Wait--question about uninstallation

after looking at the other posts in here, i think i know how to solve my problem, but i just have one question. i think i might already know the answer, but i just want to make sure before i do anything. if i uninstall itunes, will it delete all my music i've downloaded?

hi just totally rad!
if i uninstall itunes, will it delete all my music i've downloaded?
here's a good resource on that topic:
http://discussions.info.apple.com/webx?[email protected]@.68b8642a/0
and here's a good resource on backing up:
http://discussions.apple.com/click.jspa?searchID=200001&messageID=1222986
love, b

Similar Messages

Questions about uninstalling some preload stuff...

Hi all, trying to slim down my system, a few questions if you can help...
1) Can I uninstall "Thinkpad Power Manager"? If yes, I gather I would have to leave "Thinkpad Power Management Driver" installed? I don't need all those power options, and I'm happy enough to use the Windows control panel -- or do I really need the Thinkpad Power Manager for something?
2) Can I uninstall "Message Center Plus"?
3) Can I uninstall "Thinkvantage Communication Utility" and/or "Lenovo Thinkvantage Toolbox"? I do use System Update, but I don't see the point of Thinkvantage -- can I program the blue Thinkvantage button to do something more useful?
Thanks in advance for any advice!

1) Yes you can. You won't get additional informations about the battery-state and health then anymore.
2) Yes
3) The Communication Utility will be needed for mobile broadband i guess
The ThinkVantage Toolbox will be started by pressing the Thinkvantage-button - you can remove it, if you don't want to use it.
Under XP you can use the ThinkVantage-Button with the program Thinkpad Button Customizer
In my opinion you also can remove System Update - you will have less problems then caused by updates
My home-forum: http://www.thinkpad-forum.de
Wiki: Deutsches ThinkPad-Wiki English ThinkWiki
My ThinkPad-Collection

Question about "synchronized" and "wait"

Hello, everyone!
I have seen a piece of code like this,
synchronized (lock)
//do operation 1
lock.wait();
//do operation 2
I think in the above piece of code, when a thead finished operation 1, it will release the lock and let other threads waiting for the lock have chance to run the same block of code. Am I correct?
If I am correct, I have a further question, a "synchronized" block means a set of operations that can not be interrupted, but when invoke "wait" method, the thread running in the "synchronized" block will be terminated (interrupted) by release the lock and other threads will have chance to enter the "synchronized" block. In short, the execution inside the "synchronized" block will be interrupted. So, I wonder whether the above piece of code is correct and conforms to the principle of "synchronized". And what is its real use?
Thanks in advance,
George

Thanks, pkwooster buddy!You're welcome
I just wondered whether "wait inside a synchronized
block" technology is thread safe. Please look at the
following example,wait and synchronized are thread safe.
public class Foo {
int mVal= 0;
public final Object mLock = ...;
public void doIt() {
synchronized(mLock) {
mVal = ...;
mLock.wait();
if (mVal == ...) {
// do something
} else {
// do something else
}If we have two threads, T1 and T2, enter the block in
their respective order, and T1 is woken up first, T2
may have tampered with T1's execution path because T2
changed mVal while T1 was asleep. So T2 manipulate
instance field mVal is a side-effect.when you do the wait() you give up the lock and the other threads get a chance to run. When you exit the wait() you get the new value of the myVal variable which may have been changed. This is exactly what you want. To make that not thread save you could do
int temp = myVal;
wait();
if(temp == ...)in this case the variable temp contains the old vale of myVal.
>
I think the most safest way is never wait inside a
synchronized block, but it is less efficient. What do
you think about the trick of wait inside a
synchronized block? I think you are very experienced
in thread field from your kind reply.
Thanks in advance,
Georgewait(), notify() and notifyAll() are very useful. You need them when you want threads to cooperate in an predictable manner. I recommend that you review the section on consumer and producer classes and wait and notify in the Threads Tutorial. It gives good examples. For a practical example of this you could also take a look at my Multithreaded Server Example. It implements a simple chat server that switches String messages. Look especially at the send(), doSend() and popMessage() methods in the StreamConnection class. These allow the receive thread of one user to send messages out using the send thread of another user. If you have questions about that example, please post the questions on that topic.
Hope this helps.

I have been waiting for about an hour waiting for an email back form apple. I forgot my security questions.

have been waiting for about an hour waiting for an email back form apple. I forgot my security questions.

We're all just your fellow users here. You'll need to wait until you get the email.

Question about Page Builder behavior - how to get a "please wait message" ?

Hi all together,
I got a question about Portal Framework / Page Buider handling iView Integration.
We are working with a lot of App Integrator iViews and often the pages includes with app integrator are loading longer than the rest of the portal. So there is the idea to put in a "please wait while loading message" for the enduser.
I analysed the html code, the page builder is generating and foud out 3 diffrent approaches how the page buider is rendering the IFRAME with the integrated application configured with an app integrator iView.
My question is how can I influence this behavior to put a "please wait while loading message"?
Different types of iView integration in the client I have seen:
a) direct loading of the content in the IFRAME (<iframe id="" ... scr="/mysource">)
b) Filling the iframe with 'about:blank' and loading the content later by filling a form with JS
( <iframe id="" .... scr="about:blank">and after the iframe <form id="" action="mysource" ...>
c) Filling the iframe with a html file from the portal layout and loading the content later by filling a form with JS (similar to b)
( <iframe id=""" ....scr="/irj/portalapps/com.sap.test.mylayout/html/blank.html>
I checked that variant b) is getting generated when loading a page with different components on the side (not only the app integrator iview) and variant c) is generated when just one app integrator iView is positioned (no portal page).
Goal: To get the "please wait picture" I want to know how to get variant c) in cases of different elements on one page
So I would be able to put this picture on the HTML-Page in the Portal layout (blank.html)
Hope, someone with a deep portal / page builder know-how can help me out!
Another way: Does anybody knows another way how to put a "please wait message" while app integrator application is not loaded yet?
Thanks in Advance and kind regards,
Jens
Edited by: Jens Kohne on Nov 24, 2010 9:08 AM

Hi Jens,
there are several reasons why you don't get the loading animation:
Web Dynpro ABAP: https://service.sap.com/sap/support/notes/1432358 -> missing configuration
Wrong height size for iView: https://service.sap.com/sap/support/notes/1358494 -> alter configuration of the iFrame height (loading animation gets displayed, but is hidden)
FPN, BSP, BEx: https://service.sap.com/sap/support/notes/1290995 -> AI isn't showing the animation because of performance considerations. I guess that is your case. Depending on your portal version this is a simple service configuration or involves some customization.
br,
Tobias

Questions about your new HP Products? HP Expert Day: January 14th, 2015

Thank you for coming to Expert Day! The event has now concluded.
To find out about future events, please visit this page.
On behalf of the Experts, I would like to thank you for coming to the Forum to connect with us. We hope you will return to the boards to share your experiences, both good and bad.
We will be holding more of these Expert Days on different topics in the months to come. We hope to see you then!
If you still have questions to ask, feel free to post them on the Forum – we always have experts online to help you out.
So, what is HP Expert Day?
Expert Day is an online event when HP employees join our Support Forums to answer questions about your HP products. And it’s FREE.
Ok, how do I get started?
It’s easy. Come out to the HP Support Forums, post your question, and wait for a response! We’ll have experts online covering our Notebook boards, Desktop boards, Tablet boards, and Printer and all-in-one boards.
We’ll also be covering the commercial products on the HP Enterprise Business Community. We’ll have experts online covering select boards on the Printing and Digital Imaging and Desktops and Workstations categories.
What if I need more information?
For more information and a complete schedule of previous events, check out this post on the forums.
Is Expert Day an English-only event?
No. This time we’ll have experts and volunteers online across the globe, answering questions on the English, Simplified Chinese, and Korean forums. Here’s the information:
Enterprise Business Forum: January 14th 7:00am to 12:00pm and 6:00pm to 11:00pm Pacific Time
Korean Forum: January 15th 10am to 6pm Korea Time
Simplified Chinese Forum: January 15th 10am to 6pm China Time
Looking forward to seeing you on January 14th!
I am an HP employee.

My HP, purchased in June 2012, died on Saturday. I was working in recently installed Photoshop, walked away from my computer to answer the phone and when I came back the screen was blank. When I turned it on, I got a Windows Error Recovery message. The computer was locked and wouldn't let me move the arrow keys up or down and hitting f8 didn't do anything.
I'm not happy with HP. Any suggestions?

Two questions about the new iWeb

Hi
I've got two questions about the new iWeb.
1. Is it possible to blog online now? Meaning adding a new blog entry without having to be on your own Mac? This is a feature I've been waiting for since iWeb first was released.
2. Is it possible to choose the format of images? Earlier editions had the option to "optimize" images but that meant it changed it into .png meaning the site got a lot heavier than if .jpg was used. And since I have relatives who still only have an isdn connection I need to be able to have the website as light as possible.
thanks

Ah well... thanks for the quick answer
Message was edited by: Guðlogi

Question about Rescheduling Start Date of a Task

Question about Rescheduling Start Date of a Task
I'm trying to determine whether the 'Reschedule' action is appropriate to my situation...
I have a service that consists of 4 tasks. The first 3 tasks will be completed immediately and then the request's 4th task will sit in a queue for about a month so that all of these requests can be grouped together and fulfilled during a few overnight work sessions.
While the 4th task is waiting to be fulfilled, the technician will be contacting the requestor to schedule the work to be done sometime during a 3 day window. The technician needs to specify which of the 3 days each request will be worked on. I'm not sure if I should store the date in a service form field or have the technician reschedule the task so that the start date of the task is set to one of the 3 days. If I use the reschedule feature, are there any downsides?
The advantage of using the reschedule feature is that the scheduled start date can be displayed in ServiceManager's task list and can therefore be sorted on and queried. This wouldn't be possible if I stored the date in a dictionary field on the service form. In that case, I'd have to use custom reports to group the tasks by start date.
Please let me know your thoughts...
Thanks,
Scott

This strikes me as a very good use of this feature, since your need to to have the date for this task rescheduled/reflected in ServiceManager. This is the specific effect of using this feature.
For the benefit of others reading this post, remember: this rescheduled date will not change the due date for the service.

Question about broker Switchover command

Hi guys
i have one question about switchover cmd . For example, i have 1 primary database called stdby3 and 2 standby databases that are called stdby1 and stdby2. When i performed switchover cmd to stdby2 standby database, why the old primary database stdby3 could not become new standby database after i performed a switchover; furthermore the new primary and standby databases are not opened after the switchover process is completed
output screen:
DGMGRL> show configuration;
Configuration
Name: stdby1
Enabled: YES
Protection Mode: MaxProtection
Databases:
stdby3 - Primary database
stdby1 - Physical standby database
stdby2 - Physical standby database
Fast-Start Failover: DISABLED
Current status for "stdby1":
SUCCESS
DGMGRL> SWITCHOVER TO stdby2
Performing switchover NOW, please wait...
Operation requires shutdown of instance "stdby3" on database "stdby3"
Shutting down instance "stdby3"...
ORA-01109: database not open
Database dismounted.
ORACLE instance shut down.
Operation requires shutdown of instance "stdby2" on database "stdby2"
Shutting down instance "stdby2"...
ORA-01109: database not open
Database dismounted.
ORACLE instance shut down.
Operation requires startup of instance "stdby3" on database "stdby3"
Starting instance "stdby3"...
Unable to connect to database
ORA-12514: TNS:listener does not currently know of service requested in connect descriptor
Failed.
You are no longer connected to ORACLE
Please connect again.
Unable to start instance "stdby3"
You must start instance "stdby3" manually
Operation requires startup of instance "stdby2" on database "stdby2"
You must start instance "stdby2" manually
Switchover succeeded, new primary is "stdby2"
DGMGRL> show configuration;
Error:
ORA-01034: ORACLE not available
Process ID: 0
Session ID: 130 Serial number: 45
DGMGRL> exit;
oracle@localhost ~$ dgmgrl
DGMGRL for Linux: Version 11.1.0.6.0 - Production
Copyright (c) 2000, 2005, Oracle. All rights reserved.
Welcome to DGMGRL, type "help" for information.
DGMGRL> connect sys
Password:
Connected.
DGMGRL> show configuration;
Error:
ORA-01034: ORACLE not available
Process ID: 0
Session ID: 0 Serial number: 0
DGMGRL> connect sys@stdby3
Password:
Connected.
DGMGRL> show configuration;
Error:
ORA-01034: ORACLE not available
Process ID: 0
Session ID: 0 Serial number: 0
DGMGRL>
Edited by: user6981287 on Jan 6, 2010 9:27 AM

this is my configuration
DGMGRL> show configuration
Configuration
Name: matrix
Enabled: YES
Protection Mode: MaxPerformance
Databases:
stdby1 - Primary database
stdby2 - Physical standby database
stdby3 - Physical standby database
Fast-Start Failover: DISABLED
Current status for "matrix":
SUCCESS
--- this is my first successful switchover -----
DGMGRL> switchover to stdby2
Performing switchover NOW, please wait...
New primary database "stdby2" is opening...
Operation requires shutdown of instance "stdby1" on database "stdby1"
Shutting down instance "stdby1"...
ORA-01109: database not open
Database dismounted.
ORACLE instance shut down.
Operation requires startup of instance "stdby1" on database "stdby1"
Starting instance "stdby1"...
ORACLE instance started.
Database mounted.
Switchover succeeded, new primary is "stdby2"
-------------------this is my second switchover -------------
DGMGRL> switchover to stdby1
Performing switchover NOW, please wait...
New primary database "stdby1" is opening...
Operation requires shutdown of instance "stdby2" on database "stdby2"
Shutting down instance "stdby2"...
ORA-01109: database not open
Database dismounted.
ORACLE instance shut down.
Operation requires startup of instance "stdby2" on database "stdby2"
Starting instance "stdby2"...
Unable to connect to database
ORA-12514: TNS:listener does not currently know of service requested in connect descriptor
Failed.
You are no longer connected to ORACLE
Please connect again.
Unable to start instance "stdby2"
You must start instance "stdby2" manually
Switchover succeeded, new primary is "stdby1"
DGMGRL>
Edited by: user6981287 on Jan 7, 2010 12:57 AM
Edited by: user6981287 on Jan 7, 2010 1:00 AM

Questions about PDF exporting with InDe CS5.5

Hey all,
A couple questions about exporting to PDF from the latest version of InDe.
First, I have noticed that it seems to take a lot longer to get to a PDF. Any suggestions for how to speed up the process? It took 8 minutes or so to generate a low-res PDF (for print) of a 24pp document with a few placed images and vector graphics. Wow, that's a long time to wait, especially for a proof.
Second, the background task... if I get it going on making that 8-minute PDF and then work some more on the document, what exactly is in the PDF? Usually I save before making a PDF or printing. So, is the last version saved what will be in the PDF?
(As an aside, this ability to work on the doc while generating a PDF seems kind of weird. Generally one makes a PDF for proofing, or even for printing, when all the changes have been made and everything is "final". So, I see no benefit to being able to work on my document while it's making a PDF, as I'm probably finished making revisions for the time being. I have to say that I kind of like the progress bar you get when you make an interactive PDF, as you know you can't work on the document when that's on the screen... )
Thanks as always.

First, I have noticed that it seems to take a lot longer to get to a PDF. Any suggestions for how to speed up the process? It took 8 minutes or so to generate a low-res PDF (for print) of a 24pp document with a few placed images and vector graphics. Wow, that's a long time to wait, especially for a proof.
Yes, this is abnormally long (and too long), something is wrong. What's the full version of InDesign you are running, as reported by holding down Cmd or Control and selecting About InDesign?
Second, the background task... if I get it going on making that 8-minute PDF and then work some more on the document, what exactly is in the PDF? Usually I save before making a PDF or printing. So, is the last version saved what will be in the PDF?
Saving is not related. InDesign makes a database snapshot of your document the moment you begin the PDF export, and makes the export relative to that snapshot, regardless of edits you continue to make during the export process, and regardless of saving. Of course saving first is a good idea, for several reasons, not the least of which it sounds like something's fairly seriously wrong with your document or your InDesign installation.
We recommend you trash your preferences and export your document to IDML and see if either of those things changes this 8-minute behavior...err, assuming you're running 7.5.2.318.
(As an aside, this ability to work on the doc while generating a PDF seems kind of weird. Generally one makes a PDF for proofing, or even for printing, when all the changes have been made and everything is "final". So, I see no benefit to being able to work on my document while it's making a PDF, as I'm probably finished making revisions for the time being. I have to say that I kind of like the progress bar you get when you make an interactive PDF, as you know you can't work on the document when that's on the screen... )
Yeah, I think the primary benefit is if you are likely to work on 2 or more files in parallel, so you can finish A and export A and then switch to B. If you'd like a dialog box to pop up when export is done, check out my exportPop script from this post: ANN: automatic dialog after background export (exportPop.jsx.

Question about the new Yoga 10 HD+

Hi
A few questions about the new Yoga 10 HD+ which I hope you can answer.
I bought the old model last year. Loved the design and long battery time but a few major issues made me return it.
Somewhere I read that it can't read NTFS over USB so I presume that's the same with an NTFS formatted microSD card?
Can it read exFAT formatted microSD cards?
Anyone observed issues regarding audio over bluetooth?
(I know BT isn't exactly High End HiFi but the old Yoga 10 for some odd reason - most likely a driver issue which nobody cared to fix - sounded *much* worse with quite noticeably distortion while both my phone and a cheap noname tablet I have zero fidelity issues - no matter which of my bluetooth audio devices I tried aptX or not)
So to avoid buying this only to return it too I really would like to see if I can have my questions answered before buying it.
While I love the form factor and long running time the above issues are just two mayor dealbreakers to me. Bad audio quality = no joy listening to spotify, local MP3s etc. No NTFS or exFAT = no large movies.
My old noname android tablet really could use an upgrade so I'm really curious whether this can be it or I should look at the competition and sacrify form factor and battery runtime.
Thanks in advance.
EDIT:
If it's not supporting either NTFS or exFAT on the microSD have anyone tried ext3 and/or ext4?
I mean with Androids Linux roots it should be a nobrainer to support at least when it comes to royalties unlike NTFS or exFAT where there *might* be some issues with Microsoft.
Solved!
Go to Solution.

Thanks!
OK. Seems I should just stay clear of this and look elsewhere
Sony for sure I know support exFAT. I'm usure about Samsung. Odd it seems so hard to find out. File sizes of +4 GB should be taken for granted - it's not 199x anymore...
Oh well. Wonder whether to just go for one from the competition or perhaps just save the money and wait until 64 bit catches on. Rumors is that the next Nexus 8 will be 64 bit... (I really don't expect an answer on this)

I have three questions about managing my music library

Hello,
I have three questions about managing my music library, I hope you can help me with them:
1) Is there a limit of how many entries, songs, albums, art work, can iTunes handle? I have a hunch iTunes is like a database program and am curious about its capacity. I have two 2-TB drives and am wondering what is going to happen when I fill these two drives up. Other than disk space, what are iTunes limitations?
2) Talking about these two drives. How can I use both as a source for my iTunes library. Can I have two folders selected as the source of my library? I am not sure if I have enough disk space to hold all my music, but I do also have a 1TB almost empty drive is need be.
3) OK now comes te real question. I am sure that I have duplicates in my library and I sure would love to clean my library up.Possiby if I do get to clean it up, I can save some disk space and that is always a good thing. Any good techniques, software, techniques to follow while ripping music to help keep my library organized. Please be as detailed as you can.
Thanks and I can't wait to hear from you.
Waseem

Wassimn wrote:
Hello,
I have three questions about managing my music library, I hope you can help me with them:
1) Is there a limit of how many entries, songs, albums, art work, can iTunes handle? I have a hunch iTunes is like a database program and am curious about its capacity. I have two 2-TB drives and am wondering what is going to happen when I fill these two drives up. Other than disk space, what are iTunes limitations?
As far as I know you're going to run out of disc space before you hit any limits. Each object in iTunes has a 64-bit key to access it. That said as your library grows it will get less responsive as bigger indexes take exponentially longer to process.
2) Talking about these two drives. How can I use both as a source for my iTunes library. Can I have two folders selected as the source of my library? I am not sure if I have enough disk space to hold all my music, but I do also have a 1TB almost empty drive is need be.
iTunes wants to manage everything inside one big folder. Some idiosyncrasies with the way it manages things if you have to move to a new drive means it is best if you can stick to that plan. If your library grows larger then you'll have to take manual control of where some or all of your content is stored. I use a variation of a script called ConsolidateByMoving which you could adapt for your needs.
3) OK now comes te real question. I am sure that I have duplicates in my library and I sure would love to clean my library up.Possiby if I do get to clean it up, I can save some disk space and that is always a good thing. Any good techniques, software, techniques to follow while ripping music to help keep my library organized. Please be as detailed as you can.
When it comes to deduping I've written another script for that called DeDuper, see this thread for background.
And for some general tips on getting organized in iTunes see Grouping tracks into albums.
tt2

Short question about the nano controls

Hi. I'm probably going to buy a 4Gb nano today, but first I'd like to ask a short question about the << >> buttons on the click wheel.
I read in a forum that the << & >> buttons are actually 'skip' buttons (only used to play the previous or next song respectively), and that it's impossible to rewind or fast-forward within the track you're listening to. This is extremely important for me as I have several 2-3 hours mp3, and I need to be able to access different parts of the file quickly (eg. not having to actually wait 1 hour to listen to my favorite part). I found this to be an important feature, and I can't believe Apple hasn't thought about it.
Anyway, I've never used an iPod, that's why this question may sound plain stupid.
Thanks for you replies!

The iPod fast charges to about 80% and then trickle charges the rest of the way to prevent damaging the battery/iPod. A full charge takes more than an hour or two though the battery indicator will show full. The best way to tell if a full charge has occurred is to unmount the iPod from the computer but keep it connected. The screen will show an animation of a battery. When the animation stops the battery is fully charged.
Also, as your battery discharges the indicator will eventually show red indicating the battery is about to run out...in an hour or two. After you've owned your iPod for a couple months you'll figure out how much time you have left when the indicator turns red - it depends on a number of factors including play volume, equalizer use, etc. In real world use I'm getting over 11 hours.
The headphones are...average. If they didn't hurt my ears I'd find them acceptable for my pop music but not so acceptable for acoustic and symphonic nor music with booming bass - because they don't boom the bass.
I encode the majority of my music at 256 AAC and I've noticed no distortion caused by the EQ. This, plus your complaint about the earphones, leads me to think perhaps you got a bum set of phones. Borrow a pair from someone else and see what happens.

I have a question, about SSF !(u5173u4E8ESSFu7684u95EEu9898)

Hi,guys!
I have a question, about SSF.I want my webdynpro program can get employee photo in ECC6.0.So i find a BAPI,it name is:HRMSS_RFC_EP_READ_PHOTO_URI.I import parameter PENER with employeeID,other parameter is default.It returns a URI,but this URI was been encrypt.I copy the URI into IE,the IE told me:SSF error,can not decode.So my question is:in this instance,what should I do?
Thanks! I am very vexation,online waiting!

Dear Mr. XU,
this is a community driven forum, meaning most answers are given by community members volunteering and contributing free time. If you'd like to express your vexation, you might better use the SAP based support channels such as OSS.
Community members are in general not motivated to answer questions that are posted in such a mood.
As I'm an SAP employee myself, I have to apologize that I cannot answer this question due to a lack of understanding it and again have to ask you to check with OSS.
With kind regards,
Benny Schaich

Question about servlet architecture

Hello,
I have a question about Web Application / servlet architecture and development, and haven't had any luck finding an answer so far. My plan must be either unusual, or wrong, or both, so I'm hoping the community here could point me in the right direction.
I have quite a bit of background in OSGi, but very little in servlets. I know my architecture would work with something such as sever-side Equinox, but for the open source project I'm contemplating, I think that the more mainstream Tomcat/servler route would be better -- assuming it can be done. Here is a rather simplified scenario:
There is a class, Manager. It could be a Java class that implements Runnable, or a non-HTTP servlet (GenericServlet?), but somehow it should be configured such that it runs as soon as Tomcat starts.
When Manager runs, it instantiates its primary member variable: Hashtable msgHash; mshHash will map Strings (usernames) to ArrayList<String> (list of messages awaiting that user). Manager also has two primary public methods: addMsg() and getMsgs().
The pseudocode for addMsg is:
void addMsg(String username, String msg) {
if username=="*" { for each msgList in msgHash { msgList.add(msg) } return;
if username not in msgHash { msgHash.add(username, new ArrayList<String>) }
msgHash[username].add(msg)
And for getMsgs():
String getMsgs(username) {
String s = "";
for each msg in msgHash[username] { s = s + msg; }
return s;
Once Manager has started, it starts two HTTP Servlets: Sender and Receiver, passing a reference back to itself as it creates the servlets.
The HTML associated with Sender contains two text inputs (username and message) and a button (send). When the send button is pressed and data is POSTed to Sender, Sender takes it and calls Manager.addMsg(username.value, message.value);
Receiver servlet is display only. It looks in the request for HTTP GET parameter "username". When the request comes in, Receiver calls Manager.getMsgs(username) and dumps the resulting string to the browser.
In addition to starting servlets Sender and Receiver, the Manager object is also spawning other threads. For example, it might spawn a SystemResourceMonitor thread. This thread periodically wakes up, reads the available disk space and average CPU load, calls Manager.addMsg("*", diskAndLoadMsg), and goes back to sleep for a while.
I've ignored the synchronization issues in this example, but during its lifecycle Manager should be idle until it has a task to do, using for example wait() and notify(). If ever addMsg() is called where the message string is "shutdown", Manager's main loop wakes up, and Manager shuts down the two servlets and any threads that it started. Manager itself may then quit, or remain resident, awaiting a command to turn things back on.
Is any of this appropriate for servlets/Tomcat? Is there a way to do it as I outlined, or with minor tweaks? Or is this kind of application just not suited to servlets, and I should go with server-side Equinox OSGi?
Thanks very much for any guidance!
-Mike

FrolfFla wrote:
Hello,
I have a question about Web Application / servlet architecture and development, and haven't had any luck finding an answer so far. My plan must be either unusual, or wrong, or both, so I'm hoping the community here could point me in the right direction.
I have quite a bit of background in OSGi, but very little in servlets. I know my architecture would work with something such as sever-side Equinox, but for the open source project I'm contemplating, I think that the more mainstream Tomcat/servler route would be better -- assuming it can be done. Here is a rather simplified scenario:
There is a class, Manager. It could be a Java class that implements Runnable, or a non-HTTP servlet (GenericServlet?), but somehow it should be configured such that it runs as soon as Tomcat starts.You can configure a servlet to be invoked as soon as Tomcat starts. Check the tomcat documentation for more information on that (the web.xml contains such servlets already though). From this servlet you can start your Manager.
>
When Manager runs, it instantiates its primary member variable: Hashtable msgHash; mshHash will map Strings (usernames) to ArrayList<String> (list of messages awaiting that user). Manager also has two primary public methods: addMsg() and getMsgs().
The pseudocode for addMsg is:
void addMsg(String username, String msg) {
if username=="*" { for each msgList in msgHash { msgList.add(msg) } return;
if username not in msgHash { msgHash.add(username, new ArrayList<String>) }
msgHash[username].add(msg)
And for getMsgs():
String getMsgs(username) {
String s = "";
for each msg in msgHash[username] { s = s + msg; }
return s;
Once Manager has started, it starts two HTTP Servlets: Sender and Receiver, passing a reference back to itself as it creates the servlets. Not needed. You can simply create your two servlets and have them invoked through web calls, Tomcat is the only one that can manage servlets in any case. Servlets have a very short lifecycle - they stay in memory from the first time they are invoked, but the only time that they actually do something is when they are called through the webserver, generally as the result of somebody running the servlet through a webbrowser, either by navigating to it or by posting data to it from another webpage. The servlet call ends as soon as the request is completed.
>
The HTML associated with Sender contains two text inputs (username and message) and a button (send). When the send button is pressed and data is POSTed to Sender, Sender takes it and calls Manager.addMsg(username.value, message.value);
Receiver servlet is display only. It looks in the request for HTTP GET parameter "username". When the request comes in, Receiver calls Manager.getMsgs(username) and dumps the resulting string to the browser.This states already that you are going to run the servlets through a browser. You run "Sender" by navigating to it in the browser. You run "Receiver" when you post your data to it. Manager has nothing to do with that.
>
In addition to starting servlets Sender and Receiver, the Manager object is also spawning other threads. For example, it might spawn a SystemResourceMonitor thread. This thread periodically wakes up, reads the available disk space and average CPU load, calls Manager.addMsg("*", diskAndLoadMsg), and goes back to sleep for a while.Since you want to periodically run the SystemResourceMonitor, it is better to use a Timer for that in stead of your own thread.
>
I've ignored the synchronization issues in this example, but during its lifecycle Manager should be idle until it has a task to do, using for example wait() and notify(). If ever addMsg() is called where the message string is "shutdown", Manager's main loop wakes up, and Manager shuts down the two servlets and any threads that it started. Manager itself may then quit, or remain resident, awaiting a command to turn things back on.
Is any of this appropriate for servlets/Tomcat? Is there a way to do it as I outlined, or with minor tweaks? Or is this kind of application just not suited to servlets, and I should go with server-side Equinox OSGi?
Thanks very much for any guidance!
-MikeI don't see anything that cannot be done in a normal java web environment, as long as you are aware of how servlets operate.

Wait--question about uninstallation

Similar Messages

Maybe you are looking for