/*
* @(#)Beans.java 1.63 04/06/28
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package java.beans;
import java.applet.*;
import java.awt.*;
import java.beans.AppletInitializer;
import java.beans.beancontext.BeanContext;
import java.io.*;
import java.lang.reflect.Constructor;
import java.net.URL;
import java.lang.reflect.Array;
/**
* This class provides some general purpose beans control methods.
*/
public class Beans {
/**
* <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 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 {
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 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, BeanContext beanContext) throws java.io.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 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, BeanContext beanContext, AppletInitializer initializer)
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, 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 = (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);
} else {
initializer.initialize(applet, beanContext);
}
// now, if there is a BeanContext, add the bean, if applicable.
if (beanContext != null) {
beanContext.add(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) 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 java.beans.DesignMode
*/
public static boolean isDesignTime() {
return designTime;
}
/**
* 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 java.beans.Visibility
*
*/
public static boolean isGuiAvailable() {
return guiAvailable;
}
/**
* 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();
}
designTime = 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();
}
guiAvailable = isGuiAvailable;
}
private static boolean designTime;
private static boolean guiAvailable;
static {
guiAvailable = !GraphicsEnvironment.isHeadless();
}
}
/**
* 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;
}
/**
* Make a primitive array class
*/
private Class primitiveType(char type) {
switch (type) {
case 'B': return byte.class;
case 'C': return char.class;
case 'D': return double.class;
case 'F': return float.class;
case 'I': return int.class;
case 'J': return long.class;
case 'S': return short.class;
case 'Z': return boolean.class;
default: return null;
}
}
/**
* Use the given ClassLoader rather than using the system class
*/
protected Class resolveClass(ObjectStreamClass classDesc)
throws IOException, ClassNotFoundException {
String cname = classDesc.getName();
if (cname.startsWith("[")) {
// An array
Class component; // component class
int dcount; // dimension
for (dcount=1; cname.charAt(dcount)=='['; dcount++) ;
if (cname.charAt(dcount) == 'L') {
component = loader.loadClass(cname.substring(dcount+1,
cname.length()-1));
} else {
if (cname.length() != dcount+1) {
throw new ClassNotFoundException(cname);// malformed
}
component = primitiveType(cname.charAt(dcount));
}
int dim[] = new int[dcount];
for (int i=0; i<dcount; i++) {
dim[i]=0;
}
return Array.newInstance(component, dim).getClass();
} else {
return loader.loadClass(cname);
}
}
}
/**
* Package private support class. This provides a default AppletContext
* for beans which are applets.
*/
class BeansAppletContext implements AppletContext {
Applet target;
java.util.Hashtable imageCache = new java.util.Hashtable();
BeansAppletContext(Applet target) {
this.target = target;
}
public AudioClip getAudioClip(URL url) {
// We don't currently support audio clips in the Beans.instantiate
// applet context, unless by some luck there exists a URL content
// class that can generate an AudioClip from the audio URL.
try {
return (AudioClip) url.getContent();
} catch (Exception ex) {
return null;
}
}
public synchronized Image getImage(URL url) {
Object o = imageCache.get(url);
if (o != null) {
return (Image)o;
}
try {
o = url.getContent();
if (o == null) {
return null;
}
if (o instanceof Image) {
imageCache.put(url, o);
return (Image) o;
}
// Otherwise it must be an ImageProducer.
Image img = target.createImage((java.awt.image.ImageProducer)o);
imageCache.put(url, img);
return img;
} catch (Exception ex) {
return null;
}
}
public Applet getApplet(String name) {
return null;
}
public java.util.Enumeration getApplets() {
java.util.Vector applets = new java.util.Vector();
applets.addElement(target);
return applets.elements();
}
public void showDocument(URL url) {
// We do nothing.
}
public void showDocument(URL url, String target) {
// We do nothing.
}
public void showStatus(String status) {
// We do nothing.
}
public void setStream(String key, InputStream stream)throws IOException{
// We do nothing.
}
public InputStream getStream(String key){
// We do nothing.
return null;
}
public java.util.Iterator getStreamKeys(){
// We do nothing.
return null;
}
}
/**
* Package private support class. This provides an AppletStub
* for beans which are applets.
*/
class BeansAppletStub implements AppletStub {
transient boolean active;
transient Applet target;
transient AppletContext context;
transient URL codeBase;
transient URL docBase;
BeansAppletStub(Applet target,
AppletContext context, URL codeBase,
URL docBase) {
this.target = target;
this.context = context;
this.codeBase = codeBase;
this.docBase = docBase;
}
public boolean isActive() {
return active;
}
public URL getDocumentBase() {
// use the root directory of the applet's class-loader
return docBase;
}
public URL getCodeBase() {
// use the directory where we found the class or serialized object.
return codeBase;
}
public String getParameter(String name) {
return null;
}
public AppletContext getAppletContext() {
return context;
}
public void appletResize(int width, int height) {
// we do nothing.
}
}
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