javapmain.java

linux下建立JAVA虚拟机的源码KAFFE

/*
 * gnu.classpath.tools.JavapMain Copyright (C) 2001 Free Software Foundation,
 * Inc.
 * 
 * This file is part of GNU Classpath.
 * 
 * GNU Classpath is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2, or (at your option) any later version.
 * 
 * GNU Classpath is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU General Public License along with
 * GNU Classpath; see the file COPYING. If not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
package gnu.classpath.tools.javap;

public class JavapMain
{
  public static void main(String argv[])
  {
    Javap p = parseArguments(argv);
    System.exit(0);
  }

  /**
   * Parses the arguments to determine what this program should do.
   */
  private static Javap parseArguments(String s[])
  {
    Javap p = null;
    try
      {
        p = Javap.getInstance();
      }
    catch (ClassNotFoundException e)
      {
        System.err.println(e.getMessage());
        return null;
      }
    if (s.length == 0)
      usage();
    boolean processArguments = true;
    int i = 0;
    while (processArguments)
      {
        if (s[i].equals("-c"))
          p.setDisassemble(true);
        else if (s[i].equals("-classpath"))
          p.setClasspath(s[++i]);
        else if (s[i].equals("-help"))
          usage();
        else if (s[i].equals("-l"))
          {
            p.setPrintLineNumbers(true);
            p.setPrintLocalVariables(true);
          }
        else if (s[i].equals("-public"))
          p.setShowPublic(true);
        else if (s[i].equals("-protected"))
          p.setShowProtected(true);
        else if (s[i].equals("-private"))
          p.setShowPrivate(true);
        else if (s[i].equals("-s"))
          p.setPrintSignatures(true);
        else if (s[i].equals("-verbose"))
          {
            p.setPrintStackSize(true);
            p.setPrintNumberLocals(true);
            p.setPrintMethodArgs(true);
          }
        else if (s[i].startsWith("-"))
          {
            System.err.println("Invalid flag: " + s[i]);
            usage();
          }
        else
          break;
        i++;
      }
    if (s.length - i == 0)
      usage();
    for (int j = i; j < s.length; j++)
      p.printClassFile(s[j], System.out);
    return p;
  }

  /**
   * Prints generic usage message to System.out.
   */
  private static void usage()
  {
    System.out.println("Usage: javap [OPTION]... [CLASS]...");
    System.out.println("Provide information about the given classes.");
    System.out.println("");
    System.out.println("   -c                        Disassemble the code");
    System.out
      .println("   -classpath PATH           Specify where to find user class files");
    System.out.println("   -help                     Print this usage message");
    System.out
      .println("   -l                        Print line number and local variable tables");
    System.out
      .println("   -public                   Show only public classes and members");
    System.out
      .println("   -protected                Show public and protected classes and members");
    System.out
      .println("   -private                  Show all classes and members");
    System.out
      .println("   -s                        Print internal type signatures");
    System.out
      .println("   -verbose                  Print stack size, number of locals and args for methods");
    System.exit(0);
  }
}