/**
* Select the appropriate child Context to process this request, based on the specified request
* URI. If no matching Context can be found, return an appropriate HTTP error.
*
* @param request Request to be processed
* @param response Response to be produced
* @exception IOException if an input/output error occurred
* @exception ServletException if a servlet error occurred
*/
@Override
public final void invoke(Request request, Response response)
throws IOException, ServletException {
/*
* xujb:
* 和Engine一样，调用下层的context，让它来做一些处理
* 自身也处理了一些的逻辑
*
* */
// Select the Context to be used for this Request
Context context = request.getContext();
if (context == null) {
response.sendError(
HttpServletResponse.SC_INTERNAL_SERVER_ERROR, sm.getString("standardHost.noContext"));
return;
}
// Bind the context CL to the current thread
if (context.getLoader() != null) {
// Not started - it should check for availability first
// This should eventually move to Engine, it's generic.
if (Globals.IS_SECURITY_ENABLED) {
PrivilegedAction<Void> pa = new PrivilegedSetTccl(context.getLoader().getClassLoader());
AccessController.doPrivileged(pa);
} else {
Thread.currentThread().setContextClassLoader(context.getLoader().getClassLoader());
}
}
if (request.isAsyncSupported()) {
request.setAsyncSupported(context.getPipeline().isAsyncSupported());
}
boolean asyncAtStart = request.isAsync();
boolean asyncDispatching = request.isAsyncDispatching();
if (asyncAtStart || context.fireRequestInitEvent(request)) {
// Ask this Context to process this request. Requests that are in
// async mode and are not being dispatched to this resource must be
// in error and have been routed here to check for application
// defined error pages.
try {
if (!asyncAtStart || asyncDispatching) {
context.getPipeline().getFirst().invoke(request, response);
} else {
// Make sure this request/response is here because an error
// report is required.
if (!response.isErrorReportRequired()) {
throw new IllegalStateException(sm.getString("standardHost.asyncStateError"));
}
}
} catch (Throwable t) {
ExceptionUtils.handleThrowable(t);
// If a new error occurred while trying to report a previous
// error simply log the new error and allow the original error
// to be reported.
if (response.isErrorReportRequired()) {
container.getLogger().error("Exception Processing " + request.getRequestURI(), t);
} else {
request.setAttribute(RequestDispatcher.ERROR_EXCEPTION, t);
throwable(request, response, t);
}
}
// Now that the request/response pair is back under container
// control lift the suspension so that the error handling can
// complete and/or the container can flush any remaining data
response.setSuspended(false);
Throwable t = (Throwable) request.getAttribute(RequestDispatcher.ERROR_EXCEPTION);
// Protect against NPEs if the context was destroyed during a
// long running request.
if (!context.getState().isAvailable()) {
return;
}
// Look for (and render if found) an application level error page
if (response.isErrorReportRequired()) {
if (t != null) {
throwable(request, response, t);
} else {
status(request, response);
}
}
if (!request.isAsync() && (!asyncAtStart || !response.isErrorReportRequired())) {
context.fireRequestDestroyEvent(request);
}
}
// Access a session (if present) to update last accessed time, based on a
// strict interpretation of the specification
if (ACCESS_SESSION) {
request.getSession(false);
}
// Restore the context classloader
if (Globals.IS_SECURITY_ENABLED) {
PrivilegedAction<Void> pa = new PrivilegedSetTccl(StandardHostValve.class.getClassLoader());
AccessController.doPrivileged(pa);
} else {
Thread.currentThread().setContextClassLoader(StandardHostValve.class.getClassLoader());
}
}
