/*
* 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 java.beans;
import java.applet.Applet;
import java.applet.AppletContext;
import java.applet.AppletStub;
import java.applet.AudioClip;
import java.awt.Image;
import java.beans.beancontext.BeanContext;
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;
/**
* 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("unchecked")
private static Object internalInstantiate(ClassLoader cls, String beanName,
BeanContext context, Object initializer)
throws IOException, ClassNotFoundException {
Object result = null;
boolean deserialized = true;
ClassLoader loader = null;
// 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;
if (is != null) {
try{
ObjectInputStream ois = (cls == null) ? new ObjectInputStream(is)
: new CustomizedObjectInputStream(is, cls);
result = ois.readObject();
}catch(IOException exception){
//Not loadable - remember this as we may throw it later.
serializationException = exception;
}
}
//If that did not work, try to instantiate it from the given classloader.
if (result == null) {
deserialized = false;
try {
loader = cls == null ? ClassLoader.getSystemClassLoader() : cls;
Class<?> c = Class.forName(beanName, true, loader);
result = c.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, loader, 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
*/
@SuppressWarnings("unchecked")
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.
*/
@SuppressWarnings("unused")
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());
}
}
}