java/src/main/com/google/appengine/tools/development/DevAppServerClassLoader.java

   1 // Copyright 2008 Google Inc. All Rights Reserved.
   2
   3 package com.google.appengine.tools.development;
   4
   5 import com.google.appengine.tools.info.SdkImplInfo;
   6 import com.google.appengine.tools.info.SdkInfo;
   7
   8 import java.net.URL;
   9 import java.net.URLClassLoader;
  10 import java.security.AllPermission;
  11 import java.security.CodeSource;
  12 import java.security.PermissionCollection;
  13 import java.util.ArrayList;
  14 import java.util.List;
  15
  16 /**
  17  * Isolates the DevAppServer and all of its dependencies into its own classloader.
  18  * This ClassLoader refuses to load anything off of the JVM's System ClassLoader
  19  * except for JRE classes (i.e. it ignores classpath and JAR manifest entries).
  20  *
  21  */
  22 class DevAppServerClassLoader extends URLClassLoader {
  23
  24   private final ClassLoader delegate;
  25
  26   private static final String DEV_APP_SERVER_INTERFACE
  27       = "com.google.appengine.tools.development.DevAppServer";
  28
  29   private static final String APP_CONTEXT_INTERFACE
  30       = "com.google.appengine.tools.development.AppContext";
  31
  32   private static final String DEV_APP_SERVER_AGENT
  33       = "com.google.appengine.tools.development.agent.AppEngineDevAgent";
  34
  35   private static final String DEV_SOCKET_IMPL_FACTORY
  36       = "com.google.appengine.tools.development.DevSocketImplFactory";
  37
  38   /**
  39    * Creates a new {@code DevAppServerClassLoader}, which will load
  40    * libraries from the App Engine SDK.
  41    *
  42    * @param delegate A delegate ClassLoader from which a few shared
  43    * classes will be loaded (e.g. DevAppServer).
  44    */
  45   public static DevAppServerClassLoader newClassLoader(ClassLoader delegate) {
  46     List<URL> libs = new ArrayList<URL>(SdkInfo.getSharedLibs());
  47     libs.addAll(SdkImplInfo.getImplLibs());
  48     libs.addAll(SdkImplInfo.getUserJspLibs());
  49     return new DevAppServerClassLoader(libs.toArray(new URL[libs.size()]), delegate);
  50   }
  51
  52   DevAppServerClassLoader(URL[] urls, ClassLoader delegate) {
  53     super(urls, null);
  54     this.delegate = delegate;
  55   }
  56
  57   @Override
  58   protected synchronized Class<?> loadClass(String name, boolean resolve)
  59       throws ClassNotFoundException {
  60
  61     if (name.equals(DEV_APP_SERVER_INTERFACE) ||
  62         name.equals(APP_CONTEXT_INTERFACE) ||
  63         name.equals(DEV_APP_SERVER_AGENT) ||
  64         name.equals(DEV_SOCKET_IMPL_FACTORY) ||
  65         name.startsWith("com.google.appengine.tools.info.") ||
  66         name.startsWith("com.google.appengine.tools.plugins")) {
  67       Class c = delegate.loadClass(name);
  68       if (resolve) {
  69         resolveClass(c);
  70       }
  71       return c;
  72     }
  73
  74     return super.loadClass(name, resolve);
  75   }
  76
  77   @Override
  78   protected PermissionCollection getPermissions(CodeSource codesource) {
  79     PermissionCollection permissions = super.getPermissions(codesource);
  80     permissions.add(new AllPermission());
  81     return permissions;
  82   }
  83 }