Loading the correct constructor from an init file...

Question

by reading lines like that:
Apple 10 rgb000100255
Apple 20 rgb255150255
from an "init.txt" file
but i get an IllegalArgumentException
when it tries to find the correct constructor based
on the paramTypes array, which contains the
types of the parameters of the appropriate constructor
it seems that the error has to do with the unwrapping
of the class of the primitive types(Integer class in
my program)
any suggestion is welcome,
thanks
here's the complete code,
feel free to try it
(don't forget the "init.txt" file)
import java.io.*;
import java.util.*;
import java.awt.*;
import java.lang.reflect.*;
class FruitMgr
     ArrayList fruits;
     public
     FruitMgr(String name)
          fruits = new ArrayList(4);
          InitFileLoader init = new InitFileLoader("init.txt");
          init.load();
          init.close();
          return;
     public String
     toString()
          String str = "";
          for(int i = 0; i < fruits.size(); i++)
               str += fruits.get(i) + "\n";
          return str;
     private class InitFileLoader
          private String filename;
          private BufferedReader br;
          private String line;
          private int linenumber;
          private char separator;
          private boolean eof;
          private Class clazz;
          private Class[] paramTypes;
          private Object[] initArgs;
          public
          InitFileLoader(String name)
               filename = name;
               separator = ' ';
               linenumber = 0;
               eof = true;
               try
                    br = new BufferedReader(new FileReader(filename));
                    eof = false;
               catch(IOException e)
                    error("Opening file \"" + filename + "\"");
               /*getLine();
               while(!eof)
                    System.out.println(line);
                    String s;
                    while((s = getNextWord()) != "")
                         System.out.println("*" + s);
                    getLine();
               return;
          public void
          getLine()
               try
                    line = br.readLine();
               catch(IOException e)
                    error("Couldn't read line " + linenumber + " of file \"" + filename + "\"");
               if(line != null )
                    eof = false;
                    linenumber++;
               else
                    eof = true;
               return;
          public String
          getNextWord()
               String word;
               if(line.indexOf(separator) != -1)
                    word = line.substring(0, line.indexOf(separator));
                    line = line.substring(line.indexOf(separator) + 1);
                    return word;
               else if(line.indexOf(separator) == -1 && line != "")
                    word = line;
                    line = "";
                    return word;
               else
                    return "";
          public int
          getNumberOfArgs()
               int numOfArgs = 0;
               for(int i = 0; i < line.length(); i++ )
                    if(line.charAt(i) == separator)
                         numOfArgs++;
               return numOfArgs;
          public void
          load()
               getLine();
               int numOfArgs = getNumberOfArgs();
               while(!eof)
                    System.out.println(line);
                    String clazzname = getNextWord();
                    try
                         clazz = Class.forName(clazzname);
                    catch(ClassNotFoundException e)
                         error("Class " + clazzname + " not found");
                    initArgs = new Object[numOfArgs];
                    paramTypes = new Class[numOfArgs];
                    int j = 0;
                    String arg;
                    while((arg = getNextWord()) != "")
                         //System.out.println("*" + arg);
                         if(Character.isDigit(arg.charAt(0)))
                              int n = Integer.parseInt(arg);
                              initArgs[j] = new Integer(n);
                              paramTypes[j] = initArgs[j].getClass();
                              System.out.println("+++" + paramTypes[j]);
                              j++;
                         else if(arg.startsWith("rgb"))
                              int len = 3;
                              arg = arg.substring(len, arg.length());
                              int red = Integer.parseInt(arg.substring(0, len));
                              arg = arg.substring(len, arg.length());
                              int green = Integer.parseInt(arg.substring(0, len));
                              arg = arg.substring(len, arg.length());
                              int blue = Integer.parseInt(arg.substring(0, len));
                              initArgs[j] = new Color(red, green, blue);
                              paramTypes[j] = initArgs[j].getClass();
                              System.out.println("+++" + paramTypes[j]);
                              j++;
                    try
                         Constructor con[] = clazz.getConstructors();
                         for(int i = 0; i < Array.getLength(paramTypes); i++)
                              System.out.println("****" + paramTypes);
                         for( int k = 0; k < Array.getLength((Object)con); k++ )
                              Object o = con[2].newInstance(initArgs);
                              System.out.println("****" + o);
                              fruits.add(o);
                         /* preferred way */
                         /*Constructor con = clazz.getConstructor(paramTypes);
                         Object o = con.newInstance(initArgs);
                         System.out.println("****" + o);
                         fruits.add(o);*/
                    catch(InstantiationException e)
                         error("Instantiation");
                    catch(IllegalAccessException e)
                         error("IllegalAccess");
                    catch(IllegalArgumentException e)
                         error("IllegalArgument");
                    catch(InvocationTargetException e)
                         error("InvocationTarget");
                    /*catch(NoSuchMethodException e)
                         error("NoSuchMethod");
                    initArgs = null;
                    paramTypes = null;
                    getLine();
               return;
          public void
          close()
               try
                    br.close();
               catch(IOException e)
                    error("Closing file \"" + filename + "\"");
               return;
          private void
          error(String message)
               System.err.println("Exception occured : " + message);
               return;
class Fruit
     String name;
     int weight;
     public
     Fruit()
          name = "Fruit";
          weight = 1;
          return;
     public
     Fruit(int kilos)
          this();
          weight = kilos;
          return;
     public int
     getWeight()
          return weight;
     public String
     toString()
          return name + " " + weight;
class Apple extends Fruit
     Color col;
     public
     Apple()
          super();
          name = "Apple";
          col = Color.red;
     public
     Apple(Color c)
          super();
          name = "Apple";
          col = c;
     public
     Apple(int kilos, Color c)
          super(kilos);
          name = "Apple";
          col = c;
     public Color
     getColor()
          return col;
     public String
     toString()
          return name + " " + weight + " " + col;
class Foo
     public static void main( String[] args )
          FruitMgr fmgr2 = new FruitMgr("init.txt");
          /*Apple a = new Apple();
          Constructor cc[] = a.getClass().getConstructors();
          for(int i = 0; i < Array.getLength(cc); i++)
               Class c[] = cc[i].getParameterTypes();
               System.out.println(cc[i]);
               for(int j = 0; j < Array.getLength(c); j++)
                    System.out.println("\t" + c[j]);
          return;

Answer 1

http://www.adtmag.com/java/article.asp?id=4276&mon=8&yr=2001