wordanalyze.java

使用直接分析法编制C语言子集的词法分析程序

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;
import javax.swing.*;
import javax.swing.table.*;

public class WordAnalyze extends JFrame{
	ArrayList<String> wordList=new ArrayList<String>();
	//char [] operators={'=','+','-','*','/','(',')','{','}',',',';','#','[',']','<','>','\"','.'};
	StringBuffer temp=new StringBuffer();
	String origin=null;
	char ch=' ';
	int index=0;
	Properties keywords=new Properties();
	Properties operators=new Properties();
	JToolBar toolbar=new JToolBar();
	int strLength=0;
	
	
	JTextArea textArea;
	DefaultTableModel tableModel;
	JTable table;
	JSplitPane split;
	
	WordAnalyze()	{
		super("--简易C语言词法分析器--");
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		int x,y;
		Dimension size=Toolkit.getDefaultToolkit().getScreenSize();
		x=(size.width-400)/2;
		y=(size.height-400)/2;
		setSize(450,400);
		setLocation(x,y);
		textArea=new JTextArea();
		textArea.setForeground(Color.BLUE);
		textArea.setLineWrap(true);
		String [] columnNames={"单词","编码","属性"};
		tableModel=new DefaultTableModel();
		table=new JTable(tableModel);
		table.setForeground(Color.BLUE);
		tableModel.addColumn("单词");
		tableModel.addColumn("编码");
		tableModel.addColumn("说明");
		split=new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,new JScrollPane(textArea),new JScrollPane(table));
		toolbar.add(new analyze("analyze",new ImageIcon("images\\analyze.gif")));
		toolbar.add(new quit("quit",new ImageIcon("images\\quit.gif")));
		getContentPane().add(toolbar,BorderLayout.NORTH);
		getContentPane().add(split);
		split.setDividerLocation(210);
		split.setResizeWeight(1);
	}
	
	class analyze extends AbstractAction { 
		public analyze(String text, Icon icon) { 
			super(text, icon); 
			} 
			public void actionPerformed(ActionEvent e) {
				origin=textArea.getText();
				tableModel.setRowCount(0);
				strLength=origin.length();
				wordList.clear();
				loadKeywordAndOperator();
				if(analyze())
					showResault();
				
			} 
	}
	
	class quit extends AbstractAction { 
		public quit(String text, Icon icon){ 
			super(text, icon); 
			} 
			public void actionPerformed(ActionEvent e) { 
				System.exit(0);
			} 
	}
	
	void showResault() {
		//textArea.setText(Arrays.toString(wordList.toArray()));
		Object [] wordArr=wordList.toArray();
		String row[]=new String [3];
		String code=null;
		for(int i=0;i<wordArr.length;i++){
			row[0]=(String)wordArr[i];
			if((code=keywords.getProperty(row[0]))!=null){
				row[1]=code;
				row[2]="关键字";
			}
			else if((code=operators.getProperty(row[0]))!=null){
				row[1]=code;
				row[2]="运算符/界符";
			}
			else if(row[0].charAt(0)>47&&row[0].charAt(0)<58){
				row[1]="0";
				row[2]="常数";
			}
			else {
				row[1]="1";
				row[2]="标识符";
			}
			tableModel.addRow(row);
		}
		
	}
	
	void loadKeywordAndOperator()	{
		try {
			keywords.load(new FileInputStream(new File("keywords.properties")));
			operators.load(new FileInputStream(new File("operators.properties")));
		}
		catch(Exception e){
			System.out.println("导入文件keywords.properties或operators.properties出错:\n"+e.toString());
			System.exit(1);
		}
	}
	
	void getChar(){
			ch=origin.charAt(index);
			index++;
			System.out.println("index:"+index);
			System.out.println("ch:"+ch);
	}
	
	boolean isLetter(){
		if((ch>64&&ch<91)||(ch>96&&ch<123))
			return true;
		else
			return false;
	}
	
	boolean isDigit(){
		if(ch>47&&ch<58)
			return true;
		else
			return false;
	}
	
	boolean isOperator(){
		if(operators.getProperty(String.valueOf(ch))!=null)
			return true;
		return false;
	}

	void wordAdd(){
		wordList.add(temp.toString());
		temp.delete(0,temp.length());
	}
	
	boolean analyze(){
		index=0;
		while(index<strLength){
			getChar();
			if(isLetter()){
				while(isLetter()||isDigit()){
					temp.append(ch);
					if(index<strLength)
						getChar();
					else
						break;
				}
				wordAdd();
				if((index<strLength+1)&&isOperator())
					index--;
			}
			else if(isDigit()){
				while(isDigit()){
					temp.append(ch);
					if(index<strLength)
						getChar();
					else
						break;
				}
				wordAdd();
				if((index<strLength+1)&&isOperator())
					index--;
			}
			else if(isOperator())	{
					temp.append(ch);
					wordAdd();
			}
			else {
				if(ch!=' '&&ch!='\n'&&ch!='\r'&&ch!='\t')	{
					JOptionPane.showMessageDialog(this,"无法识别或暂不支持符号:"+ch,"错误!",JOptionPane.ERROR_MESSAGE);
					return false;
				}
			}
		}
		return true;
	}
	
	public static void main(String [] args) {
		new WordAnalyze().setVisible(true);
	}
}