org.snapscript.studio.agent.ClassPathUpdater Maven / Gradle / Ivy

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package org.snapscript.studio.agent;

import java.io.File;
import java.io.LineNumberReader;
import java.io.Reader;
import java.io.StringReader;
import java.lang.reflect.Method;
import java.net.URI;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
import java.util.List;

public class ClassPathUpdater {
   
   private static final String ADD_URL_METHOD = "addURL";
   
   public static List parseClassPath(String dependencies) throws Exception {
      Reader source = new StringReader(dependencies);
      LineNumberReader reader = new LineNumberReader(source);
      List files = new ArrayList();
      
      try {
         String line = reader.readLine();
         
         while(line != null) {
            String token = line.trim();
            int length = token.length();
            
            if(length > 0) {
               if(!token.startsWith("#")) {
                  File file = new File(token);
                  files.add(file);
               }
            }
            line = reader.readLine();
         }
      } finally {
         reader.close();
      }
      return files;
   }
   
   public static ClassLoader updateClassPath(String dependencies) throws Exception {  
      URLClassLoader loader = (URLClassLoader)ClassLoader.getSystemClassLoader();
      Method method = URLClassLoader.class.getDeclaredMethod(ADD_URL_METHOD, URL.class);
      List files = parseClassPath(dependencies);
      int size = files.size();
      
      if(size > 0) {
         for(int i = 0; i < size; i++){
            File file = files.get(i);
            URI location = file.toURI();
            URL path = location.toURL();
            
            method.setAccessible(true);
            method.invoke(loader, path);
         } 
      }
      return loader;
   }
}