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• Django Initial for a ManyToMany Field

  - by gramware

  I have a form that edits an instance of my model. I would like to use the form to pass all the values as hidden with an inital values of username defaulting to the logged in user so that it becomes a subscribe form. The problem is that the normal initial={'field':value} doesn't seem to work for manytomany fields. how do i go about it? my views.py @login_required def event_view(request,eventID): user = UserProfile.objects.get(pk=request.session['_auth_user_id']) event = events.objects.get(eventID = eventID) if request.method == 'POST': form = eventsSusbcribeForm( request.POST,instance=event) if form.is_valid(): form.save() return HttpResponseRedirect('/events/') else: form = eventsSusbcribeForm(instance=event) return render_to_response('event_view.html', {'user':user,'event':event, 'form':form},context_instance = RequestContext( request )) my forms.py class eventsSusbcribeForm(forms.ModelForm): eventposter = forms.ModelChoiceField(queryset=UserProfile.objects.all(), widget=forms.HiddenInput()) details = forms.CharField(widget=forms.Textarea(attrs={'cols':'50', 'rows':'5'}),label='Enter Event Description here') date = forms.DateField(widget=SelectDateWidget()) class Meta: model = events exclude = ('deleted') def __init__(self, *args, **kwargs): super(eventsSusbcribeForm, self).__init__(*args, **kwargs) self.fields['username'].initial = (user.id for user in UserProfile.objects.filter())

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• How can I set Invitee in Google Calendar through Python?

  - by Dhaval dave

  I am Setting Google Calendar via python command like this def _InsertQuickAddEvent(self, content="Tennis with dddddd on 5/19/2010 4am-5:30am"): """Creates an event with the quick_add property set to true so the content is processed as quick add content instead of as an event description.""" event = gdata.calendar.CalendarEventEntry() who = whois("[email protected]") event.content = atom.Content(text=content) event.quick_add = gdata.calendar.QuickAdd(value='true'); new_event = self.cal_client.InsertEvent(event, '/calendar/feeds/default/private/full') return new_event this code is given by Google API Can any one suggest what to do to add invitee in this? Important links for that http://code.google.com/apis/calendar/data/1.0/developers_guide_python.html

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• How to impose maxlength on textArea in HTML , Javascript

  - by Rakesh Juyal

  I would like to have some functionality by which if i write <textarea maxlength="50"></textarea> <textarea maxlength="150"></textarea> <textarea maxlength="250"></textarea> it will automatically impose the maxlength on the textArea. If possible please donot provide the solution in JQuery. Note: This can be done if i do something like this: <textarea onkeypress="return imposeMaxLength(event, this, 110);" rows="4" cols="50"> function imposeMaxLength(Event, Object, MaxLen) { return (Object.value.length <= MaxLen)||(Event.keyCode == 8 ||Event.keyCode==46||(Event.keyCode>=35&&Event.keyCode<=40)) } copied from another thread But the point is I don't want to write onKeyPress and onKeyUp every time i declare a textArea.

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• JavaScript addEvent function

  - by Yalmaz Khalil

  I have an addEvent function: function addEvent(elem, event, func ) { if (typeof (window.event) != 'undefined') elem.attachEvent('on' + event, func); else elem.addEventListener(event, func, false); } <a href="#" id="link">link</a> and I'm trying to add the following to window.onload: addEvent(window, 'load', function (){ // add another event var link= document.getElementById('link'); addEvent(link, 'click', function () {alert('Hi'); }); }); My question is: why does the link event not work?

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• Content in Context: The right medicine for your business applications

  - by Lance Shaw

  For many of you, your companies have already invested in a number of applications that are critical to the way your business is run. HR, Payroll, Legal, Accounts Payable, and while they might need an upgrade in some cases, they are all there and handling the lifeblood of your business. But are they really running as efficiently as they could be? For many companies, the answer is no. The problem has to do with the important information caught up within documents and paper. It’s everywhere except where it truly needs to be – readily available right within the context of the application itself. When the right information cannot be easily found, business processes suffer significantly. The importance of this recently struck me when I recently went to meet my new doctor and get a routine physical. Walking into the office lobby, I couldn't help but notice rows and rows of manila folders in racks from floor to ceiling, filled with documents and sensitive, personal information about various patients like myself.  As I looked at all that paper and all that history, two things immediately popped into my head.  “How do they find anything?” and then the even more alarming, “So much for information security!” It sure looked to me like all those documents could be accessed by anyone with a key to the building. Now the truth is that the offices of many general practitioners look like this all over the United States and the world.  But it had me thinking, is the same thing going on in just about any company around the world, involving a wide variety of important business processes? Probably so. Think about all the various processes going on in your company right now. Invoice payments are being processed through Accounts Payable, contracts are being reviewed by Procurement, and Human Resources is reviewing job candidate submissions and doing background checks. All of these processes and many more like them rely on access to forms and documents, whether they are paper or digital. Now consider that it is estimated that employee’s spend nearly 9 hours a week searching for information and not finding it. That is a lot of very well paid employees, spending more than one day per week not doing their regular job while they search for or re-create what already exists. Back in the doctor’s office, I saw this trend exemplified as well. First, I had to fill out a new patient form, even though my previous doctor had transferred my records over months previously. After filling out the form, I was later introduced to my new doctor who then interviewed me and asked me the exact same questions that I had answered on the form. I understand that there is value in the interview process and it was great to meet my new doctor, but this simple process could have been so much more efficient if the information already on file could have been brought directly together with the new patient information I had provided. Instead of having a highly paid medical professional re-enter the same information into the records database, the form I filled out could have been immediately scanned into the system, associated with my previous information, discrepancies identified, and the entire process streamlined significantly. We won’t solve the health records management issues that exist in the United States in this blog post, but this example illustrates how the automation of information capture and classification can eliminate a lot of repetitive and costly human entry and re-creation, even in a simple process like new patient on-boarding. In a similar fashion, by taking a fresh look at the various processes in place today in your organization, you can likely spot points along the way where automating the capture and access to the right information could be significantly improved. As you evaluate how content-process flows through your organization, take a look at how departments and regions share information between the applications they are using. Business applications are often implemented on an individual department basis to solve specific problems but a holistic approach to overall information management is not taken at the same time. The end result over the years is disparate applications with separate information repositories and in many cases these contain duplicate information, or worse, slightly different versions of the same information. This is where Oracle WebCenter Content comes into the story. More and more companies are realizing that they can significantly improve their existing application processes by automating the capture of paper, forms and other content. This makes the right information immediately accessible in the context of the business process and making the same information accessible across departmental systems which has helped many organizations realize significant cost savings. Here on the Oracle WebCenter team, one of our primary goals is to help customers find new ways to be more effective, more cost-efficient and manage information as effectively as possible. We have a series of three webcasts occurring over the next few weeks that are focused on the integration of enterprise content management within the context of business applications. We hope you will join us for one or all three and that you will find them informative. Click here to learn more about these sessions and to register for them. There are many aspects of information management to consider as you look at integrating content management within your business applications. We've barely scratched the surface here but look for upcoming blog posts where we will discuss more specifics on the value of delivering documents, forms and images directly within applications like Oracle E-Business Suite, PeopleSoft Enterprise, JD Edwards Enterprise One, Siebel CRM and many others. What do you think?  Are your important business processes as healthy as they can be?  Do you have any insights to share on the value of delivering content directly within critical business processes? Please post a comment and let us know the value you have realized, the lessons learned and what specific areas you are interested in.

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• Java Prepared Statement Error

  - by Suresh S

  Hi Guys the following code throws me an error i have an insert statement created once and in the while loop i am dynamically setting parameter , and at the end i says ps2.addBatch() again while ( (eachLine = in.readLine()) != null)) { for (int k=stat; k <=45;k++) { ps2.setString (k,main[(k-2)]); } stat=45; for (int l=1;l<= 2; l++) { ps2.setString((stat+l),pdp[(l-1)]);// Exception } ps2.addBatch(); } This is the error java.lang.ArrayIndexOutOfBoundsException: 45 at oracle.jdbc.dbaccess.DBDataSetImpl._getDBItem(DBDataSetImpl.java:378) at oracle.jdbc.dbaccess.DBDataSetImpl._createOrGetDBItem(DBDataSetImpl.java:781) at oracle.jdbc.dbaccess.DBDataSetImpl.setBytesBindItem(DBDataSetImpl.java:2450) at oracle.jdbc.driver.OraclePreparedStatement.setItem(OraclePreparedStatement.java:1155) at oracle.jdbc.driver.OraclePreparedStatement.setString(OraclePreparedStatement.java:1572) at Processor.main(Processor.java:233)

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• Is it possible to make JQuery keydown respond faster?

  - by Drew Paul

  I am writing a simple page with JQuery and HTML5 canvas tags where I move a shape on the canvas by pressing 'w' for up, 's' for down, 'a' for left, and 'd' for right. I have it all working, but I would like the shape to start moving at a constant speed upon striking a key. Right now there is some kind of hold period and then the movement starts. How can I get the movement to occur immediately? Here the important part of my code: Your browser does not support the HTML5 canvas tag. start navigating coords should pop up here key should pop up here var c=document.getElementById("myCanvas"); var ctx=c.getContext("2d"); //keypress movements var xtriggered = 0; var keys = {}; var north = -10; var east = 10; var flipednorth = 0; $(document).ready(function(e){ $("input").keydown(function(){ keys[event.which] = true; if (event.which == 13) { event.preventDefault(); } //press w for north if (event.which == 87) { north++; flipednorth--; } //press s for south if (event.which == 83) { north--; flipednorth++; } //press d for east if (event.which == 68) { east++; } //press a for west if (event.which == 65) { east--; } var msg = 'x: ' + flipednorth*5 + ' y: ' + east*5; ctx.beginPath(); ctx.arc(east*6,flipednorth*6,40,0,2*Math.PI); ctx.stroke(); $('#soul2').html(msg); $('#soul3').html(event.which ); $("input").css("background-color","#FFFFCC"); }); $("input").keyup(function(){ delete keys[event.which]; $("input").css("background-color","#D6D6FF"); }); }); </script> please let me know if I shouldn't be posting code this lengthy.

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• Flex: Problem with CollectionEvent on ArrayCollection

  - by dasnervtdoch

  Hi there, got a reference to an arrayCollection and add event listener like this: collection.addEventListener(CollectionEvent.COLLECTION_CHANGE, onCollectionChange); that´s fine. Now some other component does have the same reference and is adding items to and removing items from that collection. Each time the handler is called: private function onProjectPersonsChange(event:Event):void { if (event.kind == CollectionEventKind.ADD) { //do something } else if (event.kind == CollectionEventKind.REMOVE) { //do something //here is the problem: event.items.length = 0 } else { trace('CollectionEvent: kind not handled!'); } } Does somebody know why the removed item is not in 'items'? Thanks in advance!

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• Which is the best and appropriate way to write the code in Winforms ?

  - by Harikrishna

  What is the best way to write the code ? (1) Like directly writing the code in the button_click() event. or (2) Make the function of that code which I write in button_click() event and write this function in one class and then that function I should call in the button_Click() event.Like is it called three-tired approach to write the code ? Like in button_Click() event I write the code to save the records in csv file from datatable.So I should write that code in button_Click() event or I should make one new function and one new class and write that code in that function which is the new class and calling that function in button_Click() event. This is only one example but I am talking about all the code written in my application that which is the appropriate and best way to write the code and what are the benefits ? Note that I write the code in Winforms with c#.

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• AS3 get closest date to today

  - by fana

  Hi, I have a XML file with a few concert dates. In my flash/AS3 file, I would like to show only the up coming event, relative to current date. Like this: Event 01: 30-05-2010 Event 02: 02-06-2010 Event 03: 05-06-2010 Today is 28-05-2010, so I need to list Event 01. On 01-06-2010 I need to list Event 02. I have the basic AS3 code for listing the XML working, but I'm having trouble filtering the result. Any ideas? Thanks.

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• Question about custom events

  - by Malfist

  I'm making custom events for C# and sometimes it isn't working. This is how I'm making the event happen: private bool isDoorOpen; public bool IsDoorOpen { get { return isDoorOpen;} private set { isDoorOpen = value; DoorsChangeState(this, null);} } And these are the event declarations: //events public delegate void ChangedEventHandler(Elevator sender, EventArgs e); public event ChangedEventHandler PositionChanged; public event ChangedEventHandler DirectionChanged; public event ChangedEventHandler BreaksChangeState; public event ChangedEventHandler DoorsChangeState; This works as long as there are methods attached to the events, but if there isn't, it throws a null ref exception. What am I doing wrong?

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• Java?????????????????????(Java??????????????????)

  - by OTN-J Master

  8?30?(????)???????Java???????????????????????????????????? ???????????Java Community Lead?Tori Wieldt?????????????????? ??: Java Source ???: Tori Wieldt Java?????????????????????????????????·????CVE-2012-4681?????????????????????·??????????Java??? ???????????????????????????3?????????????????????????CVE-2012-4681?CVE- 2012-1682?CVE-2012-3136?CVE-2012-0547???????????????????Java??????·????? ???????????????Java???????????????Oracle????·?????????????????????? Normal 0 0 2 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0mm 5.4pt 0mm 5.4pt; mso-para-margin-top:0mm; mso-para-margin-right:0mm; mso-para-margin-bottom:auto; mso-para-margin-left:0mm; text-align:justify; text-justify:inter-ideograph; mso-pagination:widow-orphan; font-size:10.5pt; mso-bidi-font-size:11.0pt; font-family:"Century","serif"; mso-ascii-font-family:Century; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Century; mso-hansi-theme-font:minor-latin; mso-font-kerning:1.0pt;} Normal 0 0 2 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0mm 5.4pt 0mm 5.4pt; mso-para-margin-top:0mm; mso-para-margin-right:0mm; mso-para-margin-bottom:auto; mso-para-margin-left:0mm; text-align:justify; text-justify:inter-ideograph; mso-pagination:widow-orphan; font-size:10.5pt; mso-bidi-font-size:11.0pt; font-family:"Century","serif"; mso-ascii-font-family:Century; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Century; mso-hansi-theme-font:minor-latin; mso-font-kerning:1.0pt;} ??????????????????????????????CVE-2012-4681??????????????????????????????????????????·???????????????????????????? Normal 0 0 2 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0mm 5.4pt 0mm 5.4pt; mso-para-margin-top:0mm; mso-para-margin-right:0mm; mso-para-margin-bottom:auto; mso-para-margin-left:0mm; text-align:justify; text-justify:inter-ideograph; mso-pagination:widow-orphan; font-size:10.5pt; mso-bidi-font-size:11.0pt; font-family:"Century","serif"; mso-ascii-font-family:Century; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Century; mso-hansi-theme-font:minor-latin; mso-font-kerning:1.0pt;} ????????????????????????????????? http://www.oracle.com/technetwork/jp/java/javase/downloads/index.html Java?????????????????????JRE?????????????? http://java.com Windows??????????????????????????? Java Automatic Update JUG???????John Yeary?????????????????????????????????????????????????????????????????????????????????? ??????????????????? ???? Oracle Security Alert for CVE-2012-4681 Change to Java SE 7 and Java SE 6 Update Release Numbers

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• Does a Required Restart for Windows Update log an event? If so what is the source/id?

  - by Beuy

  Hi there, Does anyone happen to know if a required restart in order to apply Windows Updates creates a entry in the event log? If so which log is it under, and what is the source/id? I have a legacy system that needs to an account, constantly logged into console for applications to function as required (Some old PROCOMS modem software for customers without Internet access but a telephone (Dial-up? Separate issue, don't get me started -.-)). When an update is applied to this machine that requires a restart (Server 2003) I would like an e-mail alert to be sent.

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• OSX Lion - Stuck in Drag mode and mouse click events are not going through. Can I manually generate a mouseup event?

  - by Yuji Tomita

  My mouse is stuck in "drag" mode. This generally happens in Photoshop, but happens dragging files and such as well. Clicking rapidly here and there generally solves the problem. Sometimes though, it won't go away until a restart. Unplugging devices, etc., doesn't do anything. For example, right now, my mouse moves but can not click anything so I am using the keyboard to navigate this site. Is there a way to "reset" however the OS stores mouse states? Can I manually fire off a MouseUp event? It's strange that even when human input devices are unplugged, the files are still in drag state.

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• Community Outreach - Where Should I Go

  - by Roger Brinkley

  A few days ago I was talking to person new to community development and they asked me what guidelines I used to determine the worthiness of a particular event. After our conversation was over I thought about it a little bit more and figured out there are three ways to determine if any event (be it conference, blog, podcast or other social medias) is worth doing: Transferability, Multiplication, and Impact. Transferability - Is what I have to say useful to the people that are going to hear it. For instance, consider a company that has product offering that can connect up using a number of languages like Scala, Grovey or Java. Sending a Scala expert to talk about Scala and the product is not transferable to a Java User Group, but a Java expert doing the same talk with a Java slant is. Similarly, talking about JavaFX to any Java User Group meeting in Brazil was pretty much a wasted effort until it was open sourced. Once it was open sourced it was well received. You can also look at transferability in relation to the subject matter that you're dealing with. How transferable is a presentation that I create. Can I, or a technical writer on the staff, turn it into some technical document. Could it be converted into some type of screen cast. If we have a regular podcast can we make a reference to the document, catch the high points or turn it into a interview. Is there a way of using this in the sales group. In other words is the document purely one dimensional or can it be re-purposed in other forms. Multiplication - On every trip I'm looking for 2 to 5 solid connections that I can make with developers. These are long term connections, because I know that once that relationship is established it will lead to another 2 - 5 from that connection and within a couple of years were talking about some 100 connections from just one developer. For instance, when I was working on JavaHelp in 2000 I hired a science teacher with a programming background. We've developed a very tight relationship over the year though we rarely see each other more than once a year. But at this JavaOne, one of his employees came up to me and said, "Richard (Rick Hard in Czech) told me to tell you that he couldn't make it to JavaOne this year but if I saw you to tell you hi". Another example is from my Mobile & Embedded days in Brasil. On our very first FISL trip about 5 years ago there were two university students that had created a project called "Marge". Marge was a Bluetooth framework that made connecting bluetooth devices easier. I invited them to a "Sun" dinner that evening. Originally they were planning on leaving that afternoon, but they changed their plans recognizing the opportunity. Their eyes were as big a saucers when they realized the level of engineers at the meeting. They went home started a JUG in Florianoplis that we've visited more than a couple of times. One of them went to work for Brazilian government lab like Berkley Labs, MIT Lab, John Hopkins Applied Physicas Labs or Lincoln Labs in the US. That presented us with an opportunity to show Embedded Java as a possibility for some of the work they were doing there. Impact - The final criteria is how life changing is what I'm going to say be to the individuals I'm reaching. A t-shirt is just a token, but when I reach down and tug at their developer hearts then I know I've succeeded. I'll never forget one time we flew all night to reach Joan Pasoa in Northern Brazil. We arrived at 2am went immediately to our hotel only to be woken up at 6 am to travel 2 hours by car to the presentation hall. When we arrived we were totally exhausted. Outside the facility there were 500 people lined up to hear 6 speakers for the day. That itself was uplifting.  I delivered one of my favorite talks on "I have passion". It was a talk on golf and embedded java development, "Find your passion". When we finished a couple of first year students came up to me and said how much my talk had inspired them. FISL is another great example. I had been about 4 years in a row. FISL is a very young group of developers so capturing their attention is important. Several of the students will come back 2 or 3 years later and ask me questions about research or jobs. And then there's Louis. Louis is one my favorite Brazilians. I can only describe him as a big Brazilian teddy bear. I see him every year at FISL. He works primarily in Java EE but he's attended every single one of my talks over the last 4 years. I can't tell you why, but he always greets me and gives me a hug. For some reason I've had a real impact. And of course when it comes to impact you don't just measure a presentation but every single interaction you have at an event. It's the hall way conversations, the booth conversations, but more importantly it's the conversations at dinner tables or in the cars when you're getting transported to an event. There's a good story that illustrates this. Last year in the spring I was traveling to Goiânia in Brazil. I've been there many times and leaders there no me well. One young man has picked me up at the airport on more than one occasion. We were going out to dinner one evening and he brought his girl friend along. One thing let to another and I eventually asked him, in front of her, "Why haven't you asked her to marry you?" There were all kinds of excuses and she just looked at him and smiled. When I came back in December for JavaOne he came and sought me. "I just want to tell you that I thought a lot about what you said, and I asked her to marry me. We're getting married next Spring." Sometimes just one presentation is all it takes to make an impact. Other times it takes years. Some impacts are directly related to the company and some are more personal in nature. It doesn't matter which it is because it's having the impact that matters.

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• Ops Center 12c - Provisioning Solaris Using a Card-Based NIC

  - by scottdickson

  It's been a long time since last I added something here, but having some conversations this last week, I got inspired to update things. I've been spending a lot of time with Ops Center for managing and installing systems these days.  So, I suspect a number of my upcoming posts will be in that area. Today, I want to look at how to provision Solaris using Ops Center when your network is not connected to one of the built-in NICs.  We'll talk about how this can work for both Solaris 10 and Solaris 11, since they are pretty similar.  In both cases, WANboot is a key piece of the story. Here's what I want to do:  I have a Sun Fire T2000 server with a Quad-GbE nxge card installed.  The only network is connected to port 2 on that card rather than the built-in network interfaces.  I want to install Solaris on it across the network, either Solaris 10 or Solaris 11.  I have met with a lot of customers lately who have a similar architecture.  Usually, they have T4-4 servers with the network connected via 10GbE connections. Add to this mix the fact that I use Ops Center to manage the systems in my lab, so I really would like to add this to Ops Center.  If possible, I would like this to be completely hands free.  I can't quite do that yet. Close, but not quite. WANBoot or Old-Style NetBoot? When a system is installed from the network, it needs some help getting the process rolling.  It has to figure out what its network configuration (IP address, gateway, etc.) ought to be.  It needs to figure out what server is going to help it boot and install, and it needs the instructions for the installation.  There are two different ways to bootstrap an installation of Solaris on SPARC across the network.   The old way uses a broadcast of RARP or more recently DHCP to obtain the IP configuration and the rest of the information needed.  The second is to explicitly configure this information in the OBP and use WANBoot for installation WANBoot has a number of benefits over broadcast-based installation: it is not restricted to a single subnet; it does not require special DHCP configuration or DHCP helpers; it uses standard HTTP and HTTPS protocols which traverse firewalls much more easily than NFS-based package installation.  But, WANBoot is not available on really old hardware and WANBoot requires the use o Flash Archives in Solaris 10.  Still, for many people, this is a great approach. As it turns out, WANBoot is necessary if you plan to install using a NIC on a card rather than a built-in NIC. Identifying Which Network Interface to Use One of the trickiest aspects to this process, and the one that actually requires manual intervention to set up, is identifying how the OBP and Solaris refer to the NIC that we want to use to boot.  The OBP already has device aliases configured for the built-in NICs called net, net0, net1, net2, net3.  The device alias net typically points to net0 so that when you issue the command  "boot net -v install", it uses net0 for the boot.  Our task is to figure out the network instance for the NIC we want to use.  We will need to get to the OBP console of the system we want to install in order to figure out what the network should be called.  I will presume you know how to get to the ok prompt.  Once there, we have to see what networks the OBP sees and identify which one is associated with our NIC using the OBP command show-nets. SunOS Release 5.11 Version 11.0 64-bit Copyright (c) 1983, 2011, Oracle and/or its affiliates. All rights reserved. {4} ok banner Sun Fire T200, No Keyboard Copyright (c) 1998, 2010, Oracle and/or its affiliates. All rights reserved. OpenBoot 4.30.4.b, 32640 MB memory available, Serial #69057548. Ethernet address 0:14:4f:1d:bc:c, Host ID: 841dbc0c. {4} ok show-nets a) /pci@7c0/pci@0/pci@2/network@0,1 b) /pci@7c0/pci@0/pci@2/network@0 c) /pci@780/pci@0/pci@8/network@0,3 d) /pci@780/pci@0/pci@8/network@0,2 e) /pci@780/pci@0/pci@8/network@0,1 f) /pci@780/pci@0/pci@8/network@0 g) /pci@780/pci@0/pci@1/network@0,1 h) /pci@780/pci@0/pci@1/network@0 q) NO SELECTION Enter Selection, q to quit: d /pci@780/pci@0/pci@8/network@0,2 has been selected. Type ^Y ( Control-Y ) to insert it in the command line. e.g. ok nvalias mydev ^Y for creating devalias mydev for /pci@780/pci@0/pci@8/network@0,2 {4} ok devalias ... net3 /pci@7c0/pci@0/pci@2/network@0,1 net2 /pci@7c0/pci@0/pci@2/network@0 net1 /pci@780/pci@0/pci@1/network@0,1 net0 /pci@780/pci@0/pci@1/network@0 net /pci@780/pci@0/pci@1/network@0 ... name aliases By looking at the devalias and the show-nets output, we can see that our Quad-GbE card must be the device nodes starting with  /pci@780/pci@0/pci@8/network@0.  The cable for our network is plugged into the 3rd slot, so the device address for our network must be /pci@780/pci@0/pci@8/network@0,2. With that, we can create a device alias for our network interface.  Naming the device alias may take a little bit of trial and error, especially in Solaris 11 where the device alias seems to matter more with the new virtualized network stack. So far in my testing, since this is the "next" network interface to be used, I have found success in naming it net4, even though it's a NIC in the middle of a card that might, by rights, be called net6 (assuming the 0th interface on the card is the next interface identified by Solaris and this is the 3rd interface on the card).  So, we will call it net4.  We need to assign a device alias to it: {4} ok nvalias net4 /pci@780/pci@0/pci@8/network@0,2 {4} ok devalias net4 /pci@780/pci@0/pci@8/network@0,2 ... We also may need to have the MAC for this particular interface, so let's get it, too.  To do this, we go to the device and interrogate its properties. {4} ok cd /pci@780/pci@0/pci@8/network@0,2 {4} ok .properties assigned-addresses 82060210 00000000 03000000 00000000 01000000 82060218 00000000 00320000 00000000 00008000 82060220 00000000 00328000 00000000 00008000 82060230 00000000 00600000 00000000 00100000 local-mac-address 00 21 28 20 42 92 phy-type mif ... From this, we can see that the MAC for this interface is  00:21:28:20:42:92.  We will need this later. This is all we need to do at the OBP.  Now, we can configure Ops Center to use this interface. Network Boot in Solaris 10 Solaris 10 turns out to be a little simpler than Solaris 11 for this sort of a network boot.  Since WANBoot in Solaris 10 fetches a specified In order to install the system using Ops Center, it is necessary to create a OS Provisioning profile and its corresponding plan.  I am going to presume that you already know how to do this within Ops Center 12c and I will just cover the differences between a regular profile and a profile that can use an alternate interface. Create a OS Provisioning profile for Solaris 10 as usual.  However, when you specify the network resources for the primary network, click on the name of the NIC, probably GB_0, and rename it to GB_N/netN, where N is the instance number you used previously in creating the device alias.  This is where the trial and error may come into play.  You may need to try a few instance numbers before you, the OBP, and Solaris all agree on the instance number.  Mark this as the boot network. For Solaris 10, you ought to be able to then apply the OS Provisioning profile to the server and it should install using that interface.  And if you put your cards in the same slots and plug the networks into the same NICs, this profile is reusable across multiple servers. Why This Works If you watch the console as Solaris boots during the OSP process, Ops Center is going to look for the device alias netN.  Since WANBoot requires a device alias called just net, Ops Center uses the value of your netN device alias and assigns that device to the net alias.  That means that boot net will automatically use this device.  Very cool!  Here's a trace from the console as Ops Center provisions a server: Sun Sun Fire T200, No KeyboardCopyright (c) 1998, 2010, Oracle and/or its affiliates. All rights reserved.OpenBoot 4.30.4.b, 32640 MB memory available, Serial #69057548.Ethernet address 0:14:4f:1d:bc:c, Host ID: 841dbc0c.auto-boot? =            false{0} ok  {0} ok printenv network-boot-argumentsnetwork-boot-arguments =  host-ip=10.140.204.234,router-ip=10.140.204.1,subnet-mask=255.255.254.0,hostname=atl-sewr-52,client-id=0100144F1DBC0C,file=http://10.140.204.22:5555/cgi-bin/wanboot-cgi{0} ok {0} ok devalias net net                      /pci@780/pci@0/pci@1/network@0{0} ok devalias net4 net4                     /pci@780/pci@0/pci@8/network@0,2{0} ok devalias net /pci@780/pci@0/pci@8/network@0,2{0} ok setenv network-boot-arguments host-ip=10.140.204.234,router-ip=10.140.204.1,subnet-mask=255.255.254.0,hostname=atl-sewr-52,client-id=0100144F1DBC0C,file=http://10.140.204.22:8004/cgi-bin/wanboot-cginetwork-boot-arguments =  host-ip=10.140.204.234,router-ip=10.140.204.1,subnet-mask=255.255.254.0,hostname=atl-sewr-52,client-id=0100144F1DBC0C,file=http://10.140.204.22:8004/cgi-bin/wanboot-cgi{0} ok {0} ok boot net - installBoot device: /pci@780/pci@0/pci@8/network@0,2  File and args: - install/pci@780/pci@0/pci@8/network@0,2: 1000 Mbps link up<time unavailable> wanboot info: WAN boot messages->console<time unavailable> wanboot info: configuring /pci@780/pci@0/pci@8/network@0,2 See what happened?  Ops Center looked for the network device alias called net4 that we specified in the profile, took the value from it, and made it the net device alias for the boot.  Pretty cool! WANBoot and Solaris 11 Solaris 11 requires an additional step since the Automated Installer in Solaris 11 uses the MAC address of the network to figure out which manifest to use for system installation.  In order to make sure this is available, we have to take an extra step to associate the MAC of the NIC on the card with the host.  So, in addition to creating the device alias like we did above, we also have to declare to Ops Center that the host has this new MAC. Declaring the NIC Start out by discovering the hardware as usual.  Once you have discovered it, take a look under the Connectivity tab to see what networks it has discovered.  In the case of this system, it shows the 4 built-in networks, but not the networks on the additional cards.  These are not directly visible to the system controller.  In order to add the additional network interface to the hardware asset, it is necessary to Declare it.  We will declare that we have a server with this additional NIC, but we will also  specify the existing GB_0 network so that Ops Center can associate the right resources together.  The GB_0 acts as sort of a key to tie our new declaration to the old system already discovered.  Go to the Assets tab, select All Assets, and then in the Actions tab, select Add Asset.  Rather than going through a discovery this time, we will manually declare a new asset. When we declare it, we will give the hostname, IP address, system model that match those that have already been discovered.  Then, we will declare both GB_0 with its existing MAC and the new GB_4 with its MAC.  Remember that we collected the MAC for GB_4 when we created its device alias. After you declare the asset, you will see the new NIC in the connectivity tab for the asset.  You will notice that only the NICs you listed when you declared it are seen now.  If you want Ops Center to see all of the existing NICs as well as the additional one, declare them as well.  Add the other GB_1, GB_2, GB_3 links and their MACs just as you did GB_0 and GB_4.  Installing the OS  Once you have declared the asset, you can create an OS Provisioning profile for Solaris 11 in the same way that you did for Solaris 10.  The only difference from any other provisioning profile you might have created already is the network to use for installation.  Again, use GB_N/netN where N is the interface number you used for your device alias and in your declaration.  And away you go.  When the system boots from the network, the automated installer (AI) is able to see which system manifest to use, based on the new MAC that was associated, and the system gets installed. {0} ok {0} ok printenv network-boot-argumentsnetwork-boot-arguments =  host-ip=10.140.204.234,router-ip=10.140.204.1,subnet-mask=255.255.254.0,hostname=atl-sewr-52,client-id=01002128204292,file=http://10.140.204.22:5555/cgi-bin/wanboot-cgi{0} ok {0} ok devalias net net                      /pci@780/pci@0/pci@1/network@0{0} ok devalias net4 net4                     /pci@780/pci@0/pci@8/network@0,2{0} ok devalias net /pci@780/pci@0/pci@8/network@0,2{0} ok setenv network-boot-arguments host-ip=10.140.204.234,router-ip=10.140.204.1,subnet-mask=255.255.254.0,hostname=atl-sewr-52,client-id=01002128204292,file=http://10.140.204.22:5555/cgi-bin/wanboot-cginetwork-boot-arguments =  host-ip=10.140.204.234,router-ip=10.140.204.1,subnet-mask=255.255.254.0,hostname=atl-sewr-52,client-id=01002128204292,file=http://10.140.204.22:5555/cgi-bin/wanboot-cgi{0} ok {0} ok boot net - installBoot device: /pci@780/pci@0/pci@8/network@0,2  File and args: - install/pci@780/pci@0/pci@8/network@0,2: 1000 Mbps link up<time unavailable> wanboot info: WAN boot messages->console<time unavailable> wanboot info: configuring /pci@780/pci@0/pci@8/network@0,2...SunOS Release 5.11 Version 11.0 64-bitCopyright (c) 1983, 2011, Oracle and/or its affiliates. All rights reserved.Remounting root read/writeProbing for device nodes ...Preparing network image for useDownloading solaris.zlib--2012-02-17 15:10:17--  http://10.140.204.22:5555/var/js/AI/sparc//solaris.zlibConnecting to 10.140.204.22:5555... connected.HTTP request sent, awaiting response... 200 OKLength: 126752256 (121M) [text/plain]Saving to: `/tmp/solaris.zlib'100%[======================================>] 126,752,256 28.6M/s   in 4.4s    2012-02-17 15:10:21 (27.3 MB/s) - `/tmp/solaris.zlib' saved [126752256/126752256] Conclusion So, why go to all of this trouble?  More and more, I find that customers are wiring their data center to only use higher speed networks - 10GbE only to the hosts.  Some customers are moving aggressively toward consolidated networks combining storage and network on CNA NICs.  All of this means that network-based provisioning cannot rely exclusively on the built-in network interfaces.  So, it's important to be able to provision a system using other than the built-in networks.  Turns out, that this is pretty straight-forward for both Solaris 10 and Solaris 11 and fits into the Ops Center deployment process quite nicely. Hopefully, you will be able to use this as you build out your own private cloud solutions with Ops Center.

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• How to safely reboot via First Boot script

  - by unixman

  With the cost and performance benefits of the SPARC T4 and SPARC T5 systems undeniably validated, the banking sector is actively moving to Solaris 11.  I was recently asked to help a banking customer of ours look at migrating some of their Solaris 10 logic over to Solaris 11.  While we've introduced a number of holistic improvements in Solaris 11, in terms of how we ease long-term software lifecycle management, it is important to appreciate that customers may not be able to move all of their Solaris 10 scripts and procedures at once; there are years of scripts that reflect fine-tuned requirements of proprietary banking software that gets layered on top of the operating system. One of these requirements is to go through a cycle of reboots, after the system is installed, in order to ensure appropriate software dependencies and various configuration files are in-place. While Solaris 10 introduced a facility that aids here, namely SMF, many of our customers simply haven't yet taken the time to take advantage of this - proceeding with logic that, while functional, without further analysis has an appearance of not being optimal in terms of taking advantage of all the niceties bundled in Solaris 11 at no extra cost. When looking at Solaris 11, we recognize that one of the vehicles that bridges the gap between getting the operating system image payload delivered, and the customized banking software installed, is a notion of a First Boot script.  I had a working example of this at one of the Oracle OpenWorld sessions a few years ago - we've since improved our documentation and have introduced sections where this is described in better detail.   If you're looking at this for the first time and you've not worked with IPS and SMF previously, you might get the sense that the tasks are daunting.   There is a set of technologies involved that are jointly engineered in order to make the process reliable, predictable and extensible. As you go down the path of writing your first boot script, you'll be faced with a need to wrap it into a SMF service and then packaged into a IPS package. The IPS package would then need to be placed onto your IPS repository, in order to subsequently be made available to all of your AI (Automated Install) clients (i.e. the systems that you're installing Solaris and your software onto).     With this blog post, I wanted to create a single place that outlines the entire process (simplistically), and provide a hint of how a good old "at" command may make the requirement of forcing an initial reboot handy. The syntax and references to commands here is based on running this on a version of Solaris 11 that has been updated since its initial release in 2011 (i.e. I am writing this on Solaris 11.1) Assuming you've built an AI server (see this How To article for an example), you might be asking yourself: "Ok, I've got some logic that I need executed AFTER Solaris is deployed and I need my own little script that would make that happen. How do I go about hooking that script into the Solaris 11 AI framework?"  You might start here, in Chapter 13 of the "Installing Oracle Solaris 11.1 Systems" guide, which talks about "Running a Custom Script During First Boot".  And as you do, you'll be confronted with command that might be unfamiliar to you if you're new to Solaris 11, like our dear new friend: svcbundle svcbundle is an aide to creating manifests and profiles.  It is awesome, but don't let its awesomeness overwhelm you. (See this How To article by my colleague Glynn Foster for a nice working example).  In order to get your script's logic integrated into the Solaris 11 deployment process, you need to wrap your (shell) script into 2 manifests -  a SMF service manifest and a IPS package manifest.  ....and if you're new to XML, well then -- buckle up We have some examples of small first boot scripts shown here, as templates to build upon. Necessary structure of the script, particularly in leveraging SMF interfaces, is key. I won't go into that here as that is covered nicely in the doc link above.    Let's say your script ends up looking like this (btw: if things appear to be cut-off in your browser, just select them, copy and paste into your editor and it'll be grabbed - the source gets captured eventhough the browser may not render it "correctly" - ah, computers). #!/bin/sh # Load SMF shell support definitions . /lib/svc/share/smf_include.sh # If nothing to do, exit with temporary disable completed=`svcprop -p config/completed site/first-boot-script-svc:default` [ "${completed}" = "true" ] && \ smf_method_exit $SMF_EXIT_TEMP_DISABLE completed "Configuration completed" # Obtain the active BE name from beadm: The active BE on reboot has an R in # the third column of 'beadm list' output. Its name is in column one. bename=`beadm list -Hd|nawk -F ';' '$3 ~ /R/ {print $1}'` beadm create ${bename}.orig echo "Original boot environment saved as ${bename}.orig" # ---- Place your one-time configuration tasks here ---- # For example, if you have to pull some files from your own pre-existing system: /usr/bin/wget -P /var/tmp/ $PULL_DOWN_ADDITIONAL_SCRIPTS_FROM_A_CORPORATE_SYSTEM /usr/bin/chmod 755 /var/tmp/$SCRIPTS_THAT_GOT_PULLED_DOWN_IN_STEP_ABOVE # Clearly the above 2 lines represent some logic that you'd have to customize to fit your needs. # # Perhaps additional things you may want to do here might be of use, like # (gasp!) configuring ssh server for root login and X11 forwarding (for testing), and the like... # # Oh and by the way, after we're done executing all of our proprietary scripts we need to reboot # the system in accordance with our operational software requirements to ensure all layered bits # get initialized properly and pull-in their own modules and components in the right sequence, # subsequently. # We need to set a "time bomb" reboot, that would take place upon completion of this script. # We already know that *this* script depends on multi-user-server SMF milestone, so it should be # safe for us to schedule a reboot for 5 minutes from now. The "at" job get scheduled in the queue # while our little script continues thru the rest of the logic. /usr/bin/at now + 5 minutes <<REBOOT /usr/bin/sync /usr/sbin/reboot REBOOT # ---- End of your customizations ---- # Record that this script's work is done svccfg -s site/first-boot-script-svc:default setprop config/completed = true svcadm refresh site/first-boot-script-svc:default smf_method_exit $SMF_EXIT_TEMP_DISABLE method_completed "Configuration completed"  ...and you're happy with it and are ready to move on. Where do you go and what do you do? The next step is creating the IPS package for your script. Since running the logic of your script constitutes a service, you need to create a service manifest. This is described here, in the middle of Chapter 13 of "Creating an IPS package for the script and service".  Assuming the name of your shell script is first-boot-script.sh, you could end up doing the following: $ cd some_working_directory_for_this_project$ mkdir -p proto/lib/svc/manifest/site$ mkdir -p proto/opt/site $ cp first-boot-script.sh proto/opt/site  Then you would create the service manifest  file like so: $ svcbundle -s service-name=site/first-boot-script-svc \ -s start-method=/opt/site/first-boot-script.sh \ -s instance-property=config:completed:boolean:false -o \ first-boot-script-svc-manifest.xml   ...as described here, and place it into the directory hierarchy above. But before you place it into the directory, make sure to inspect the manifest and adjust the appropriate service dependencies.  That is to say, you want to properly specify what milestone should be reached before your service runs.  There's a <dependency> section that looks like this, before you modify it: <dependency restart_on="none" type="service" name="multi_user_dependency" grouping="require_all"> <service_fmri value="svc:/milestone/multi-user"/>  </dependency>  So if you'd like to have your service run AFTER the multi-user-server milestone has been reached (i.e. later, as multi-user-server has more dependencies then multi-user and our intent to reboot the system may have significant ramifications if done prematurely), you would modify that section to read:  <dependency restart_on="none" type="service" name="multi_user_server_dependency" grouping="require_all"> <service_fmri value="svc:/milestone/multi-user-server"/>  </dependency> Save the file and validate it: $ svccfg validate first-boot-script-svc-manifest.xml Assuming there are no errors returned, copy the file over into the directory hierarchy: $ cp first-boot-script-svc-manifest.xml proto/lib/svc/manifest/site Now that we've created the service manifest (.xml), create the package manifest (.p5m) file named: first-boot-script.p5m.  Populate it as follows: set name=pkg.fmri value=first-boot-script-AT-1-DOT-0,5.11-0 set name=pkg.summary value="AI first-boot script" set name=pkg.description value="Script that runs at first boot after AI installation" set name=info.classification value=\ "org.opensolaris.category.2008:System/Administration and Configuration" file lib/svc/manifest/site/first-boot-script-svc-manifest.xml \ path=lib/svc/manifest/site/first-boot-script-svc-manifest.xml owner=root \ group=sys mode=0444 dir path=opt/site owner=root group=sys mode=0755 file opt/site/first-boot-script.sh path=opt/site/first-boot-script.sh \ owner=root group=sys mode=0555 Now we are going to publish this package into a IPS repository. If you don't have one yet, don't worry. You have 2 choices: You can either  publish this package into your mirror of the Oracle Solaris IPS repo or create your own customized repo.  The best practice is to create your own customized repo, leaving your mirror of the Oracle Solaris IPS repo untouched.  From this point, you have 2 choices as well - you can either create a repo that will be accessible by your clients via HTTP or via NFS.  Since HTTP is how the default Solaris repo is accessed, we'll go with HTTP for your own IPS repo.   This nice and comprehensive How To by Albert White describes how to create multiple internal IPS repos for Solaris 11. We'll zero in on the basic elements for our needs here: We'll create the IPS repo directory structure hanging off a separate ZFS file system, and we'll tie it into an instance of pkg.depotd. We do this because we want our IPS repo to be accessible to our AI clients through HTTP, and the pkg.depotd SMF service bundled in Solaris 11 can help us do this. We proceed as follows: # zfs create rpool/export/MyIPSrepo # pkgrepo create /export/MyIPSrepo # svccfg -s pkg/server add MyIPSrepo # svccfg -s pkg/server:MyIPSrepo addpg pkg application # svccfg -s pkg/server:MyIPSrepo setprop pkg/port=10081 # svccfg -s pkg/server:MyIPSrepo setprop pkg/inst_root=/export/MyIPSrepo # svccfg -s pkg/server:MyIPSrepo addpg general framework # svccfg -s pkg/server:MyIPSrepo addpropvalue general/complete astring: MyIPSrepo # svccfg -s pkg/server:MyIPSrepo addpropvalue general/enabled boolean: true # svccfg -s pkg/server:MyIPSrepo setprop pkg/readonly=true # svccfg -s pkg/server:MyIPSrepo setprop pkg/proxy_base = astring: http://your_internal_websrvr/MyIPSrepo # svccfg -s pkg/server:MyIPSrepo setprop pkg/threads = 200 # svcadm refresh application/pkg/server:MyIPSrepo # svcadm enable application/pkg/server:MyIPSrepo Now that the IPS repo is created, we need to publish our package into it: # pkgsend publish -d ./proto -s /export/MyIPSrepo first-boot-script.p5m If you find yourself making changes to your script, remember to up-rev the version in the .p5m file (which is your IPS package manifest), and re-publish the IPS package. Next, you need to go to your AI install server (which might be the same machine) and modify the AI manifest to include a reference to your newly created package.  We do that by listing an additional publisher, which would look like this (replacing the IP address and port with your own, from the "svccfg" commands up above): <publisher name="firstboot"> <origin name="http://192.168.1.222:10081"/> </publisher>  Further down, in the  <software_data action="install">  section add: <name>pkg:/first-boot-script</name> Make sure to update your Automated Install service with the new AI manifest via installadm update-manifest command.  Don't forget to boot your client from the network to watch the entire process unfold and your script get tested.  Once the system makes the initial reboot, the first boot script will be executed and whatever logic you've specified in it should be executed, too, followed by a nice reboot. When the system comes up, your service should stay in a disabled state, as specified by the tailing lines of your SMF script - this is normal and should be left as is as it helps provide an auditing trail for you.   Because the reboot is quite a significant action for the system, you may want to add additional logic to the script that actually places and then checks for presence of certain lock files in order to avoid doing a reboot unnecessarily. You may also want to, alternatively, remove the SMF service entirely - if you're unsure of the potential for someone to try and accidentally enable that service -- eventhough its role in life is to only run once upon the system's first boot. That is how I spent a good chunk of my pre-Halloween time this week, hope yours was just as SPARCkly^H^H^H^H fun!    

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• 2014 Conferences - JFokus, JavaLand & GeeCon!

  - by Heather VanCura

  There has been a delay in publishing these past event summaries from early 2014--JFokus in February, JavaLand in March, and GeeCon in May. As we plan for Devoxx UK next week, I found these summaries that did not make it past 'draft' stage.  We had some great successes with the first three events of 2014, a Java developer conference trifecta! Participation topics included Java, the JCP program overall and the Adopt-a-JSR programs.   First up in February was JFokus in Stockholm. The energy and talent in Stockholm is amazing and the conference organizers do a stellar job running it and welcoming the speakers of this event.  I enjoyed the city walk and speaker dinner, as well as many opportunities to interact with conference speakers and attendees, both during and after the conference hours. Reza Rehman invited me to speak during his Java EE 7 lab session about the Adopt-a-JSR program, and I gave a quickie session on the JCP and Adopt-a-JSR.  There was also a late night Birds of a Feather (BoF) session held jointly with Cecelia Borg, Martijn Verburg and Reza Rehman.  This was an interactive conversation with a focus on the Java EE community survey results and encouraging more community participation and collaboration in Java development.  The Java 8 keynote by Georges Saab and Mark Reinhold was also very entertaining,  I was sorry to miss FOSDEM happening the previous weekend this year in Brussels, but I hope to attend in 2015.  Favorite take home gift -- Lambdas cap! In March, the inaugural version of the JavaLand conference happened inside Phantasialand, an amusement park in Germany. Markus Eisele suggested having an Early Adopters area at the conference, which I was keen to implement. In 2013 at Devoxx Belgium we held some activities in the Hackergaren area around Lambdas and Java EE 7, so this was a great opportunity to expand on a more interactive conference format and Andreas Badelt from the program committee helped in the planning for this area.  Daniel Bryant and Mani Sarkar from the London Java Community led some general Adopt-a-JSR discussions and AdoptOpen JDK activities.  JCP Spec Leads, Anatole Tresch from Credit Suisse, leading JSR 354, Money & Currency API, and Ed Burns from Oracle, leading JSR 344, JavaServer Faces 2.2, attended to engage with conference attendees on their JSRs.  Favorite - Stephen Chin's roller coaster video. In May, GeeCon in Krakow was anther awesome conference!  The conference organizers were warm and welcoming and I enjoyed time getting to know the other speakers at the event. There was a JCP and Adopt-a-JSR participation session as well as a moderated panel session on Early Adopters.  We had an amazing panel -- Daniel Bryant, Arun Gupta, Tomasz Borek , and Peter Lawrey. The panel discussed the Adopt-a-JSR and Adopt OpenJDK program, and how the participants work together to get involved and contribute to both the Java SE and Java EE platforms.  If was an interesting discussion and sparked some new ideas on how Java User Groups in Poland and around the world can contribute in a significant and meaningful way to create better and more practical Java standards today and in the future.  Favorite take home gift - GeeCon mug!   These were some of the highlights of the events--looking forward to Devoxx UK next week.  I will publish these details tomorrow!

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• A more elegant way to start a multithread alarm in Rebol VID ? (What's the equivalent of load event?

  - by Rebol Tutorial

  I want to trigger an alarm when the GUI starts. I can't see what's the equivalent of load event of other language in Rebol VID, so I put it in the periodic handler which is quite circumvoluted. So how to do this more cleanly ? alarm-data: none set-alarm: func [ "Set alarm for future time." seconds "Seconds from now to ring alarm." message [string! unset!] "Message to print on alarm." ] [ alarm-data: reduce [now/time + seconds message] ] ring: func [ "Action for when alarm comes due." message [string! unset!] ] [ set-face monitor either message [message]["RIIIING!"] ; Your sound playing can also go here (my computer doesn't have speakers). ] periodic: func [ "Called every second, checks alarms." fact action event ] [ either alarm-data [ ; Update alarm countdown. set-face monitor rejoin [ "Alarm will ring in " to integer! alarm-data/1 - now/time " seconds." ] ; Check alarm. if now/time > alarm-data/1 [ ring alarm-data/2 ;alarm-data: none ; Reset once fired. ] ][ either value? 'message [ set-alarm seconds message ][ set-alarm seconds "Alarm triggered!" ] ] ] alarm: func[seconds message [string! unset!]][ system/words/seconds: seconds if value? 'message [ system/words/message: message ] view layout [ monitor: text 256 "" rate 1 feel [engage: :periodic] button 256 "re/start countdown" [ either value? 'message [ set-alarm seconds message ][ set-alarm seconds "Alarm triggered!" ] set-face monitor "Alarm set." ] ] ]

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• C# .Net 3.5 Asynchronous Socket Server Performance Problem

  - by iBrAaAa

  I'm developing an Asynchronous Game Server using .Net Socket Asynchronous Model( BeginAccept/EndAccept...etc.) The problem I'm facing is described like that: When I have only one client connected, the server response time is very fast but once a second client connects, the server response time increases too much. I've measured the time from a client sends a message to the server until it gets the reply in both cases. I found that the average time in case of one client is about 17ms and in case of 2 clients about 280ms!!! What I really see is that: When 2 clients are connected and only one of them is moving(i.e. requesting service from the server) it is equivalently equal to the case when only one client is connected(i.e. fast response). However, when the 2 clients move at the same time(i.e. requests service from the server at the same time) their motion becomes very slow (as if the server replies each one of them in order i.e. not simultaneously). Basically, what I am doing is that: When a client requests a permission for motion from the server and the server grants him the request, the server then broadcasts the new position of the client to all the players. So if two clients are moving in the same time, the server is eventually trying to broadcast to both clients the new position of each of them at the same time. EX: Client1 asks to go to position (2,2) Client2 asks to go to position (5,5) Server sends to each of Client1 & Client2 the same two messages: message1: "Client1 at (2,2)" message2: "Client2 at (5,5)" I believe that the problem comes from the fact that Socket class is thread safe according MSDN documentation http://msdn.microsoft.com/en-us/library/system.net.sockets.socket.aspx. (NOT SURE THAT IT IS THE PROBLEM) Below is the code for the server: /// /// This class is responsible for handling packet receiving and sending /// public class NetworkManager { /// /// An integer to hold the server port number to be used for the connections. Its default value is 5000. /// private readonly int port = 5000; /// /// hashtable contain all the clients connected to the server. /// key: player Id /// value: socket /// private readonly Hashtable connectedClients = new Hashtable(); /// /// An event to hold the thread to wait for a new client /// private readonly ManualResetEvent resetEvent = new ManualResetEvent(false); /// /// keeps track of the number of the connected clients /// private int clientCount; /// /// The socket of the server at which the clients connect /// private readonly Socket mainSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); /// /// The socket exception that informs that a client is disconnected /// private const int ClientDisconnectedErrorCode = 10054; /// /// The only instance of this class. /// private static readonly NetworkManager networkManagerInstance = new NetworkManager(); /// /// A delegate for the new client connected event. /// /// the sender object /// the event args public delegate void NewClientConnected(Object sender, SystemEventArgs e); /// /// A delegate for the position update message reception. /// /// the sender object /// the event args public delegate void PositionUpdateMessageRecieved(Object sender, PositionUpdateEventArgs e); /// /// The event which fires when a client sends a position message /// public PositionUpdateMessageRecieved PositionUpdateMessageEvent { get; set; } /// /// keeps track of the number of the connected clients /// public int ClientCount { get { return clientCount; } } /// /// A getter for this class instance. /// /// only instance. public static NetworkManager NetworkManagerInstance { get { return networkManagerInstance; } } private NetworkManager() {} /// Starts the game server and holds this thread alive /// public void StartServer() { //Bind the mainSocket to the server IP address and port mainSocket.Bind(new IPEndPoint(IPAddress.Any, port)); //The server starts to listen on the binded socket with max connection queue //1024 mainSocket.Listen(1024); //Start accepting clients asynchronously mainSocket.BeginAccept(OnClientConnected, null); //Wait until there is a client wants to connect resetEvent.WaitOne(); } /// /// Receives connections of new clients and fire the NewClientConnected event /// private void OnClientConnected(IAsyncResult asyncResult) { Interlocked.Increment(ref clientCount); ClientInfo newClient = new ClientInfo { WorkerSocket = mainSocket.EndAccept(asyncResult), PlayerId = clientCount }; //Add the new client to the hashtable and increment the number of clients connectedClients.Add(newClient.PlayerId, newClient); //fire the new client event informing that a new client is connected to the server if (NewClientEvent != null) { NewClientEvent(this, System.EventArgs.Empty); } newClient.WorkerSocket.BeginReceive(newClient.Buffer, 0, BasePacket.GetMaxPacketSize(), SocketFlags.None, new AsyncCallback(WaitForData), newClient); //Start accepting clients asynchronously again mainSocket.BeginAccept(OnClientConnected, null); } /// Waits for the upcoming messages from different clients and fires the proper event according to the packet type. /// /// private void WaitForData(IAsyncResult asyncResult) { ClientInfo sendingClient = null; try { //Take the client information from the asynchronous result resulting from the BeginReceive sendingClient = asyncResult.AsyncState as ClientInfo; // If client is disconnected, then throw a socket exception // with the correct error code. if (!IsConnected(sendingClient.WorkerSocket)) { throw new SocketException(ClientDisconnectedErrorCode); } //End the pending receive request sendingClient.WorkerSocket.EndReceive(asyncResult); //Fire the appropriate event FireMessageTypeEvent(sendingClient.ConvertBytesToPacket() as BasePacket); // Begin receiving data from this client sendingClient.WorkerSocket.BeginReceive(sendingClient.Buffer, 0, BasePacket.GetMaxPacketSize(), SocketFlags.None, new AsyncCallback(WaitForData), sendingClient); } catch (SocketException e) { if (e.ErrorCode == ClientDisconnectedErrorCode) { // Close the socket. if (sendingClient.WorkerSocket != null) { sendingClient.WorkerSocket.Close(); sendingClient.WorkerSocket = null; } // Remove it from the hash table. connectedClients.Remove(sendingClient.PlayerId); if (ClientDisconnectedEvent != null) { ClientDisconnectedEvent(this, new ClientDisconnectedEventArgs(sendingClient.PlayerId)); } } } catch (Exception e) { // Begin receiving data from this client sendingClient.WorkerSocket.BeginReceive(sendingClient.Buffer, 0, BasePacket.GetMaxPacketSize(), SocketFlags.None, new AsyncCallback(WaitForData), sendingClient); } } /// /// Broadcasts the input message to all the connected clients /// /// public void BroadcastMessage(BasePacket message) { byte[] bytes = message.ConvertToBytes(); foreach (ClientInfo client in connectedClients.Values) { client.WorkerSocket.BeginSend(bytes, 0, bytes.Length, SocketFlags.None, SendAsync, client); } } /// /// Sends the input message to the client specified by his ID. /// /// /// The message to be sent. /// The id of the client to receive the message. public void SendToClient(BasePacket message, int id) { byte[] bytes = message.ConvertToBytes(); (connectedClients[id] as ClientInfo).WorkerSocket.BeginSend(bytes, 0, bytes.Length, SocketFlags.None, SendAsync, connectedClients[id]); } private void SendAsync(IAsyncResult asyncResult) { ClientInfo currentClient = (ClientInfo)asyncResult.AsyncState; currentClient.WorkerSocket.EndSend(asyncResult); } /// Fires the event depending on the type of received packet /// /// The received packet. void FireMessageTypeEvent(BasePacket packet) { switch (packet.MessageType) { case MessageType.PositionUpdateMessage: if (PositionUpdateMessageEvent != null) { PositionUpdateMessageEvent(this, new PositionUpdateEventArgs(packet as PositionUpdatePacket)); } break; } } } The events fired are handled in a different class, here are the event handling code for the PositionUpdateMessage (Other handlers are irrelevant): private readonly Hashtable onlinePlayers = new Hashtable(); /// /// Constructor that creates a new instance of the GameController class. /// private GameController() { //Start the server server = new Thread(networkManager.StartServer); server.Start(); //Create an event handler for the NewClientEvent of networkManager networkManager.PositionUpdateMessageEvent += OnPositionUpdateMessageReceived; } /// /// this event handler is called when a client asks for movement. /// private void OnPositionUpdateMessageReceived(object sender, PositionUpdateEventArgs e) { Point currentLocation = ((PlayerData)onlinePlayers[e.PositionUpdatePacket.PlayerId]).Position; Point locationRequested = e.PositionUpdatePacket.Position; ((PlayerData)onlinePlayers[e.PositionUpdatePacket.PlayerId]).Position = locationRequested; // Broadcast the new position networkManager.BroadcastMessage(new PositionUpdatePacket { Position = locationRequested, PlayerId = e.PositionUpdatePacket.PlayerId }); }

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• wxWidgets in Code::Blocks

  - by Vlad

  Hello all, I'm trying to compile the minimal sample from the "Cross-Platform GUI Programming with wxWidgets" book but the following compile errors: ||=== minimal, Debug ===| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_frame.o):frame.cpp:(.text+0x918)||undefined reference to `__Unwind_Resume' | C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_frame.o):frame.cpp:(.text+0x931)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_frame.o):frame.cpp:(.text+0xa96)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_frame.o):frame.cpp:(.text+0xada)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_frame.o):frame.cpp:(.text+0xb1e)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_frame.o):frame.cpp:(.eh_frame+0x12)||undefined reference to `___gxx_personality_v0'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_datacmn.o):datacmn.cpp:(.eh_frame+0x11)||undefined reference to `___gxx_personality_v0'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_gdicmn.o):gdicmn.cpp:(.text+0x63a)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_gdicmn.o):gdicmn.cpp:(.text+0x696)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_gdicmn.o):gdicmn.cpp:(.text+0x6f2)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_gdicmn.o):gdicmn.cpp:(.text+0x74a)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_gdicmn.o):gdicmn.cpp:(.text+0x7a2)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_gdicmn.o):gdicmn.cpp:(.eh_frame+0x12)||undefined reference to `___gxx_personality_v0'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_menu.o):menu.cpp:(.text+0x88f)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_menu.o):menu.cpp:(.text+0x927)||undefined reference to `__Unwind_Resume' | C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_menu.o):menu.cpp:(.text+0x9bf)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_menu.o):menu.cpp:(.text+0xb8b)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_menu.o):menu.cpp:(.text+0xc87)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_menu.o):menu.cpp:(.eh_frame+0x12)||undefined reference to `___gxx_personality_v0'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_menucmn.o):menucmn.cpp:(.text+0xbc0)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_menucmn.o):menucmn.cpp:(.text+0xc59)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_menucmn.o):menucmn.cpp:(.text+0xcf5)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_menucmn.o):menucmn.cpp:(.text+0xda6)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_menucmn.o):menucmn.cpp:(.text+0xdce)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_menucmn.o):menucmn.cpp:(.eh_frame+0x12)||undefined reference to `___gxx_personality_v0'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_icon.o):icon.cpp:(.text+0x1ff)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_icon.o):icon.cpp:(.text+0x257)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_icon.o):icon.cpp:(.text+0x2af)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_icon.o):icon.cpp:(.text+0x2fc)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_icon.o):icon.cpp:(.text+0x36d)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_icon.o):icon.cpp:(.eh_frame+0x12)||undefined reference to `___gxx_personality_v0'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_gdiimage.o):gdiimage.cpp:(.text+0x4a8)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_gdiimage.o):gdiimage.cpp:(.text+0x73a)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_gdiimage.o):gdiimage.cpp:(.text+0x813)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_gdiimage.o):gdiimage.cpp:(.text+0xc06)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_gdiimage.o):gdiimage.cpp:(.text+0xd3e)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_gdiimage.o):gdiimage.cpp:(.eh_frame+0x12)||undefined reference to `___gxx_personality_v0'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_event.o):event.cpp:(.text+0x970)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_event.o):event.cpp:(.text+0xa80)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_event.o):event.cpp:(.text+0xb8c)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_event.o):event.cpp:(.text+0xc78)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_event.o):event.cpp:(.text+0xd4f)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_event.o):event.cpp:(.eh_frame+0x12)||undefined reference to `___gxx_personality_v0'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_appcmn.o):appcmn.cpp:(.text+0x2ef)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_appcmn.o):appcmn.cpp:(.text+0x32b)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_appcmn.o):appcmn.cpp:(.text+0x43d)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_appcmn.o):appcmn.cpp:(.text+0x586)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_appcmn.o):appcmn.cpp:(.text+0x601)||undefined reference to `__Unwind_Resume'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_appcmn.o):appcmn.cpp:(.eh_frame+0x12)||undefined reference to `___gxx_personality_v0'| C:\SourceCode\Libraries\wxWidgets2.8\lib\gcc_lib\libwxmsw28u_core.a(corelib_app.o):app.cpp:(.text+0x1da)||undefined reference to `__Unwind_Resume'| ||More errors follow but not being shown.| ||Edit the max errors limit in compiler options...| ||=== Build finished: 50 errors, 0 warnings ===| Here's the code sample from the book: #include "wx/wx.h" #include "mondrian.xpm" // Declare the application class class MyApp : public wxApp { public: // Called on application startup virtual bool OnInit(); }; // Declare our main frame class class MyFrame : public wxFrame { public: // Constructor MyFrame(const wxString& title); // Event handlers void OnQuit(wxCommandEvent& event); void OnAbout(wxCommandEvent& event); private: // This class handles events DECLARE_EVENT_TABLE() }; // Implements MyApp& GetApp() DECLARE_APP(MyApp) // Give wxWidgets the means to create a MyApp object IMPLEMENT_APP(MyApp) // Initialize the application bool MyApp::OnInit() { // Create the main application window MyFrame *frame = new MyFrame(wxT("Minimal wxWidgets App")); // Show it frame->Show(true); // Start the event loop return true; } // Event table for MyFrame BEGIN_EVENT_TABLE(MyFrame, wxFrame) EVT_MENU(wxID_ABOUT, MyFrame::OnAbout) EVT_MENU(wxID_EXIT, MyFrame::OnQuit) END_EVENT_TABLE() void MyFrame::OnAbout(wxCommandEvent& event) { wxString msg; msg.Printf(wxT("Hello and welcome to %s"), wxVERSION_STRING); wxMessageBox(msg, wxT("About Minimal"), wxOK | wxICON_INFORMATION, this); } void MyFrame::OnQuit(wxCommandEvent& event) { // Destroy the frame Close(); } MyFrame::MyFrame(const wxString& title) : wxFrame(NULL, wxID_ANY, title) { // Set the frame icon SetIcon(wxIcon(mondrian_xpm)); // Create a menu bar wxMenu *fileMenu = new wxMenu; // The “About” item should be in the help menu wxMenu *helpMenu = new wxMenu; helpMenu->Append(wxID_ABOUT, wxT("&About...\tF1"), wxT("Show about dialog")); fileMenu->Append(wxID_EXIT, wxT("E&xit\tAlt-X"), wxT("Quit this program")); // Now append the freshly created menu to the menu bar... wxMenuBar *menuBar = new wxMenuBar(); menuBar->Append(fileMenu, wxT("&File")); menuBar->Append(helpMenu, wxT("&Help")); // ... and attach this menu bar to the frame SetMenuBar(menuBar); // Create a status bar just for fun CreateStatusBar(2); SetStatusText(wxT("Welcome to wxWidgets!")); } So what's happenning? Thanks! P.S.: I installed wxWidgets through wxPack wich afaik comes with everything precomplied and i also added the wxWidgets directory to Global variables-base in Code::Blocks so everything should be correctly set, right?

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• .Net 3.5 Asynchronous Socket Server Performance Problem

  - by iBrAaAa

  I'm developing an Asynchronous Game Server using .Net Socket Asynchronous Model( BeginAccept/EndAccept...etc.) The problem I'm facing is described like that: When I have only one client connected, the server response time is very fast but once a second client connects, the server response time increases too much. I've measured the time from a client sends a message to the server until it gets the reply in both cases. I found that the average time in case of one client is about 17ms and in case of 2 clients about 280ms!!! What I really see is that: When 2 clients are connected and only one of them is moving(i.e. requesting service from the server) it is equivalently equal to the case when only one client is connected(i.e. fast response). However, when the 2 clients move at the same time(i.e. requests service from the server at the same time) their motion becomes very slow (as if the server replies each one of them in order i.e. not simultaneously). Basically, what I am doing is that: When a client requests a permission for motion from the server and the server grants him the request, the server then broadcasts the new position of the client to all the players. So if two clients are moving in the same time, the server is eventually trying to broadcast to both clients the new position of each of them at the same time. EX: Client1 asks to go to position (2,2) Client2 asks to go to position (5,5) Server sends to each of Client1 & Client2 the same two messages: message1: "Client1 at (2,2)" message2: "Client2 at (5,5)" I believe that the problem comes from the fact that Socket class is thread safe according MSDN documentation http://msdn.microsoft.com/en-us/library/system.net.sockets.socket.aspx. (NOT SURE THAT IT IS THE PROBLEM) Below is the code for the server: /// /// This class is responsible for handling packet receiving and sending /// public class NetworkManager { /// /// An integer to hold the server port number to be used for the connections. Its default value is 5000. /// private readonly int port = 5000; /// /// hashtable contain all the clients connected to the server. /// key: player Id /// value: socket /// private readonly Hashtable connectedClients = new Hashtable(); /// /// An event to hold the thread to wait for a new client /// private readonly ManualResetEvent resetEvent = new ManualResetEvent(false); /// /// keeps track of the number of the connected clients /// private int clientCount; /// /// The socket of the server at which the clients connect /// private readonly Socket mainSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); /// /// The socket exception that informs that a client is disconnected /// private const int ClientDisconnectedErrorCode = 10054; /// /// The only instance of this class. /// private static readonly NetworkManager networkManagerInstance = new NetworkManager(); /// /// A delegate for the new client connected event. /// /// the sender object /// the event args public delegate void NewClientConnected(Object sender, SystemEventArgs e); /// /// A delegate for the position update message reception. /// /// the sender object /// the event args public delegate void PositionUpdateMessageRecieved(Object sender, PositionUpdateEventArgs e); /// /// The event which fires when a client sends a position message /// public PositionUpdateMessageRecieved PositionUpdateMessageEvent { get; set; } /// /// keeps track of the number of the connected clients /// public int ClientCount { get { return clientCount; } } /// /// A getter for this class instance. /// /// only instance. public static NetworkManager NetworkManagerInstance { get { return networkManagerInstance; } } private NetworkManager() {} /// Starts the game server and holds this thread alive /// public void StartServer() { //Bind the mainSocket to the server IP address and port mainSocket.Bind(new IPEndPoint(IPAddress.Any, port)); //The server starts to listen on the binded socket with max connection queue //1024 mainSocket.Listen(1024); //Start accepting clients asynchronously mainSocket.BeginAccept(OnClientConnected, null); //Wait until there is a client wants to connect resetEvent.WaitOne(); } /// /// Receives connections of new clients and fire the NewClientConnected event /// private void OnClientConnected(IAsyncResult asyncResult) { Interlocked.Increment(ref clientCount); ClientInfo newClient = new ClientInfo { WorkerSocket = mainSocket.EndAccept(asyncResult), PlayerId = clientCount }; //Add the new client to the hashtable and increment the number of clients connectedClients.Add(newClient.PlayerId, newClient); //fire the new client event informing that a new client is connected to the server if (NewClientEvent != null) { NewClientEvent(this, System.EventArgs.Empty); } newClient.WorkerSocket.BeginReceive(newClient.Buffer, 0, BasePacket.GetMaxPacketSize(), SocketFlags.None, new AsyncCallback(WaitForData), newClient); //Start accepting clients asynchronously again mainSocket.BeginAccept(OnClientConnected, null); } /// Waits for the upcoming messages from different clients and fires the proper event according to the packet type. /// /// private void WaitForData(IAsyncResult asyncResult) { ClientInfo sendingClient = null; try { //Take the client information from the asynchronous result resulting from the BeginReceive sendingClient = asyncResult.AsyncState as ClientInfo; // If client is disconnected, then throw a socket exception // with the correct error code. if (!IsConnected(sendingClient.WorkerSocket)) { throw new SocketException(ClientDisconnectedErrorCode); } //End the pending receive request sendingClient.WorkerSocket.EndReceive(asyncResult); //Fire the appropriate event FireMessageTypeEvent(sendingClient.ConvertBytesToPacket() as BasePacket); // Begin receiving data from this client sendingClient.WorkerSocket.BeginReceive(sendingClient.Buffer, 0, BasePacket.GetMaxPacketSize(), SocketFlags.None, new AsyncCallback(WaitForData), sendingClient); } catch (SocketException e) { if (e.ErrorCode == ClientDisconnectedErrorCode) { // Close the socket. if (sendingClient.WorkerSocket != null) { sendingClient.WorkerSocket.Close(); sendingClient.WorkerSocket = null; } // Remove it from the hash table. connectedClients.Remove(sendingClient.PlayerId); if (ClientDisconnectedEvent != null) { ClientDisconnectedEvent(this, new ClientDisconnectedEventArgs(sendingClient.PlayerId)); } } } catch (Exception e) { // Begin receiving data from this client sendingClient.WorkerSocket.BeginReceive(sendingClient.Buffer, 0, BasePacket.GetMaxPacketSize(), SocketFlags.None, new AsyncCallback(WaitForData), sendingClient); } } /// /// Broadcasts the input message to all the connected clients /// /// public void BroadcastMessage(BasePacket message) { byte[] bytes = message.ConvertToBytes(); foreach (ClientInfo client in connectedClients.Values) { client.WorkerSocket.BeginSend(bytes, 0, bytes.Length, SocketFlags.None, SendAsync, client); } } /// /// Sends the input message to the client specified by his ID. /// /// /// The message to be sent. /// The id of the client to receive the message. public void SendToClient(BasePacket message, int id) { byte[] bytes = message.ConvertToBytes(); (connectedClients[id] as ClientInfo).WorkerSocket.BeginSend(bytes, 0, bytes.Length, SocketFlags.None, SendAsync, connectedClients[id]); } private void SendAsync(IAsyncResult asyncResult) { ClientInfo currentClient = (ClientInfo)asyncResult.AsyncState; currentClient.WorkerSocket.EndSend(asyncResult); } /// Fires the event depending on the type of received packet /// /// The received packet. void FireMessageTypeEvent(BasePacket packet) { switch (packet.MessageType) { case MessageType.PositionUpdateMessage: if (PositionUpdateMessageEvent != null) { PositionUpdateMessageEvent(this, new PositionUpdateEventArgs(packet as PositionUpdatePacket)); } break; } } } The events fired are handled in a different class, here are the event handling code for the PositionUpdateMessage (Other handlers are irrelevant): private readonly Hashtable onlinePlayers = new Hashtable(); /// /// Constructor that creates a new instance of the GameController class. /// private GameController() { //Start the server server = new Thread(networkManager.StartServer); server.Start(); //Create an event handler for the NewClientEvent of networkManager networkManager.PositionUpdateMessageEvent += OnPositionUpdateMessageReceived; } /// /// this event handler is called when a client asks for movement. /// private void OnPositionUpdateMessageReceived(object sender, PositionUpdateEventArgs e) { Point currentLocation = ((PlayerData)onlinePlayers[e.PositionUpdatePacket.PlayerId]).Position; Point locationRequested = e.PositionUpdatePacket.Position; ((PlayerData)onlinePlayers[e.PositionUpdatePacket.PlayerId]).Position = locationRequested; // Broadcast the new position networkManager.BroadcastMessage(new PositionUpdatePacket { Position = locationRequested, PlayerId = e.PositionUpdatePacket.PlayerId }); }

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• Why is Java EE 6 better than Spring ?

  - by arungupta

  Java EE 6 was released over 2 years ago and now there are 14 compliant application servers. In all my talks around the world, a question that is frequently asked is Why should I use Java EE 6 instead of Spring ? There are already several blogs covering that topic: Java EE wins over Spring by Bill Burke Why will I use Java EE instead of Spring in new Enterprise Java projects in 2012 ? by Kai Waehner (more discussion on TSS) Spring to Java EE migration (Part 1 and 2, 3 and 4 coming as well) by David Heffelfinger Spring to Java EE - A Migration Experience by Lincoln Baxter Migrating Spring to Java EE 6 by Bert Ertman and Paul Bakker at NLJUG Moving from Spring to Java EE 6 - The Age of Frameworks is Over at TSS Java EE vs Spring Shootout by Rohit Kelapure and Reza Rehman at JavaOne 2011 Java EE 6 and the Ewoks by Murat Yener Definite excuse to avoid Spring forever - Bert Ertman and Arun Gupta I will try to share my perspective in this blog. First of all, I'd like to start with a note: Thank you Spring framework for filling the interim gap and providing functionality that is now included in the mainstream Java EE 6 application servers. The Java EE platform has evolved over the years learning from frameworks like Spring and provides all the functionality to build an enterprise application. Thank you very much Spring framework! While Spring was revolutionary in its time and is still very popular and quite main stream in the same way Struts was circa 2003, it really is last generation's framework - some people are even calling it legacy. However my theory is "code is king". So my approach is to build/take a simple Hello World CRUD application in Java EE 6 and Spring and compare the deployable artifacts. I started looking at the official tutorial Developing a Spring Framework MVC Application Step-by-Step but it is using the older version 2.5. I wasn't able to find any updated version in the current 3.1 release. Next, I downloaded Spring Tool Suite and thought that would provide some template samples to get started. A least a quick search did not show any handy tutorials - either video or text-based. So I searched and found a link to their SVN repository at src.springframework.org/svn/spring-samples/. I tried the "mvc-basic" sample and the generated WAR file was 4.43 MB. While it was named a "basic" sample it seemed to come with 19 different libraries bundled but it was what I could find: ./WEB-INF/lib/aopalliance-1.0.jar./WEB-INF/lib/hibernate-validator-4.1.0.Final.jar./WEB-INF/lib/jcl-over-slf4j-1.6.1.jar./WEB-INF/lib/joda-time-1.6.2.jar./WEB-INF/lib/joda-time-jsptags-1.0.2.jar./WEB-INF/lib/jstl-1.2.jar./WEB-INF/lib/log4j-1.2.16.jar./WEB-INF/lib/slf4j-api-1.6.1.jar./WEB-INF/lib/slf4j-log4j12-1.6.1.jar./WEB-INF/lib/spring-aop-3.0.5.RELEASE.jar./WEB-INF/lib/spring-asm-3.0.5.RELEASE.jar./WEB-INF/lib/spring-beans-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-support-3.0.5.RELEASE.jar./WEB-INF/lib/spring-core-3.0.5.RELEASE.jar./WEB-INF/lib/spring-expression-3.0.5.RELEASE.jar./WEB-INF/lib/spring-web-3.0.5.RELEASE.jar./WEB-INF/lib/spring-webmvc-3.0.5.RELEASE.jar./WEB-INF/lib/validation-api-1.0.0.GA.jar And it is not even using any database! The app deployed fine on GlassFish 3.1.2 but the "@Controller Example" link did not work as it was missing the context root. With a bit of tweaking I could deploy the application and assume that the account got created because no error was displayed in the browser or server log. Next I generated the WAR for "mvc-ajax" and the 5.1 MB WAR had 20 JARs (1 removed, 2 added): ./WEB-INF/lib/aopalliance-1.0.jar./WEB-INF/lib/hibernate-validator-4.1.0.Final.jar./WEB-INF/lib/jackson-core-asl-1.6.4.jar./WEB-INF/lib/jackson-mapper-asl-1.6.4.jar./WEB-INF/lib/jcl-over-slf4j-1.6.1.jar./WEB-INF/lib/joda-time-1.6.2.jar./WEB-INF/lib/jstl-1.2.jar./WEB-INF/lib/log4j-1.2.16.jar./WEB-INF/lib/slf4j-api-1.6.1.jar./WEB-INF/lib/slf4j-log4j12-1.6.1.jar./WEB-INF/lib/spring-aop-3.0.5.RELEASE.jar./WEB-INF/lib/spring-asm-3.0.5.RELEASE.jar./WEB-INF/lib/spring-beans-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-support-3.0.5.RELEASE.jar./WEB-INF/lib/spring-core-3.0.5.RELEASE.jar./WEB-INF/lib/spring-expression-3.0.5.RELEASE.jar./WEB-INF/lib/spring-web-3.0.5.RELEASE.jar./WEB-INF/lib/spring-webmvc-3.0.5.RELEASE.jar./WEB-INF/lib/validation-api-1.0.0.GA.jar 2 more JARs for just doing Ajax. Anyway, deploying this application gave the following error: Caused by: java.lang.NoSuchMethodError: org.codehaus.jackson.map.SerializationConfig.<init>(Lorg/codehaus/jackson/map/ClassIntrospector;Lorg/codehaus/jackson/map/AnnotationIntrospector;Lorg/codehaus/jackson/map/introspect/VisibilityChecker;Lorg/codehaus/jackson/map/jsontype/SubtypeResolver;)V    at org.springframework.samples.mvc.ajax.json.ConversionServiceAwareObjectMapper.<init>(ConversionServiceAwareObjectMapper.java:20)    at org.springframework.samples.mvc.ajax.json.JacksonConversionServiceConfigurer.postProcessAfterInitialization(JacksonConversionServiceConfigurer.java:40)    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsAfterInitialization(AbstractAutowireCapableBeanFactory.java:407) Seems like some incorrect repos in the "pom.xml". Next one is "mvc-showcase" and the 6.49 MB WAR now has 28 JARs as shown below: ./WEB-INF/lib/aopalliance-1.0.jar./WEB-INF/lib/aspectjrt-1.6.10.jar./WEB-INF/lib/commons-fileupload-1.2.2.jar./WEB-INF/lib/commons-io-2.0.1.jar./WEB-INF/lib/el-api-2.2.jar./WEB-INF/lib/hibernate-validator-4.1.0.Final.jar./WEB-INF/lib/jackson-core-asl-1.8.1.jar./WEB-INF/lib/jackson-mapper-asl-1.8.1.jar./WEB-INF/lib/javax.inject-1.jar./WEB-INF/lib/jcl-over-slf4j-1.6.1.jar./WEB-INF/lib/jdom-1.0.jar./WEB-INF/lib/joda-time-1.6.2.jar./WEB-INF/lib/jstl-api-1.2.jar./WEB-INF/lib/jstl-impl-1.2.jar./WEB-INF/lib/log4j-1.2.16.jar./WEB-INF/lib/rome-1.0.0.jar./WEB-INF/lib/slf4j-api-1.6.1.jar./WEB-INF/lib/slf4j-log4j12-1.6.1.jar./WEB-INF/lib/spring-aop-3.1.0.RELEASE.jar./WEB-INF/lib/spring-asm-3.1.0.RELEASE.jar./WEB-INF/lib/spring-beans-3.1.0.RELEASE.jar./WEB-INF/lib/spring-context-3.1.0.RELEASE.jar./WEB-INF/lib/spring-context-support-3.1.0.RELEASE.jar./WEB-INF/lib/spring-core-3.1.0.RELEASE.jar./WEB-INF/lib/spring-expression-3.1.0.RELEASE.jar./WEB-INF/lib/spring-web-3.1.0.RELEASE.jar./WEB-INF/lib/spring-webmvc-3.1.0.RELEASE.jar./WEB-INF/lib/validation-api-1.0.0.GA.jar The app at least deployed and showed results this time. But still no database! Next I tried building "jpetstore" and got the error: [ERROR] Failed to execute goal on project org.springframework.samples.jpetstore:Could not resolve dependencies for project org.springframework.samples:org.springframework.samples.jpetstore:war:1.0.0-SNAPSHOT: Failed to collect dependencies for [commons-fileupload:commons-fileupload:jar:1.2.1 (compile), org.apache.struts:com.springsource.org.apache.struts:jar:1.2.9 (compile), javax.xml.rpc:com.springsource.javax.xml.rpc:jar:1.1.0 (compile), org.apache.commons:com.springsource.org.apache.commons.dbcp:jar:1.2.2.osgi (compile), commons-io:commons-io:jar:1.3.2 (compile), hsqldb:hsqldb:jar:1.8.0.7 (compile), org.apache.tiles:tiles-core:jar:2.2.0 (compile), org.apache.tiles:tiles-jsp:jar:2.2.0 (compile), org.tuckey:urlrewritefilter:jar:3.1.0 (compile), org.springframework:spring-webmvc:jar:3.0.0.BUILD-SNAPSHOT (compile), org.springframework:spring-orm:jar:3.0.0.BUILD-SNAPSHOT (compile), org.springframework:spring-context-support:jar:3.0.0.BUILD-SNAPSHOT (compile), org.springframework.webflow:spring-js:jar:2.0.7.RELEASE (compile), org.apache.ibatis:com.springsource.com.ibatis:jar:2.3.4.726 (runtime), com.caucho:com.springsource.com.caucho:jar:3.2.1 (compile), org.apache.axis:com.springsource.org.apache.axis:jar:1.4.0 (compile), javax.wsdl:com.springsource.javax.wsdl:jar:1.6.1 (compile), javax.servlet:jstl:jar:1.2 (runtime), org.aspectj:aspectjweaver:jar:1.6.5 (compile), javax.servlet:servlet-api:jar:2.5 (provided), javax.servlet.jsp:jsp-api:jar:2.1 (provided), junit:junit:jar:4.6 (test)]: Failed to read artifact descriptor for org.springframework:spring-webmvc:jar:3.0.0.BUILD-SNAPSHOT: Could not transfer artifact org.springframework:spring-webmvc:pom:3.0.0.BUILD-SNAPSHOT from/to JBoss repository (http://repository.jboss.com/maven2): Access denied to: http://repository.jboss.com/maven2/org/springframework/spring-webmvc/3.0.0.BUILD-SNAPSHOT/spring-webmvc-3.0.0.BUILD-SNAPSHOT.pom It appears the sample is broken - maybe I was pulling from the wrong repository - would be great if someone were to point me at a good target to use here. With a 50% hit on samples in this repository, I started searching through numerous blogs, most of which have either outdated information (using XML-heavy Spring 2.5), some piece of configuration (which is a typical "feature" of Spring) is missing, or too much complexity in the sample. I finally found this blog that worked like a charm. This blog creates a trivial Spring MVC 3 application using Hibernate and MySQL. This application performs CRUD operations on a single table in a database using typical Spring technologies.  I downloaded the sample code from the blog, deployed it on GlassFish 3.1.2 and could CRUD the "person" entity. The source code for this application can be downloaded here. More details on the application statistics below. And then I built a similar CRUD application in Java EE 6 using NetBeans wizards in a couple of minutes. The source code for the application can be downloaded here and the WAR here. The Spring Source Tool Suite may also offer similar wizard-driven capabilities but this blog focus primarily on comparing the runtimes. The lack of STS tutorials was slightly disappointing as well. NetBeans however has tons of text-based and video tutorials and tons of material even by the community. One more bit on the download size of tools bundle ... NetBeans 7.1.1 "All" is 211 MB (which includes GlassFish and Tomcat) Spring Tool Suite  2.9.0 is 347 MB (~ 65% bigger) This blog is not about the tooling comparison so back to the Java EE 6 version of the application .... In order to run the Java EE version on GlassFish, copy the MySQL Connector/J to glassfish3/glassfish/domains/domain1/lib/ext directory and create a JDBC connection pool and JDBC resource as: ./bin/asadmin create-jdbc-connection-pool --datasourceclassname \\ com.mysql.jdbc.jdbc2.optional.MysqlDataSource --restype \\ javax.sql.DataSource --property \\ portNumber=3306:user=mysql:password=mysql:databaseName=mydatabase \\ myConnectionPool ./bin/asadmin create-jdbc-resource --connectionpoolid myConnectionPool jdbc/myDataSource I generated WARs for the two projects and the table below highlights some differences between them: Java EE 6 Spring WAR File Size 0.021030 MB 10.87 MB (~516x) Number of files 20 53 (> 2.5x) Bundled libraries 0 36 Total size of libraries 0 12.1 MB XML files 3 5 LoC in XML files 50 (11 + 15 + 24) 129 (27 + 46 + 16 + 11 + 19) (~ 2.5x) Total .properties files 1 Bundle.properties 2 spring.properties, log4j.properties Cold Deploy 5,339 ms 11,724 ms Second Deploy 481 ms 6,261 ms Third Deploy 528 ms 5,484 ms Fourth Deploy 484 ms 5,576 ms Runtime memory ~73 MB ~101 MB Some points worth highlighting from the table ... 516x WAR file, 10x deployment time - With 12.1 MB of libraries (for a very basic application) bundled in your application, the WAR file size and the deployment time will naturally go higher. The WAR file for Spring-based application is 516x bigger and the deployment time is double during the first deployment and ~ 10x during subsequent deployments. The Java EE 6 application is fully portable and will run on any Java EE 6 compliant application server. 36 libraries in the WAR - There are 14 Java EE 6 compliant application servers today. Each of those servers provide all the functionality like transactions, dependency injection, security, persistence, etc typically required of an enterprise or web application. There is no need to bundle 36 libraries worth 12.1 MB for a trivial CRUD application. These 14 compliant application servers provide all the functionality baked in. Now you can also deploy these libraries in the container but then you don't get the "portability" offered by Spring in that case. Does your typical Spring deployment actually do that ? 3x LoC in XML - The number of XML files is about 1.6x and the LoC is ~ 2.5x. So much XML seems circa 2003 when the Java language had no annotations. The XML files can be further reduced, e.g. faces-config.xml can be replaced without providing i18n, but I just want to compare stock applications. Memory usage - Both the applications were deployed on default GlassFish 3.1.2 installation and any additional memory consumed as part of deployment/access was attributed to the application. This is by no means scientific but at least provides an initial ballpark. This area definitely needs more investigation. Another table that compares typical Java EE 6 compliant application servers and the custom-stack created for a Spring application ... Java EE 6 Spring Web Container ? 53 MB (tcServer 2.6.3 Developer Edition) Security ? 12 MB (Spring Security 3.1.0) Persistence ? 6.3 MB (Hibernate 4.1.0, required) Dependency Injection ? 5.3 MB (Framework) Web Services ? 796 KB (Spring WS 2.0.4) Messaging ? 3.4 MB (RabbitMQ Server 2.7.1) 936 KB (Java client 936) OSGi ? 1.3 MB (Spring OSGi 1.2.1) GlassFish and WebLogic (starting at 33 MB) 83.3 MB There are differentiating factors on both the stacks. But most of the functionality like security, persistence, and dependency injection is baked in a Java EE 6 compliant application server but needs to be individually managed and patched for a Spring application. This very quickly leads to a "stack explosion". The Java EE 6 servers are tested extensively on a variety of platforms in different combinations whereas a Spring application developer is responsible for testing with different JDKs, Operating Systems, Versions, Patches, etc. Oracle has both the leading OSS lightweight server with GlassFish and the leading enterprise Java server with WebLogic Server, both Java EE 6 and both with lightweight deployment options. The Web Container offered as part of a Java EE 6 application server not only deploys your enterprise Java applications but also provide operational management, diagnostics, and mission-critical capabilities required by your applications. The Java EE 6 platform also introduced the Web Profile which is a subset of the specifications from the entire platform. It is targeted at developers of modern web applications offering a reasonably complete stack, composed of standard APIs, and is capable out-of-the-box of addressing the needs of a large class of Web applications. As your applications grow, the stack can grow to the full Java EE 6 platform. The GlassFish Server Web Profile starting at 33MB (smaller than just the non-standard tcServer) provides most of the functionality typically required by a web application. WebLogic provides battle-tested functionality for a high throughput, low latency, and enterprise grade web application. No individual managing or patching, all tested and commercially supported for you! Note that VMWare does have a server, tcServer, but it is non-standard and not even certified to the level of the standard Web Profile most customers expect these days. Customers who choose this risk proprietary lock-in since VMWare does not seem to want to formally certify with either Java EE 6 Enterprise Platform or with Java EE 6 Web Profile but of course it would be great if they were to join the community and help their customers reduce the risk of deploying on VMWare software. Some more points to help you decide choose between Java EE 6 and Spring ... Freedom to choose container - There are 14 Java EE 6 compliant application servers today, with a variety of open source and commercial offerings. A Java EE 6 application can be deployed on any of those containers. So if you deployed your application on GlassFish today and would like to scale up with your demands then you can deploy the same application to WebLogic. And because of the portability of a Java EE 6 application, you can even take it a different vendor altogether. Spring requires a runtime which could be any of these app servers as well. But why use Spring when all the required functionality is already baked into the application server itself ? Spring also has a different definition of portability where they claim to bundle all the libraries in the WAR file and move to any application server. But we saw earlier how bloated that archive could be. The equivalent features in Spring runtime offerings (mainly tcServer) are not all open source, not as mature, and often require manual assembly.  Vendor choice - The Java EE 6 platform is created using the Java Community Process where all the big players like Oracle, IBM, RedHat, and Apache are conritbuting to make the platform successful. Each application server provides the basic Java EE 6 platform compliance and has its own competitive offerings. This allows you to choose an application server for deploying your Java EE 6 applications. If you are not happy with the support or feature of one vendor then you can move your application to a different vendor because of the portability promise offered by the platform. Spring is a set of products from a single company, one price book, one support organization, one sustaining organization, one sales organization, etc. If any of those cause a customer headache, where do you go ? Java EE, backed by multiple vendors, is a safer bet for those that are risk averse. Production support - With Spring, typically you need to get support from two vendors - VMWare and the container provider. With Java EE 6, all of this is typically provided by one vendor. For example, Oracle offers commercial support from systems, operating systems, JDK, application server, and applications on top of them. VMWare certainly offers complete production support but do you really want to put all your eggs in one basket ? Do you really use tcServer ? ;-) Maintainability - With Spring, you are likely building your own distribution with multiple JAR files, integrating, patching, versioning, etc of all those components. Spring's claim is that multiple JAR files allow you to go à la carte and pick the latest versions of different components. But who is responsible for testing whether all these versions work together ? Yep, you got it, its YOU! If something does not work, who patches and maintains the JARs ? Of course, you! Commercial support for such a configuration ? On your own! The Java EE application servers manage all of this for you and provide a well-tested and commercially supported bundle. While it is always good to realize that there is something new and improved that updates and replaces older frameworks like Spring, the good news is not only does a Java EE 6 container offer what is described here, most also will let you deploy and run your Spring applications on them while you go through an upgrade to a more modern architecture. End result, you get the best of both worlds - keeping your legacy investment but moving to a more agile, lightweight world of Java EE 6. A message to the Spring lovers ... The complexity in J2EE 1.2, 1.3, and 1.4 led to the genesis of Spring but that was in 2004. This is 2012 and the name has changed to "Java EE 6" :-) There are tons of improvements in the Java EE platform to make it easy-to-use and powerful. Some examples: Adding @Stateless on a POJO makes it an EJB EJBs can be packaged in a WAR with no special packaging or deployment descriptors "web.xml" and "faces-config.xml" are optional in most of the common cases Typesafe dependency injection is now part of the Java EE platform Add @Path on a POJO allows you to publish it as a RESTful resource EJBs can be used as backing beans for Facelets-driven JSF pages providing full MVC Java EE 6 WARs are known to be kilobytes in size and deployed in milliseconds Tons of other simplifications in the platform and application servers So if you moved away from J2EE to Spring many years ago and have not looked at Java EE 6 (which has been out since Dec 2009) then you should definitely try it out. Just be at least aware of what other alternatives are available instead of restricting yourself to one stack. Here are some workshops and screencasts worth trying: screencast #37 shows how to build an end-to-end application using NetBeans screencast #36 builds the same application using Eclipse javaee-lab-feb2012.pdf is a 3-4 hours self-paced hands-on workshop that guides you to build a comprehensive Java EE 6 application using NetBeans Each city generally has a "spring cleanup" program every year. It allows you to clean up the mess from your house. For your software projects, you don't need to wait for an annual event, just get started and reduce the technical debt now! Move away from your legacy Spring-based applications to a lighter and more modern approach of building enterprise Java applications using Java EE 6. Watch this beautiful presentation that explains how to migrate from Spring -> Java EE 6: List of files in the Java EE 6 project: ./index.xhtml./META-INF./person./person/Create.xhtml./person/Edit.xhtml./person/List.xhtml./person/View.xhtml./resources./resources/css./resources/css/jsfcrud.css./template.xhtml./WEB-INF./WEB-INF/classes./WEB-INF/classes/Bundle.properties./WEB-INF/classes/META-INF./WEB-INF/classes/META-INF/persistence.xml./WEB-INF/classes/org./WEB-INF/classes/org/javaee./WEB-INF/classes/org/javaee/javaeemysql./WEB-INF/classes/org/javaee/javaeemysql/AbstractFacade.class./WEB-INF/classes/org/javaee/javaeemysql/Person.class./WEB-INF/classes/org/javaee/javaeemysql/Person_.class./WEB-INF/classes/org/javaee/javaeemysql/PersonController$1.class./WEB-INF/classes/org/javaee/javaeemysql/PersonController$PersonControllerConverter.class./WEB-INF/classes/org/javaee/javaeemysql/PersonController.class./WEB-INF/classes/org/javaee/javaeemysql/PersonFacade.class./WEB-INF/classes/org/javaee/javaeemysql/util./WEB-INF/classes/org/javaee/javaeemysql/util/JsfUtil.class./WEB-INF/classes/org/javaee/javaeemysql/util/PaginationHelper.class./WEB-INF/faces-config.xml./WEB-INF/web.xml List of files in the Spring 3.x project: ./META-INF ./META-INF/MANIFEST.MF./WEB-INF./WEB-INF/applicationContext.xml./WEB-INF/classes./WEB-INF/classes/log4j.properties./WEB-INF/classes/org./WEB-INF/classes/org/krams ./WEB-INF/classes/org/krams/tutorial ./WEB-INF/classes/org/krams/tutorial/controller ./WEB-INF/classes/org/krams/tutorial/controller/MainController.class ./WEB-INF/classes/org/krams/tutorial/domain ./WEB-INF/classes/org/krams/tutorial/domain/Person.class ./WEB-INF/classes/org/krams/tutorial/service ./WEB-INF/classes/org/krams/tutorial/service/PersonService.class ./WEB-INF/hibernate-context.xml ./WEB-INF/hibernate.cfg.xml ./WEB-INF/jsp ./WEB-INF/jsp/addedpage.jsp ./WEB-INF/jsp/addpage.jsp ./WEB-INF/jsp/deletedpage.jsp ./WEB-INF/jsp/editedpage.jsp ./WEB-INF/jsp/editpage.jsp ./WEB-INF/jsp/personspage.jsp ./WEB-INF/lib ./WEB-INF/lib/antlr-2.7.6.jar ./WEB-INF/lib/aopalliance-1.0.jar ./WEB-INF/lib/c3p0-0.9.1.2.jar ./WEB-INF/lib/cglib-nodep-2.2.jar ./WEB-INF/lib/commons-beanutils-1.8.3.jar ./WEB-INF/lib/commons-collections-3.2.1.jar ./WEB-INF/lib/commons-digester-2.1.jar ./WEB-INF/lib/commons-logging-1.1.1.jar ./WEB-INF/lib/dom4j-1.6.1.jar ./WEB-INF/lib/ejb3-persistence-1.0.2.GA.jar ./WEB-INF/lib/hibernate-annotations-3.4.0.GA.jar ./WEB-INF/lib/hibernate-commons-annotations-3.1.0.GA.jar ./WEB-INF/lib/hibernate-core-3.3.2.GA.jar ./WEB-INF/lib/javassist-3.7.ga.jar ./WEB-INF/lib/jstl-1.1.2.jar ./WEB-INF/lib/jta-1.1.jar ./WEB-INF/lib/junit-4.8.1.jar ./WEB-INF/lib/log4j-1.2.14.jar ./WEB-INF/lib/mysql-connector-java-5.1.14.jar ./WEB-INF/lib/persistence-api-1.0.jar ./WEB-INF/lib/slf4j-api-1.6.1.jar ./WEB-INF/lib/slf4j-log4j12-1.6.1.jar ./WEB-INF/lib/spring-aop-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-asm-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-beans-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-context-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-context-support-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-core-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-expression-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-jdbc-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-orm-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-tx-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-web-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-webmvc-3.0.5.RELEASE.jar ./WEB-INF/lib/standard-1.1.2.jar ./WEB-INF/lib/xml-apis-1.0.b2.jar ./WEB-INF/spring-servlet.xml ./WEB-INF/spring.properties ./WEB-INF/web.xml So, are you excited about Java EE 6 ? Want to get started now ? Here are some resources: Java EE 6 SDK (including runtime, samples, tutorials etc) GlassFish Server Open Source Edition 3.1.2 (Community) Oracle GlassFish Server 3.1.2 (Commercial) Java EE 6 using WebLogic 12c and NetBeans (Video) Java EE 6 with NetBeans and GlassFish (Video) Java EE with Eclipse and GlassFish (Video)

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• Building applications with WPF, MVVM and Prism(aka CAG)

  - by skjagini

  In this article I am going to walk through an application using WPF and Prism (aka composite application guidance, CAG) which simulates engaging a taxi (cab).  The rules are simple, the app would have3 screens A login screen to authenticate the user An information screen. A screen to engage the cab and roam around and calculating the total fare Metered Rate of Fare The meter is required to be engaged when a cab is occupied by anyone $3.00 upon entry $0.35 for each additional unit The unit fare is: one-fifth of a mile, when the cab is traveling at 6 miles an hour or more; or 60 seconds when not in motion or traveling at less than 12 miles per hour. Night surcharge of $.50 after 8:00 PM & before 6:00 AM Peak hour Weekday Surcharge of $1.00 Monday - Friday after 4:00 PM & before 8:00 PM New York State Tax Surcharge of $.50 per ride. Example: Friday (2010-10-08) 5:30pm Start at Lexington Ave & E 57th St End at Irving Pl & E 15th St Start = $3.00 Travels 2 miles at less than 6 mph for 15 minutes = $3.50 Travels at more than 12 mph for 5 minutes = $1.75 Peak hour Weekday Surcharge = $1.00 (ride started at 5:30 pm) New York State Tax Surcharge = $0.50 Before we dive into the app, I would like to give brief description about the framework.  If you want to jump on to the source code, scroll all the way to the end of the post. MVVM MVVM pattern is in no way related to the usage of PRISM in your application and should be considered if you are using WPF irrespective of PRISM or not. Lets say you are not familiar with MVVM, your typical UI would involve adding some UI controls like text boxes, a button, double clicking on the button,  generating event handler, calling a method from business layer and updating the user interface, it works most of the time for developing small scale applications. The problem with this approach is that there is some amount of code specific to business logic wrapped in UI specific code which is hard to unit test it, mock it and MVVM helps to solve the exact problem. MVVM stands for Model(M) – View(V) – ViewModel(VM),  based on the interactions with in the three parties it should be called VVMM,  MVVM sounds more like MVC (Model-View-Controller) so the name. Why it should be called VVMM: View – View Model - Model WPF allows to create user interfaces using XAML and MVVM takes it to the next level by allowing complete separation of user interface and business logic. In WPF each view will have a property, DataContext when set to an instance of a class (which happens to be your view model) provides the data the view is interested in, i.e., view interacts with view model and at the same time view model interacts with view through DataContext. Sujith, if view and view model are interacting directly with each other how does MVVM is helping me separation of concerns? Well, the catch is DataContext is of type Object, since it is of type object view doesn’t know exact type of view model allowing views and views models to be loosely coupled. View models aggregate data from models (data access layer, services, etc) and make it available for views through properties, methods etc, i.e., View Models interact with Models. PRISM Prism is provided by Microsoft Patterns and Practices team and it can be downloaded from codeplex for source code,  samples and documentation on msdn.  The name composite implies, to compose user interface from different modules (views) without direct dependencies on each other, again allowing  loosely coupled development. Well Sujith, I can already do that with user controls, why shall I learn another framework?  That’s correct, you can decouple using user controls, but you still have to manage some amount of coupling, like how to do you communicate between the controls, how do you subscribe/unsubscribe, loading/unloading views dynamically. Prism is not a replacement for user controls, provides the following features which greatly help in designing the composite applications. Dependency Injection (DI)/ Inversion of Control (IoC) Modules Regions Event Aggregator  Commands Simply put, MVVM helps building a single view and Prism helps building an application using the views There are other open source alternatives to Prism, like MVVMLight, Cinch, take a look at them as well. Lets dig into the source code.  1. Solution The solution is made of the following projects Framework: Holds the common functionality in building applications using WPF and Prism TaxiClient: Start up project, boot strapping and app styling TaxiCommon: Helps with the business logic TaxiModules: Holds the meat of the application with views and view models TaxiTests: To test the application 2. DI / IoC Dependency Injection (DI) as the name implies refers to injecting dependencies and Inversion of Control (IoC) means the calling code has no direct control on the dependencies, opposite of normal way of programming where dependencies are passed by caller, i.e inversion; aside from some differences in terminology the concept is same in both the cases. The idea behind DI/IoC pattern is to reduce the amount of direct coupling between different components of the application, the higher the dependency the more tightly coupled the application resulting in code which is hard to modify, unit test and mock.  Initializing Dependency Injection through BootStrapper TaxiClient is the starting project of the solution and App (App.xaml)  is the starting class that gets called when you run the application. From the App’s OnStartup method we will invoke BootStrapper.   namespace TaxiClient { /// <summary> /// Interaction logic for App.xaml /// </summary> public partial class App : Application { protected override void OnStartup(StartupEventArgs e) { base.OnStartup(e);   (new BootStrapper()).Run(); } } } BootStrapper is your contact point for initializing the application including dependency injection, creating Shell and other frameworks. We are going to use Unity for DI and there are lot of open source DI frameworks like Spring.Net, StructureMap etc with different feature set  and you can choose a framework based on your preferences. Note that Prism comes with in built support for Unity, for example we are deriving from UnityBootStrapper in our case and for any other DI framework you have to extend the Prism appropriately   namespace TaxiClient { public class BootStrapper: UnityBootstrapper { protected override IModuleCatalog CreateModuleCatalog() { return new ConfigurationModuleCatalog(); } protected override DependencyObject CreateShell() { Framework.FrameworkBootStrapper.Run(Container, Application.Current.Dispatcher);   Shell shell = new Shell(); shell.ResizeMode = ResizeMode.NoResize; shell.Show();   return shell; } } } Lets take a look into  FrameworkBootStrapper to check out how to register with unity container. namespace Framework { public class FrameworkBootStrapper { public static void Run(IUnityContainer container, Dispatcher dispatcher) { UIDispatcher uiDispatcher = new UIDispatcher(dispatcher); container.RegisterInstance<IDispatcherService>(uiDispatcher);   container.RegisterType<IInjectSingleViewService, InjectSingleViewService>( new ContainerControlledLifetimeManager());   . . . } } } In the above code we are registering two components with unity container. You shall observe that we are following two different approaches, RegisterInstance and RegisterType.  With RegisterInstance we are registering an existing instance and the same instance will be returned for every request made for IDispatcherService   and with RegisterType we are requesting unity container to create an instance for us when required, i.e., when I request for an instance for IInjectSingleViewService, unity will create/return an instance of InjectSingleViewService class and with RegisterType we can configure the life time of the instance being created. With ContaienrControllerLifetimeManager, the unity container caches the instance and reuses for any subsequent requests, without recreating a new instance. Lets take a look into FareViewModel.cs and it’s constructor. The constructor takes one parameter IEventAggregator and if you try to find all references in your solution for IEventAggregator, you will not find a single location where an instance of EventAggregator is passed directly to the constructor. The compiler still finds an instance and works fine because Prism is already configured when used with Unity container to return an instance of EventAggregator when requested for IEventAggregator and in this particular case it is called constructor injection. public class FareViewModel:ObservableBase, IDataErrorInfo { ... private IEventAggregator _eventAggregator;   public FareViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator; InitializePropertyNames(); InitializeModel(); PropertyChanged += OnPropertyChanged; } ... 3. Shell Shells are very similar in operation to Master Pages in asp.net or MDI in Windows Forms. And shells contain regions which display the views, you can have as many regions as you wish in a given view. You can also nest regions. i.e, one region can load a view which in itself may contain other regions. We have to create a shell at the start of the application and are doing it by overriding CreateShell method from BootStrapper From the following Shell.xaml you shall notice that we have two content controls with Region names as ‘MenuRegion’ and ‘MainRegion’.  The idea here is that you can inject any user controls into the regions dynamically, i.e., a Menu User Control for MenuRegion and based on the user action you can load appropriate view into MainRegion.    <Window x:Class="TaxiClient.Shell" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Regions="clr-namespace:Microsoft.Practices.Prism.Regions;assembly=Microsoft.Practices.Prism" Title="Taxi" Height="370" Width="800"> <Grid Margin="2"> <ContentControl Regions:RegionManager.RegionName="MenuRegion" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" />   <ContentControl Grid.Row="1" Regions:RegionManager.RegionName="MainRegion" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" /> <!--<Border Grid.ColumnSpan="2" BorderThickness="2" CornerRadius="3" BorderBrush="LightBlue" />-->   </Grid> </Window> 4. Modules Prism provides the ability to build composite applications and modules play an important role in it. For example if you are building a Mortgage Loan Processor application with 3 components, i.e. customer’s credit history,  existing mortgages, new home/loan information; and consider that the customer’s credit history component involves gathering data about his/her address, background information, job details etc. The idea here using Prism modules is to separate the implementation of these 3 components into their own visual studio projects allowing to build components with no dependency on each other and independently. If we need to add another component to the application, the component can be developed by in house team or some other team in the organization by starting with a new Visual Studio project and adding to the solution at the run time with very little knowledge about the application. Prism modules are defined by implementing the IModule interface and each visual studio project to be considered as a module should implement the IModule interface.  From the BootStrapper.cs you shall observe that we are overriding the method by returning a ConfiguratingModuleCatalog which returns the modules that are registered for the application using the app.config file  and you can also add module using code. Lets take a look into configuration file.   <?xml version="1.0"?> <configuration> <configSections> <section name="modules" type="Microsoft.Practices.Prism.Modularity.ModulesConfigurationSection, Microsoft.Practices.Prism"/> </configSections> <modules> <module assemblyFile="TaxiModules.dll" moduleType="TaxiModules.ModuleInitializer, TaxiModules" moduleName="TaxiModules"/> </modules> </configuration> Here we are adding TaxiModules project to our solution and TaxiModules.ModuleInitializer implements IModule interface   5. Module Mapper With Prism modules you can dynamically add or remove modules from the regions, apart from that Prism also provides API to control adding/removing the views from a region within the same module. Taxi Information Screen: Engage the Taxi Screen: The sample application has two screens, ‘Taxi Information’ and ‘Engage the Taxi’ and they both reside in same module, TaxiModules. ‘Engage the Taxi’ is again made of two user controls, FareView on the left and TotalView on the right. We have created a Shell with two regions, MenuRegion and MainRegion with menu loaded into MenuRegion. We can create a wrapper user control called EngageTheTaxi made of FareView and TotalView and load either TaxiInfo or EngageTheTaxi into MainRegion based on the user action. Though it will work it tightly binds the user controls and for every combination of user controls, we need to create a dummy wrapper control to contain them. Instead we can apply the principles we learned so far from Shell/regions and introduce another template (LeftAndRightRegionView.xaml) made of two regions Region1 (left) and Region2 (right) and load  FareView and TotalView dynamically.  To help with loading of the views dynamically I have introduce an helper an interface, IInjectSingleViewService,  idea suggested by Mike Taulty, a must read blog for .Net developers. using System; using System.Collections.Generic; using System.ComponentModel;   namespace Framework.PresentationUtility.Navigation {   public interface IInjectSingleViewService : INotifyPropertyChanged { IEnumerable<CommandViewDefinition> Commands { get; } IEnumerable<ModuleViewDefinition> Modules { get; }   void RegisterViewForRegion(string commandName, string viewName, string regionName, Type viewType); void ClearViewFromRegion(string viewName, string regionName); void RegisterModule(string moduleName, IList<ModuleMapper> moduleMappers); } } The Interface declares three methods to work with views: RegisterViewForRegion: Registers a view with a particular region. You can register multiple views and their regions under one command.  When this particular command is invoked all the views registered under it will be loaded into their regions. ClearViewFromRegion: To unload a specific view from a region. RegisterModule: The idea is when a command is invoked you can load the UI with set of controls in their default position and based on the user interaction, you can load different contols in to different regions on the fly.  And it is supported ModuleViewDefinition and ModuleMappers as shown below. namespace Framework.PresentationUtility.Navigation { public class ModuleViewDefinition { public string ModuleName { get; set; } public IList<ModuleMapper> ModuleMappers; public ICommand Command { get; set; } }   public class ModuleMapper { public string ViewName { get; set; } public string RegionName { get; set; } public Type ViewType { get; set; } } } 6. Event Aggregator Prism event aggregator enables messaging between components as in Observable pattern, Notifier notifies the Observer which receives notification it is interested in. When it comes to Observable pattern, Observer has to unsubscribes for notifications when it no longer interested in notifications, which allows the Notifier to remove the Observer’s reference from it’s local cache. Though .Net has managed garbage collection it cannot remove inactive the instances referenced by an active instance resulting in memory leak, keeping the Observers in memory as long as Notifier stays in memory.  Developers have to be very careful to unsubscribe when necessary and it often gets overlooked, to overcome these problems Prism Event Aggregator uses weak references to cache the reference (Observer in this case)  and releases the reference (memory) once the instance goes out of scope. Using event aggregator is very simple, declare a generic type of CompositePresenationEvent by inheriting from it. using Microsoft.Practices.Prism.Events; using TaxiCommon.BAO;   namespace TaxiCommon.CompositeEvents { public class TaxiOnMoveEvent:CompositePresentationEvent<TaxiOnMove> { } }   TaxiOnMove.cs includes the properties which we want to exchange between the parties, FareView and TotalView. using System;   namespace TaxiCommon.BAO { public class TaxiOnMove { public TimeSpan MinutesAtTweleveMPH { get; set; } public double MilesAtSixMPH { get; set; } } }   Lets take a look into FareViewodel (Notifier) and how it raises the event.  Here we are raising the event by getting the event through GetEvent<..>() and publishing it with the payload private void OnAddMinutes(object obj) { TaxiOnMove payload = new TaxiOnMove(); if(MilesAtSixMPH != null) payload.MilesAtSixMPH = MilesAtSixMPH.Value; if(MinutesAtTweleveMPH != null) payload.MinutesAtTweleveMPH = new TimeSpan(0,0,MinutesAtTweleveMPH.Value,0);   _eventAggregator.GetEvent<TaxiOnMoveEvent>().Publish(payload); ResetMinutesAndMiles(); } And TotalViewModel(Observer) subscribes to notifications by getting the event through GetEvent<..>() namespace TaxiModules.ViewModels { public class TotalViewModel:ObservableBase { .... private IEventAggregator _eventAggregator;   public TotalViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator; ... }   private void SubscribeToEvents() { _eventAggregator.GetEvent<TaxiStartedEvent>() .Subscribe(OnTaxiStarted, ThreadOption.UIThread,false,(filter) => true); _eventAggregator.GetEvent<TaxiOnMoveEvent>() .Subscribe(OnTaxiMove, ThreadOption.UIThread, false, (filter) => true); _eventAggregator.GetEvent<TaxiResetEvent>() .Subscribe(OnTaxiReset, ThreadOption.UIThread, false, (filter) => true); }   ... private void OnTaxiMove(TaxiOnMove taxiOnMove) { OnMoveFare fare = new OnMoveFare(taxiOnMove); Fares.Add(fare); SetTotalFare(new []{fare}); }   .... 7. MVVM through example In this section we are going to look into MVVM implementation through example.  I have all the modules declared in a single project, TaxiModules, again it is not necessary to have them into one project. Once the user logs into the application, will be greeted with the ‘Engage the Taxi’ screen which is made of two user controls, FareView.xaml and TotalView.Xaml. As you can see from the solution explorer, each of them have their own code behind files and  ViewModel classes, FareViewMode.cs, TotalViewModel.cs Lets take a look in to the FareView and how it interacts with FareViewModel using MVVM implementation. FareView.xaml acts as a view and FareViewMode.cs is it’s view model. The FareView code behind class   namespace TaxiModules.Views { /// <summary> /// Interaction logic for FareView.xaml /// </summary> public partial class FareView : UserControl { public FareView(FareViewModel viewModel) { InitializeComponent(); this.Loaded += (s, e) => { this.DataContext = viewModel; }; } } } The FareView is bound to FareViewModel through the data context  and you shall observe that DataContext is of type Object, i.e. the FareView doesn’t really know the type of ViewModel (FareViewModel). This helps separation of View and ViewModel as View and ViewModel are independent of each other, you can bind FareView to FareViewModel2 as well and the application compiles just fine. Lets take a look into FareView xaml file  <UserControl x:Class="TaxiModules.Views.FareView" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Toolkit="clr-namespace:Microsoft.Windows.Controls;assembly=WPFToolkit" xmlns:Commands="clr-namespace:Microsoft.Practices.Prism.Commands;assembly=Microsoft.Practices.Prism"> <Grid Margin="10" > ....   <Border Style="{DynamicResource innerBorder}" Grid.Row="0" Grid.Column="0" Grid.RowSpan="11" Grid.ColumnSpan="2" Panel.ZIndex="1"/>   <Label Grid.Row="0" Content="Engage the Taxi" Style="{DynamicResource innerHeader}"/> <Label Grid.Row="1" Content="Select the State"/> <ComboBox Grid.Row="1" Grid.Column="1" ItemsSource="{Binding States}" Height="auto"> <ComboBox.ItemTemplate> <DataTemplate> <TextBlock Text="{Binding Name}"/> </DataTemplate> </ComboBox.ItemTemplate> <ComboBox.SelectedItem> <Binding Path="SelectedState" Mode="TwoWay"/> </ComboBox.SelectedItem> </ComboBox> <Label Grid.Row="2" Content="Select the Date of Entry"/> <Toolkit:DatePicker Grid.Row="2" Grid.Column="1" SelectedDate="{Binding DateOfEntry, ValidatesOnDataErrors=true}" /> <Label Grid.Row="3" Content="Enter time 24hr format"/> <TextBox Grid.Row="3" Grid.Column="1" Text="{Binding TimeOfEntry, TargetNullValue=''}"/> <Button Grid.Row="4" Grid.Column="1" Content="Start the Meter" Commands:Click.Command="{Binding StartMeterCommand}" />   <Label Grid.Row="5" Content="Run the Taxi" Style="{DynamicResource innerHeader}"/> <Label Grid.Row="6" Content="Number of Miles &lt;@6mph"/> <TextBox Grid.Row="6" Grid.Column="1" Text="{Binding MilesAtSixMPH, TargetNullValue='', ValidatesOnDataErrors=true}"/> <Label Grid.Row="7" Content="Number of Minutes @12mph"/> <TextBox Grid.Row="7" Grid.Column="1" Text="{Binding MinutesAtTweleveMPH, TargetNullValue=''}"/> <Button Grid.Row="8" Grid.Column="1" Content="Add Minutes and Miles " Commands:Click.Command="{Binding AddMinutesCommand}"/> <Label Grid.Row="9" Content="Other Operations" Style="{DynamicResource innerHeader}"/> <Button Grid.Row="10" Grid.Column="1" Content="Reset the Meter" Commands:Click.Command="{Binding ResetCommand}"/>   </Grid> </UserControl> The highlighted code from the above code shows data binding, for example ComboBox which displays list of states has it’s ItemsSource bound to States property, with DataTemplate bound to Name and SelectedItem  to SelectedState. You might be wondering what are all these properties and how it is able to bind to them.  The answer lies in data context, i.e., when you bound a control, WPF looks for data context on the root object (Grid in this case) and if it can’t find data context it will look into root’s root, i.e. FareView UserControl and it is bound to FareViewModel.  Each of those properties have be declared on the ViewModel for the View to bind correctly. To put simply, View is bound to ViewModel through data context of type object and every control that is bound on the View actually binds to the public property on the ViewModel. Lets look into the ViewModel code (the following code is not an exact copy of FareViewMode.cs, pasted relevant code for this section)   namespace TaxiModules.ViewModels { public class FareViewModel:ObservableBase, IDataErrorInfo { public List<USState> States { get { return USStates.StateList; } }   public USState SelectedState { get { return _selectedState; } set { _selectedState = value; RaisePropertyChanged(_selectedStatePropertyName); } }   public DateTime? DateOfEntry { get { return _dateOfEntry; } set { _dateOfEntry = value; RaisePropertyChanged(_dateOfEntryPropertyName); } }   public TimeSpan? TimeOfEntry { get { return _timeOfEntry; } set { _timeOfEntry = value; RaisePropertyChanged(_timeOfEntryPropertyName); } }   public double? MilesAtSixMPH { get { return _milesAtSixMPH; } set { _milesAtSixMPH = value; RaisePropertyChanged(_distanceAtSixMPHPropertyName); } }   public int? MinutesAtTweleveMPH { get { return _minutesAtTweleveMPH; } set { _minutesAtTweleveMPH = value; RaisePropertyChanged(_minutesAtTweleveMPHPropertyName); } }   public ICommand StartMeterCommand { get { if(_startMeterCommand == null) { _startMeterCommand = new DelegateCommand<object>(OnStartMeter, CanStartMeter); } return _startMeterCommand; } }   public ICommand AddMinutesCommand { get { if(_addMinutesCommand == null) { _addMinutesCommand = new DelegateCommand<object>(OnAddMinutes, CanAddMinutes); } return _addMinutesCommand; } }   public ICommand ResetCommand { get { if(_resetCommand == null) { _resetCommand = new DelegateCommand<object>(OnResetCommand); } return _resetCommand; } }   } private void OnStartMeter(object obj) { _eventAggregator.GetEvent<TaxiStartedEvent>().Publish( new TaxiStarted() { EngagedOn = DateOfEntry.Value.Date + TimeOfEntry.Value, EngagedState = SelectedState.Value });   _isMeterStarted = true; OnPropertyChanged(this,null); } And views communicate user actions like button clicks, tree view item selections, etc using commands. When user clicks on ‘Start the Meter’ button it invokes the method StartMeterCommand, which calls the method OnStartMeter which publishes the event to TotalViewModel using event aggregator  and TaxiStartedEvent. namespace TaxiModules.ViewModels { public class TotalViewModel:ObservableBase { ... private IEventAggregator _eventAggregator;   public TotalViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator;   InitializePropertyNames(); InitializeModel(); SubscribeToEvents(); }   public decimal? TotalFare { get { return _totalFare; } set { _totalFare = value; RaisePropertyChanged(_totalFarePropertyName); } } .... private void SubscribeToEvents() { _eventAggregator.GetEvent<TaxiStartedEvent>().Subscribe(OnTaxiStarted, ThreadOption.UIThread,false,(filter) => true); _eventAggregator.GetEvent<TaxiOnMoveEvent>().Subscribe(OnTaxiMove, ThreadOption.UIThread, false, (filter) => true); _eventAggregator.GetEvent<TaxiResetEvent>().Subscribe(OnTaxiReset, ThreadOption.UIThread, false, (filter) => true); }   private void OnTaxiStarted(TaxiStarted taxiStarted) { Fares.Add(new EntryFare()); Fares.Add(new StateTaxFare(taxiStarted)); Fares.Add(new NightSurchargeFare(taxiStarted)); Fares.Add(new PeakHourWeekdayFare(taxiStarted));   SetTotalFare(Fares); }   private void SetTotalFare(IEnumerable<IFare> fares) { TotalFare = (_totalFare ?? 0) + TaxiFareHelper.GetTotalFare(fares); } ....   } }   TotalViewModel subscribes to events, TaxiStartedEvent and rest. When TaxiStartedEvent gets invoked it calls the OnTaxiStarted method which sets the total fare which includes entry fee, state tax, nightly surcharge, peak hour weekday fare.   Note that TotalViewModel derives from ObservableBase which implements the method RaisePropertyChanged which we are invoking in Set of TotalFare property, i.e, once we update the TotalFare property it raises an the event that  allows the TotalFare text box to fetch the new value through the data context. ViewModel is communicating with View through data context and it has no knowledge about View, helping in loose coupling of ViewModel and View.   I have attached the source code (.Net 4.0, Prism 4.0, VS 2010) , download and play with it and don’t forget to leave your comments.  

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• SQLAuthority News – Speaking Sessions at TechEd India – 3 Sessions – 1 Panel Discussion

  - by pinaldave

  Microsoft Tech-Ed India 2010 is considered as the major Technology event of the year for various IT professionals and developers. This event will feature a comprehensive forum in order   to learn, connect, explore, and evolve the current technologies we have today. I would recommend this event to you since here you will learn about today’s cutting-edge trends, thereby enhancing your work profile and getting ahead of the rest. But, the most important benefit of all might be the networking opportunity that that you can attain by attending the forum. You can build personal connections with various Microsoft experts and peers that will last even far beyond this event! It also feels good to let you know that I will be speaking at this year’s event! So, here are the sessions that await you in this mega-forum. Session 1: True Lies of SQL Server – SQL Myth Buster Date: April 12, 2010  Time: 11:15pm – 11:45pm In this 30-minute demo session, I am going to briefly demonstrate few SQL Server Myth and their resolution backing up with some demo. This demo session is a must-attend for all developers and administrators who would come to the event. This is going to be a very quick yet  fun session. Session 2: Master Data Services in Microsoft SQL Server 2008 R2 Date: April 12, 2010  Time: 2:30pm-3:30pm SQL Server Master Data Services will ship with SQL Server 2008 R2 and will improve Microsoft’s platform appeal. This session provides an in depth demonstration of MDS features and highlights important usage scenarios. Master Data Services enables consistent decision making by allowing you to create, manage and propagate changes from single master view of your business entities. Also with MDS – Master Data-hub which is the vital component helps ensure reporting consistency across systems and deliver faster more accurate results across the enterprise. We will talk about establishing the basis for a centralized approach to defining, deploying, and managing master data in the enterprise. Session 3: Developing with SQL Server Spatial and Deep Dive into Spatial Indexing Date: April 14, 2010 Time: 5:00pm-6:00pm Microsoft SQL Server 2008 delivers new spatial data types that enable you to consume, use, and extend location-based data through spatial-enabled applications. Attend this session to learn how to use spatial functionality in next version of SQL Server to build and optimize spatial queries. This session outlines the new geography data type to store geodetic spatial data and perform operations on it, use the new geometry data type to store planar spatial data and perform operations on it, take advantage of new spatial indexes for high performance queries, use the new spatial results tab to quickly and easily view spatial query results directly from within Management Studio, extend spatial data capabilities by building or integrating location-enabled applications through support for spatial standards and specifications and much more. Panel Discussion: Harness the power of Web – SEO and Technical Blogging Date: April 12, 2010 Time: 5:00pm-6:00pm Here you will learn lots of tricks and tips about SEO and Technical Blogging from various Industry Technical Blogging Experts. This event will surely be one of the most important Tech conventions of 2010. TechEd is going to be a very busy time for Tech developers and enthusiasts, since every evening there will be a fun session to attend. If you are interested in any of the above topics for every session, I suggest that you visit each of them as you will learn so many things about the topic to be discussed. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: MVP, Pinal Dave, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, SQLAuthority News, T SQL, Technology Tagged: TechEd, TechEdIn

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