/** Use the given ClassLoader rather than using the system class */
@SuppressWarnings("rawtypes")
protected Class resolveClass(ObjectStreamClass classDesc)
throws IOException, ClassNotFoundException {
String cname = classDesc.getName();
return ClassFinder.resolveClass(cname, this.loader);
}
/**
* 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).
*
* @return a JavaBean
* @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, AppletInitializer 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 =
AccessController.doPrivileged(
new PrivilegedAction<InputStream>() {
public InputStream 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;
}
if (!Modifier.isPublic(cl.getModifiers())) {
throw new ClassNotFoundException("" + cl + " : no public access");
}
/*
* 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.
AppletStub stub = null;
if (result instanceof Applet) {
Applet applet = (Applet) result;
boolean needDummies = initializer == null;
if (needDummies) {
// 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 =
AccessController.doPrivileged(
new PrivilegedAction<URL>() {
public URL 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);
} else {
initializer.initialize(applet, beanContext);
}
// now, if there is a BeanContext, add the bean, if applicable.
if (beanContext != null) {
unsafeBeanContextAdd(beanContext, result);
}
// 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();
}
if (needDummies) {
((BeansAppletStub) stub).active = true;
} else initializer.activate(applet);
} else if (beanContext != null) unsafeBeanContextAdd(beanContext, result);
}
return result;
}