Loader.java

/*******************************************************************************
 * Copyright 2010 Simon Mieth
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/

package org.kabeja;

import java.io.File;
import java.lang.reflect.Method;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.StringTokenizer;


/**
 * @author <a href="mailto:simon.mieth@gmx.de>simon.mieth@gmx.de</a>
 *
 */
public class Loader {
	
	
	
    public static final String OPTION_MAIN_CLASS="-main";
    public static final String OPTION_LIB_FOLDER="-lib";
    public static final String OPTION_CLASSES_FOLDER="-classes";
    public String mainClass = "org.kabeja.Main";

    private Set classpathEntries = new HashSet();
    
    
    
    
    public Loader() {
    	//default classpath relative to this 
		this.classpathEntries.add("lib");
		this.classpathEntries.add("classes");

	}

	public static void main(String[] args) {
        Loader l = new Loader();
        l.launch(args);
    }

    public void launch(String[] args) {
        args = parseMainClass(args);

        URLClassLoader cl = new URLClassLoader(getClasspath());

        try {
            Class clazz = cl.loadClass(this.mainClass);
            Object obj = clazz.newInstance();
      
            
            // init the project
            Method method = clazz.getDeclaredMethod("main",
                    new Class[] { args.getClass() });
            method.invoke(obj, new Object[] { args });
        } catch (Exception e) {
            e.printStackTrace();
        } 
    }

    protected URL[] getClasspath() {
        List urls = new ArrayList();

         Iterator i = this.classpathEntries.iterator();
         while(i.hasNext()){
            File f = new File((String)i.next());

            try {
                if (f.isDirectory() && f.exists()) {
                    File[] files = f.listFiles();

                    for (int x = 0; x < files.length; x++) {
                        String name = files[x].getName().toLowerCase();

                        if (name.endsWith(".jar") || name.endsWith(".zip")) {
                            urls.add(files[x].toURL());
                        }
                    }
                }

                urls.add(f.toURL());
            } catch (MalformedURLException e) {
                e.printStackTrace();
            }
        }

        return (URL[]) urls.toArray(new URL[urls.size()]);
    }

    protected String[] parseMainClass(String[] args) {
        List list = new ArrayList();

        for (int i = 0; i < args.length; i++) {
            if (OPTION_MAIN_CLASS.equals(args[i]) && ((i + 1) < args.length)) {
                i++;
                this.mainClass = args[i];
            }else if(OPTION_LIB_FOLDER.equals(args[i])){
            	i++;
            	this.addPathEntries(args[i]);
            }else if(OPTION_CLASSES_FOLDER.equals(args[i])){
            	i++;
            	this.addPathEntries(args[i]);
            }else {
                list.add(args[i]);
            }
        }
        
        return (String[]) list.toArray(new String[list.size()]);
    }
    
    
 
    
    
    protected void addPathEntries(String path){
    	StringTokenizer st = new StringTokenizer(path,":");
    
    	while(st.hasMoreElements()){
    		String el = (String)st.nextElement();
    		this.classpathEntries.add(el);
    	}
    }
    
}