How to print the complete stack trace of the exception using a velocity template
My present template has $exception as template variable, which contains the exception.
In velocity this is how i solved this problem.
#foreach ($i in [1..3])
#if($exception.Cause)
#set($exception = $exception.Cause)
#foreach($stack in $exception.getStackTrace())
$stack.toString()
#end
#end
#end
In case you want to display the trace on the output you could wrap the evaluate method inside try-catch-finally block. In catch write the stack trace or just the message of the exception to the writer. In the finally section just flush the writer.
Something like this if I remember right:
StringWriter w = new StringWriter();
try {
Velocity.evaluate( context, w, "mystring", s );
} catch (Exceptions... e)
w.write(e.getMessage());
} finally {
w.flush();
}
Related
For the code given below. How will the code behave and why?
// code goes here..
try {
if(a==0) throw "a is 0";
}
catch(int a) { ; }
a = 19;
//code goes here.....
Since you are throwing a string (aka const char*) but you are only catching values of type int, the exception will not be caught and will go on unwinding the function stack until it finds a try-block willing to catch your exception or it reaches main and aborts your program.
That is, if your catch block does not catch the thrown exception type it is as if it was not there.
"Only the types that are inherited from the Throwable class can be thrown".
Could anybody explain me. Why not every type are throwable? If in doc there no mention about function can throw exception, it's mean that it do not have exception?
For example I thought that next try-catch block would work. But it is not.
try
{
writeln("(((((((((");
latestdtonpage = dts.sort!((a,b) => a>b).front; //latest date-time. from page.
}
catch(Exception e)
{
writeln("Can't select the latest Date from parsed date");
writeln(e);
}
But output in case of exception is next (no exception text):
(((((((((
core.exception.AssertError#C:\D\dmd2\windows\bin\..\..\src\phobos\std\array.d(73
9): Attempting to fetch the front of an empty array of DateTime
----------------
0x0051C4C9 in _d_assert_msg
0x00468E78 in pure nothrow ref #property #nogc #safe std.datetime.DateTime std.r
ange.__T11SortedRangeTAS3std8datetime8DateTimeS473app19StackOverflowParser5parse
MFAyaZ9__lambda2Z.SortedRange.front() at C:\D\dmd2\windows\bin\..\..\src\phobos\
std\range.d(8418)
0x0044F908 in void app.StackOverflowParser.parse(immutable(char)[]) at D:\code\T
rendoMetr\source\app.d(173)
0x0044F700 in app.StackOverflowParser app.StackOverflowParser.__ctor(app.DBConne
ct) at D:\code\TrendoMetr\source\app.d(150)
0x0044F199 in _Dmain at D:\code\TrendoMetr\source\app.d(33)
0x0052EDCA in D2rt6dmain211_d_run_mainUiPPaPUAAaZiZ6runAllMFZ9__lambda1MFZv
0x0052ED9F in void rt.dmain2._d_run_main(int, char**, extern (C) int function(ch
ar[][])*).runAll()
0x0052ECB5 in _d_run_main
0x00470198 in main
0x005667D1 in mainCRTStartup
0x76D1336A in BaseThreadInitThunk
0x772A9F72 in RtlInitializeExceptionChain
0x772A9F45 in RtlInitializeExceptionChain
Error executing command run: Program exited with code 1
How I can throw exception in this code?
Your code throws an AssertError, indicating that dts.sort!((a,b) => a>b) is empty, and you shouldn't call .front on it. Instead, query .empty first, and act accordingly when it's true.
AssertError inherits from Error which in turn inherits from Throwable but not from Exception. So catch(Exception e) doesn't catch it. And you should not catch Errors anyway, as they indicate that the program is in an unrecoverable error-state.
AssertError in particular signals a logic bug in your program. Here: calling .front on an empty range. Don't catch AssertError, but fix your code instead.
I have a project on WinForms with this code:
AppDomain.CurrentDomain.UnhandledException += CurrentDomainUnhandledException;
private void CurrentDomainUnhandledException(object sender, UnhandledExceptionEventArgs e)
{ }
The e.ExceptionObject contains full StackTrace.
In Win Store project:
this.UnhandledException += (s, e) =>{
{
MarkedUp.AnalyticClient.LogLastChanceException(e);
};
e.Exception.StackTrace is null.
Both exceptions were generated by this code:
int a=0;
....
try
{
int i = 1 / a;
}
catch (Exception exp)
{
throw;
}
Any Ideas?
The reference on MSDN suggests that this is a limitation: http://msdn.microsoft.com/en-us/library/windows/apps/windows.ui.xaml.application.unhandledexception
A notable limitation is that the UnhandledException event arguments don’t contain as much detail as the original exception as propagated from app code. Whenever possible, if the app requires specific processing of a certain exception, it’s always better to catch the exception as it propagates, because more detail will be available then. The UnhandledException event arguments expose an exception object through the Exception property. However, the type, message, and stack trace of this exception object are not guaranteed to match those of the original exception that was raised. The event arguments do expose a Message property. In most cases, this will contain the message of the originally raised exception.
Are you running the solution in Debug mode? There seems to be happening something in the App.g.i.cs file when you run the solution in Debug mode. When I run your sample in Release mode the stacktrace is available in the UnhandledException event.
In my test solution it breaks first here:
#if DEBUG && !DISABLE_XAML_GENERATED_BREAK_ON_UNHANDLED_EXCEPTION
UnhandledException += (sender, e) =>
{
if (global::System.Diagnostics.Debugger.IsAttached) global::System.Diagnostics.Debugger.Break();
};
#endif
And after that one it goes to the UnhandledException handler that I have defined in the app.xaml.cs file. In Debug the stacktrace is gone, in Release mode the stacktrace and the exception details are there.
I am running into an extremely strange behavior in Groovy. When I throw an exception from a closure in a Script, the end exception that was thrown was different.
Here are the code and the details:
public class TestDelegate {
def method(Closure closure) {
closure.setResolveStrategy(Closure.DELEGATE_FIRST);
closure.delegate = this;
closure.call();
}
public static void main(String[] args) {
// Make Script from File
File dslFile = new File("src/Script.dsl");
GroovyShell shell = new GroovyShell();
Script dslScript = shell.parse(dslFile);
TestDelegate myDelegate = new TestDelegate();
dslScript.metaClass.methodMissing = {
// will run method(closure)
String name, arguments ->
myDelegate.invokeMethod(name, arguments);
}
dslScript.metaClass.propertyMissing = {
String name ->
println "Will throw error now!"
throw new MyOwnException("errrrror");
}
dslScript.run();
}
}
class MyOwnException extends Exception {
public MyOwnException(String message) {
super(message);
}
}
Script.dsl:
method {
println a;
}
So the plan is that when I run the main() method in TestDelegate, it will run the DSL script, which calls for the method method(). Not finding it in the script, it will invoke methodMissing, which then invokes method() from myDelegate, which in turns invoke the closure, setting the delegate to the testDelegate. So far, so good. Then the closure is supposed to try printing out "a", which is not defined and will thus set off propertyMissing, which will will throw MyOwnException.
When I run the code, however, I get the following output:
Will throw error now!
Exception in thread "main" groovy.lang.MissingPropertyException: No such property: a for class: TestDelegate
Now, it must have reached that catch block, since it printed "Will throw error now!" It must have thrown MyOwnException too! But somewhere along the lines, MyOwnException was converted to MissingPropertyException, and I have no idea why. Does anyone have any idea?
P.S. if I remove closure.setResolveStrategy(Closure.DELEGATE_FIRST) from TestDelegate#method(), the code acts as expected and throws MyOwnException. But I really need the setResolveStrategy(Closure.DELEGATE_FIRST) for my DSL project. And I would prefer to know the root cause of this rather than just removing a line or two and see that it works without understanding why.
I think this is what essentially happens: With a delegate-first resolve strategy, the Groovy runtime first tries to access property a on myDelegate, which results in a MissingPropertyException because no such property exists. Then it tries propertyMissing, which causes a MyOwnException to be thrown. Eventually the runtime gives up and rethrows the first exception encountered (a design decision), which happens to be the MissingPropertyException.
With an owner-first resolve strategy, propertyMissing is consulted first, and hence MyOwnException is eventually rethrown.
Looking at the stack trace and source code underneath should provide more evidence.
There is a web-service deployed on tomcat 6 and exposed via apache-cxf 2.3.3. A generated sources stubs using wsdl2java to be able to call this service.
Things seemed fine until I sent big request(~1Mb). This request wasn't processed and failing with exception:
Interceptor for {http://localhost/}ResourceAllocationServiceSoapService has thrown
exception, unwinding now org.apache.cxf.binding.soap.SoapFault:
Error reading XMLStreamReader.
...
com.ctc.wstx.exc.WstxEOFException: Unexpected EOF in prolog
at [row,col {unknown-source}]: [1,0]
Is some kind of max request length here, I'm totally stuck with it.
Vladimir's suggestion worked. This code below will help others with understanding where to put the 1000000.
public void handleMessage(SoapMessage message) throws Fault {
// Get message content for dirty editing...
InputStream inputStream = message.getContent(InputStream.class);
if (inputStream != null)
{
String processedSoapEnv = "";
// Cache InputStream so it can be read independently
CachedOutputStream cachedInputStream = new CachedOutputStream(1000000);
try {
IOUtils.copy(inputStream,cachedInputStream);
inputStream.close();
cachedInputStream.close();
InputStream tmpInputStream = cachedInputStream.getInputStream();
try{
String inputBuffer = "";
int data;
while((data = tmpInputStream.read()) != -1){
byte x = (byte)data;
inputBuffer += (char)x;
}
/**
* At this point you can choose to reformat the SOAP
* envelope or simply view it just make sure you put
* an InputStream back when you done (see below)
* otherwise CXF will complain.
*/
processedSoapEnv = fixSoapEnvelope(inputBuffer);
}
catch(IOException e){
}
}
catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// Re-set the SOAP InputStream with the new envelope
message.setContent(InputStream.class,new ByteArrayInputStream( processedSoapEnv.getBytes()));
/**
* If you just want to read the InputStream and not
* modify it then you just need to put it back where
* it was using the CXF cached inputstream
*
* message.setContent(InputStream.class,cachedInputStream.getInputStream());
*/
}
}
I figured out what was wrong. Actually it was bug inside interceptor's code:
CachedOutputStream requestStream = new CachedOutputStream()
When I replaced this with
CachedOutputStream requestStream = new CachedOutputStream(1000000);
things start working fine.
So the request was just trunkated during copying of streams.
I run into same issue of geting "com.ctc.wstx.exc.WstxEOFException: Unexpected EOF in prolog" when using CachedOutputStream class.
Looking at sources of CachedOutputStream class the threshold is used to switch between storing stream's data from "in memory" to "a file".
Assuming stream operates on data that exceeds threshold it gets stored in a file thus following code is going to break
IOUtils.copy(inputStream,cachedInputStream);
inputStream.close();
cachedInputStream.close(); //closes the stream, the file on disk gets deleted
InputStream tmpInputStream = cachedInputStream.getInputStream(); //returned tmpInputStream is brand *empty* one
// ... reading tmpInputStream here will produce WstxEOFException
Increasing 'threshold' does help as all stream data is stored into memory and in such scenario calling cachedInputStream.close() does not really close the underlying stream implementation so one can still read from it later on.
Here is 'fixed' version of above code (at least it worked without exception for me)
IOUtils.copy(inputStream,cachedInputStream);
inputStream.close();
InputStream tmpInputStream = cachedInputStream.getInputStream();
cachedInputStream.close();
// reading from tmpInputStream here works fine
Temporary file gets deleted when close() is called on tmpInputStream and there are no more other references to it, see source code of CachedOutputStream.maybeDeleteTempFile()