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  • OIM 11g notification framework

    - by Rajesh G Kumar
    OIM 11g has introduced an improved and template based Notifications framework. New release has removed the limitation of sending text based emails (out-of-the-box emails) and enhanced to support html features. New release provides in-built out-of-the-box templates for events like 'Reset Password', 'Create User Self Service' , ‘User Deleted' etc. Also provides new APIs to support custom templates to send notifications out of OIM. OIM notification framework supports notification mechanism based on events, notification templates and template resolver. They are defined as follows: Ø Events are defined as XML file and imported as part of MDS database in order to make notification event available for use. Ø Notification templates are created using OIM advance administration console. The template contains the text and the substitution 'variables' which will be replaced with the data provided by the template resolver. Templates support internationalization and can be defined as HTML or in form of simple text. Ø Template resolver is a Java class that is responsible to provide attributes and data to be used at runtime and design time. It must be deployed following the OIM plug-in framework. Resolver data provided at design time is to be used by end user to design notification template with available entity variables and it also provides data at runtime to replace the designed variable with value to be displayed to recipients. Steps to define custom notifications in OIM 11g are: Steps# Steps 1. Define the Notification Event 2. Create the Custom Template Resolver class 3. Create Template with notification contents to be sent to recipients 4. Create Event triggering spots in OIM 1. Notification Event metadata The Notification Event is defined as XML file which need to be imported into MDS database. An event file must be compliant with the schema defined by the notification engine, which is NotificationEvent.xsd. The event file contains basic information about the event.XSD location in MDS database: “/metadata/iam-features-notification/NotificationEvent.xsd”Schema file can be viewed by exporting file from MDS using weblogicExportMetadata.sh script.Sample Notification event metadata definition: 1: <?xml version="1.0" encoding="UTF-8"?> 2: <Events xmlns:xsi=http://www.w3.org/2001/XMLSchema-instance xsi:noNamespaceSchemaLocation="../../../metadata/NotificationEvent.xsd"> 3: <EventType name="Sample Notification"> 4: <StaticData> 5: <Attribute DataType="X2-Entity" EntityName="User" Name="Granted User"/> 6: </StaticData> 7: <Resolver class="com.iam.oim.demo.notification.DemoNotificationResolver"> 8: <Param DataType="91-Entity" EntityName="Resource" Name="ResourceInfo"/> 9: </Resolver> 10: </EventType> 11: </Events> Line# Description 1. XML file notation tag 2. Events is root tag 3. EventType tag is to declare a unique event name which will be available for template designing 4. The StaticData element lists a set of parameters which allow user to add parameters that are not data dependent. In other words, this element defines the static data to be displayed when notification is to be configured. An example of static data is the User entity, which is not dependent on any other data and has the same set of attributes for all event instances and notification templates. Available attributes are used to be defined as substitution tokens in the template. 5. Attribute tag is child tag for StaticData to declare the entity and its data type with unique reference name. User entity is most commonly used Entity as StaticData. 6. StaticData closing tag 7. Resolver tag defines the resolver class. The Resolver class must be defined for each notification. It defines what parameters are available in the notification creation screen and how those parameters are replaced when the notification is to be sent. Resolver class resolves the data dynamically at run time and displays the attributes in the UI. 8. The Param DataType element lists a set of parameters which allow user to add parameters that are data dependent. An example of the data dependent or a dynamic entity is a resource object which user can select at run time. A notification template is to be configured for the resource object. Corresponding to the resource object field, a lookup is displayed on the UI. When a user selects the event the call goes to the Resolver class provided to fetch the fields that are displayed in the Available Data list, from which user can select the attribute to be used on the template. Param tag is child tag to declare the entity and its data type with unique reference name. 9. Resolver closing tag 10 EventType closing tag 11. Events closing tag Note: - DataType needs to be declared as “X2-Entity” for User entity and “91-Entity” for Resource or Organization entities. The dynamic entities supported for lookup are user, resource, and organization. Once notification event metadata is defined, need to be imported into MDS database. Fully qualified resolver class name need to be define for XML but do not need to load the class in OIM yet (it can be loaded later). 2. Coding the notification resolver All event owners have to provide a resolver class which would resolve the data dynamically at run time. Custom resolver class must implement the interface oracle.iam.notification.impl.NotificationEventResolver and override the implemented methods with actual implementation. It has 2 methods: S# Methods Descriptions 1. public List<NotificationAttribute> getAvailableData(String eventType, Map<String, Object> params); This API will return the list of available data variables. These variables will be available on the UI while creating/modifying the Templates and would let user select the variables so that they can be embedded as a token as part of the Messages on the template. These tokens are replaced by the value passed by the resolver class at run time. Available data is displayed in a list. The parameter "eventType" specifies the event Name for which template is to be read.The parameter "params" is the map which has the entity name and the corresponding value for which available data is to be fetched. Sample code snippet: List<NotificationAttribute> list = new ArrayList<NotificationAttribute>(); long objKey = (Long) params.get("resource"); //Form Field details based on Resource object key HashMap<String, Object> formFieldDetail = getObjectFormName(objKey); for (Iterator<?> itrd = formFieldDetail.entrySet().iterator(); itrd.hasNext(); ) { NotificationAttribute availableData = new NotificationAttribute(); Map.Entry formDetailEntrySet = (Entry<?, ?>)itrd.next(); String fieldLabel = (String)formDetailEntrySet.getValue(); availableData.setName(fieldLabel); list.add(availableData); } return list; 2. Public HashMap<String, Object> getReplacedData(String eventType, Map<String, Object> params); This API would return the resolved value of the variables present on the template at the runtime when notification is being sent. The parameter "eventType" specifies the event Name for which template is to be read.The parameter "params" is the map which has the base values such as usr_key, obj_key etc required by the resolver implementation to resolve the rest of the variables in the template. Sample code snippet: HashMap<String, Object> resolvedData = new HashMap<String, Object>();String firstName = getUserFirstname(params.get("usr_key"));resolvedData.put("fname", firstName); String lastName = getUserLastName(params.get("usr_key"));resolvedData.put("lname", lastname);resolvedData.put("count", "1 million");return resolvedData; This code must be deployed as per OIM 11g plug-in framework. The XML file defining the plug-in is as below: <?xml version="1.0" encoding="UTF-8"?> <oimplugins xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <plugins pluginpoint="oracle.iam.notification.impl.NotificationEventResolver"> <plugin pluginclass= " com.iam.oim.demo.notification.DemoNotificationResolver" version="1.0" name="Sample Notification Resolver"/> </plugins> </oimplugins> 3. Defining the template To create a notification template: Log in to the Oracle Identity Administration Click the System Management tab and then click the Notification tab From the Actions list on the left pane, select Create On the Create page, enter values for the following fields under the Template Information section: Template Name: Demo template Description Text: Demo template Under the Event Details section, perform the following: From the Available Event list, select the event for which the notification template is to be created from a list of available events. Depending on your selection, other fields are displayed in the Event Details section. Note that the template Sample Notification Event created in the previous step being used as the notification event. The contents of the Available Data drop down are based on the event XML StaticData tag, the drop down basically lists all the attributes of the entities defined in that tag. Once you select an element in the drop down, it will show up in the Selected Data text field and then you can just copy it and paste it into either the message subject or the message body fields prefixing $ symbol. Example if list has attribute like First_Name then message body will contains this as $First_Name which resolver will parse and replace it with actual value at runtime. In the Resource field, select a resource from the lookup. This is the dynamic data defined by the Param DataType element in the XML definition. Based on selected resource getAvailableData method of resolver will be called to fetch the resource object attribute detail, if method is overridden with required implementation. For current scenario, Map<String, Object> params will get populated with object key as value and key as “resource” in the map. This is the only input will be provided to resolver at design time. You need to implement the further logic to fetch the object attributes detail to populate the available Data list. List string should not have space in between, if object attributes has space for attribute name then implement logic to replace the space with ‘_’ before populating the list. Example if attribute name is “First Name” then make it “First_Name” and populate the list. Space is not supported while you try to parse and replace the token at run time with real value. Make a note that the Available Data and Selected Data are used in the substitution tokens definition only, they do not define the final data that will be sent in the notification. OIM will invoke the resolver class to get the data and make the substitutions. Under the Locale Information section, enter values in the following fields: To specify a form of encoding, select either UTF-8 or ASCII. In the Message Subject field, enter a subject for the notification. From the Type options, select the data type in which you want to send the message. You can choose between HTML and Text/Plain. In the Short Message field, enter a gist of the message in very few words. In the Long Message field, enter the message that will be sent as the notification with Available data token which need to be replaced by resolver at runtime. After you have entered the required values in all the fields, click Save. A message is displayed confirming the creation of the notification template. Click OK 4. Triggering the event A notification event can be triggered from different places in OIM. The logic behind the triggering must be coded and plugged into OIM. Examples of triggering points for notifications: Event handlers: post process notifications for specific data updates in OIM users Process tasks: to notify the users that a provisioning task was executed by OIM Scheduled tasks: to notify something related to the task The scheduled job has two parameters: Template Name: defines the notification template to be sent User Login: defines the user record that will provide the data to be sent in the notification Sample Code Snippet: public void execute(String templateName , String userId) { try { NotificationService notService = Platform.getService(NotificationService.class); NotificationEvent eventToSend=this.createNotificationEvent(templateName,userId); notService.notify(eventToSend); } catch (Exception e) { e.printStackTrace(); } } private NotificationEvent createNotificationEvent(String poTemplateName, String poUserId) { NotificationEvent event = new NotificationEvent(); String[] receiverUserIds= { poUserId }; event.setUserIds(receiverUserIds); event.setTemplateName(poTemplateName); event.setSender(null); HashMap<String, Object> templateParams = new HashMap<String, Object>(); templateParams.put("USER_LOGIN",poUserId); event.setParams(templateParams); return event; } public HashMap getAttributes() { return null; } public void setAttributes() {} }

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  • Round Table - Minimum Cost Algorithm

    - by 7Aces
    Problem Link - http://www.iarcs.org.in/zco2013/index.php/problems/ROUNDTABLE It's dinner time in Castle Camelot, and the fearsome Knights of the Round Table are clamouring for dessert. You, the chef, are in a soup. There are N knights, including King Arthur, each with a different preference for dessert, but you cannot afford to make desserts for all of them. You are given the cost of manufacturing each Knight's preferred dessert-since it is a round table, the list starts with the cost of King Arthur's dessert, and goes counter-clockwise. You decide to pick the cheapest desserts to make, such that for every pair of adjacent Knights, at least one gets his dessert. This will ensure that the Knights do not protest. What is the minimum cost of tonight's dinner, given this condition? I used the Dynamic Programming approach, considering the smallest of i-1 & i-2, & came up with the following code - #include<cstdio> #include<algorithm> using namespace std; int main() { int n,i,j,c,f; scanf("%d",&n); int k[n],m[n][2]; for(i=0;i<n;++i) scanf("%d",&k[i]); m[0][0]=k[0]; m[0][1]=0; m[1][0]=k[1]; m[1][1]=1; for(i=2;i<n;++i) { c=1000; for(j=i-2;j<i;++j) { if(m[j][0]<c) { c=m[j][0]; f=m[j][1];} } m[i][0]=c+k[i]; m[i][1]=f; } if(m[n-2][0]<m[n-1][0] && m[n-2][1]==0) printf("%d\n",m[n-2][0]); else printf("%d\n",m[n-1][0]); } I used the second dimension of the m array to store from which knight the given sequence started (1st or 2nd). I had to do this because of the case when m[n-2]<m[n-1] but the sequence started from knight 2, since that would create two adjacent knights without dessert. The problem arises because of the table's round shape. Now an anomaly arises when I consider the case - 2 1 1 2 1 2. The program gives an answer 5 when the answer should be 4, by picking the 1st, 3rd & 5th knight. At this point, I started to doubt my initial algorithm (approach) itself! Where did I go wrong?

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  • Issuing Current Time Increments in StreamInsight (A Practical Example)

    The issuing of a Current Time Increment, Cti, in StreamInsight is very definitely one of the most important concepts to learn if you want your Streams to be responsive. A full discussion of how to issue Ctis is beyond the scope of this article but a very good explanation in addition to Books Online can be found in these three articles by a member of the StreamInsight team at Microsoft, Ciprian Gerea. Time in StreamInsight Series http://blogs.msdn.com/b/streaminsight/archive/2010/07/23/time-in-streaminsight-i.aspx http://blogs.msdn.com/b/streaminsight/archive/2010/07/30/time-in-streaminsight-ii.aspx http://blogs.msdn.com/b/streaminsight/archive/2010/08/03/time-in-streaminsight-iii.aspx A lot of the problems I see with unresponsive or stuck streams on the MSDN Forums are to do with how Ctis are enqueued or in a lot of cases not enqueued. If you enqueue events and never enqueue a Cti then StreamInsight will be perfectly happy. You, on the other hand, will never see data on the output as you have not told StreamInsight to flush the stream. This article deals with a specific implementation problem I had recently whilst working on a StreamInsight project. I look at some possible options and discuss why they would not work before showing the way I solved the problem. The stream of data I was dealing with on this project was very bursty that is to say when events were flowing they came through very quickly and in large numbers (1000 events/sec), but when the stream calmed down it could be a few seconds between each event. When enqueuing events into the StreamInsight engne it is best practice to do so with a StartTime that is given to you by the system producing the event . StreamInsight processes events and it doesn't matter whether those events are being pushed into the engine by a source system or the events are being read from something like a flat file in a directory somewhere. You can apply the same logic and temporal algebra to both situations. Reading from a file is an excellent example of where the time of the event on the source itself is very important. We could be reading that file a long time after it was written. Being able to read the StartTime from the events allows us to define windows that will hold the correct sets of events. I was able to do this with my stream but this is where my problems started. Below is a very simple script to create a SQL Server table and populate it with sample data that will show exactly the problem I had. CREATE TABLE [dbo].[t] ( [c1] [int] PRIMARY KEY, [c2] [datetime] NULL ) INSERT t VALUES (1,'20100810'),(2,'20100810'),(3,'20100810') Column c2 defines the StartTime of the event on the source and as you can see the values in all 3 rows of data is the same. If we read Ciprian’s articles we know that we can define how Ctis get injected into the stream in 3 different places The Stream Definition The Input Factory The Input Adapter I personally have always been a fan of enqueing Ctis through the factory. Below is code typical of what I would use to do this On the class itself I do some inheriting public class SimpleInputFactory : ITypedInputAdapterFactory<SimpleInputConfig>, ITypedDeclareAdvanceTimeProperties<SimpleInputConfig> And then I implement the following function public AdapterAdvanceTimeSettings DeclareAdvanceTimeProperties<TPayload>(SimpleInputConfig configInfo, EventShape eventShape) { return new AdapterAdvanceTimeSettings( new AdvanceTimeGenerationSettings(configInfo.CtiFrequency, TimeSpan.FromTicks(-1)), AdvanceTimePolicy.Adjust); } The configInfo .CtiFrequency property is a value I pass through to define after how many events I want a Cti to be injected and this in turn will flush through the stream of data. I usually pass a value of 1 for this setting. The second parameter determines the CTI timestamp in terms of a delay relative to the events. -1 ticks in the past results in 1 tick in the future, i.e., ahead of the event. The problem with this method though is that if consecutive events have the same StartTime then only one of those events will be enqueued. In this example I use the following to define how I assign the StartTime of my events currEvent.StartTime = (DateTimeOffset)dt.c2; If I go ahead and run my StreamInsight process with this configuration i can see on the output adapter that two events have been removed To see this in a little more depth I can use the StreamInsight Debugger and see what happens internally. What is happening here is that the first event arrives and a Cti is injected with a time of 1 tick after the StartTime of that event (Also the EndTime of the event). The second event arrives and it has a StartTime of before the Cti and even though we specified AdvanceTimePolicy.Adjust on the factory we know that a point event can never be adjusted like this and the event is dropped. The same happens for the third event as well (The second and third events get trumped by the Cti). For a more detailed discussion of why this happens look here http://www.sqlis.com/sqlis/post/AdvanceTimePolicy-and-Point-Event-Streams-In-StreamInsight.aspx We end up with a single event being pushed into the output adapter and our result now makes sense. The next way I tried to solve this problem by changing the value of the second parameter to TimeSpan.Zero Here is how my factory code now looks public AdapterAdvanceTimeSettings DeclareAdvanceTimeProperties<TPayload>(SimpleInputConfig configInfo, EventShape eventShape) { return new AdapterAdvanceTimeSettings( new AdvanceTimeGenerationSettings(configInfo.CtiFrequency, TimeSpan.Zero), AdvanceTimePolicy.Adjust); } What I am doing here is declaring a policy that says inject a Cti together with every event and stamp it with a StartTime that is equal to the start time of the event itself (TimeSpan.Zero). This method has plus points as well as a downside. The upside is that no events will be lost by having the same StartTime as previous events. The Downside is that because the Cti is declared with the StartTime of the event itself then it does not actually flush that particular event because in the StreamInsight algebra, a Cti commits only those events that occurred strictly before them. To flush the events we need a Cti to be enqueued with a greater StartTime than the events themselves. Here is what happened when I ran this configuration As you can see all we got through was the Cti and none of the events. The debugger output shows the stamps on the Cti and the events themselves. Because the Cti issued has the same timestamp (StartTime) as the events then none of the events get flushed. I was nearly there but not quite. Because my stream was bursty it was possible that the next event would not come along for a few seconds and this was far too long for an event to be enqueued and not be flushed to the output adapter. I needed another solution. Two possible solutions crossed my mind although only one of them made sense when I explored it some more. Where multiple events have the same StartTime I could add 1 tick to the first event, two to the second, three to third etc thereby giving them unique StartTime values. Add a timer to manually inject Ctis The problem with the first implementation is that I would be giving the events a new StartTime. This would cause me the following problems If I want to define windows over the stream then some events may not be captured in the right windows and therefore any calculations on those windows I did would be wrong What would happen if we had 10,000 events with the same StartTime? I would enqueue them with StartTime + n ticks. Along comes a genuine event with a StartTime of the very first event + 1 tick. It is now too far in the past as far as my stream is concerned and it would be dropped. Not what I would want to do at all. I decided then to look at the Timer based solution I created a timer on my input adapter that elapsed every 200ms. private Timer tmr; public SimpleInputAdapter(SimpleInputConfig configInfo) { ctx = new SimpleTimeExtractDataContext(configInfo.ConnectionString); this.configInfo = configInfo; tmr = new Timer(200); tmr.Elapsed += new ElapsedEventHandler(t_Elapsed); tmr.Enabled = true; } void t_Elapsed(object sender, ElapsedEventArgs e) { ts = DateTime.Now - dtCtiIssued; if (ts.TotalMilliseconds >= 200 && TimerIssuedCti == false) { EnqueueCtiEvent(System.DateTime.Now.AddTicks(-100)); TimerIssuedCti = true; } }   In the t_Elapsed event handler I find out the difference in time between now and when the last event was processed (dtCtiIssued). I then check to see if that is greater than or equal to 200ms and if the last issuing of a Cti was done by the timer or by a genuine event (TimerIssuedCti). If I didn’t do this check then I would enqueue a Cti every time the timer elapsed which is not something I wanted. If the difference between the two times is greater than or equal to 500ms and the last event enqueued was by a real event then I issue a Cti through the timer to flush the event Queue, otherwise I do nothing. When I enqueue the Ctis into my stream in my ProduceEvents method I also set the values of dtCtiIssued and TimerIssuedCti   currEvent = CreateInsertEvent(); currEvent.StartTime = (DateTimeOffset)dt.c2; TimerIssuedCti = false; dtCtiIssued = currEvent.StartTime; If I go ahead and run this configuration I see the following in my output. As we can see the first Cti gets enqueued as before but then another is enqueued by the timer and because this has a later timestamp it flushes the enqueued events through the engine. Conclusion Hopefully this has shown how the enqueuing of Ctis can have a dramatic effect on the responsiveness of your output in StreamInsight. Understanding the temporal nature of the product is for me one of the most important things you can learn. I have attached my solution for the demos. It is all in one project and testing each variation is a simple matter of commenting and un-commenting the parts in the code we have been dealing with here.

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  • What are the best ways to cope with «one of those days»? [closed]

    - by Júlio Santos
    I work in a fast-paced startup and am absolutely in love with what I do. Still, I wake up to a bad mood as often as the next guy. I find that forcing myself to play out my day as usual doesn't help — in fact, it only makes it worse, possibly ruining my productivity for the rest of the week. There are several ways I can cope with this, for instance: dropping the current task for the day and getting that awesome but low-priority feature in place; doing some pending research for future development (i.e. digging up ruby gems); spending the day reading and educating myself; just taking the day off. The first three items are productive in themselves, and taking the day off recharges my coding mana for the rest of the week. Being a young developer, I'm pretty sure there's a multitude of alternatives that I haven't come across yet. How can programmers cope with off days? Edit: I am looking for answers related specifically to this profession. I therefore believe that coping with off days in our field is fundamentally different that doing so in other areas. Programmers (especially in a start-up) are a unique breed in this context in the sense that they tend to have a multitude of tasks at hand on any given moment, so they can easily switch between these without wreaking too much havoc. Programmers also tend to work based on clear, concise objectives — provided they are well managed either by themselves or a third party — and hence have a great deal of flexibility when it comes to managing their time. Finally, our line of work creates the opportunity — necessity, if you will — to fit a plethora of tasks not directly related to the current one, such as research and staying on top of new releases and software updates.

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  • Progressive Enhancement vs. Single Page Apps

    - by SeanPlusPlus
    I just got back from a conference in Boston called An Event Apart. A really popular theme amongst the speakers was the idea of progressive enhancement - a site's content should go in the HTML, and JavaScript should only be used to enhance behavior. The arguments that the speakers gave for progressive enhancement were very compelling. Not only is it a solid pattern for supporting older browsers, and devices on a network with low bandwidth, but HTML fails much more gracefully than JavaScript (i.e. markup that is not supported is just ignored, while if a browser throws an exception while executing your script - you are hosed). Jeremy Keith gave a particularly insightful talk about this. But what about single page web apps like Backbone and Angular? The whole design behind these frameworks seems to push the developer toward moving content out of the HTML, and into something like a JSON API. I can not seem to gel these two design patterns: progressive enhancement vs. single page web apps. Are there instances when one is better than the other? Or are they not even antagonistic technologies, and I am missing something here with my mental model?

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  • PHP Aspect Oriented Design

    - by Devin Dixon
    This is a continuation of this Code Review question. What was taken away from that post, and other aspect oriented design is it is hard to debug. To counter that, I implemented the ability to turn tracing of the design patterns on. Turning trace on works like: //This can be added anywhere in the code Run::setAdapterTrace(true); Run::setFilterTrace(true); Run::setObserverTrace(true); //Execute the functon echo Run::goForARun(8); In the actual log with the trace turned on, it outputs like so: adapter 2012-02-12 21:46:19 {"type":"closure","object":"static","call_class":"\/public_html\/examples\/design\/ClosureDesigns.php","class":"Run","method":"goForARun","call_method":"goForARun","trace":"Run::goForARun","start_line":68,"end_line":70} filter 2012-02-12 22:05:15 {"type":"closure","event":"return","object":"static","class":"run_filter","method":"\/home\/prodigyview\/public_html\/examples\/design\/ClosureDesigns.php","trace":"Run::goForARun","start_line":51,"end_line":58} observer 2012-02-12 22:05:15 {"type":"closure","object":"static","class":"run_observer","method":"\/home\/prodigyview\/public_html\/public\/examples\/design\/ClosureDesigns.php","trace":"Run::goForARun","start_line":61,"end_line":63} When the information is broken down, the data translates to: Called by an adapter or filter or observer The function called was a closure The location of the closure Class:method the adapter was implemented on The Trace of where the method was called from Start Line and End Line The code has been proven to work in production environments and features various examples of to implement, so the proof of concept is there. It is not DI and accomplishes things that DI cannot. I wouldn't call the code boilerplate but I would call it bloated. In summary, the weaknesses are bloated code and a learning curve in exchange for aspect oriented functionality. Beyond the normal fear of something new and different, what are other weakness in this implementation of aspect oriented design, if any? PS: More examples of AOP here: https://github.com/ProdigyView/ProdigyView/tree/master/examples/design

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  • Understanding normal maps on terrain

    - by JohnB
    I'm having trouble understanding some of the math behind normal map textures even though I've got it to work using borrowed code, I want to understand it. I have a terrain based on a heightmap. I'm generating a mesh of triangles at load time and rendering that mesh. Now for each vertex I need to calculate a normal, a tangent, and a bitangent. My understanding is as follows, have I got this right? normal is a unit vector facing outwards from the surface of the triangle. For a vertex I take the average of the normals of the triangles using that vertex. tangent is a unit vector in the direction of the 'u' coordinates of the texture map. As my texture u,v coordinates follow the x and y coordinates of the terrain, then my understanding is that this vector is simply the vector along the surface in the x direction. So should be able to calculate this as simply the difference between vertices in the x direction to get a vector, (and normalize it). bitangent is a unit vector in the direction of the 'v' coordinates of the texture map. As my texture u,v coordinates follow the x and y coordinates of the terrain, then my understanding is that this vector is simply the vector along the surface in the y direction. So should be able to calculate this as simply the difference between vertices in the y direction to get a vector, (and normalize it). However the code I have borrowed seems much more complicated than this and takes into account the actual values of u, and v at each vertex which I don't understand the need for as they increase in exactly the same direction as x, and y. I implemented what I thought from above, and it simply doesn't work, the normals are clearly not working for lighting. Have I misunderstood something? Or can someone explain to me the physical meaning of the tangent and bitangent vectors when applied to a mesh generated from a hightmap like this, when u and v texture coordinates map along the x and y directions. Thanks for any help understanding this.

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  • Collision Resolution

    - by ultifinitus
    Hey all, I'm making a simple side-scrolling game, and I would appreciate some input! My collision detection system is a simple bounding box detection, so it's really easy to implement. However my collision resolution is ridiculous! Currently I have a little formula like this: if (colliding(firstObject,secondObject)) firstObject.resolve_collision(yAxisOffset); if (colliding(firstObject,secondObject)) firstObject.resolve_collision(xAxisOffset); where yAxisOffset is only set if the first object's previous y position was outside the second object's collision frame, respectively xAxisOffset as well. Now this is working great, in general. However there is a single problem. When I have a stack of objects and I push the first object against that stack, the first object get's "stuck," on the stack. What's I think is happening is the object's collision system checks and resolves for collisions based on creation time, so If I check one axis, then the other, the object will "sink" object directly along the checking axis. This sinking action causes the collision detection routine to think there's a gap between our position and the other object's position, and when I finally check the object that I've already sunk into, my object's position is resolved to it's original position... All this is great, and I'm sure if I bang my head against a wall long enough i'll come up with a working algorithm, but I'd rather not =). So what in the heck do you think I should do? How could I change my collision resolution system to fix this? Here's the program (temporary link, not sure how long it'll last) (notes: arrow keys to navigate, click to drop block, x to jump) I'd appreciate any help you can offer!

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  • Design pattern for client/server sessions?

    - by nonot1
    Are there any common patterns or general guidance I can learn from for how to design a client/server system where the both the client and server must maintain some kind per-client session state? I've found any number of libraries that can help with some of the plumbing, but it's the overall design I'm wondering about. Open issues in my mind: How to structure the client/server communication so that bidirectional synchronous and asynchronous requests are possible? The server side needs to spawn a couple of per-connected-client session-long helper process. How to manage that? How to manage the mapping from a given client (and any of it's requests) to server state and helper process instances in the face of multiple clients and intermittent network connectivity. Most communication can be simple blocking request/reply, but some will be long running processing tasks that the client will want to keep tabs on. To the extent that it matters, the platform is Linux/C/C++. Not web based. Just an existing thick-client software app being modified to talk to backend servers for some tasks.

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  • Creating an expandable, cross-platform compatible program "core".

    - by Thomas Clayson
    Hi there. Basically the brief is relatively simple. We need to create a program core. An engine that will power all sorts of programs with a large number of distinct potential applications and deployments. The core will be an analytics and algorithmic processor which will essentially take user-specific input and output scenarios based on the information it gets, whilst recording this information for reporting. It needs to be cross platform compatible. Something that can have platform specific layers put on top which can interface with the core. It also needs to be able to be expandable, for instance, modular with developers being able to write "add-ons" or "extensions" which can alter the function of the end program and can use the core to its full extent. (For instance, a good example of what I'm looking to create is a browser. It has its main core, the web-kit engine, for instance, and then on top of this is has a platform-specific GUI and can also have add-ons and extensions which can change the behavior of the program.) Our problem is that the extensions need to interface directly with the main core and expand/alter that functionality rather than the platform specific "layer". So, given that I have no experience in this whatsoever (I have a PHP background and recently objective-c), where should I start, and is there any knowledge/wisdom you can impart on me please? Thanks for all the help and advice you can give me. :) If you need any more explanation just ask. At the moment its in the very early stages of development, so we're just researching all possible routes of development. Thanks a lot

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  • How to handle a player's level and its consequent privileges?

    - by Songo
    I'm building a game similar to Mafia Wars where a player can do tasks for his gang and gain experience and thus advancing his level. The game is built using PHP and a Mysql database. In the game I want to limit the resources allowed to player based on his level. For example: ________| (Max gold) | (Max army size) | (Max moves) | ... Level 1 | 1000 | 100 | 10 | ... Level 2 | 1500 | 200 | 20 | ... Level 3 | 3000 | 300 | 25 | ... . . . In addition certain features of the game won't be allowed until a certain level is reached such as players under Level 10 can't trade in the game market, players under Level 20 can't create alliances,...etc. The way I have modeled it is by implementing a very loooong ACL (Access Control List) with about 100 entries (an entry for each level). However, I think there may be a simpler approach to this seeing that this feature have been implemented in many games before.

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  • Broad topics needed for teaching game development

    - by livingtech
    I am going to be doing a presentation on game development to an iPhone user group in the near(ish) future. My audience are iPhone developers, but not necessarily very experienced ones, and this is meant to be an introduction. My question is, what broad topics are needed to understand game development? I acknowledge that this is fairly subjective, but I really am hoping for a comprehensive list of high-level topics that apply to a broad enough swath of games that anyone interested in the topic SHOULD know about them. I would be ecstatic with some pointers to any resources that attempt to make a list such as this this. (I have looked, but my google-fu is failing me tonight.) Here's what I have so far: The Game Loop a sub-note about event driven games 2D Animation sprites/texture maps 3D Animation importance of frameworks modeling software Particles and particle effects hit detection AI Obviously I will not be covering all these topics with any depth, more like simply defining them so that after my talk, the audience will (hopefully) be able to wrap their heads around how any given game might be developed. What am I missing?

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  • Should I modify an entity with many parameters or with the entity itself?

    - by Saeed Neamati
    We have a SOA-based system. The service methods are like: UpdateEntity(Entity entity) For small entities, it's all fine. However, when entities get bigger and bigger, to update one property we should follow this pattern in UI: Get parameters from UI (user) Create an instance of the Entity, using those parameters Get the entity from service Write code to fill the unchanged properties Give the result entity to the service Another option that I've experienced in previous experiences is to create semantic update methods for each update scenario. In other words instead of having one global all-encompasing update method, we had many ad-hoc parametric methods. For example, for the User entity, instead of having UpdateUser (User user) method, we had these methods: ChangeUserPassword(int userId, string newPassword) AddEmailToUserAccount(int userId, string email) ChangeProfilePicture(int userId, Image image) ... Now, I don't know which method is truly better, and for each approach, we encounter problems. I mean, I'm going to design the infrastructure for a new system, and I don't have enough reasons to pick any of these approaches. I couldn't find good resources on the Internet, because of the lack of keywords I could provide. What approach is better? What pitfalls each has? What benefits can we get from each one?

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  • Java Applet Tower Defence Game needs tweeking

    - by Ephiras
    Hello :) i have made a tower defence Game for my computer science class as one of my major projects, but have encountered some rather fatal roadblocks. here they are creating a menu screen (class Menu) that can set the total number of enimies, the max number of towers, starting money and the map. i tried creating a constructor in my Main class that sets all the values to whatever the Menu class passes in. I want the Menu screen to close after a difficulty has been selected and the main class to begin. Another problem i would really like some help with is instead of having to write entire arrays i would like to create a small segment of code that runs through an entire picture and sets up an array based on that pixels color.this way i can have multiple levels just dragged into a level folder and have the program read through them. users can even create their own. so a 1 if its yellow, a two if blue and a 3 if purple, then everything else = 0; you can download all the classes and code uif you'd like here sorry about having to redirect you but i wasn't sure how to efficently add a code spoiler. help is greatly appreciated

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  • What is the philosophy/reasoning behind C#'s Pascal-casing method names?

    - by Nocturne
    I'm just starting to learn C#. Coming from a background in Java, C++ and Objective-C, I find C#'s Pascal-casing its method-names rather unique, and a tad difficult to get used to at first. What is the reasoning and philosophy behind this? I'm guessing it is because of C# properties. Unlike in Objective-C, where method names can be exactly the same as an instance variables, this is not the case with C#. I would guess one of the goals with properties (as it is with most of the languages that support it) is to make properties truly indistinguishable from variables and methods. So, one can have an "int x" in C#, and the corresponding property becomes X. To ensure that properties and methods are indistinguishable, all method names I'm guessing are also therefore expected to start with an uppercase letter. (This is just my hypothesis based on what I know of C# so far—I'm still learning). I'm very curious to know how this curious guideline came into being (given that it's not something one sees in most other languages where method names are expected to start with a lowercase letter) (EDIT: By Pascal-casing, I mean PascalCase (which is basically camelCase but starting with a capital letter). Method names typically start with a lowercase letter in most languages)

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  • Is it bad to be the only person supporting software you have developed?

    - by trpt4him
    My employer has a need for a web-based application to manage and share data within the department, with approximately 50-75 possible users. I feel I have the ability to write it for them. I would likely use Python/Django with a MySQL database, so it would be open source. However, I'm the only IT person in my department (our larger organization has a separate IT support staff with which I often work, but not for web development). I want to develop this application, but if I leave in 1-2 years, and someone else has to come in after me and support it, will this be seen as a bad decision? This is assuming all the obvious points -- I will write documentation, I will comment my code, and I will strive to follow good application design principles. But will that be enough? In principle, is it acceptable for one person to develop and support an entire web application? Is this a "do first, then show and ask" kind of situation, or should I be certain it will be adopted by everyone involved first?

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  • Attributes of an Ethical Programmer?

    - by ahmed
    Software that we write has ramifications in the real world. If not, it wouldn't be very useful. Thus, it has the potential to sweep across the world faster than a deadly manmade virus or to affect society every bit as much as genetic manipulation. Maybe we can't see how right now, but in the future our code will have ever-greater potential for harm or good. Of course, there's the issue of hacking. That's clearly a crime. Or is it that clear? Isn't hacking acceptable for our government in the event of national security? What about for other governments? Cases of life-and-death emergency? Tracking down deadbeat parents? Screening the genetic profile of job candidates? Where is the line drawn? Who decides? Do programmers have responsibility for how their code is used? What if a programmer writes code to pry into confidential information or copy-protected material? Does he bear responsibility along with the person who used the program? What about a programmer who knowingly or unknowingly writes code to "fix the books?" Should he be liable?

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  • The advantages & disadvantages to be had from using a Web Framework?

    - by JHarley1
    Hello, This question is focused on extracting the advantages and disadvantages of using Web based Frameworks: such as Cake PHP, Zend, jQuery, ASP.NET). This question is completely language agnostic. Let me start with the notion of "Standing on the shoulders of Giants". Advantages: Empowers Developers - by taking features that would have previously have taken 100's of lines of code and compressing them into one simple function call empowers developers to integrate more complex features into their Web Sites. Allow for Quicker development of applications - this is very relevant for people that need websites created in a very small window (has anyone any examples of this?) Lower Costs - allows programmers to pass cost savings onto the customer, a whole new range of customers generated that wanted a website but previously could not afford the higher development costs. Disadvantages: Lost Understanding - by relying on the features of a framework a developer is in danger of loosing understanding on how things work (underneath the hood). The configuration cliff - once you go further than the configuration of your framework your productivity drops right off, it can be difficult to implement features outside of a frameworks configuration. Developer tramlines - you (the developer) has to do things the way that the developer want you to do things. Security issues - giving people these tools to develop professional looking websites fast is a potential risk, people can quickly create professional looking websites for fraudulent companies. I wonder what people make of my points, and whether any body disagrees with them? Also if people have additional points I would be grateful. Many Thanks, J

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  • Java and .NET cost of use [on hold]

    - by 1110
    I work with .NET technology stack for about 4 years. I am learning and enjoy working with ASP MVC framework and I never did anything serious in other languages. This is not the question like what is better (I read all similar questions). What interest me is the cost of switching. For example: If you are about to start a start-up company today and you are in my situation not too much money, some good idea that you think others will use and have a knowledge of .NET. In my head I have a few questions that I can't answer and I know that somebody with experience can: 1) Java & .NET hosting. Suppose shared hosting is not good enough anymore, your site has grown and you need more resources. How much Java services is cheaper compared to .NET? 2) I didn't follow hype about ORACLE will kill java long time. Does oracle show interest in investing in java. I mean is is safe to bet on java as a technology when starting start-up (basically did oracle show some will to destroy java platform)? 3) I am not sure what I am asking here. When you use Java you can use JEEE stack or Java with third party stack (spring, hibernate, maven etc.). I saw a lot of project that work with second option if web application is not enterprise level but social networking site for example which stack is best pick? Summary of this question is is it safe to jump in to Java learn it and build product based on it. It's not too hard for me to learn it. But how much can I get from it.

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  • Why is Java the lingua franca at so many institutions?

    - by Billy ONeal
    EDIT: This question at first seems to be bashing Java, and I guess at this point it is a bit. However, the bigger point I am trying to make is why any one single language is chosen as the one end all be all solution to all problems. Java happens to be the one that's used so that's the one I had to beat on here, but I'm not intentionality ripping Java a new one :) I don't like Java in most academic settings. I'm not saying the language itself is bad -- it has several extremely desirable aspects, most importantly the ability to run without recompilation on most any platform. Nothing wrong with using the language for Your Next App ^TM. (Not something I would personally do, but that's more because I have less experience with it, rather than it's design being poor) I think it is a waste that high level CS courses are taught using Java as a language. Too many of my co-students cannot program worth a damn, because they don't know how to work in a non-garbage-collected world. They don't fundamentally understand the machines they are programming for. When someone can work outside of a garbage collected world, they can work inside of one, but not vice versa. GC is a tool, not a crutch. But the way it is used to teach computer science students is a as a crutch. Computer science should not teach an entire suite of courses tailored to a single language. Students leave with the idea that all good design is idiomatic Java design, and that Object Oriented Design is the ONE TRUE WAY THAT IS THE ONLY WAY THINGS CAN BE DONE. Other languages, at least one of them not being a garbage collected language, should be used in teaching, in order to give the graduate a better understanding of the machines. It is an embarrassment that somebody with a PHD in CS from a respected institution cannot program their way out of a paper bag. What's worse, is that when I talk to those CS professors who actually do understand how things operate, they share feelings like this, that we're doing a disservice to our students by doing everything in Java. (Note that the above would be the same if I replaced it with any other language, generally using a single language is the problem, not Java itself) In total, I feel I can no longer respect any kind of degree at all -- when I can't see those around me able to program their way out of fizzbuzz problems. Why/how did it get to be this way?

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  • Do functional generics exist and what is the correct name for them if they do?

    - by voroninp
    Consider the following generic class: public class EntityChangeInfo<EntityType,TEntityKey> { ChangeTypeEnum ChangeType {get;} TEntityKeyType EntityKey {get;} } Here EntityType unambiguously defines TEntityKeyType. So it would be nice to have some kind of types' map: public class EntityChangeInfo<EntityType,TEntityKey> with map < [ EntityType : Person -> TEntityKeyType : int] [ EntityType : Car -> TEntityKeyType : CarIdType ]> { ChangeTypeEnum ChangeType {get;} TEntityKeyType EntityKey {get;} } Another one example is: public class Foo<TIn> with map < [TIn : Person -> TOut1 : string, TOut2 : int, ..., TOutN : double ] [TIn : Car -> TOut1 : int, TOut2 :int, ..., TOutN : Price ] > { TOut1 Prop1 {get;set;} TOut2 Prop2 {get;set;} ... TOutN PropN {get;set;} } The reasonable question: how can this be interpreted by the compiler? Well, for me it is just the shortcut for two structurally similar classes: public sealed class Foo<Person> { string Prop1 {get;set;} int Prop2 {get;set;} ... double PropN {get;set;} } public sealed class Foo<Car> { int Prop1 {get;set;} int Prop2 {get;set;} ... Price PropN {get;set;} } But besides this we could imaging some update of the Foo<>: public class Foo<TIn> with map < [TIn : Person -> TOut1 : string, TOut2 : int, ..., TOutN : double ] [TIn : Car -> TOut1 : int, TOut2 :int, ..., TOutN : Price ] > { TOut1 Prop1 {get;set;} TOut2 Prop2 {get;set;} ... TOutN PropN {get;set;} public override string ToString() { return string.Format("prop1={0}, prop2={1},...propN={N-1}, Prop1, Prop2,...,PropN); } } This all can seem quite superficial but the idea came when I was designing the messages for our system. The very first class. Many messages with the same structure should be discriminated by the EntityType. So the question is whether such construct exists in any programming language?

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  • Do functional generics exist or what is the correct name for them if they do?

    - by voroninp
    Consider the following generic class public class EntityChangeInfo<EntityType,TEntityKey> { ChangeTypeEnum ChangeType {get;} TEntityKeyType EntityKey {get;} } Here EntityType unambiguously defines TEntityKeyType. So it would be nice to have some kind of types' map public class EntityChangeInfo<EntityType,TEntityKey> with map < [ EntityType : Person -> TEntityKeyType : int] [ EntityType : Car -> TEntityKeyType : CarIdType ]> { ChangeTypeEnum ChangeType {get;} TEntityKeyType EntityKey {get;} } Another one example is: public class Foo<TIn> with map < [TIn : Person -> TOut1 : string, TOut2 : int, ..., TOutN : double ] [TIn : Car -> TOut1 : int, TOut2 :int, ..., TOutN : Price ] > { TOut1 Prop1 {get;set;} TOut2 Prop2 {get;set;} ... TOutN PropN {get;set;} } The reasonable question how this can be interpreted by the compiler? Well, for me it is just the sortcut for two structurally similar classes: public sealed class Foo<Person> { string Prop1 {get;set;} int Prop2 {get;set;} ... double PropN {get;set;} } public sealed class Foo<Car> { int Prop1 {get;set;} int Prop2 {get;set;} ... Price PropN {get;set;} } But besides this we could imaging some update of the Foo<: public class Foo<TIn> with map < [TIn : Person -> TOut1 : string, TOut2 : int, ..., TOutN : double ] [TIn : Car -> TOut1 : int, TOut2 :int, ..., TOutN : Price ] > { TOut1 Prop1 {get;set;} TOut2 Prop2 {get;set;} ... TOutN PropN {get;set;} public override string ToString() { return string.Format("prop1={0}, prop2={1},...propN={N-1}, Prop1, Prop2,...,PropN); } } This all can seem quite superficial but the idea came when I was designing the messages for our system. The very first class. Many messages with the same structrue should be discriminated by the EntityType. So the question is whether such construct exist in any programming language?

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  • Web based KVM management for Ubuntu

    - by Tim
    Hey all, We've got a single Ubuntu 9.10 root server on which we want to run multiple KVM virtual machines. To administer these virtual machines I'd like a web based KVM management tool, but I don't know which one to choose from the list of tools mentioned on linux-kvm.org. I've used virsh & virt-manager on my desktop, but would like a web interface for the server. I tested ConVirt on my desktop, but it failed to pickup KVM machines from virsh / virt-manager, and I could not get KVM virtual machine import to work (only Xen). oVirt looks good, but I can't find out if and how I can install it on Ubuntu 9.10.. (And I'd really rather not waste another few days on testing stuff that might not work in the end.) Can anyone recommend any good web based KVM management tools that are easy to install on Ubuntu 9.10? I'm looking for something that will also allow me to run other services like apache and postgresql besides hosting virtual machines, so preferably fairly lightweight & no dedicated OS installs. We don't need any professional clustering / migration or anything, just something that will let us create, start, inspect, administer & stop virtual machines from a web page. Best regards, Tim

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  • Is fish or zsh better for shell programming?

    - by Julien Nicoulaud
    I'm a bash user willing to switch to a more friendly and advanced shell. I read a lot of good things about zsh, but I gave a quick test at fish and it seems great too. Both seem very close in term of features, what is your opinion about those two shells especially as regards shell programming?

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  • Squid - Active Directory - permissions based on Nodes rather than Groups

    - by Genboy
    Hi, I have squid running on a gateway machine & I am trying to integrate it with Active Directory for authentication & also for giving different browsing permissions for different users. 1) /usr/lib/squid/ldap_auth -b OU=my,DC=company,DC=com -h ldapserver -f sAMAccountName=%s -D "CN=myadmin,OU=Unrestricted Users,OU=my,DC=company,DC=com" -w mypwd 2) /usr/lib/squid/squid_ldap_group -b "OU=my,DC=company,DC=com" -f "(&(sAMAccountName=%u)(memberOf=cn=%g,cn=users,dc=company,dc=com))" -h ldapserver -D "CN=myadmin,OU=Unrestricted Users,OU=my,DC=company,DC=com" -w zxcv Using the first command above, I am able to authenticate users. Using the second command above, I am able to figure out if a user belongs to a particular active directory group. So I should be able to set ACL's based on groups. However, my customer's AD setup is such that he has users arranged in different Nodes. For eg. He has users setup in the following way cn=usr1,ou=Lev1,ou=Users,ou=my,ou=company,ou=com cn=usr2,ou=Lev2,ou=Users,ou=my,ou=company,ou=com cn=usr3,ou=Lev3,ou=Users,ou=my,ou=company,ou=com etc. So, he wants that I have different permissions based on whether a user belongs to Lev1 or Lev2 or Lev3 nodes. Note that these aren't groups, but nodes. Is there a way to do this with squid? My squid is running on a debian machine.

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