/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 com.googlecode.openbeans;
import java.applet.Applet;
import java.applet.AppletContext;
import java.applet.AppletStub;
import java.applet.AudioClip;
import java.awt.Image;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.Vector;
import org.apache.harmony.beans.internal.nls.Messages;
import com.googlecode.openbeans.beancontext.BeanContext;
/**
* This class <code>Beans</code> provides some methods for manipulting bean controls.
*
*/
public class Beans
{
private static boolean designTime = false;
private static boolean guiAvailable = true;
/**
* Constructs a Beans instance.
*/
public Beans()
{
// expected
}
@SuppressWarnings({ "resource", "unchecked" })
private static Object internalInstantiate(ClassLoader cls, String beanName, BeanContext context, Object initializer) throws IOException,
ClassNotFoundException
{
// First try to load it from a serialization file.
String beanResourceName = getBeanResourceName(beanName);
InputStream is = (cls == null) ? ClassLoader.getSystemResourceAsStream(beanResourceName) : cls.getResourceAsStream(beanResourceName);
IOException serializationException = null;
Object result = null;
if (is != null)
{
try
{
ObjectInputStream ois = (cls == null) ? new ObjectInputStream(is) : new CustomizedObjectInputStream(is, cls);
result = ois.readObject();
}
catch (IOException e)
{
// Not loadable - remember this as we may throw it later.
serializationException = e;
}
}
// If it didn't work, try to instantiate it from the given classloader
boolean deserialized = true;
ClassLoader classLoader = cls == null ? ClassLoader.getSystemClassLoader() : cls;
if (result == null)
{
deserialized = false;
try
{
result = Class.forName(beanName, true, classLoader).newInstance();
}
catch (Exception e)
{
if (serializationException != null)
{
throw serializationException;
}
throw new ClassNotFoundException(e.getClass() + ": " //$NON-NLS-1$
+ e.getMessage());
}
}
if (result != null)
{
// Applet specific initialization
boolean isApplet = false;
try
{
isApplet = result instanceof Applet;
}
catch (Throwable t)
{
// Ignored - leave isApplet as false.
}
if (isApplet)
{
appletLoaded((Applet) result, classLoader, beanName, context, (AppletInitializer) initializer, deserialized);
}
if (null != context)
{
context.add(result);
}
}
return result;
}
/**
* Obtains an instance of a JavaBean specified the bean name using the specified class loader.
* <p>
* If the specified class loader is null, the system class loader is used.
* </p>
*
* @param loader
* the specified class loader. It can be null.
* @param name
* the name of the JavaBean
* @return an isntance of the bean.
* @throws IOException
* @throws ClassNotFoundException
*/
public static Object instantiate(ClassLoader loader, String name) throws IOException, ClassNotFoundException
{
return internalInstantiate(loader, name, null, null);
}
/**
* Obtains an instance of a JavaBean specified the bean name using the specified class loader, and adds the instance into the specified bean context.
*
* <p>
* If the specified class loader is null, the system class loader is used.
* </p>
*
* @param cls
* the specified class loader. It can be null.
* @param beanName
* the name of the JavaBean
* @param beanContext
* the beancontext in which the bean instance will be added.
* @return an instance of the specified JavaBean.
* @throws IOException
* @throws ClassNotFoundException
*/
public static Object instantiate(ClassLoader cls, String beanName, BeanContext beanContext) throws IOException, ClassNotFoundException
{
return internalInstantiate(cls, beanName, beanContext, null);
}
/**
* Obtains an instance of a JavaBean specified by the bean name using the specified class loader, and adds the instance into the specified bean context.
* <p>
* The parameter name must be a qualified name relative to the specified class loader. For example, "java.awt.Button" and "x.y.z".
* </p>
* <p>
* If the specified class loader is null, the system class loader is used.
* </p>
* <p>
* Firstly, The class <code>Beans</code> regards the bean name as a serialized object name. The class <code>Beans</code> convert bean name into pathname,
* append a suffix ".ser" to the pathname. then try to load the resource using the specified class loader. If <code>Beans</code> fails to load the resource,
* <code>Beans</code> will regard the <code>name</code> as a class name and construct a new instance of the bean class.
* </p>
* <p>
* For example, if the name is specified as "x.y.z", The class <code>Beans</code> will try to load the serialized object from the resource "x/y/z.ser"; If
* <code>Beans</code> fails to load the resource "x/y/z.ser", it will create a new instance of "x.y.z".
* </p>
* <p>
* If the bean is an instance of java.applet.Applet, <code>Beans</code> will do some special initialization for this applet bean. First, <code>Beans</code>
* will set the default AppletStub and AppletContext for the applet bean (If the specified <code>AppletInitializer</code> is not null, <code>Beans</code>
* will call the <code>AppletInitializer.initialize</code> to set the default AppletStub and AppletContext for the applet bean). Second, <code>Beans</code>
* will call the <code>init</code> method of the applet. (If the applet bean is loaded as a serialized object, the <code>init</code> method will not be
* called.)
* </p>
*
* @param cls
* the specified class loader. It can be null.
* @param beanName
* the name of the JavaBean
* @param context
* the beancontext in which the bean instance will be added.
* @param initializer
* the AppletInitializer for applet bean instance.
* @return Obtains an instance of the JavaBean.
* @throws IOException
* @throws ClassNotFoundException
*/
public static Object instantiate(ClassLoader cls, String beanName, BeanContext context, AppletInitializer initializer) throws IOException,
ClassNotFoundException
{
return internalInstantiate(cls, beanName, context, initializer);
}
/**
* Obtain an alternative type view of the given bean. The view type is specified by the parameter <code>type</code>.
* <p>
* If the type view cannot be obtained, the original bean object is returned.
* </p>
*
* @param bean
* the original bean object.
* @param targetType
* the specified view type.
* @return a type view of the given bean.
*/
public static Object getInstanceOf(Object bean, Class<?> targetType)
{
return bean;
}
/**
* Determine if the the specified bean object can be viewed as the specified type.
*
* @param bean
* the specified bean object.
* @param targetType
* the specifed view type.
* @return true if the specified bean object can be viewed as the specified type; otherwise, return false;
*/
public static boolean isInstanceOf(Object bean, Class<?> targetType)
{
if (bean == null)
{
throw new NullPointerException(Messages.getString("beans.1D")); //$NON-NLS-1$
}
return targetType == null ? false : targetType.isInstance(bean);
}
/**
* Set whether or not a GUI is available in the bean's current environment.
*
* @param isGuiAvailable
* should be <code>true</code> to signify that a GUI is available, <code>false</code> otherwise.
* @throws SecurityException
* if the caller does not have the required permission to access or modify system properties.
*/
public static synchronized void setGuiAvailable(boolean isGuiAvailable) throws SecurityException
{
checkPropertiesAccess();
guiAvailable = isGuiAvailable;
}
/**
* Used to indicate whether of not it's in an application construction environment.
*
* @param isDesignTime
* true to indicate that it's in application construction environment.
* @throws SecurityException
*/
public static void setDesignTime(boolean isDesignTime) throws SecurityException
{
checkPropertiesAccess();
synchronized (Beans.class)
{
designTime = isDesignTime;
}
}
/**
* Returns a boolean indication of whether or not a GUI is available for beans.
*
* @return <code>true</code> if a GUI is available, otherwise <code>false</code>.
*/
public static synchronized boolean isGuiAvailable()
{
return guiAvailable;
}
/**
* Determine if it's in design-mode.
*
* @return true if it's in an application construction environment.
*/
public static synchronized boolean isDesignTime()
{
return designTime;
}
private static void checkPropertiesAccess() throws SecurityException
{
SecurityManager sm = System.getSecurityManager();
if (sm != null)
{
sm.checkPropertiesAccess();
}
}
private static String getBeanResourceName(String beanName)
{
return beanName.replace('.', '/') + ".ser"; //$NON-NLS-1$
}
private static void appletLoaded(Applet applet, ClassLoader loader, String name, BeanContext context, AppletInitializer initializer, boolean deserialized)
throws ClassNotFoundException
{
// If there is an initializer
if (initializer != null)
{
initializer.initialize(applet, context);
}
else
{
setStub(applet, loader, deserialized, name);
}
if (!deserialized)
{
applet.init();
}
if (initializer != null)
{
initializer.activate(applet);
}
}
private static void setStub(Applet applet, final ClassLoader loader, boolean serialized, String beanName) throws ClassNotFoundException
{
// Get path to the resource representing the applet.
String pathName = beanName.replace('.', '/');
final String resourceName = serialized ? pathName.concat(".ser") : pathName.concat(".class"); //$NON-NLS-1$ //$NON-NLS-2$
URL objectUrl = AccessController.doPrivileged(new PrivilegedAction<URL>() {
public URL run()
{
if (loader == null)
{
return ClassLoader.getSystemResource(resourceName);
}
return loader.getResource(resourceName);
}
});
// If we can't get to the applet itself, the codebase and doc base are
// left as null.
if (objectUrl == null)
{
applet.setStub(getAppletStub(getStubAppletContext(applet), null, null));
return;
}
// Try to decompose the resource URL to get to the doc/code URL
String urlString = objectUrl.toExternalForm();
// This is the URL of the directory that contains the applet.
int codeURLlength = urlString.length() - resourceName.length();
URL codeBase = safeURL(urlString.substring(0, codeURLlength));
// URL of the document containing the applet.
int docURLlength = urlString.lastIndexOf('/');
URL docBase = safeURL(urlString.substring(0, docURLlength + 1));
applet.setStub(getAppletStub(getStubAppletContext(applet), codeBase, docBase));
}
private static AppletStub getAppletStub(final AppletContext context, final URL codeBase, final URL docBase)
{
return new AppletStub() {
public boolean isActive()
{
return true;
}
public URL getDocumentBase()
{
return docBase;
}
public URL getCodeBase()
{
return codeBase;
}
public String getParameter(String name)
{
// Applet beans have no params.
return null;
}
public AppletContext getAppletContext()
{
return context;
}
public void appletResize(int width, int height)
{
// Do nothing.
}
};
}
private static AppletContext getStubAppletContext(final Applet target)
{
return new AppletContext() {
public AudioClip getAudioClip(URL url)
{
return null;
}
public synchronized Image getImage(URL url)
{
return null;
}
public Applet getApplet(String name)
{
return null;
}
public Enumeration<Applet> getApplets()
{
Vector<Applet> applets = new Vector<Applet>();
applets.addElement(target);
return applets.elements();
}
public void showDocument(URL url)
{
// Do nothing.
}
public void showDocument(URL url, String aTarget)
{
// Do nothing.
}
public void showStatus(String status)
{
// Do nothing.
}
public void setStream(String key, InputStream stream) throws IOException
{
// Do nothing.
}
public InputStream getStream(String key)
{
return null;
}
public Iterator<String> getStreamKeys()
{
return null;
}
};
}
// Maps malformed URL exception to ClassNotFoundException
private static URL safeURL(String urlString) throws ClassNotFoundException
{
try
{
return new URL(urlString);
}
catch (MalformedURLException exception)
{
throw new ClassNotFoundException(exception.getMessage());
}
}
}