/**
   * Instantiate a JavaBean.
   *
   * @param classLoader the class-loader from which we should create the bean. If this is null, then
   *     the system class-loader is used.
   * @param beanName the name of the bean within the class-loader. For example "sun.beanbox.foobah"
   * @exception java.lang.ClassNotFoundException if the class of a serialized object could not be
   *     found.
   * @exception java.io.IOException if an I/O error occurs.
   */
  public static Object instantiate(ClassLoader cls, String beanName)
      throws java.io.IOException, ClassNotFoundException {
    java.io.InputStream ins;
    java.io.ObjectInputStream oins = null;
    Object result = null;
    boolean serialized = false;
    java.io.IOException serex = null;
    // If the given classloader is null, we check if an
    // system classloader is available and (if so)
    // use that instead.
    // Note that calls on the system class loader will
    // look in the bootstrap class loader first.
    if (cls == null) {
      try {
        cls = ClassLoader.getSystemClassLoader();
      } catch (SecurityException ex) { // We're not allowed to access the system class loader.
        // Drop through.
      }
    }
    // Try to find a serialized object with this name
    final String serName = beanName.replace('.', '/').concat(".ser");
    final ClassLoader loader = cls;
    ins =
        (InputStream)
            java.security.AccessController.doPrivileged(
                new java.security.PrivilegedAction() {
                  public Object run() {
                    if (loader == null) return ClassLoader.getSystemResourceAsStream(serName);
                    else return loader.getResourceAsStream(serName);
                  }
                });
    if (ins != null) {
      try {
        if (cls == null) {
          oins = new ObjectInputStream(ins);
        } else {
          oins = new ObjectInputStreamWithLoader(ins, cls);
        }
        result = oins.readObject();
        serialized = true;
        oins.close();
      } catch (java.io.IOException ex) {
        ins.close();
        // Drop through and try opening the class.  But remember
        // the exception in case we can't find the class either.
        serex = ex;
      } catch (ClassNotFoundException ex) {
        ins.close();
        throw ex;
      }
    }
    if (result == null) {
      // No serialized object, try just instantiating the class
      Class cl;
      try {
        if (cls == null) {
          cl = Class.forName(beanName);
        } else {
          cl = cls.loadClass(beanName);
        }
      } catch (ClassNotFoundException ex) {
        // There is no appropriate class.  If we earlier tried to
        // deserialize an object and got an IO exception, throw that,
        // otherwise rethrow the ClassNotFoundException.
        if (serex != null) {
          throw serex;
        }
        throw ex;
      }
      /*
       * Try to instantiate the class.
       */

      try {
        result = cl.newInstance();
      } catch (Exception ex) {
        // We have to remap the exception to one in our signature.
        // But we pass extra information in the detail message.
        throw new ClassNotFoundException("" + cl + " : " + ex);
      }
    }
    if (result != null) { // Ok, if the result is an applet initialize it.
      AppletStub stub = null;

      if (result instanceof Applet) {
        Applet applet = (Applet) result;

        // Figure our the codebase and docbase URLs.  We do this
        // by locating the URL for a known resource, and then
        // massaging the URL.

        // First find the "resource name" corresponding to the bean
        // itself.  So a serialzied bean "a.b.c" would imply a
        // resource name of "a/b/c.ser" and a classname of "x.y"
        // would imply a resource name of "x/y.class".

        final String resourceName;

        if (serialized) {
          // Serialized bean
          resourceName = beanName.replace('.', '/').concat(".ser");
        } else {
          // Regular class
          resourceName = beanName.replace('.', '/').concat(".class");
        }

        URL objectUrl = null;
        URL codeBase = null;
        URL docBase = null;

        // Now get the URL correponding to the resource name.

        final ClassLoader cloader = cls;
        objectUrl =
            (URL)
                java.security.AccessController.doPrivileged(
                    new java.security.PrivilegedAction() {
                      public Object run() {
                        if (cloader == null) return ClassLoader.getSystemResource(resourceName);
                        else return cloader.getResource(resourceName);
                      }
                    });

        // If we found a URL, we try to locate the docbase by taking
        // of the final path name component, and the code base by taking
        // of the complete resourceName.
        // So if we had a resourceName of "a/b/c.class" and we got an
        // objectURL of "file://bert/classes/a/b/c.class" then we would
        // want to set the codebase to "file://bert/classes/" and the
        // docbase to "file://bert/classes/a/b/"

        if (objectUrl != null) {
          String s = objectUrl.toExternalForm();

          if (s.endsWith(resourceName)) {
            int ix = s.length() - resourceName.length();
            codeBase = new URL(s.substring(0, ix));
            docBase = codeBase;

            ix = s.lastIndexOf('/');

            if (ix >= 0) {
              docBase = new URL(s.substring(0, ix + 1));
            }
          }
        }

        // Setup a default context and stub.
        BeansAppletContext context = new BeansAppletContext(applet);

        stub = (AppletStub) new BeansAppletStub(applet, context, codeBase, docBase);
        applet.setStub(stub);

        // If it was deserialized then it was already init-ed.
        // Otherwise we need to initialize it.

        if (!serialized) {
          // We need to set a reasonable initial size, as many
          // applets are unhappy if they are started without
          // having been explicitly sized.
          applet.setSize(100, 100);
          applet.init();
        }
        ((BeansAppletStub) stub).active = true;
      }
    }
    return result;
  }
示例#2
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  /**
   * Load the applet into memory. Runs in a seperate (and interruptible) thread from the rest of the
   * applet event processing so that it can be gracefully interrupted from things like HotJava.
   */
  @SuppressWarnings("deprecation")
  private void runLoader() {
    if (status != APPLET_DISPOSE) {
      showAppletStatus("notdisposed");
      return;
    }

    dispatchAppletEvent(APPLET_LOADING, null);

    // REMIND -- might be cool to visually indicate loading here --
    // maybe do animation?
    status = APPLET_LOAD;

    // Create a class loader
    loader = getClassLoader(getCodeBase(), getClassLoaderCacheKey());

    // Load the archives if present.
    // REMIND - this probably should be done in a separate thread,
    // or at least the additional archives (epll).

    String code = getCode();

    // setup applet AppContext
    // this must be called before loadJarFiles
    setupAppletAppContext();

    try {
      loadJarFiles(loader);
      applet = createApplet(loader);
    } catch (ClassNotFoundException e) {
      status = APPLET_ERROR;
      showAppletStatus("notfound", code);
      showAppletLog("notfound", code);
      showAppletException(e);
      return;
    } catch (InstantiationException e) {
      status = APPLET_ERROR;
      showAppletStatus("nocreate", code);
      showAppletLog("nocreate", code);
      showAppletException(e);
      return;
    } catch (IllegalAccessException e) {
      status = APPLET_ERROR;
      showAppletStatus("noconstruct", code);
      showAppletLog("noconstruct", code);
      showAppletException(e);
      // sbb -- I added a return here
      return;
    } catch (Exception e) {
      status = APPLET_ERROR;
      showAppletStatus("exception", e.getMessage());
      showAppletException(e);
      return;
    } catch (ThreadDeath e) {
      status = APPLET_ERROR;
      showAppletStatus("death");
      return;
    } catch (Error e) {
      status = APPLET_ERROR;
      showAppletStatus("error", e.getMessage());
      showAppletException(e);
      return;
    } finally {
      // notify that loading is no longer going on
      dispatchAppletEvent(APPLET_LOADING_COMPLETED, null);
    }

    // Fixed #4508194: NullPointerException thrown during
    // quick page switch
    //
    if (applet != null) {
      // Stick it in the frame
      applet.setStub(this);
      applet.hide();
      add("Center", applet);
      showAppletStatus("loaded");
      validate();
    }
  }