/*
* Creates a thread to run the applet. This method is called
* each time an applet is loaded and reloaded.
*/
synchronized void createAppletThread() {
// Create a thread group for the applet, and start a new
// thread to load the applet.
String nm = "applet-" + getCode();
loader = getClassLoader(getCodeBase(), getClassLoaderCacheKey());
loader.grab(); // Keep this puppy around!
// 4668479: Option to turn off codebase lookup in AppletClassLoader
// during resource requests. [stanley.ho]
String param = getParameter("codebase_lookup");
if (param != null && param.equals("false")) loader.setCodebaseLookup(false);
else loader.setCodebaseLookup(true);
ThreadGroup appletGroup = loader.getThreadGroup();
handler = new Thread(appletGroup, this, "thread " + nm, 0, false);
// set the context class loader for this thread
AccessController.doPrivileged(
new PrivilegedAction<Object>() {
@Override
public Object run() {
handler.setContextClassLoader(loader);
return null;
}
});
handler.start();
}
/** Is called when the applet wants to be resized. */
@Override
public void appletResize(int width, int height) {
currentAppletSize.width = width;
currentAppletSize.height = height;
final Dimension currentSize = new Dimension(currentAppletSize.width, currentAppletSize.height);
if (loader != null) {
AppContext appCtxt = loader.getAppContext();
if (appCtxt != null) appEvtQ = (java.awt.EventQueue) appCtxt.get(AppContext.EVENT_QUEUE_KEY);
}
final AppletPanel ap = this;
if (appEvtQ != null) {
appEvtQ.postEvent(
new InvocationEvent(
Toolkit.getDefaultToolkit(),
new Runnable() {
@Override
public void run() {
if (ap != null) {
ap.dispatchAppletEvent(APPLET_RESIZE, currentSize);
}
}
}));
}
}
/**
* This kludge is specific to get over AccessControlException thrown during Applet.stop() or
* destroy() when static thread is suspended. Set a flag in AppletClassLoader to indicate that an
* AccessControlException for RuntimePermission "modifyThread" or "modifyThreadGroup" had
* occurred.
*/
private void setExceptionStatus(AccessControlException e) {
Permission p = e.getPermission();
if (p instanceof RuntimePermission) {
if (p.getName().startsWith("modifyThread")) {
if (loader == null) loader = getClassLoader(getCodeBase(), getClassLoaderCacheKey());
loader.setExceptionStatus();
}
}
}
protected void loadJarFiles(AppletClassLoader loader) throws IOException, InterruptedException {
// Load the archives if present.
// REMIND - this probably should be done in a separate thread,
// or at least the additional archives (epll).
String jarFiles = getJarFiles();
if (jarFiles != null) {
StringTokenizer st = new StringTokenizer(jarFiles, ",", false);
while (st.hasMoreTokens()) {
String tok = st.nextToken().trim();
try {
loader.addJar(tok);
} catch (IllegalArgumentException e) {
// bad archive name
continue;
}
}
}
}
protected Applet createApplet(final AppletClassLoader loader)
throws ClassNotFoundException, IllegalAccessException, IOException, InstantiationException,
InterruptedException {
String code = getCode();
if (code != null) {
applet = (Applet) loader.loadCode(code).newInstance();
} else {
String msg = "nocode";
status = APPLET_ERROR;
showAppletStatus(msg);
showAppletLog(msg);
repaint();
}
// Determine the JDK level that the applet targets.
// This is critical for enabling certain backward
// compatibility switch if an applet is a JDK 1.1
// applet. [stanley.ho]
findAppletJDKLevel(applet);
if (Thread.interrupted()) {
try {
status = APPLET_DISPOSE; // APPLET_ERROR?
applet = null;
// REMIND: This may not be exactly the right thing: the
// status is set by the stop button and not necessarily
// here.
showAppletStatus("death");
} finally {
Thread.currentThread().interrupt(); // resignal interrupt
}
return null;
}
return applet;
}
void release() {
if (loader != null) {
loader.release();
loader = null;
}
}
/** Determine JDK level of an applet. */
private void findAppletJDKLevel(Applet applet) {
// To determine the JDK level of an applet, the
// most reliable way is to check the major version
// of the applet class file.
// synchronized on applet class object, so calling from
// different instances of the same applet will be
// serialized.
Class<?> appletClass = applet.getClass();
synchronized (appletClass) {
// Determine if the JDK level of an applet has been
// checked before.
Boolean jdk11Target = loader.isJDK11Target(appletClass);
Boolean jdk12Target = loader.isJDK12Target(appletClass);
// if applet JDK level has been checked before, retrieve
// value and return.
if (jdk11Target != null || jdk12Target != null) {
jdk11Applet = (jdk11Target == null) ? false : jdk11Target.booleanValue();
jdk12Applet = (jdk12Target == null) ? false : jdk12Target.booleanValue();
return;
}
String name = appletClass.getName();
// first convert any '.' to '/'
name = name.replace('.', '/');
// append .class
final String resourceName = name + ".class";
byte[] classHeader = new byte[8];
try (InputStream is =
AccessController.doPrivileged(
(PrivilegedAction<InputStream>) () -> loader.getResourceAsStream(resourceName))) {
// Read the first 8 bytes of the class file
int byteRead = is.read(classHeader, 0, 8);
// return if the header is not read in entirely
// for some reasons.
if (byteRead != 8) return;
} catch (IOException e) {
return;
}
// Check major version in class file header
int major_version = readShort(classHeader, 6);
// Major version in class file is as follows:
// 45 - JDK 1.1
// 46 - JDK 1.2
// 47 - JDK 1.3
// 48 - JDK 1.4
// 49 - JDK 1.5
if (major_version < 46) jdk11Applet = true;
else if (major_version == 46) jdk12Applet = true;
// Store applet JDK level in AppContext for later lookup,
// e.g. page switch.
loader.setJDK11Target(appletClass, jdk11Applet);
loader.setJDK12Target(appletClass, jdk12Applet);
}
}
