Search Results

Search found 6 results on 1 pages for 'robv'.

Page 1/1 | 1 

• -w test on OS X gives command not found error

  - by RobV

  I'm writing a bash script which I'm testing on OS X though it will ultimately run on a standard Linux environment and running into a weird error. I have tests like this in my script: if [ ! -w $BP ]; then echo "'$1' not writable" exit 1 fi Which seems pretty sane to me and works fine under Linux but when trying to test on OS X I get the following error message: startSvr.sh: line 135: [: missing `]' startSvr.sh: line 135: -w: command not found So is this a case of OS X not supporting the -w test or is there some other reason this isn't working for me? e.g. environment

  Read the article

• If I specify a System property multiple times when invoking JVM which value is used?

  - by RobV

  If I specify a system property multiple times when invoking the JVM which value will I actually get when I retrieve the property? e.g. java -Dprop=A -Dprop=B -jar my.jar What will be the result when I call System.getProperty("prop");? The Java documentation on this does not really tell me anything useful on this front. In my non-scientific testing on a couple of machines running different JVMs it seems like the last value is the one returned (which is actually the behavior I need) but I wondered if this behavior is actually defined officially anywhere or can it vary between JVMs?

  Read the article

• Two questions on ensuring EndInvoke() gets called on a list of IAsyncResult objects

  - by RobV

  So this question is regarding the .Net IAsyncResult design pattern and the necessity of calling EndInvoke as covered in this question Background I have some code where I'm firing off potentially many asynchronous calls to a particular function and then waiting for all these calls to finish before using EndInvoke() to get back all the results. Question 1 I don't know whether any of the calls has encountered an exception until I call EndInvoke() and in the event that an exception occurs in one of the calls the entire method should fail and the exception gets wrapped into an API specific exception and thrown upwards. So my first question is what's the best way then to ensure that the remainder of the async calls get properly terminated? Is a finally block which calls EndInvoke() on the remainder of the unterminated calls (and ignores any further exceptions) the best way to do this? Question 2 Secondly when I first fire off all my asyc calls I then call WaitHandle.WaitAll() on the array of WaitHandle instances that I've got from my IAsyncResult instances. The method which is firing all these async calls has a timeout to adhere to so I provide this to the WaitAll() method. Then I test whether all the calls have completed, if not then the timeout must have been reached so the method should also fail and throw another API specific exception. So my second question is what should I do in this case? I need to call EndInvoke() to terminate all these async calls before I throw the error but at the same time I don't want the code to get stuck since EndInvoke() is blocking. In theory at least if the WaitAll() call times out then all the async calls should themselves have timed out and thrown exceptions (thus completing the call) since they are also governed by a timeout but this timeout is potentially different from the main timeout

  Read the article

• Is the .Net HashSet uniqueness calculation completely based on Hash Codes?

  - by RobV

  I was wondering whether the .Net HashSet<T> is based completely on hash codes or whether it uses equality as well? I have a particular class that I may potentially instantiate millions of instances of and there is a reasonable chance that some hash codes will collide at that point. I'm considering using HashSet's to store some instances of this class and am wondering if it's actually worth doing - if the uniqueness of an element is only determined on its hash code then that's of no use to me for real applications MSDN documentation seems to be rather vague on this topic - any enlightenment would be appreciated

  Read the article

• .Net Hash Codes no longer persistent?

  - by RobV

  I have an API where various types have custom hash codes. These hash codes are based on getting the hash of a string representation of the object in question. Various salting techniques are used so that as far as possible Hash Codes do not collide and that Objects of different types with equivalent string representations have different Hash Codes. Obviously since the Hash Codes are based on strings there are some collisions (infinite strings vs the limited range of 32 bit integers). I use hashes based on string representations since I need the hashes to persist over sessions and particularly for use in database storage of objects. Suddenly today my code has started generating different hash codes for Objects which is breaking all kinds of things. It was working earlier today and I haven't touched any of the code involved in Hash Code generation. I'm aware that the .Net documentation allows for implementation of hash codes between .Net framework versions to change (and between 32 and 64 bit versions) but I haven't changed the framework version and there has been no framework updates recently as far as I can remember Any ideas because this seems really weird? Edit Hash Codes are generated like follows: //Compute Hash Code this._hashcode = (this._nodetype + this.ToString() + PlainLiteralHashCodeSalt).GetHashCode();

  Read the article

• Can I use a single instance of a delegate to start multiple Asynchronous Requests?

  - by RobV

  Just wondered if someone could clarify the use of BeginInvoke on an instance of some delegate when you want to make multiple asynchronous calls since the MSDN documentation doesn't really cover/mention this at all. What I want to do is something like the following: MyDelegate d = new MyDelegate(this.TargetMethod); List<IAsyncResult> results = new List<IAsyncResult>(); //Start multiple asynchronous calls for (int i = 0; i < 4; i++) { results.Add(d.BeginInvoke(someParams, null, null)); } //Wait for all my calls to finish WaitHandle.WaitAll(results.Select(r => r.AsyncWaitHandle).ToArray()); //Process the Results The question is can I do this with one instance of the delegate or do I need an instance of the delegate for each individual call? Given that EndInvoke() takes an IAsyncResult as a parameter I would assume that the former is correct but I can't see anything in the documentation to indicate either way.

  Read the article

1