOKEN, this.CHAR);

          //追加出错信息
         textC.append(this.TOKEN+" [error]"+'\n');
          this.ASTATE = false;

          //clear up token
          this.TOKEN = "";
          break;*/
      }
      if (this.ASTATE == false) {
        break;
      }
    }
    return this.finalAccidence;
  }
 //以下为字符的处理方法
/////////////////////////////////////////////////////
//////////////字符方法开始///////////////////////////
/////////////////////////////////////////////////////
  
  public char GETBC(char[] sentenceChar) {
    try {
      while ( (sentenceChar[this.index]) == ' ') {
        this.index++;
      }
      this.index++;
    }
    catch (java.lang.ArrayIndexOutOfBoundsException e) {
      return ';'; //表示此行已经结束
    }
    return sentenceChar[index - 1];
  }

 
  public char GETCHAR(char[] sentenceChar) {
    next();
    return sentenceChar[this.index - 1];
  }


  public void next() {
    this.index++;
  }


  public boolean ISLETTER(char letter) { //判断是否是letter
    return java.lang.Character.isLetter(letter);
  }

  
  public boolean ISDIGIT(char letter) { //判断是否是数字
    return java.lang.Character.isDigit(letter);
  }
  public boolean keyWord(String TOKEN)
	{
		String[] keyWords = {"abstract","boolean","break","byte","case","catch","char","class","const","continue","default","do",
								"dobule","else","extends","final","finally","float","for","goto","if","implements","import","instanceof",
								"int","interface","long","native","new","package","private","protected","public","return","short","static",};//关键字数组
			for(int i=0;i<keyWords.length;i++)
			
				if(TOKEN.equals(keyWords[i]))
					return true;
				return false;		
		
  }

 
  public String CONTACT(String TOKEN, char CHAR) {
    String tmpS = TOKEN + String.valueOf(CHAR);
    TOKEN = tmpS;
    return TOKEN;
  }

  public void RETRACT() {
    this.index--;
  }
/////////////////////////////////////////////////////
//////////////字符方法结束///////////////////////////
/////////////////////////////////////////////////////
    
}