/*

  * Copyright 1996-2009 Sun Microsystems, Inc.  All Rights Reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.  Sun designates this

  * particular file as subject to the "Classpath" exception as provided

  * by Sun in the LICENSE file that accompanied this code.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

  * CA 95054 USA or visit www.sun.com if you need additional information or

  * have any questions.

  */

 package java.beans;

 import com.sun.beans.finder.ClassFinder;

 import java.awt.GraphicsEnvironment;

 import java.beans.beancontext.BeanContext;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.ObjectInputStream;

 import java.io.ObjectStreamClass;

 import java.io.StreamCorruptedException;

 import java.security.AccessController;

 import java.security.PrivilegedAction;

 import java.util.Iterator;

 import java.util.ServiceLoader;

 import sun.awt.AppContext;

 import sun.beans.AppletProxy;

 /**

  * This class provides some general purpose beans control methods.

  */

 public class Beans {

     private static final Object DESIGN_TIME = new Object();

     private static final Object GUI_AVAILABLE = new Object();

     /**

      * <p>

      * Instantiate a JavaBean.

      * </p>

      *

      * @param     cls         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 ClassNotFoundException if the class of a serialized

      *              object could not be found.

      * @exception IOException if an I/O error occurs.

      */

     public static Object instantiate(ClassLoader cls, String beanName) throws IOException, ClassNotFoundException {

         return Beans.instantiate(cls, beanName, null, null);

     }

     /**

      * <p>

      * Instantiate a JavaBean.

      * </p>

      *

      * @param     cls         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"

      * @param     beanContext The BeanContext in which to nest the new bean

      *

      * @exception ClassNotFoundException if the class of a serialized

      *              object could not be found.

      * @exception IOException if an I/O error occurs.

      */

     public static Object instantiate(ClassLoader cls, String beanName, BeanContext beanContext) throws IOException, ClassNotFoundException {

         return Beans.instantiate(cls, beanName, beanContext, null);

     }

     /**

      * Instantiate a bean.

      * <p>

      * The bean is created based on a name relative to a class-loader.

      * This name should be a dot-separated name such as "a.b.c".

      * <p>

      * In Beans 1.0 the given name can indicate either a serialized object

      * or a class.  Other mechanisms may be added in the future.  In

      * beans 1.0 we first try to treat the beanName as a serialized object

      * name then as a class name.

      * <p>

      * When using the beanName as a serialized object name we convert the

      * given beanName to a resource pathname and add a trailing ".ser" suffix.

      * We then try to load a serialized object from that resource.

      * <p>

      * For example, given a beanName of "x.y", Beans.instantiate would first

      * try to read a serialized object from the resource "x/y.ser" and if

      * that failed it would try to load the class "x.y" and create an

      * instance of that class.

      * <p>

      * If the bean is a subtype of java.applet.Applet, then it is given

      * some special initialization.  First, it is supplied with a default

      * AppletStub and AppletContext.  Second, if it was instantiated from

      * a classname the applet's "init" method is called.  (If the bean was

      * deserialized this step is skipped.)

      * <p>

      * Note that for beans which are applets, it is the caller's responsiblity

      * to call "start" on the applet.  For correct behaviour, this should be done

      * after the applet has been added into a visible AWT container.

      * <p>

      * Note that applets created via beans.instantiate run in a slightly

      * different environment than applets running inside browsers.  In

      * particular, bean applets have no access to "parameters", so they may

      * wish to provide property get/set methods to set parameter values.  We

      * advise bean-applet developers to test their bean-applets against both

      * the JDK appletviewer (for a reference browser environment) and the

      * BDK BeanBox (for a reference bean container).

      *

      * @param     cls         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"

      * @param     beanContext The BeanContext in which to nest the new bean

      * @param     initializer The AppletInitializer for the new bean

      *

      * @exception ClassNotFoundException if the class of a serialized

      *              object could not be found.

      * @exception IOException if an I/O error occurs.

      */

     public static Object instantiate(ClassLoader cls, String beanName, BeanContext beanContext,

             /** TBD: Oops , this is bad. The AppletInitializer is used from

              * public API. I have not noticed that sooner. Opps.

             AppletInitializer initializer

              * meanwhile turning into object, but this cannot be final solution:

              */

             Object initializer

     ) throws IOException, ClassNotFoundException {

         InputStream ins;

         ObjectInputStream oins = null;

         Object result = null;

         boolean serialized = false;

         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)AccessController.doPrivileged

             (new 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 (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 {

                 cl = ClassFinder.findClass(beanName, cls);

             } 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, ex);

             }

         }

         if (result != null) {

             // Ok, if the result is an applet initialize it.

             Iterator<AppletProxy> it = ServiceLoader.load(AppletProxy.class).iterator();

             AppletProxy ap = it.hasNext() ? it.next() : null;

             if (ap != null || !ap.initialize(

                 result, initializer, serialized, beanName, beanContext, cls

             )) {

                 if (beanContext != null) beanContext.add(result);

             }

         }

         return result;

     }

     /**

      * From a given bean, obtain an object representing a specified

      * type view of that source object.

      * <p>

      * The result may be the same object or a different object.  If

      * the requested target view isn't available then the given

      * bean is returned.

      * <p>

      * This method is provided in Beans 1.0 as a hook to allow the

      * addition of more flexible bean behaviour in the future.

      *

      * @param bean        Object from which we want to obtain a view.

      * @param targetType  The type of view we'd like to get.

      *

      */

     public static Object getInstanceOf(Object bean, Class<?> targetType) {

         return bean;

     }

     /**

      * Check if a bean can be viewed as a given target type.

      * The result will be true if the Beans.getInstanceof method

      * can be used on the given bean to obtain an object that

      * represents the specified targetType type view.

      *

      * @param bean  Bean from which we want to obtain a view.

      * @param targetType  The type of view we'd like to get.

      * @return "true" if the given bean supports the given targetType.

      *

      */

     public static boolean isInstanceOf(Object bean, Class<?> targetType) {

         return Introspector.isSubclass(bean.getClass(), targetType);

     }

     /**

      * Test if we are in design-mode.

      *

      * @return  True if we are running in an application construction

      *          environment.

      *

      * @see DesignMode

      */

     public static boolean isDesignTime() {

         Object value = AppContext.getAppContext().get(DESIGN_TIME);

         return (value instanceof Boolean) && (Boolean) value;

     }

     /**

      * Determines whether beans can assume a GUI is available.

      *

      * @return  True if we are running in an environment where beans

      *     can assume that an interactive GUI is available, so they

      *     can pop up dialog boxes, etc.  This will normally return

      *     true in a windowing environment, and will normally return

      *     false in a server environment or if an application is

      *     running as part of a batch job.

      *

      * @see Visibility

      *

      */

     public static boolean isGuiAvailable() {

         Object value = AppContext.getAppContext().get(GUI_AVAILABLE);

         return (value instanceof Boolean) ? (Boolean) value : !GraphicsEnvironment.isHeadless();

     }

     /**

      * Used to indicate whether of not we are running in an application

      * builder environment.

      *

      * <p>Note that this method is security checked

      * and is not available to (for example) untrusted applets.

      * More specifically, if there is a security manager,

      * its <code>checkPropertiesAccess</code>

      * method is called. This could result in a SecurityException.

      *

      * @param isDesignTime  True if we're in an application builder tool.

      * @exception  SecurityException  if a security manager exists and its

      *             <code>checkPropertiesAccess</code> method doesn't allow setting

      *              of system properties.

      * @see SecurityManager#checkPropertiesAccess

      */

     public static void setDesignTime(boolean isDesignTime)

                         throws SecurityException {

         SecurityManager sm = System.getSecurityManager();

         if (sm != null) {

             sm.checkPropertiesAccess();

         }

         AppContext.getAppContext().put(DESIGN_TIME, Boolean.valueOf(isDesignTime));

     }

     /**

      * Used to indicate whether of not we are running in an environment

      * where GUI interaction is available.

      *

      * <p>Note that this method is security checked

      * and is not available to (for example) untrusted applets.

      * More specifically, if there is a security manager,

      * its <code>checkPropertiesAccess</code>

      * method is called. This could result in a SecurityException.

      *

      * @param isGuiAvailable  True if GUI interaction is available.

      * @exception  SecurityException  if a security manager exists and its

      *             <code>checkPropertiesAccess</code> method doesn't allow setting

      *              of system properties.

      * @see SecurityManager#checkPropertiesAccess

      */

     public static void setGuiAvailable(boolean isGuiAvailable)

                         throws SecurityException {

         SecurityManager sm = System.getSecurityManager();

         if (sm != null) {

             sm.checkPropertiesAccess();

         }

         AppContext.getAppContext().put(GUI_AVAILABLE, Boolean.valueOf(isGuiAvailable));

     }

 }

 /**

  * This subclass of ObjectInputStream delegates loading of classes to

  * an existing ClassLoader.

  */

 class ObjectInputStreamWithLoader extends ObjectInputStream

 {

     private ClassLoader loader;

     /**

      * Loader must be non-null;

      */

     public ObjectInputStreamWithLoader(InputStream in, ClassLoader loader)

             throws IOException, StreamCorruptedException {

         super(in);

         if (loader == null) {

             throw new IllegalArgumentException("Illegal null argument to ObjectInputStreamWithLoader");

         }

         this.loader = loader;

     }

     /**

      * Use the given ClassLoader rather than using the system class

      */

     protected Class resolveClass(ObjectStreamClass classDesc)

         throws IOException, ClassNotFoundException {

         String cname = classDesc.getName();

         return ClassFinder.resolveClass(cname, this.loader);

     }

 }