Posts by ~s.o.s~

..so, what about the first bit of my question?

That check is a standard way of dealing with objects composed of others objects which can be NULL. Basically, you start off with a prime, keep adding the hash codes of the constituent objects and use 0 if a given field is NULL (since you can't invoke hashCode() on a NULL reference).

Just to clarify the above post, the announcement at the top of the forum says:

Also, to keep DaniWeb a student-friendly place to learn, don't expect quick solutions to your homework. We'll help you get started and exchange algorithm ideas, but only if you show that you're willing to put in effort as well.

Anyways, never done 'speech recognition' but searching for 'java speech recognition' should turn up quite a few things IMO.

India won, but Tendullar was not impressive enough. But heh, india still won in the right

...which I think isn't and shouldn't be a problem. It's high time team India stopped relying on old-timers and take the collective responsibility of seeing things till the end. Plus, to me, as long as the team wins, it doesn't matter who plays good or bad since it's a team effort in the end. :-)

HELL YEAH!!!

True champions indeed. :)

Wow, I don't know whether you made that up, or if it is a normal way of handling this, but it's brilliant
Thank you for your help in this thread

You are of course welcome. :-)

Just one last thing: is there away to determine whether an exception has been thrown by in or out?

Yup, there is; I ignored it for examples' sake but good job noticing it. You can print out the toString() representation of the "closeable" and it should print out whether it's an 'in' or 'out'.

public class Utils {
    public static void closeAll(final boolean ignoreExceptions, Closeable...closeables) {
        for(final Closeable closeable : closeables) {
            try {
                if(closeable != null) {
                    closeable.close();
                }
            } catch(final Throwable t) {
                if(!ignoreExceptions) {
                    // OR LOG.error("Exception closing stream " + closeable, e); in case you are using a logging library
                    System.out.println("Error closing stream " + closeable);
                    t.printStackTrace();
                }
            }
        }
    }
}

This would print out something like java.io.FileInputStream@19821f for a FileInputStream and so on.

Simply put, a hash code is ideally a best effort numeric (integer) representation of a Java object. Each Java object which lives in the JVM has a default hashCode() which is mapped to the integer representation of the address of that object (which as you can see is a good enough representation, since objects have unique addresses. This breaks in cases where the underlying address space is more than the range of an integer but don't worry about that for now).

But why allow the hashCode() to be overridden? The short answer is: because it can be used in a clever way to implement hash tables in Java. The logic used in the hashCode() method can be thought of as a hash function used to generate hash codes for the given object.

As an example, let's suppose you decide to put the hashCode() method to good use for the String object. The objective here would be to make sure that we almost always get the same hashCode() for equal strings. The most logical way here would to consider the characters of the string to generate the hash code since if a string has same characters and same length, it has to be same. But, we have to make sure that the order of the characters are also taken into consideration when generating the hash code (we don't want 'sad' and 'das' to end up having the same hash code). But be warned, it is quite *possible* …

~sos~:
That seems very reasonable.
About closing the streams:
would using IOUtils.closeQuietly(); make sure the second stream is closed, even if the first stream fails to close?

I have rewritten my code snippet now, (no error handling yet)
could you maybe give it quick look and tell me if I'm doing anything stupid?
One thing that irritates me is that I think it would be best to open the in- and output streams in the same try-catch block,
but that makes error handling difficult, as there is no telling which of the streams throws an IOException for instance.
Or am I mistaken?

import java.io.*;

public class TextMan {
	public static void main (String[] args) {
		try {
			BufferedReader in = null;
			BufferedWriter out = null;
			
			try {
				in = new BufferedReader(new InputStreamReader(new FileInputStream("bhaarat.txt"), "UTF-8"));
			} catch (Exception e) {
				e.printStackTrace();
			}
			
			try {
				out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream("out.txt"), "UTF-8"));

				String strCache;
				strCache = in.readLine();
				int count = 1;
				
                                //Silly string manipulation, you can probably just ignore this :)
				while (strCache != null) {
					strCache = strCache.split(" ", 0)[1];
					if (strCache.charAt(0) == 'H' || strCache.charAt(0) == 'S') {
						out.write(count + ". " + strCache + "\n"); 
						count++;
					}
					strCache = in.readLine();
				}
			} finally {
				if(in != null) in.close();
				if (out != null) out.close();
			}
			
		}catch (Exception e) {
			e.printStackTrace();
		}
	}
}

I realize this could be done with a one-liner using awk and grep, but I'm trying to learn a little programming …

@ ~s.o.s~

maybe you still around

Not sure what you are trying to say here?

<OffTopic> where I can find something similair http://forums.oracle.com/forums/thread.jspa?threadID=2175486&tstart=15 'cos last two days were full of zoobies and spammers </OffTopic>

If I'm not wrong, you need a feature wherein you can report necromancers and spammers? Yes, there is; click on the "Flag Bad Post" button which is present to the left of every post and that post will be shown in the Reported Posts forum and be brought to the attention of the moderators.

So the 'trick' is to instantiate (correct term?) the in/out objects outside the try block, and then open the actual streams inside it?

The correct term is "declare".

f I may ask: why shouldn't I handle errors?
For debugging, printing the stacktrace, as you suggest,
is obviously more exact than my own guesses as to what causes the exception to be thrown.
But shouldn't the final program be able to handle the exceptions appropriately?
And I'm guessing you then want me to log the exceptions for potential 'bug-reports'
(which will of course never be relevant for my little hobby-project but nevertheless, it's probably a good idea to get into the habit of doing it)

I never mentioned "not to handle errors". To re-quote myself:

BTW, make sure that in your first attempt of code, you don't end up catching each and every exception

I am a big fan of "start small and make it big" methodology. The first attempt of *any* code should be to get the functionality right and then move on to other important things. Your code right now has more error handling and less important stuff (copying the contents of a file?).

And yes, you are right, *every* exception in the system should be logged unless you know what you are doing.

maaaaan in all due respect to you, don't do it, never, never... , sure you have to (maybe) wrote lots of code without, you are probably wrong, …

The try-catch-finally (try-catch) is a well known vicious cycle when dealing with closeable resources. There are two ways around this:

* Using the nested-try method (NOT RECOMMENDED, since multiple resources can make the code ugly and this doesn't handle closing of 'out' in case closing of 'in' fails)

public static void main(final String[] args) {
    try {
        Scanner in = null;
        BufferedWriter out = null;
        try {
            in = new Scanner(new File("bhaarat.txt"), "UTF-8");
            out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(new File("output.txt")), "UTF-8"));    // yuck
            while(in.hasNextLine()) {
                out.write(in.nextLine());
                out.newLine();
            }
        } finally {
            if(in != null)  in.close();
            if(out != null) out.close();
        }
    } catch(final Exception e) {
        e.printStackTrace();
    }
}

* Creating helper methods or using external libraries which take care of exception handling (RECOMMENDED):

public static void main(final String[] args) {
    Scanner in = null;
    BufferedWriter out = null;
    try {
        in = new Scanner(new File("bhaarat.txt"), "UTF-8");
        out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(new File("output.txt")), "UTF-8"));    // yuck
        while(in.hasNextLine()) {
            out.write(in.nextLine());
            out.newLine();
        }
    } finally {
        // http://commons.apache.org/io/api-1.2/org/apache/commons/io/IOUtils.html#closeQuietly%28java.io.InputStream%29
        IOUtils.closeQuietly(in);
        IOUtils.closeQuietly(out);
    }
}

BTW, make sure that in your first attempt of code, you don't end up catching each and every exception. Just let them propagate to the main thread so that the JVM automatically exits by spitting out a stack trace. Add helpful error messages only in case where in the user doesn't need to see the trace but at the same time do make sure that the original exception is "logged" somewhere and not eaten up.

The FilenameFilter is used to filter out files in visual components (e.g. when you navigate to a folder, only *.java files would be seen) and in cases where you need to return file names which satisfy a given criteria. Basically for filtering needs based on "file names", FilenameFilter is used.

FileFilter on the other hand deals with "File" objects i.e. filtering based on a given File attributes like; is the file hidden, is it read only; something which a file name can't give you.

Of course, it's pretty trivial to create a File object based on its name and parent directory so I guess these "two" filters are more of convenient wrappers over the same concept but slightly different use cases.

Not sure if that's a genuine question or not but here ya go: http://www.homemademech.com/anime-articles/12/

Sprinkling a lot of "static" constructs (variables/methods) throughout your code normally leads to hard to maintain code. Regarding the question of running the race multiple times, simply moving the Thread instantiation to the main() method and looping over it should do the job.

// untested
public static void main(final String[] args) {
  for(int i = 0; i < 10; ++i) {
    Thread hare = new Thread(/* */);
    Thread tortoise = new Thread(/* */);
    hare.start();
    tortoise.start();
    hare.join();
    tortoise.join();    
  }
}

The join() call ensures that new "races" are not started as long as a race is in progress.

BTW, I think that this design can be made much more simpler and logical. You can have a Racer class which has the attributes like speed, chance, name etc. Tortoise and Hare would be subclasses of this Racer class. Your ThreadRunner (better name would be RacingSimulator) would take a Racer along with a RaceCompletonHandler (which is basically a class with a single method finished()). So, the code would look something like this:

// untested
public class Main {

    public static void main(final String[] args) {
        RaceCompletionHandler handler = new RaceCompletionHandler();
        Hare h = new Hare();
        Tortoise t = new Tortoise();
        RacingSimulator simulatorHare = new RacingSimulator(h, handler);
        RacingSimulator simulatorTor = new RacingSimulator(t, handler);
        for(int i = 0; i < 10; ++i) {
            Thread hThread = new Thread(simulatorHare);
            Thread tThraed = new Thread(simulatorTor);
            
            // start threads
            hThread.start();
            tThread.start();

            // join them
            hThread.join();
            tThread.join();
        }
    }

}

class Racer() {
    // attributes
} …

You are missing a `return` statement in your catch block:

try {
   Thread.sleep(100);
} catch(InterruptedException e) {
   // print win
    return;
}

Basically, when the 'loser' thread is interrupted by the main class, you catch the exception, log the message but continue with the loop and hence the program keeps going on.

I never wanted to offend anyone, and I was never the first to initiate any negative comments here. I was trying to clarify my previous post but another poster insisted on arguing

IMO, it doesn't seem that way. Tip: if you don't find a particular reply suiting your taste, all you have to do it is ignore it. If you feel the reply is against the rules, just report it. It's really very simple. You started an argument by asking a particular forum member to "stop" contributing/posting to this thread, which you can't.

Regarding code request: even though it wasn't your intention to "ask" for code, failure to post code coupled with a lot of hand waving comes across as being lazy.

1. When annotating a field the ActionMethodHandler.activate(...) gets the object currently referred to by the field and checks whether that object has an addActionListener(ActionListener) method. If so, it adds the listener. Thus it works for buttons, menu items, etc but logs an error for objects without that method.

When I mentioned 'target', I was actually referring to @Target annotation.

I don't do a lot of UI programming but a few more queries/suggestions:

• What kind of targets are supported by this annotation?
• How well does this annotation cope up with dynamically created UI components (think of a calculator)? Maybe an example? And how would the method `ActionMethodHandler.activate(this);` come into play with dynamic components?
• What's the behaviour when ActionMethodHandler is called multiple times? It simply returns? Overrides the previous bindings?
• Any error/warning shown when the user uses conflicting configuration (i.e. method "abc()" is annotated for button "Btn1" whereas "Btn1" actually refers method "xyz()")?

I personally feel that the same annotation name used for both cases is a bit confusing. How about @ActionMethod decorator for methods and @ActionedComponent for the targeted Swing components?

Hi folks,

The new anime season is just around the corner (hats off to Japan!) and it seems to be a pretty busy season with around "42" new shows! The preview can be found at 'random curiosity'.

As always, I'll be picking up anything related to romance and harem. The most awaited shows are:

• STEINS;GATE
• Ao no Exorcist
• C: The Money of Soul and Possibility Control
• Deadman Wonderland

James, a side by side comparison using a non-trivial example would be helpful in evaluating this. My reasoning being if the LOC/effort being saved isn't significant, there is no need to ditch the compile time checks IMO. Plus, given that no source code is supplied, you might want to delve a bit deeper on how it works under the hood.

Create a new instance of the Properties class, call setProperty and then store. See this: http://www.mkyong.com/java/java-properties-file-examples/

You need to improve your 'google-fu' :-)

http://www.mkyong.com/applet/jmf-unable-to-handle-format-mpeglayer3/

I haven't used JMF but as per this thread JMF is horrible. You have been warned, or something like that...

You know you are old when you smile & shake your head after seeing kids post in the threads meant for relics... ;-)

I am arguing that whether we can trust wikipedia and how much stories can be trusted.

... and this certainly isn't the right thread for the discussion. A bit of off-topic chat is never frowned upon but this thread has gone *way* too off-topic.

I know you knew the reason, just wanted to clarify it for others who stumble upon this thread for the same reason. :)

You are of course welcome.

But just to clarify, if the RSS feeds showed the entire thread, no one would bother visiting the forums thereby bringing down the traffic, something which is very valuable to any forum out there. My bet is that the majority of forums out there expose "teaser" feeds which show you the gist of the thread/post but require you to visit the forum to actually view the entire thing. :-)

Java (along with its standard libraries) doesn't directly support this. The only way is to drop down to the platform specific stuff and interface that with your Java application using JNI/JNA.

There was an entire discussion pertaining to this topic with example code I guess but the link (http://forums.sun.com/thread.jspa?threadID=632369) now seems to be broken (thanks Oracle).

But consider thinking about the enum approach which I mentioned for the reasons already stated above.

AFAIK, RSS/Atom readers only show feeds which were exposed by the site in consideration. So if the feeds published by Daniweb don't show the entire thread, no feed reader would be able to show the entire thread.

As an example, consider this feed exposed by Github which shows the entire blog post with images since that's how they expose their feed to be.

What is the use-case for this Coin class (i.e. client code)? I think that this class could be much better modeled as an enum (limited and finite states) in which case you automatically get a good equals and hashCode implementation. Also, when you say 'weight', is it the physical weight of the coin or something else?

On a related note, since you are already using Eclipse, you can ask Eclipse to generate a equals() and hashCode() implementation for you. ALT + SHIFT + S then h.

Yeah, the first item of the array will be the object on which the method was invoked and the second item would be the newly created Cell with the same attributes as that of the original Cell object.

It returns an array of two C objects; one object is the object on which the 'action' method is invoked and the second one been a clone of the first one. Your mitosis method can use the same trick i.e. return return Pair.newPair(this, new Cell(this)) .

You get it, The IRC you post is only for support forums and technical difficulties

You've got it wrong; IRC is not a place to ask support questions, it's a chillout zone/place. Click on the link jonsca has posted in this thread and just hang out there. You don't need to answer / ask questions. Just *relaaax*. :-)

You can return a Pair object which contains a pair of Cell instances. A sample Pair class implementation can be found here.

Also, cloning in Java is pretty much broken (read the experts view here) and you would be better off creating a copy constructor which does the same stuff.

class Pair<F, S> {
    
    final F first;
    
    final S second;
    
    private Pair(final F first, final S second) {
        this.first = first;
        this.second = second;
    }
    
    public static <A, B> Pair<A, B> newPair(final A first, final B second) {
        return new Pair<A, B>(first, second);
    }
    
    // getters here i.e. getFirst() and getSecond()
}

class Cell {
    
    private final String name;
    
    private Cell(final String name) {
        this.name = name;
    }
 
    // copy constructor
    public Cell(final Cell other) {
        this.name = other.name;
    }
    
    public static Cell newCell(final String name) {
        return new Cell(name);
    }
    
    public Pair<Cell, Cell> mitosis() {
        return Pair.newPair(new Cell(this), new Cell(this));
    }
    
}

Yes, you definitely can do it. If I've captured your requirements correctly, you basically want to "invoke" the functionality implemented by native extensions in your Java code. In that case, look into JNI (the actual specification) and a easier way to go about it using JNA (JNI is too much chore and boilerplate code).

Yes, I already have, from the same page.

Also, I've created a thread along the same lines to guide people in case they are interested in helping out. I would be nice if you could donate (any amount would help) and help spread the word by posting in that thread.

I know this is kind of late but in case you folks didn't know, Japan is still trying to recover from the aftereffects of the calamity which struck it few days back. In these horrid times, every bit of sentiment and help counts. No help given with good intentions is a 'small' help.

In case you can want to lend a helping hand by contributing financially to the relief efforts (which I think everyone should) but are unaware of a tried and tested channel which is not part of the 'sick scam' which some people are trying to pull, I would highly recommend the Google crisis response page.

http://www.google.com/crisisresponse/japanquake2011.html

The donations made from here are safe, trusted and go directly to the Japanese Red Cross. Please don't shy away from donating just because you think you aren't donating much, a small donation is better than no donation.

Remember, 'today you, tomorrow me'. Thank you.

I'm pretty sure many people have already done this. But in case there are some who still want to donate but are not sure which avenue to choose, I'd recommend the disaster help page hosted by Google. That way you can directly donate to the Japan Red Cross and be sure that you are using trusted means to do so (Google).

Being a caring person who wants to help does not negate being an idiot.

Non sequitur; idiocy and caring nature are two orthogonal things.

I work very hard for my money and give regularly to a number of charities, but i try to do as much research into how much of my money will make it to the people i am trying to help before i donate.

Again, doesn't related to the discussion here since I already mentioned that these people are non-computer-savvy who normally don't inspect "mail headers" like we do and would be more than convinced to see a "Japan Red Cross" name in the "From" field...

Scammers are scum, but idiots who buy into the scams are only pitiable

That's a pretty harsh statement. Not computer savvy? Maybe. Idiots? Definitely not. There is a thin line between idiocy and innocence...

I'm not sure why you think it won't be a good idea to request the sys admins for setting things straight. It's not as if you are asking for a permission to unblock youtube or gmail. Plus, the filter is obviously broken; it allows you to browse some parts of the site but not others like Web Development.

You can always give the reason that this site shows up in google results when you search for fixes to your issues. The worst possible thing that could happen would be the sys admins blocking entire Daniweb domain. Or if you are lucky, they might just realize how stupid their blocking criteria is and modify their rules.

The IT Professional's Lounge might be a good sub-forum for that.

There already exists a database forum hidden inside the Web development forum; here ya go.

EDIT: Also I'm surprised you missed this thread in the same forum. :-)

It's already there, hidden inside web development (click Databases).

Your problem is that you are using 'long' type where 'double' is desirable. For e.g. what should be power of 10.1^2 ? What does your invocation of 'power(10.1, 2)' print? Your power method is broken but it doesn't throw a compile time error because of your use of `*=` construct. Try replacing it with `result = result * x` and you'll notice where you are going wrong.

This is because each thread spawned is effectively a garbage collection root i.e. the central point at which the GC starts working. As far as an official source is concerned, the same is mentioned (but in a bit cryptic way) here (read the unreachable section).

OK, my bad, must have missed that. Anyways, did you try inspecting the HTTP request sent to your servlet using Firebug as suggested previously?

I don't see any form element with the name "mmsTitleAdded" which kind of explains why you are not getting any values (unless you have not posted the code which shows this element). If you are trying to get the multiple values of the "SELECT" in your first code snippet, try using "mmsTitle" instead. Also, you can always view what kind of data is submitted to the server using a tool like Firebug extension for Firefox. Really handy I must say to see *what* gets submitted to your server.

Oh and BTW, your code is *really* messy. Avoid using scriptlets in your JSP markup and make sure your internal Ajax requests return a JSON object instead of a "HTML fragment". Sure, the way you have done it makes it easier but unless it's a short term project (school project), maintaining this complicated piece of code would become more and more difficult as the code base grows.

I know this sounds crazy but I have in the past faced issues with anti-virus and firewall softwares messing around with my browsing experience. So if you have recently got an update, that's where you can try looking... :-)

I'm not sure I buy into this idea that if one provides code, they "deprive" or "ruin" anybody's thinking process. Maybe it's because I'm older, have already "been there, done that" as far as formal schooling goes, and I'm a professional programmer now. I've already proved myself and hence no longer need the "if I just give it you, you'll never learn to think for yourself" lecture. I give that lecture to my ten year old nephew, but I know him and feel somewhat responsible for instilling good habits in him. Yeah, I know all sorts of students come here with homework dumps and, if given the verbatim code, won't put any effort into it and hence never learn to think.

IMO it's got nothing to do with age (after all almost everyone advocating it in this thread is a middle aged bloke [rude assumption? maybe :>); it's just a matter of whether you want to give a solution to the OP or want to go out of your way and help him reach the solution, nothing more, nothing less.

There are all kinds of students who post here; those who already have the solution and want to understand how it works, those who don't have the solution and won't mind a ready solution but at the same time have a desire to learn something new and those who have no intention of learning. Posting code is a much bigger problem in a thread which already has an ongoing …

It wasn't meant to sound like an attack and i apologise.After you sent me that message i've re read the rules and i couldn't find myself breaking any.I'm not saying i don't deserve my down-reps but i definitely don't deserve all of them.I apologise for my bad english and i would like to see you handling with my language .I didn't know you had a forum for complains so my bad again.My personal opinion is that you should have a rule saying you can't post full solutions and i will try to stick with this not yet implemented rule if that's ok with you.I didn't really think i should take it from anyone else but a moderator since you're the person in charge here but i did mind the 8 down reps before telling me what i did wrong.Anyway i'm sorry for this and i hope i didn't offended you in any way.

No one can infract you for posting complete solutions (the reason why you haven't received an infraction till now). Reputation, is a different matter. Unless you have a member specifically targeting you with -ve rep, there is little we can do; after all, reputation was meant to be a measure of how individual members feel about the post. If most of the regulars of C++ forum are against posting complete solutions, you would get downvoted.

You have two choices:

• Continue posting complete solutions if you think that's the right way. I'm pretty sure you have …