Is it ever bad practice to use threads?

Hi there ppl,
this may sound like a really silly question is it ever bad practice to use threads? I actually have never explicitly used threads and came across a simple swing application recently which used a thread in the code. Then I started to think that if ever a scenario came up where I was expected to use threads I'd have to learn something new that I should I have already known from birth, then run and hide behind the JAVA API (which is big, real big, BIGGER THAN OPRAH!!!).
So for now I'll "synchronise my watch" (PUN INTENDED), and await the flood of replies.
Thx already ;)

Main Entry: 1pun
Pronunciation: 'p&n
Function: noun
Etymology: perhaps from Italian puntiglio fine point,
quibble -- more at PUNCTILIO
: the usually humorous use of a word in such a
way as to suggest two or more of its meanings or the
meaning of another word similar in sound
emphasis mine (synchronize watch vs. synchronize
threads)...
Ironic that it derives from "fine point, quibble."
¶

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mazz2000 wrote:
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What are the best practices for using the enhancement framework?

Hello enhancement framework experts,
Recently, my company upgraded to SAP NW 7.1 EhP6. This presents us with the capability to use the enhancement framework.
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Thank you,
Kimberly
Edited by: Kimberly Carmack on Aug 11, 2011 5:31 PM

Found an article that answers this question quite well:
[How to Get the Most From the Enhancement and Switch Framework as a Customer or Partner - Tips from the Experts|http://www.sdn.sap.com/irj/scn/index?rid=/library/uuid/c0f0373e-a915-2e10-6e88-d4de0c725ab3]
Thank you Thomas Weiss!

Best practice when using Tangosol with an app server

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Hi Gene,
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Workaround good/bad practice or does it not matter...??

Hi,
I have a project that requires other shared actions to hide./show something and was wanting a quick workaround for Hide 1 show 9 so I did as follows..(bear in mind I am using CP7 not 8)
I copied my hide1 show 20 slide from another project, which retains the connection between buttons and images etc, but as this was too many for my other project, I just set things on the copied slide not to displlay in output etc adn then renamed the ones I wan to refer to in the new project adn it all works great, however, if wer are doing this is this bad practice as any other CP editor further down the track, needs to edit the project, might think that this is a mess and mish mash with ttoo many objects (although hidden) on the slide and maybe make it more difficult for them.
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Cheers
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Hi Lilybiri,
Sorry for the delay in responding.
I would be interested in your workflow for editing shared actions.
Hopefully this will be clearer for my explanation of how I initially thought of for editing my shared action...please let me know if this is still not clear.
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Cheers
Rossco

Using threads and collecting responses

Hello,
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Thanks in advance.

Hi,
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Greetings
Brash

Is this bad practice?

Consider the follwing two classes:
public class Widget
public class CustomWidget extends Widget
}Now consider another class that has a Widget class member:
public class OrdinaryClass
private Widget w = new Widget();
public Widget getTheWidget()
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}Now suppose I were to subclass OrdinaryClass as follows:
public class SpecialClass extends OrdinaryClass
private CustomWidget cw = new CustomWidget();
public CustomWidget getTheWidget() // violate LSP?
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}My questions are:
1) does SpecialClass violate Liskov's Principle in that the getWidget return type has changed?
2) if it's not in violation, is it bad practice anyway? Or is this some polymorphic trick that is not only acceptable, but very useful (and encouraged)?
Please advise.

A custom model was subclassd from AbstractListModel.
One of the getter methods from ALM has a return of
f type Object. The custom model used the same
getter, but returned the toString() of the Object (a
property) instead of the Object in its entirety.Given this specific class hierarchy, you're into territory for design lawyers. A list mode maintains data that's used by a JList[i/]. The contract, as a result, is fairly open, and you could define the model as maintaining string representations for an object. The purists would respond with "no, the view should decide the representation," and I'd probably agree with them.
By comparison, the contract for a [i]java.util.List is much more explicit: you put objects into the list, and you get the same objects out. If your colleague was creating a List implementation that returned toString() of an object rather than the object itself, then your argument would have much more force.
It seems as if changing the return type of a method
in a subclass seems wrong, even if the new return
type is a sub of the original return type.
I have nothing against returning the subclass, mind
you. Just keep the contract (i.e, the return type)
the same.However, the "contract" is not defined just by method signature. If that were the case, then this would be a perfectly valid implementation of List.get():
public Object get(index i)
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}Instead, the "contract" is defined by the class as a whole, and furthermore is defined by your application for each instance of a class that it creates (eg, "this List is used to pass strings between these two methods").

Multi-functional Servlet considered bad practice?

Hi,
is it considered bad practice using doGet() for fetching say a blog entry and using doPost() for saving new entries or comments?
Such as:
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
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protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
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}I like to think that this is the reasoning or at least part of the reason why doGet and doPost are separate methods.
Thank you.
Regards,
Adam

Asham wrote:
Hi,
is it considered bad practice using doGet() for fetching say a blog entry and using doPost() for saving new entries or comments?Depends on current environment and requirements. In a small hobby application you can do so. In real business I wouldn't do so, it might bite in the future if you plan to extend that servlet with more logic.
I like to think that this is the reasoning or at least part of the reason why doGet and doPost are separate methods.No, it is not. The HTTP protocol specification (1) offers several request methods, GET, POST, HEAD, PUT, DELETE, etc. The HttpServlet API (2) offers overrideable methods for each of those request methods so that you can handle it using some Java logic. A "plain vanilla" request is always GET. A form submit can be either GET or POST -generally POST is preferred as it can transfer more data and does "hide" query parameters.
(1) http://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html
(2) http://java.sun.com/javaee/5/docs/api/javax/servlet/http/HttpServlet.html

Force quitting InDesign as a Matter of Routine. Bad Practice?

I am trying to convince InDesign users here (CS4, CS5) that using Force Quit as a matter of routine for quitting out of InDesign at the end of the day is a bad practice. I think this started because when we were using K4 (enterprise InCopy/InDesign plug-ins), InDesign DID take a long time to quit because of communication to the K4 database and disconnecting.
I need some good evidence to convince everyone to quit out of InDesign normally. And also other programs they use. My argument is that when InDesign quits, it updates its preferences and perhaps may even clean something up. Anyone know?

I work on local files only, and I still have to either leave my desk for 10 minutes after I try to quit then shut down, or force quit and shut down. I do work on some large files though (50-100 meg catalogs) with lots of photos linked in. I guess it takes forever to clear all the cached memory or something. If I try to do a shutdown with InDesign open. I always get a time out error. Also when I go back to InDesign after working in Photoshop, FreeHand, Entourage or FireFox it takes a long time to redraw the InDesign screen and menus.
I also have a couple of indexing scripts, but don't run them often. Don't see how that would affect anything.
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Thanks,
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Mac OS 10.4.11
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Is it bad practice to capture an image that was deployed from mdt after adjustment?

is it bad practice to capture an image that was deployed from mdt after adjustment?
or there is no any consequences?
"When you hit a wrong note it's the next note that makes it good or bad". Miles Davis

During years I never captured the image deployed from mdt.
Today was a rush.
The request:
to install time consuming configuration application into the image.
I restored acronis image that used during couple of weeks for captures after small changes.
And decided to capture it again before the installation of local progam and final capture.
It failed after multiple trials. I posted the error yesterday here:
http://social.technet.microsoft.com/Forums/windowsserver/en-US/a702bf17-8375-4bc7-b458-8ce4894f99e9/error-2147467259-during-capture?forum=mdt
As a last tip before suggesting to deploy existing image and sysprep it 20 times I deployed the image from MDT applied just Windows KBs and captured again with MDT it worked without any prob.
So against my usual habit I gave a deployd image for installing the tricky software and then will capture it for future deployment for 20 "special" computers. Feel not so good. But like you told:
"Will it hurt anything? Probably not" I took a chance. In the image no AV, just small things like 7Z and Adobe.
Encourage me for this case :)
Thanks.
"When you hit a wrong note it's the next note that makes it good or bad". Miles Davis

Is it a bad idea to use Task.Delay() in a polling function?

Is the following a bad idea considering the expense of Task.Delay()?
async void WatchDog()
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Hong

I've not used the DispatcherTimer, so I can't say anything from experience about how efficient it is or not. The few times I needed this sort of functionality in the few WPF apps I've done, I've used Task.Delay() ... I agree that it is certainly
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Ah, WinRT ... didn't know that was the platform you're writing for.
I've got no experience with WinRT. I don't know if there's a separate MSDN forum for that, the only thing I could find was a forum for Surface (https://social.msdn.microsoft.com/Forums/vstudio/en-US/home?forum=surfaceappdevelopment),
but I don't know if posting questions there would help you or not. Probably the WPF forum would work just as well (https://social.msdn.microsoft.com/Forums/vstudio/en-US/home?forum=wpf).
~~Bonnie DeWitt [C# MVP]
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Catalogue of SQL and PL/SQL bad practices: Call for participation

I started compiling a list of Oracle SQL and PL/SQL bad practices, with the intention of producing a comprehensive catalogue of common and recurring programming mistakes, that can be used as a check-list for code reviews or given to junior developers. I have identified about 30 bad practices so far. For each bad practice, I provided a list of symptoms in the code, an explanation why it causes problems and a list of preferred solutions.
My goal with this list is primarily to start a discussion about similar recurring issues that other people have noticed. That discussion should lead to a more complete list which the community will then be able to use, hopefully, to learn something from the mistakes of others and to produce better code.
I would really appreciate your feedback - if you are interested in discussing these practices we can either do it in this forum, or start a separate mailing list.
You can download the first version of the catalogue in PDF form from http://gojko.net/effective-oracle
gojko adzic
http://gojko.net

exception handler (already covered), the philosophy
behind not using stored procedures, and having beenHi riedelme,
I'm not advocating not using stored procedures, but I am advocating not using exclusively stored procedures. I've seen that approach often, typically with people coming from SQL server or Oracle forms backgrounds, I never could understand the reasons behind it. Even for a simple select or update, they would write a stored proc that wraps the call and then require the client to execute a stored proc.
I think that views are much better for getting the data out of the database in general, and forcing people to use stored procedures with ref output cursors makes little sense. If the only possible interface is a stored proc, then one proc must be created for every required combination of data and every required filtering or grouping method, so there is much much more code in the database, and more code means harder maintenance.
If client apps can get data out using views, then they can join them with other views, filter or group the data as they require, which means that there is a lot less code in the database to maintain.
My other problem with stored-proc only approach is when people wrap simple insert/update/delete commands into a stored proc. Again, I'm not advocating using complex instead-of triggers to implement workflows and forcing people to use views, but I simply don't see any benefit of implementing a stored proc to do a simple update. I see a bad side of it because a stored proc needs to be implemented for every combination of columns that a client may need to update and every criteria that can be used for that. If a client is allowed to update a view, there is much less code in the database.
Views are, in my experience, also a lot easier to maintain and optimise without downtime because they can be revalidated without causing any problems to currently connected clients, where revalidated stored procedure or package will throw an exception the first time a connected client that had called it before calls it again.
If I'm missing something, please tell me. I'd really love to understand why someone would build a client API exclusively from stored procedures.
So far, I've been given explanations that it is for security purposes, or for performance. I don't know of any security restriction that can be implemented on a stored procedure or package that cannot be implemented with a view, and if bound variables and statement caching is used, sql statements don't suffer from sql injection and support pre-compilation.
Again, i'm not advocating throwing stored procs completely out, i'm against using them exclusively and throwing out any chance of SQL access.
gojko adzic
http://gojko.net

Using threads in a process of two or more tasks concurrently?

Dear,
I need to develop through a Java application in a process that allows the same process using Threads on two or more tasks can be executed concurrently. The goal is to optimize the runtime of a program.
Then, through a program, display the behavior of a producer and two consumers at runtime!
Below is the code and problem description.
Could anyone help me on this issue?
Sincerely,
Sérgio Pitta
The producer-consumer problem
Known as the problem of limited buffer. The two processes share a common buffer of fixed size. One, the producer puts information into the buffer and the other the consumer to pull off.
The problem arises when the producer wants to put a new item in the buffer, but it is already full. The solution is to put the producer to sleep and wake it up only when the consumer to remove one or more items. Likewise, if the consumer wants to remove an item from the buffer and realize that it is empty, he will sleep until the producer put something in the buffer and awake.
To keep track of the number of items in the buffer, we need a variable, "count". If the maximum number of items that may contain the buffer is N, the producer code first checks whether the value of the variable "count" is N. If the producer sleep, otherwise, the producer adds an item and increment the variable "count".
The consumer code is similar: first checks if the value of the variable "count" is 0. If so, go to sleep if not zero, removes an item and decreases the counter by one. Each case also tests whether the other should be agreed and, if so, awakens. The code for both producer and consumer, is shown in the code below:
#define N 100                     / * number of posts in the buffer * /
int count = 0,                     / * number of items in buffer * /
void producer(void)
int item;
while (TRUE) {                    / * number of items in buffer * /
produce_item item = ()           / * generates the next item * /
if (count == N) sleep ()           / * if the buffer is full, go to sleep * /
insert_item (item)                / * put an item in the buffer * /
count = count + 1                / * increment the count of items in buffer * /
if (count == 1) wakeup (consumer);      / * buffer empty? * /
void consumer(void)
int item;
while (TRUE) {                    / * repeat forever * /
if (count == 0) sleep ()           / * if the buffer is full, go to sleep * /
remove_item item = ()           / * generates the next item * /
count = count - 1                / * decrement a counter of items in buffer * /
if (count == N - 1) wakeup (producer)      / * buffer empty? * /
consume_item (item)      / * print the item * /
To express system calls such as sleep and wakeup in C, they are shown how to call library routines. They are not part of standard C library, but presumably would be available on any system that actually have those system calls. Procedures "insert_item and remove_item" which are not shown, they register themselves on the insertion and removal of the item buffer.
Now back to the race condition. It can occur because the variable "count" unfettered access. Could the following scenario occurs: the buffer is empty and the consumer just read the variable "count" to check if its value is 0. In that instant, the scheduler decides to stop running temporarily and the consumer starting to run the producer. The producer inserts an item in the buffer, increment the variable "count" and realizes that its value is now 1. Inferring the value of "count" was 0 and that the consumer should go to bed, the producer calls "wakeup" to wake up the consumer.
Unfortunately, the consumer is not logically asleep, so the signal is lost to agree. The next time the consumer to run, test the value of "count" previously read by him, shall verify that the value is 0, and sleep. Sooner or later the producer fills the whole buffer and also sleep. Both sleep forever.
The essence of the problem is that you lose sending a signal to wake up a process that (still) not sleeping. If he were not lost, everything would work. A quick solution is to modify the rules, adding context to a "bit of waiting for the signal to wake up (wakeup waiting bit)." When a signal is sent to wake up a process that is still awake, this bit is turned on. Then, when the process trying to sleep, if the bit waiting for the signal to wake up is on, it will shut down, but the process will remain awake. The bit waiting for the signal to wake up is actually a piggy bank that holds signs of waking.
Even the bit waiting for the signal to wake the nation have saved in this simple example, it is easy to think of cases with three or more cases in which a bit of waiting for the signal to wake up is insufficient. We could do another improvisation and add a second bit of waiting for the signal to wake up or maybe eight or 32 of them, but in principle, the problem still exists.

user12284350 wrote:
Hi!
Thanks for the feedback!
I need a program to provide through an interface with the user behavior of a producer and two consumers at runtime, using Threads!So hire somebody to write one.
Or, if what you really mean is that you need to write such a program, as part of your course work, then write one.
You can't just dump your requirements here and expect someone to do your work for you though. If this is your assignment, then you need to do it. If you get stuck, ask a specific question about the part that's giving you trouble. "How do I write a producer/consumer program?" is not a valid question.

Best practice to use MediaPlayer?

Is the best practice to use attributes of MediaPlayer (such as playing) or to request the PlayTrait and read its playState attribute?
(This question comes from a customer. Reposting here for the OSMF team to respond and for the benefit of the whole group.)
Sumner Paine
osmf product manager

For playback use cases, I'd recommend you stick with MediaPlayer, as it's simpler to use and manages all of the trait event registration.

Is it ever bad practice to use threads?

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