options.java

一个JAVA编写的简单编译器

package util;


public class Options {
  private static final String[] paramText = {
    "-tscan",     // trace Scanner
    "-tparse",    // trace Parser
    "-tsymbol",   // display Symboltabel 
    "-genxml",    // create xml 
    "-nocodegen", // no Code generation
    "-testscan",  // test the Scanners
  };
  
  private static boolean
    pscan      = false, // no trace Scanner
    pparse     = false, // no trace Parser
    psymbol    = false, // no Symboltabel display
    pgenxml    = false, // no xml to create
    pnocodegen = false, // Code generation
    ptestscan  = false; // no: test the Scanners

  public static boolean getpscan () {
    return pscan;
  }
  public static boolean getpparse () {
    return pparse;
  }
  public static boolean getpsymbol () {
    return psymbol;
  }
  public static boolean getpgenxml () {
    return pgenxml;
  }
  public static boolean getpnocodegen () {
    return pnocodegen;
  }
  public static boolean getptestscan () {
    return ptestscan;
  }

  private static String[]  errorText ={
    "invoke: java JSub Options file name",
    "-tscan       // trace Scanner",
    "-tparse      // trace Parser",
    "-tsymbol     // Symbol tabel display",
    "-genxml      // create xml",
    "-nocodegen   // no Code generation",
    "-testscan,   // test the Scanners",
  };
  
  private static void errorMessageAndExit () {
    for (int i = 0; i< errorText.length; i++) 
      System.err.println (errorText[i]);
    System.exit (1);
  }
  
  private static String fileName = null;
  
  public static String getFileName() {
    return fileName;
  }
  
  public static void parseArgs (String args[])
   {
    if (args == null)
      errorMessageAndExit ();
    for (int i = 0; i < args.length; i++) 
    {
    boolean found = false;
    if (args[i].startsWith ("-")) 
    {
      for (int j = 0; j < paramText.length; j++) 
      {
        if (paramText[j].equals (args[i])) 
        {
          switch (j) {
            case 0: pscan      = true; break; // trace Scanner
            case 1: pparse     = true; break; // trace Parser
            case 2: psymbol    = true; break; // display Symbol table 
            case 3: pgenxml    = true; break; // create xml
            case 4: pnocodegen = true; break; // Code generation
            case 5: ptestscan  = true; break; // run Scanner tests 
          }
          found = true;
          break;
        }
      }
      if (!found)
        errorMessageAndExit ();
    } else
      if (fileName == null) 
        fileName = args[i];
      else 
        errorMessageAndExit ();
    }
    if (fileName == null)
      errorMessageAndExit ();   
  }

  public static String nToS (int num, int number) {
    StringBuffer b = new StringBuffer ();
    b.append (num);
    while (b.length() < number)
      b.insert (0, ' ');
    return b.toString ();
  } 

}