/*
    * Copyright (c) 2003, Henri Yandell
    * All rights reserved.
    * 
    * Redistribution and use in source and binary forms, with or 
    * without modification, are permitted provided that the 
    * following conditions are met:
    * 
    * + Redistributions of source code must retain the above copyright notice, 
   *   this list of conditions and the following disclaimer.
   * 
   * + Redistributions in binary form must reproduce the above copyright notice, 
   *   this list of conditions and the following disclaimer in the documentation 
   *   and/or other materials provided with the distribution.
   * 
   * + Neither the name of Genjava-Core nor the names of its contributors 
   *   may be used to endorse or promote products derived from this software 
   *   without specific prior written permission.
   * 
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
   * POSSIBILITY OF SUCH DAMAGE.
   */
  package com.generationjava.lang;
  
  import java.lang.reflect.InvocationTargetException;
  import java.lang.reflect.Method;
  
  import com.generationjava.collections.CollectionsW;
  
  /***
   * A set of static utilities for use with Classes.
   *
   * @author bayard@generationjava.com
   * @date   2001-05-19
   */
  final public class ClassW {
  
      /***
       * Create an object from the classname. Must have an empty constructor.
       *
       * @param classname String name of the class
       *
       * @return Object instance of the class or null
       */
      static public Object createObject(String classname) {
          Class tmpClass = null;
  
          tmpClass = getClass(classname);
  
          if(tmpClass == null) {
  //            System.err.println("No class for: "+classname);
              return null;
          }
  
  
          return createObject(tmpClass);
      }
  
      /***
       * Create an object from a class. 
       *
       * @param clss Class object to instantiate
       *
       * @return Object instance of the class or null
       */
      static public Object createObject(Class clss) {
          if(clss == null) {
  //            System.err.println("Null class passed in. ");
              return null;
          }
  
          try {
              return clss.newInstance();
          } catch (IllegalAccessException  iae) {
  //            System.err.println("Cant instantiate " + clss.getName() + " because " +
  //                   iae.getMessage());
          } catch (InstantiationException  ie) {
  //            System.err.println("Cant instantiate " + clss.getName() + " because " +
  //                   ie.getMessage());
          }
  
          return null;
      }
  
      /***
       * Is this Class in the CLASSPATH
       *
       * @param classname String of the class
       *
       * @return boolean exists or not.
      */
     static public boolean classExists(String classname) {
         Class tmpClass = null;
 
         /* try and load class */
         try {
 //            tmpClass = Class.forName(classname);
             tmpClass = Thread.currentThread().getContextClassLoader().loadClass(classname);
         } catch (ClassNotFoundException cnfe) {
             return false;
         } catch (IllegalArgumentException iae) {
             return false;
         }
      
         return true;   
     }
 
     /***
      * Get the Class object for a classname.
      *
      * @param classname String of the class
      *
      * @return Class instance for the class.
      */
     static public Class getClass(String classname) {
         Class tmpClass = null;
 
         /* try an load class */
         try {
 //            tmpClass = Class.forName(classname);
             tmpClass = Thread.currentThread().getContextClassLoader().loadClass(classname);
         } catch (ClassNotFoundException cnfe) {
 //            System.err.println("Can not resolve classname " + classname);
         } catch (IllegalArgumentException iae) {
 //            System.err.println("Can nott resolve " + tmpClass.getName() + " because " + iae.getMessage());
         }
      
         return tmpClass;   
     }
 
     static public void callMain(String[] args) {
         callMain(args[0], CollectionsW.getSubArray(args, 1) );
     }
     static public void callMain(String classname, String[] args) {
         callStatic(classname, "main", new Class[] { String[].class }, new Object[] { args } );
     }
     static public void callMain(Class clss, String[] args) {
         callStatic(clss, "main", new Class[] { String[].class }, new Object[] { args } );
     }
 // figure out types from object args
    // static public void callStatic(String classname, String method, Object[] args) {
    // }
     /***
      * Runs a static method on a class.
      *
      * @param classname     String name of class to invoke on.
      * @param methodName    String name of method to call.
      * @param args          Object[] arguments to method.
      */
     static public Object callStatic(String classname, String methodName, 
                                     Class[] types, Object[] args) 
     {
         return callStatic(getClass(classname), methodName, types, args);
     }
 
     static public Object callStatic(Class clss, String methodName, 
                                   Class[] types, Object[] args) 
     {
         try {
             Method method = clss.getMethod(methodName, types );
             return method.invoke( null, args );
         } catch(NoSuchMethodException nsme) {
         } catch(IllegalAccessException iae) {
         } catch(InvocationTargetException ite) {
         }
         return null;
     }
 
 }