Search Results

Search found 17345 results on 694 pages for 'next'.

Page 142/694 | < Previous Page | 138 139 140 141 142 143 144 145 146 147 148 149  | Next Page >

• Using the OAM Mobile & Social SDK to secure native mobile apps - Part 2 : OAM Mobile & Social Server configuration

  - by kanishkmahajan

  Objective  In the second part of this blog post I'll now cover configuration of OAM to secure our sample native apps developed using the iOS SDK. First, here are some key server side concepts: Application Profiles: An application profile is a logical representation of your application within OAM server. It could be a web (html/javascript) or native (iOS or Android) application. Applications may have different requirements for AuthN/AuthZ, and therefore each application that interacts with OAM Mobile & Social REST services must be uniquely defined. Service Providers: Service providers represent the back end services that are accessed by applications. With OAM Mobile & Social these services are in the areas of authentication, authorization and user profile access. A Service Provider then defines a type or class of service for authentication, authorization or user profiles. For example, the JWTAuthentication provider performs authentication and returns JWT (JSON Web Tokens) to the application. In contrast, the OAMAuthentication also provides authentication but uses OAM SSO tokens Service Profiles:  A Service Profile is a logical envelope that defines a service endpoint URL for a service provider for the OAM Mobile & Social Service. You can create multiple service profiles for a service provider to define token capabilities and service endpoints. Each service provider instance requires atleast one corresponding service profile.The  OAM Mobile & Social Service includes a pre-configured service profile for each pre-configured service provider. Service Domains: Service domains bind together application profiles and service profiles with an optional security handler. So now let's configure the OAM server. Additional details are in the OAM Documentation and this post simply provides an outline of configuration tasks required to configure OAM for securing native apps.  Configuration  Create The Application Profile Log on to the Oracle Access Management console and from System Configuration -> Mobile and Social -> Mobile Services, select "Create" under Application Profiles. You would do this  step twice - once for each of the native apps - AvitekInventory and AvitekScheduler. Enter the parameters for the new Application profile: Name:  The application name. In this example we use 'InventoryApp' for the AvitekInventory app and 'SchedulerApp' for the AvitekScheduler app. The application name configured here must match the application name in the settings for the deployed iOS application. BaseSecret: Enter a password here. This does not need to match any existing password. It is used as an encryption key between the client and the OAM server.  Mobile Configuration: Enable this checkbox for any mobile applications. This enables the SDK to collect and send Mobile specific attributes to the OAM server.  Webview: Controls the type of browser that the iOS application will use. The embedded browser (default) will render the browser within the application. External will use the system standalone browser. External can sometimes be preferable for debugging URLScheme: The URL scheme associated with the iOS apps that is also used as a custom URL scheme to register O/S handlers that will take control when OAM transfers control to device. For the AvitekInventory and the AvitekScheduler apps I used osa:// and client:// respectively. You set this scheme in Xcode while developing your iOS Apps under Info->URL Types.  Bundle Identifier : The fully qualified name of your iOS application. You typically set this when you create a new Xcode project or under General->Identity in Xcode. For the AvitekInventory and AvitekScheduler apps these were com.us.oracle.AvitekInventory and com.us.oracle.AvitekScheduler respectively.  Create The Service Domain Select create under Service domains. Create a name for your domain (AvitekDomain is what I've used). The name configured must match the service domain set in the iOS application settings. Under "Application Profile Selection" click the browse button. Choose the application profiles that you created in the previous step one by one. Set the InventoryApp as the SSO agent (with an automatic priority of 1) and the SchedulerApp as the SSO client. This associates these applications with this service domain and configures them in a 'circle of trust'.  Advance to the next page of the wizard to configure the services for this domain. For this example we will use the following services:  Authentication:   This will use the JWT (JSON Web Token) format authentication provider. The iOS application upon successful authentication will receive a signed JWT token from OAM Mobile & Social service. This token will be used in subsequent calls to OAM. Use 'MobileOAMAuthentication' here. Authorization:  The authorization provider. The SDK makes calls to this provider endpoint to obtain authorization decisions on resource requests. Use 'OAMAuthorization' here. User Profile Service:  This is the service that provides user profile services (attribute lookup, attribute modification). It can be any directory configured as a data source in OAM.  And that's it! We're done configuring our native apps. In the next section, let's look at some additional features that were mentioned in the earlier post that are automated by the SDK for the app developer i.e. these are areas that require no additional coding by the app developer when developing with the SDK as they only require server side configuration: Additional Configuration  Offline Authentication Select this option in the service domain configuration to allow users to log in and authenticate to the application locally. Clear the box to block users from authenticating locally. Strong Authentication By simply selecting the OAAMSecurityHandlerPlugin while configuring mobile related Service Domains, the OAM Mobile&Social service allows sophisticated device and client application registration logic as well as the advanced risk and fraud analysis logic found in OAAM to be applied to mobile authentication. Let's look at some scenarios where the OAAMSecurityHandlerPlugin gets used. First, when we configure OAM and OAAM to integrate together using the TAP scheme, then that integration kicks off by selecting the OAAMSecurityHandlerPlugin in the mobile service domain. This is how the mobile device is now prompted for KBA,OTP etc depending on the TAP scheme integration and the OAM users registered in the OAAM database. Second, when we configured the service domain, there were claim attributes there that are already pre-configured in OAM Mobile&Social service and we simply accepted the default values- these are the set of attributes that will be fetched from the device and passed to the server during registration/authentication as device profile attributes. When a mobile application requests a token through the Mobile Client SDK, the SDK logic will send the Device Profile attributes as a part of an HTTP request. This set of Device Profile attributes enhances security by creating an audit trail for devices that assists device identification. When the OAAM Security Plug-in is used, a particular combination of Device Profile attribute values is treated as a device finger print, known as the Digital Finger Print in the OAAM Administration Console. Each finger print is assigned a unique fingerprint number. Each OAAM session is associated with a finger print and the finger print makes it possible to log (and audit) the devices that are performing authentication and token acquisition. Finally, if the jail broken option is selected while configuring an application profile, the SDK detects a device is jail broken based on configured policy and if the OAAM handler is configured the plug-in can allow or block access to client device depending on the OAAM policy as well as detect blacklisted, lost or stolen devices and send a wipeout command that deletes all the mobile &social relevant data and blocks the device from future access. 1024x768 Social Logins Finally, let's complete this post by adding configuration to configure social logins for mobile applications. Although the Avitek sample apps do not demonstrate social logins this would be an ideal exercise for you based on the sample code provided in the earlier post. I'll cover the server side configuration here (with Facebook as an example) and you can retrofit the code to accommodate social logins by following the steps outlined in "Invoking Authentication Services" and add code in LoginViewController and maybe create a new delegate - AvitekRPDelegate based on the description in the previous post. So, here all you will need to do is configure an application profile for social login, configure a new service domain that uses the social login application profile, register the app on Facebook and finally configure the Facebook OAuth provider in OAM with those settings. Navigate to Mobile and Social, click on "Internet Identity Services" and create a new application profile. Here are the relevant parameters for the new application profile (-also we're not registering the social user in OAM with this configuration below, however that is a key feature as well): Name:  The application name. This must match the name of the of mobile application profile created for your application under Mobile Services. We used InventoryApp for this example. SharedSecret: Enter a password here. This does not need to match any existing password. It is used as an encryption key between the client and the OAM Mobile and Social service.  Mobile Application Return URL: After the Relying Party (social) login, the OAM Mobile & Social service will redirect to the iOS application using this URI. This is defined under Info->URL type and we used 'osa', so we define this here as 'osa://' Login Type: Choose to allow only internet identity authentication for this exercise. Authentication Service Endpoint : Make sure that /internetidentityauthentication is selected. Login to http://developers.facebook.com using your Facebook account and click on Apps and register the app as InventoryApp. Note that the consumer key and API secret gets generated automatically by the Facebook OAuth server. Navigate back to OAM and under Mobile and Social, click on "Internet Identity Services" and edit the Facebook OAuth Provider. Add the consumer key and API secret from the Facebook developers site to the Facebook OAuth Provider: Navigate to Mobile Services. Click on New to create a new service domain. In this example we call the domain "AvitekDomainRP". The type should be 'Mobile Application' and the application credential type 'User Token'. Add the application "InventoryApp" to the domain. Advance the next page of the wizard. Select the  default service profiles but ensure that the Authentication Service is set to 'InternetIdentityAuthentication'. Finish the creation of the service domain.

  Read the article

• BizTalk: History of one project architecture

  - by Leonid Ganeline

  "In the beginning God made heaven and earth. Then he started to integrate." At the very start was the requirement: integrate two working systems. Small digging up: It was one system. It was good but IT guys want to change it to the new one, much better, chipper, more flexible, and more progressive in technologies, more suitable for the future, for the faster world and hungry competitors. One thing. One small, little thing. We cannot turn off the old system (call it A, because it was the first), turn on the new one (call it B, because it is second but not the last one). The A has a hundreds users all across a country, they must study B. A still has a lot nice custom features, home-made features that cannot disappear. These features have to be moved to the B and it is a long process, months and months of redevelopment. So, the decision was simple. Let’s move not jump, let’s both systems working side-by-side several months. In this time we could teach the users and move all custom A’s special functionality to B. That automatically means both systems should work side-by-side all these months and use the same data. Data in A and B must be in sync. That’s how the integration projects get birth. Moreover, the specific of the user tasks requires the both systems must be in sync in real-time. Nightly synchronization is not working, absolutely.   First draft The first draft seems simple. Both systems keep data in SQL databases. When data changes, the Create, Update, Delete operations performed on the data, and the sync process could be started. The obvious decision is to use triggers on tables. When we are talking about data, we are talking about several entities. For example, Orders and Items [in Orders]. We decided to use the BizTalk Server to synchronize systems. Why it was chosen is another story. Second draft   Let’s take an example how it works in more details. 1.       User creates a new entity in the A system. This fires an insert trigger on the entity table. Trigger has to pass the message “Entity created”. This message includes all attributes of the new entity, but I focused on the Id of this entity in the A system. Notation for this message is id.A. System A sends id.A to the BizTalk Server. 2.       BizTalk transforms id.A to the format of the system B. This is easiest part and I will not focus on this kind of transformations in the following text. The message on the picture is still id.A but it is in slightly different format, that’s why it is changing in color. BizTalk sends id.A to the system B. 3.       The system B creates the entity on its side. But it uses different id-s for entities, these id-s are id.B. System B saves id.A+id.B. System B sends the message id.A+id.B back to the BizTalk. 4.       BizTalk sends the message id.A+id.B to the system A. 5.       System A saves id.A+id.B. Why both id-s should be saved on both systems? It was one of the next requirements. Users of both systems have to know the systems are in sync or not in sync. Users working with the entity on the system A can see the id.B and use it to switch to the system B and work there with the copy of the same entity. The decision was to store the pairs of entity id-s on both sides. If there is only one id, the entities are not in sync yet (for the Create operation). Third draft Next problem was the reliability of the synchronization. The synchronizing process can be interrupted on each step, when message goes through the wires. It can be communication problem, timeout, temporary shutdown one of the systems, the second system cannot be synchronized by some internal reason. There were several potential problems that prevented from enclosing the whole synchronization process in one transaction. Decision was to restart the whole sync process if it was not finished (in case of the error). For this purpose was created an additional service. Let’s call it the Resync service. We still keep the id pairs in both systems, but only for the fast access not for the synchronization process. For the synchronizing these id-s now are kept in one main place, in the Resync service database. The Resync service keeps record as: ·       Id.A ·       Id.B ·       Entity.Type ·       Operation (Create, Update, Delete) ·       IsSyncStarted (true/false) ·       IsSyncFinished (true/false0 The example now looks like: 1.       System A creates id.A. id.A is saved on the A. Id.A is sent to the BizTalk. 2.       BizTalk sends id.A to the Resync and to the B. id.A is saved on the Resync. 3.       System B creates id.B. id.A+id.B are saved on the B. id.A+id.B are sent to the BizTalk. 4.       BizTalk sends id.A+id.B to the Resync and to the A. id.A+id.B are saved on the Resync. 5.       id.A+id.B are saved on the B. Resync changes the IsSyncStarted and IsSyncFinished flags accordingly. The Resync service implements three main methods: ·       Save (id.A, Entity.Type, Operation) ·       Save (id.A, id.B, Entity.Type, Operation) ·       Resync () Two Save() are used to save id-s to the service storage. See in the above example, in 2 and 4 steps. What about the Resync()? It is the method that finishes the interrupted synchronization processes. If Save() is started by the trigger event, the Resync() is working as an independent process. It periodically scans the Resync storage to find out “unfinished” records. Then it restarts the synchronization processes. It tries to synchronize them several times then gives up.     One more thing, both systems A and B must tolerate duplicates of one synchronizing process. Say on the step 3 the system B was not able to send id.A+id.B back. The Resync service must restart the synchronization process that will send the id.A to B second time. In this case system B must just send back again also created id.A+id.B pair without errors. That means “tolerate duplicates”. Fourth draft Next draft was created only because of the aesthetics. As it always happens, aesthetics gave significant performance gain to the whole system. First was the stupid question. Why do we need this additional service with special database? Can we just master the BizTalk to do something like this Resync() does? So the Resync orchestration is doing the same thing as the Resync service. It is started by the Id.A and finished by the id.A+id.B message. The first works as a Start message, the second works as a Finish message.     Here is a diagram the whole process without errors. It is pretty straightforward. The Resync orchestration is waiting for the Finish message specific period of time then resubmits the Id.A message. It resubmits the Id.A message specific number of times then gives up and gets suspended. It can be resubmitted then it starts the whole process again: waiting [, resubmitting [, get suspended]], finishing. Tuning up The Resync orchestration resubmits the id.A message with special “Resubmitted” flag. The subscription filter on the Resync orchestration includes predicate as (Resubmit_Flag != “Resubmitted”). That means only the first Sync orchestration starts the Resync orchestration. Other Sync orchestration instantiated by the resubmitting can finish this Resync orchestration but cannot start another instance of the Resync   Here is a diagram where system B was inaccessible for some period of time. The Resync orchestration resubmitted the id.A two times. Then system B got the response the id.A+id.B and this finished the Resync service execution. What is interesting about this, there were submitted several identical id.A messages and only one id.A+id.B message. Because of this, the system B and the Resync must tolerate the duplicate messages. We also told about this requirement for the system B. Now the same requirement is for the Resunc. Let’s assume the system B was very slow in the first response and the Resync service had time to resubmit two id.A messages. System B responded not, as it was in previous case, with one id.A+id.B but with two id.A+id.B messages. First of them finished the Resync execution for the id.A. What about the second id.A+id.B? Where it goes? So, we have to add one more internal requirement. The whole solution must tolerate many identical id.A+id.B messages. It is easy task with the BizTalk. I added the “SinkExtraMessages” subscriber (orchestration with one receive shape), that just get these messages and do nothing. Real design Real architecture is much more complex and interesting. In reality each system can submit several id.A almost simultaneously and completely unordered. There are not only the “Create entity” operation but the Update and Delete operations. And these operations relate each other. Say the Update operation after Delete means not the same as Update after Create. In reality there are entities related each other. Say the Order and Order Items. Change on one of it could start the series of the operations on another. Moreover, the system internals are the “black boxes” and we cannot predict the exact content and order of the operation series. It worth to say, I had to spend a time to manage the zombie message problems. The zombies are still here, but this is not a problem now. And this is another story. What is interesting in the last design? One orchestration works to help another to be more reliable. Why two orchestration design is more reliable, isn’t it something strange? The Synch orchestration takes all the message exchange between systems, here is the area where most of the errors could happen. The Resync orchestration sends and receives messages only within the BizTalk server. Is there another design? Sure. All Resync functionality could be implemented inside the Sync orchestration. Hey guys, some other ideas?

  Read the article

• E.T. Phone "Home" - Hey I've discovered a leak..!

  - by Martin Deh

  Being a member of the WebCenter ATEAM, we are often asked to performance tune a WebCenter custom portal application or a WebCenter Spaces deployment.  Most of the time, the process is pretty much the same.  For example, we often use tools like httpWatch and FireBug to monitor the application, and then perform load tests using JMeter or Selenium.  In addition, there are the fine tuning of the different performance based tuning parameters that are outlined in the documentation and by blogs that have been written by my fellow ATEAMers (click on the "performance" tag in this ATEAM blog).  While performing the load test where the outcome produces a significant reduction in the systems resources (memory), one of the causes that plays a role in memory "leakage" is due to the implementation of the navigation menu UI.  OOTB in both JDeveloper and WebCenter Spaces, there are sample (page) templates that include a "default" navigation menu.  In WebCenter Spaces, this is through the SpacesNavigationModel taskflow region, and in a custom portal (i.e. pageTemplate_globe.jspx) the menu UI is contructed using standard ADF components.  These sample menu UI's basically enable the underlying navigation model to visualize itself to some extent.  However, due to certain limitations of these sample menu implementations (i.e. deeper sub-level of navigations items, look-n-feel, .etc), many customers have developed their own custom navigation menus using a combination of HTML, CSS and JQuery.  While this is supported somewhat by the framework, it is important to know what are some of the best practices in ensuring that the navigation menu does not leak.  In addition, in this blog I will point out a leak (BUG) that is in the sample templates.  OK, E.T. the suspence is killing me, what is this leak? Note: for those who don't know, info on E.T. can be found here In both of the included templates, the example given for handling the navigation back to the "Home" page, will essentially provide a nice little memory leak every time the link is clicked. Let's take a look a simple example, which uses the default template in Spaces. The outlined section below is the "link", which is used to enable a user to navigation back quickly to the Group Space Home page. When you (mouse) hover over the link, the browser displays the target URL. From looking initially at the proposed URL, this is the intended destination.  Note: "home" in this case is the navigation model reference (id), that enables the display of the "pretty URL". Next, notice the current URL, which is displayed in the browser.  Remember, that PortalSiteHome = home.  The other highlighted item adf.ctrl-state, is very important to the framework.  This item is basically a persistent query parameter, which is used by the (ADF) framework to managing the current session and page instance.  Without this parameter present, among other things, the browser back-button navigation will fail.  In this example, the value for this parameter is currently 95K25i7dd_4.  Next, through the navigation menu item, I will click on the Page2 link. Inspecting the URL again, I can see that it reports that indeed the navigation is successful and the adf.ctrl-state is also in the URL.  For those that are wondering why the URL displays Page3.jspx, instead of Page2.jspx. Basically the (file) naming convention for pages created ar runtime in Spaces start at Page1, and then increment as you create additional pages.  The name of the actual link (i.e. Page2) is the page "title" attribute.  So the moral of the story is, unlike design time created pages, run time created pages the name of the file will 99% never match the name that appears in the link. Next, is to click on the quick link for navigating back to the Home page. Quick investigation yields that the navigation was indeed successful.  In the browser's URL there is a home (pretty URL) reference, and there is also a reference to the adf.ctrl-state parameter.  So what's the issue?  Can you remember what the value was for the adf.ctrl-state?  The current value is 3D95k25i7dd_149.  However, the previous value was 95k25i7dd_4.  Here is what happened.  Remember when (mouse) hovering over the link produced the following target URL: http://localhost:8888/webcenter/spaces/NavigationTest/home This is great for the browser as this URL will navigate to the intended targer.  However, what is missing is the adf.ctrl-state parameter.  Since this parameter was not present upon navigation "within" the framework, the ADF framework produced another adf.ctrl-state (object).  The previous adf.ctrl-state basically is orphaned while continuing to be alive in memory.  Note: the auto-creation of the adf.ctrl state does happen initially when you invoke the Spaces application  for the first time.  The following is the line of code which produced the issue: <af:goLink destination="#{boilerBean.globalLogoURIInSpace} ... Here the boilerBean is responsible for returning the "string" url, which in this case is /spaces/NavigationTest/home. Unfortunately, again what is missing is adf.ctrl-state. Note: there are more than one instance of the goLinks in the sample templates. So E.T. how can I correct this? There are 2 simple fixes.  For the goLink's destination, use the navigation model to return the actually "node" value, then use the goLinkPrettyUrl method to add the current adf.ctrl-state: <af:goLink destination="#{navigationContext.defaultNavigationModel.node['home'].goLinkPrettyUrl}"} ... />  Note: the node value is the [navigation model id]  Using a goLink does solve the main issue.  However, since the link basically does a redirect, some browsers like IE will produce a somewhat significant "flash".  In a Spaces application, this may be an annoyance to the users.  Another way to solve the leakage problem, and also remove the flash between navigations is to use a af:commandLink.  For example, here is the code example for this scenario: <af:commandLink id="pt_cl2asf" actionListener="#{navigationContext.processAction}" action="pprnav">    <f:attribute name="node" value="#{navigationContext.defaultNavigationModel.node['home']}"/> </af:commandLink> Here, the navigation node to where home is located is delivered by way of the attribute to the commandLink.  The actual navigation is performed by the processAction, which is needing the "node" value. E.T. OK, you solved the OOTB sample BUG, what about my custom navigation code? I have seen many implementations of creating a navigation menu through custom code.  In addition, there are some blog sites that also give detailed examples.  The majority of these implementations are very similar.  The code usually involves using standard HTML tags (i.e. DIVS, UL, LI, .,etc) and either CSS or JavaScript (JQuery) to produce the flyout/drop-down effect.  The navigation links in these cases are standard <a href... > tags.  Although, this type of approach is not fully accepted by the ADF community, it does work.  The important thing to note here is that the <a> tag value must use the goLinkPrettyURL method of contructing the target URL.  For example: <a href="${contextRoot}${menu.goLinkPrettyUrl}"> The main reason why this type of approach is popular is that links that are created this way (also with using af:goLinks), the pages become crawlable by search engines.  CommandLinks are currently not search friendly.  However, in the case of a Spaces instance this may be acceptable.  So in this use-case, af:commandLinks, which would replace the <a>  (or goLink) tags. The example code given of the af:commandLink above is still valid. One last important item.  If you choose to use af:commandLinks, special attention must be given to the scenario in which java script has been used to produce the flyout effect in the custom menu UI.  In many cases that I have seen, the commandLink can only be invoked once, since there is a conflict between the custom java script with the ADF frameworks own scripting to control the view.  The recommendation here, would be to use a pure CSS approach to acheive the dropdown effects. One very important thing to note.  Due to another BUG, the WebCenter environement must be patched to BP3 (patch  p14076906).  Otherwise the leak is still present using the goLinkPrettyUrl method.  Thanks E.T.!  Now I can phone home and not worry about my application running out of resources due to my custom navigation! 

  Read the article

• Applications: The mathematics of movement, Part 1

  - by TechTwaddle

  Before you continue reading this post, a suggestion; if you haven’t read “Programming Windows Phone 7 Series” by Charles Petzold, go read it. Now. If you find 150+ pages a little too long, at least go through Chapter 5, Principles of Movement, especially the section “A Brief Review of Vectors”. This post is largely inspired from this chapter. At this point I assume you know what vectors are, how they are represented using the pair (x, y), what a unit vector is, and given a vector how you would normalize the vector to get a unit vector. Our task in this post is simple, a marble is drawn at a point on the screen, the user clicks at a random point on the device, say (destX, destY), and our program makes the marble move towards that point and stop when it is reached. The tricky part of this task is the word “towards”, it adds a direction to our problem. Making a marble bounce around the screen is simple, all you have to do is keep incrementing the X and Y co-ordinates by a certain amount and handle the boundary conditions. Here, however, we need to find out exactly how to increment the X and Y values, so that the marble appears to move towards the point where the user clicked. And this is where vectors can be so helpful. The code I’ll show you here is not ideal, we’ll be working with C# on Windows Mobile 6.x, so there is no built-in vector class that I can use, though I could have written one and done all the math inside the class. I think it is trivial to the actual problem that we are trying to solve and can be done pretty easily once you know what’s going on behind the scenes. In other words, this is an excuse for me being lazy. The first approach, uses the function Atan2() to solve the “towards” part of the problem. Atan2() takes a point (x, y) as input, Atan2(y, x), note that y goes first, and then it returns an angle in radians. What angle you ask. Imagine a line from the origin (0, 0), to the point (x, y). The angle which Atan2 returns is the angle the positive X-axis makes with that line, measured clockwise. The figure below makes it clear, wiki has good details about Atan2(), give it a read. The pair (x, y) also denotes a vector. A vector whose magnitude is the length of that line, which is Sqrt(x*x + y*y), and a direction ?, as measured from positive X axis clockwise. If you’ve read that chapter from Charles Petzold’s book, this much should be clear. Now Sine and Cosine of the angle ? are special. Cosine(?) divides x by the vectors length (adjacent by hypotenuse), thus giving us a unit vector along the X direction. And Sine(?) divides y by the vectors length (opposite by hypotenuse), thus giving us a unit vector along the Y direction. Therefore the vector represented by the pair (cos(?), sin(?)), is the unit vector (or normalization) of the vector (x, y). This unit vector has a length of 1 (remember sin2(?) + cos2(?) = 1 ?), and a direction which is the same as vector (x, y). Now if I multiply this unit vector by some amount, then I will always get a point which is a certain distance away from the origin, but, more importantly, the point will always be on that line. For example, if I multiply the unit vector with the length of the line, I get the point (x, y). Thus, all we have to do to move the marble towards our destination point, is to multiply the unit vector by a certain amount each time and draw the marble, and the marble will magically move towards the click point. Now time for some code. The application, uses a timer based frame draw method to draw the marble on the screen. The timer is disabled initially and whenever the user clicks on the screen, the timer is enabled. The callback function for the timer follows the standard Update and Draw cycle. private double totLenToTravelSqrd = 0; private double startPosX = 0, startPosY = 0; private double destX = 0, destY = 0; private void Form1_MouseUp(object sender, MouseEventArgs e) {     destX = e.X;     destY = e.Y;     double x = marble1.x - destX;     double y = marble1.y - destY;     //calculate the total length to be travelled     totLenToTravelSqrd = x * x + y * y;     //store the start position of the marble     startPosX = marble1.x;     startPosY = marble1.y;     timer1.Enabled = true; } private void timer1_Tick(object sender, EventArgs e) {     UpdatePosition();     DrawMarble(); } Form1_MouseUp() method is called when ever the user touches and releases the screen. In this function we save the click point in destX and destY, this is the destination point for the marble and we also enable the timer. We store a few more values which we will use in the UpdatePosition() method to detect when the marble has reached the destination and stop the timer. So we store the start position of the marble and the square of the total length to be travelled. I’ll leave out the term ‘sqrd’ when speaking of lengths from now on. The time out interval of the timer is set to 40ms, thus giving us a frame rate of about ~25fps. In the timer callback, we update the marble position and draw the marble. We know what DrawMarble() does, so here, we’ll only look at how UpdatePosition() is implemented; private void UpdatePosition() {     //the vector (x, y)     double x = destX - marble1.x;     double y = destY - marble1.y;     double incrX=0, incrY=0;     double distanceSqrd=0;     double speed = 6;     //distance between destination and current position, before updating marble position     distanceSqrd = x * x + y * y;     double angle = Math.Atan2(y, x);     //Cos and Sin give us the unit vector, 6 is the value we use to magnify the unit vector along the same direction     incrX = speed * Math.Cos(angle);     incrY = speed * Math.Sin(angle);     marble1.x += incrX;     marble1.y += incrY;     //check for bounds     if ((int)marble1.x < MinX + marbleWidth / 2)     {         marble1.x = MinX + marbleWidth / 2;     }     else if ((int)marble1.x > (MaxX - marbleWidth / 2))     {         marble1.x = MaxX - marbleWidth / 2;     }     if ((int)marble1.y < MinY + marbleHeight / 2)     {         marble1.y = MinY + marbleHeight / 2;     }     else if ((int)marble1.y > (MaxY - marbleHeight / 2))     {         marble1.y = MaxY - marbleHeight / 2;     }     //distance between destination and current point, after updating marble position     x = destX - marble1.x;     y = destY - marble1.y;     double newDistanceSqrd = x * x + y * y;     //length from start point to current marble position     x = startPosX - (marble1.x);     y = startPosY - (marble1.y);     double lenTraveledSqrd = x * x + y * y;     //check for end conditions     if ((int)lenTraveledSqrd >= (int)totLenToTravelSqrd)     {         System.Console.WriteLine("Stopping because destination reached");         timer1.Enabled = false;     }     else if (Math.Abs((int)distanceSqrd - (int)newDistanceSqrd) < 4)     {         System.Console.WriteLine("Stopping because no change in Old and New position");         timer1.Enabled = false;     } } Ok, so in this function, first we subtract the current marble position from the destination point to give us a vector. The first three lines of the function construct this vector (x, y). The vector (x, y) has the same length as the line from (marble1.x, marble1.y) to (destX, destY) and is in the direction pointing from (marble1.x, marble1.y) to (destX, destY). Note that marble1.x and marble1.y denote the center point of the marble. Then we use Atan2() to get the angle which this vector makes with the positive X axis and use Cosine() and Sine() of that angle to get the unit vector along that same direction. We multiply this unit vector with 6, to get the values which the position of the marble should be incremented by. This variable, speed, can be experimented with and determines how fast the marble moves towards the destination. After this, we check for bounds to make sure that the marble stays within the screen limits and finally we check for the end condition and stop the timer. The end condition has two parts to it. The first case is the normal case, where the user clicks well inside the screen. Here, we stop when the total length travelled by the marble is greater than or equal to the total length to be travelled. Simple enough. The second case is when the user clicks on the very corners of the screen. Like I said before, the values marble1.x and marble1.y denote the center point of the marble. When the user clicks on the corner, the marble moves towards the point, and after some time tries to go outside of the screen, this is when the bounds checking comes into play and corrects the marble position so that the marble stays inside the screen. In this case the marble will never travel a distance of totLenToTravelSqrd, because of the correction is its position. So here we detect the end condition when there is not much change in marbles position. I use the value 4 in the second condition above. After experimenting with a few values, 4 seemed to work okay. There is a small thing missing in the code above. In the normal case, case 1, when the update method runs for the last time, marble position over shoots the destination point. This happens because the position is incremented in steps (which are not small enough), so in this case too, we should have corrected the marble position, so that the center point of the marble sits exactly on top of the destination point. I’ll add this later and update the post. This has been a pretty long post already, so I’ll leave you with a video of how this program looks while running. Notice in the video that the marble moves like a bot, without any grace what so ever. And that is because the speed of the marble is fixed at 6. In the next post we will see how to make the marble move a little more elegantly. And also, if Atan2(), Sine() and Cosine() are a little too much to digest, we’ll see how to achieve the same effect without using them, in the next to next post maybe. Ciao!

  Read the article

• Solving Big Problems with Oracle R Enterprise, Part I

  - by dbayard

  Abstract: This blog post will show how we used Oracle R Enterprise to tackle a customer’s big calculation problem across a big data set. Overview: Databases are great for managing large amounts of data in a central place with rigorous enterprise-level controls.  R is great for doing advanced computations.  Sometimes you need to do advanced computations on large amounts of data, subject to rigorous enterprise-level concerns.  This blog post shows how Oracle R Enterprise enables R plus the Oracle Database enabled us to do some pretty sophisticated calculations across 1 million accounts (each with many detailed records) in minutes. The problem: A financial services customer of mine has a need to calculate the historical internal rate of return (IRR) for its customers’ portfolios.  This information is needed for customer statements and the online web application.  In the past, they had solved this with a home-grown application that pulled trade and account data out of their data warehouse and ran the calculations.  But this home-grown application was not able to do this fast enough, plus it was a challenge for them to write and maintain the code that did the IRR calculation. IRR – a problem that R is good at solving: Internal Rate of Return is an interesting calculation in that in most real-world scenarios it is impractical to calculate exactly.  Rather, IRR is a calculation where approximation techniques need to be used.  In this blog post, we will discuss calculating the “money weighted rate of return” but in the actual customer proof of concept we used R to calculate both money weighted rate of returns and time weighted rate of returns.  You can learn more about the money weighted rate of returns here: http://www.wikinvest.com/wiki/Money-weighted_return First Steps- Calculating IRR in R We will start with calculating the IRR in standalone/desktop R.  In our second post, we will show how to take this desktop R function, deploy it to an Oracle Database, and make it work at real-world scale.  The first step we did was to get some sample data.  For a historical IRR calculation, you have a balances and cash flows.  In our case, the customer provided us with several accounts worth of sample data in Microsoft Excel.      The above figure shows part of the spreadsheet of sample data.  The data provides balances and cash flows for a sample account (BMV=beginning market value. FLOW=cash flow in/out of account. EMV=ending market value). Once we had the sample spreadsheet, the next step we did was to read the Excel data into R.  This is something that R does well.  R offers multiple ways to work with spreadsheet data.  For instance, one could save the spreadsheet as a .csv file.  In our case, the customer provided a spreadsheet file containing multiple sheets where each sheet provided data for a different sample account.  To handle this easily, we took advantage of the RODBC package which allowed us to read the Excel data sheet-by-sheet without having to create individual .csv files.  We wrote ourselves a little helper function called getsheet() around the RODBC package.  Then we loaded all of the sample accounts into a data.frame called SimpleMWRRData. Writing the IRR function At this point, it was time to write the money weighted rate of return (MWRR) function itself.  The definition of MWRR is easily found on the internet or if you are old school you can look in an investment performance text book.  In the customer proof, we based our calculations off the ones defined in the The Handbook of Investment Performance: A User’s Guide by David Spaulding since this is the reference book used by the customer.  (One of the nice things we found during the course of this proof-of-concept is that by using R to write our IRR functions we could easily incorporate the specific variations and business rules of the customer into the calculation.) The key thing with calculating IRR is the need to solve a complex equation with a numerical approximation technique.  For IRR, you need to find the value of the rate of return (r) that sets the Net Present Value of all the flows in and out of the account to zero.  With R, we solve this by defining our NPV function: where bmv is the beginning market value, cf is a vector of cash flows, t is a vector of time (relative to the beginning), emv is the ending market value, and tend is the ending time. Since solving for r is a one-dimensional optimization problem, we decided to take advantage of R’s optimize method (http://stat.ethz.ch/R-manual/R-patched/library/stats/html/optimize.html). The optimize method can be used to find a minimum or maximum; to find the value of r where our npv function is closest to zero, we wrapped our npv function inside the abs function and asked optimize to find the minimum.  Here is an example of using optimize: where low and high are scalars that indicate the range to search for an answer.   To test this out, we need to set values for bmv, cf, t, emv, tend, low, and high.  We will set low and high to some reasonable defaults. For example, this account had a negative 2.2% money weighted rate of return. Enhancing and Packaging the IRR function With numerical approximation methods like optimize, sometimes you will not be able to find an answer with your initial set of inputs.  To account for this, our approach was to first try to find an answer for r within a narrow range, then if we did not find an answer, try calling optimize() again with a broader range.  See the R help page on optimize()  for more details about the search range and its algorithm. At this point, we can now write a simplified version of our MWRR function.  (Our real-world version is  more sophisticated in that it calculates rate of returns for 5 different time periods [since inception, last quarter, year-to-date, last year, year before last year] in a single invocation.  In our actual customer proof, we also defined time-weighted rate of return calculations.  The beauty of R is that it was very easy to add these enhancements and additional calculations to our IRR package.)To simplify code deployment, we then created a new package of our IRR functions and sample data.  For this blog post, we only need to include our SimpleMWRR function and our SimpleMWRRData sample data.  We created the shell of the package by calling: To turn this package skeleton into something usable, at a minimum you need to edit the SimpleMWRR.Rd and SimpleMWRRData.Rd files in the \man subdirectory.  In those files, you need to at least provide a value for the “title” section. Once that is done, you can change directory to the IRR directory and type at the command-line: The myIRR package for this blog post (which has both SimpleMWRR source and SimpleMWRRData sample data) is downloadable from here: myIRR package Testing the myIRR package Here is an example of testing our IRR function once it was converted to an installable package: Calculating IRR for All the Accounts So far, we have shown how to calculate IRR for a single account.  The real-world issue is how do you calculate IRR for all of the accounts?This is the kind of situation where we can leverage the “Split-Apply-Combine” approach (see http://www.cscs.umich.edu/~crshalizi/weblog/815.html).  Given that our sample data can fit in memory, one easy approach is to use R’s “by” function.  (Other approaches to Split-Apply-Combine such as plyr can also be used.  See http://4dpiecharts.com/2011/12/16/a-quick-primer-on-split-apply-combine-problems/). Here is an example showing the use of “by” to calculate the money weighted rate of return for each account in our sample data set.  Recap and Next Steps At this point, you’ve seen the power of R being used to calculate IRR.  There were several good things: R could easily work with the spreadsheets of sample data we were given R’s optimize() function provided a nice way to solve for IRR- it was both fast and allowed us to avoid having to code our own iterative approximation algorithm R was a convenient language to express the customer-specific variations, business-rules, and exceptions that often occur in real-world calculations- these could be easily added to our IRR functions The Split-Apply-Combine technique can be used to perform calculations of IRR for multiple accounts at once. However, there are several challenges yet to be conquered at this point in our story: The actual data that needs to be used lives in a database, not in a spreadsheet The actual data is much, much bigger- too big to fit into the normal R memory space and too big to want to move across the network The overall process needs to run fast- much faster than a single processor The actual data needs to be kept secured- another reason to not want to move it from the database and across the network And the process of calculating the IRR needs to be integrated together with other database ETL activities, so that IRR’s can be calculated as part of the data warehouse refresh processes In our next blog post in this series, we will show you how Oracle R Enterprise solved these challenges.

  Read the article

• Using LINQ to Twitter OAuth with Windows 8

  - by Joe Mayo

  In previous posts, I explained how to use LINQ to Twitter with Windows 8, but the example was a Twitter Search, which didn’t require authentication. Much of the Twitter API requires authentication, so this post will explain how you can perform OAuth authentication with LINQ to Twitter in a Windows 8 Metro-style application. Getting Started I have earlier posts on how to create a Windows 8 app and add pages, so I’ll assume it isn’t necessary to repeat here. One difference is that I’m using Visual Studio 2012 RC and some of the terminology and/or library code might be slightly different.  Here are steps to get started: Create a new Windows metro style app, selecting the Blank App project template. Create a new Basic Page and name it OAuth.xaml.  Note: You’ll receive a prompt window for adding files and you should click Yes because those files are necessary for this demo. Add a new Basic Page named TweetPage.xaml. Open App.xaml.cs and change !rootFrame.Navigate(typeof(MainPage)) to !rootFrame.Navigate(typeof(TweetPage)). Now that the project is set up you’ll see the reason why authentication is required by setting up the TweetPage. Setting Up to Tweet a Status In this section, I’ll show you how to set up the XAML and code-behind for a tweet.  The tweet logic will check to see if the user is authenticated before performing the tweet. To tweet, I put a TextBox and Button on the XAML page. The following code omits most of the page, concentrating primarily on the elements of interest in this post: <StackPanel Grid.Row="1"> <TextBox Name="TweetTextBox" Margin="15" /> <Button Name="TweetButton" Content="Tweet" Click="TweetButton_Click" Margin="15,0" /> </StackPanel> Given the UI above, the user types the message they want to tweet, and taps Tweet. This invokes TweetButton_Click, which checks to see if the user is authenticated.  If the user is not authenticated, the app navigates to the OAuth page.  If they are authenticated, LINQ to Twitter does an UpdateStatus to post the user’s tweet.  Here’s the TweetButton_Click implementation: void TweetButton_Click(object sender, RoutedEventArgs e) { PinAuthorizer auth = null; if (SuspensionManager.SessionState.ContainsKey("Authorizer")) { auth = SuspensionManager.SessionState["Authorizer"] as PinAuthorizer; } if (auth == null || !auth.IsAuthorized) { Frame.Navigate(typeof(OAuthPage)); return; } var twitterCtx = new TwitterContext(auth); Status tweet = twitterCtx.UpdateStatus(TweetTextBox.Text); new MessageDialog(tweet.Text, "Successful Tweet").ShowAsync(); } For authentication, this app uses PinAuthorizer, one of several authorizers available in the LINQ to Twitter library. I’ll explain how PinAuthorizer works in the next section. What’s important here is that LINQ to Twitter needs an authorizer to post a Tweet. The code above checks to see if a valid authorizer is available. To do this, it uses the SuspensionManager class, which is part of the code generated earlier when creating OAuthPage.xaml. The SessionState property is a Dictionary<string, object> and I’m using the Authorizer key to store the PinAuthorizer.  If the user previously authorized during this session, the code reads the PinAuthorizer instance from SessionState and assigns it to the auth variable. If the user is authorized, auth would not be null and IsAuthorized would be true. Otherwise, the app navigates the user to OAuthPage.xaml, which I’ll discuss in more depth in the next section. When the user is authorized, the code passes the authorizer, auth, to the TwitterContext constructor. LINQ to Twitter uses the auth instance to build OAuth signatures for each interaction with Twitter.  You no longer need to write any more code to make this happen. The code above accepts the tweet just posted in the Status instance, tweet, and displays a message with the text to confirm success to the user. You can pull the PinAuthorizer instance from SessionState, instantiate your TwitterContext, and use it as you need. Just remember to make sure you have a valid authorizer, like the code above. As shown earlier, the code navigates to OAuthPage.xaml when a valid authorizer isn’t available. The next section shows how to perform the authorization upon arrival at OAuthPage.xaml. Doing the OAuth Dance This section shows how to authenticate with LINQ to Twitter’s built-in OAuth support. From the user perspective, they must be navigated to the Twitter authentication page, add credentials, be navigated to a Pin number page, and then enter that Pin in the Windows 8 application. The following XAML shows the relevant elements that the user will interact with during this process. <StackPanel Grid.Row="2"> <WebView x:Name="OAuthWebBrowser" HorizontalAlignment="Left" Height="400" Margin="15" VerticalAlignment="Top" Width="700" /> <TextBlock Text="Please perform OAuth process (above), enter Pin (below) when ready, and tap Authenticate:" Margin="15,15,15,5" /> <TextBox Name="PinTextBox" Margin="15,0,15,15" Width="432" HorizontalAlignment="Left" IsEnabled="False" /> <Button Name="AuthenticatePinButton" Content="Authenticate" Margin="15" IsEnabled="False" Click="AuthenticatePinButton_Click" /> </StackPanel> The WebView in the code above is what allows the user to see the Twitter authentication page. The TextBox is for entering the Pin, and the Button invokes code that will take the Pin and allow LINQ to Twitter to complete the authentication process. As you can see, there are several steps to OAuth authentication, but LINQ to Twitter tries to minimize the amount of code you have to write. The two important parts of the code to make this happen are the part that starts the authentication process and the part that completes the authentication process. The following code, from OAuthPage.xaml.cs, shows a couple events that are instrumental in making this process happen: public OAuthPage() { this.InitializeComponent(); this.Loaded += OAuthPage_Loaded; OAuthWebBrowser.LoadCompleted += OAuthWebBrowser_LoadCompleted; } The OAuthWebBrowser_LoadCompleted event handler enables UI controls when the browser is done loading – notice that the TextBox and Button in the previous XAML have their IsEnabled attributes set to False. When the Page.Loaded event is invoked, the OAuthPage_Loaded handler starts the OAuth process, shown here: void OAuthPage_Loaded(object sender, RoutedEventArgs e) { auth = new PinAuthorizer { Credentials = new InMemoryCredentials { ConsumerKey = "", ConsumerSecret = "" }, UseCompression = true, GoToTwitterAuthorization = pageLink => Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () => OAuthWebBrowser.Navigate(new Uri(pageLink, UriKind.Absolute))) }; auth.BeginAuthorize(resp => Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () => { switch (resp.Status) { case TwitterErrorStatus.Success: break; case TwitterErrorStatus.RequestProcessingException: case TwitterErrorStatus.TwitterApiError: new MessageDialog(resp.Error.ToString(), resp.Message).ShowAsync(); break; } })); } The PinAuthorizer, auth, a field of this class instantiated in the code above, assigns keys to the Credentials property. These are credentials that come from registering an application with Twitter, explained in the LINQ to Twitter documentation, Securing Your Applications. Notice how I use Dispatcher.RunAsync to marshal the web browser navigation back onto the UI thread. Internally, LINQ to Twitter invokes the lambda expression assigned to GoToTwitterAuthorization when starting the OAuth process.  In this case, we want the WebView control to navigate to the Twitter authentication page, which is defined with a default URL in LINQ to Twitter and passed to the GoToTwitterAuthorization lambda as pageLink. Then you need to start the authorization process by calling BeginAuthorize. This starts the OAuth dance, running asynchronously.  LINQ to Twitter invokes the callback assigned to the BeginAuthorize parameter, allowing you to take whatever action you need, based on the Status of the response, resp. As mentioned earlier, this is where the user performs the authentication process, enters the Pin, and clicks authenticate. The handler for authenticate completes the process and saves the authorizer for subsequent use by the application, as shown below: void AuthenticatePinButton_Click(object sender, RoutedEventArgs e) { auth.CompleteAuthorize( PinTextBox.Text, completeResp => Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () => { switch (completeResp.Status) { case TwitterErrorStatus.Success: SuspensionManager.SessionState["Authorizer"] = auth; Frame.Navigate(typeof(TweetPage)); break; case TwitterErrorStatus.RequestProcessingException: case TwitterErrorStatus.TwitterApiError: new MessageDialog(completeResp.Error.ToString(), completeResp.Message).ShowAsync(); break; } })); } The PinAuthorizer CompleteAuthorize method takes two parameters: Pin and callback. The Pin is from what the user entered in the TextBox prior to clicking the Authenticate button that invoked this method. The callback handles the response from completing the OAuth process. The completeResp holds information about the results of the operation, indicated by a Status property of type TwitterErrorStatus. On success, the code assigns auth to SessionState. You might remember SessionState from the previous description of TweetPage – this is where the valid authorizer comes from. After saving the authorizer, the code navigates the user back to TweetPage, where they can type in a message, click the Tweet button, and observe that they have successfully tweeted. Summary You’ve seen how to get started with using LINQ to Twitter in a Metro-style application. The generated code contained a SuspensionManager class with way to manage information across multiple pages via its SessionState property. You also saw how LINQ to Twitter performs authorization in two steps of starting the process and completing the process when the user provides a Pin number. Remember to marshal callback thread back onto the UI – you saw earlier how to use Dispatcher.RunAsync to accomplish this. There were a few steps in the process, but LINQ to Twitter did minimize the amount of code you needed to write to make it happen. You can download the MetroOAuthDemo.zip sample on the LINQ to Twitter Samples Page.   @JoeMayo

  Read the article

• Inside the DLR – Invoking methods

  - by Simon Cooper

  So, we’ve looked at how a dynamic call is represented in a compiled assembly, and how the dynamic lookup is performed at runtime. The last piece of the puzzle is how the resolved method gets invoked, and that is the subject of this post. Invoking methods As discussed in my previous posts, doing a full lookup and bind at runtime each and every single time the callsite gets invoked would be far too slow to be usable. The results obtained from the callsite binder must to be cached, along with a series of conditions to determine whether the cached result can be reused. So, firstly, how are the conditions represented? These conditions can be anything; they are determined entirely by the semantics of the language the binder is representing. The binder has to be able to return arbitary code that is then executed to determine whether the conditions apply or not. Fortunately, .NET 4 has a neat way of representing arbitary code that can be easily combined with other code – expression trees. All the callsite binder has to return is an expression (called a ‘restriction’) that evaluates to a boolean, returning true when the restriction passes (indicating the corresponding method invocation can be used) and false when it does’t. If the bind result is also represented in an expression tree, these can be combined easily like so: if ([restriction is true]) { [invoke cached method] } Take my example from my previous post: public class ClassA { public static void TestDynamic() { CallDynamic(new ClassA(), 10); CallDynamic(new ClassA(), "foo"); } public static void CallDynamic(dynamic d, object o) { d.Method(o); } public void Method(int i) {} public void Method(string s) {} } When the Method(int) method is first bound, along with an expression representing the result of the bind lookup, the C# binder will return the restrictions under which that bind can be reused. In this case, it can be reused if the types of the parameters are the same: if (thisArg.GetType() == typeof(ClassA) && arg1.GetType() == typeof(int)) { thisClassA.Method(i); } Caching callsite results So, now, it’s up to the callsite to link these expressions returned from the binder together in such a way that it can determine which one from the many it has cached it should use. This caching logic is all located in the System.Dynamic.UpdateDelegates class. It’ll help if you’ve got this type open in a decompiler to have a look yourself. For each callsite, there are 3 layers of caching involved: The last method invoked on the callsite. All methods that have ever been invoked on the callsite. All methods that have ever been invoked on any callsite of the same type. We’ll cover each of these layers in order Level 1 cache: the last method called on the callsite When a CallSite<T> object is first instantiated, the Target delegate field (containing the delegate that is called when the callsite is invoked) is set to one of the UpdateAndExecute generic methods in UpdateDelegates, corresponding to the number of parameters to the callsite, and the existance of any return value. These methods contain most of the caching, invoke, and binding logic for the callsite. The first time this method is invoked, the UpdateAndExecute method finds there aren’t any entries in the caches to reuse, and invokes the binder to resolve a new method. Once the callsite has the result from the binder, along with any restrictions, it stitches some extra expressions in, and replaces the Target field in the callsite with a compiled expression tree similar to this (in this example I’m assuming there’s no return value): if ([restriction is true]) { [invoke cached method] return; } if (callSite._match) { _match = false; return; } else { UpdateAndExecute(callSite, arg0, arg1, ...); } Woah. What’s going on here? Well, this resulting expression tree is actually the first level of caching. The Target field in the callsite, which contains the delegate to call when the callsite is invoked, is set to the above code compiled from the expression tree into IL, and then into native code by the JIT. This code checks whether the restrictions of the last method that was invoked on the callsite (the ‘primary’ method) match, and if so, executes that method straight away. This means that, the next time the callsite is invoked, the first code that executes is the restriction check, executing as native code! This makes this restriction check on the primary cached delegate very fast. But what if the restrictions don’t match? In that case, the second part of the stitched expression tree is executed. What this section should be doing is calling back into the UpdateAndExecute method again to resolve a new method. But it’s slightly more complicated than that. To understand why, we need to understand the second and third level caches. Level 2 cache: all methods that have ever been invoked on the callsite When a binder has returned the result of a lookup, as well as updating the Target field with a compiled expression tree, stitched together as above, the callsite puts the same compiled expression tree in an internal list of delegates, called the rules list. This list acts as the level 2 cache. Why use the same delegate? Stitching together expression trees is an expensive operation. You don’t want to do it every time the callsite is invoked. Ideally, you would create one expression tree from the binder’s result, compile it, and then use the resulting delegate everywhere in the callsite. But, if the same delegate is used to invoke the callsite in the first place, and in the caches, that means each delegate needs two modes of operation. An ‘invoke’ mode, for when the delegate is set as the value of the Target field, and a ‘match’ mode, used when UpdateAndExecute is searching for a method in the callsite’s cache. Only in the invoke mode would the delegate call back into UpdateAndExecute. In match mode, it would simply return without doing anything. This mode is controlled by the _match field in CallSite<T>. The first time the callsite is invoked, _match is false, and so the Target delegate is called in invoke mode. Then, if the initial restriction check fails, the Target delegate calls back into UpdateAndExecute. This method sets _match to true, then calls all the cached delegates in the rules list in match mode to try and find one that passes its restrictions, and invokes it. However, there needs to be some way for each cached delegate to inform UpdateAndExecute whether it passed its restrictions or not. To do this, as you can see above, it simply re-uses _match, and sets it to false if it did not pass the restrictions. This allows the code within each UpdateAndExecute method to check for cache matches like so: foreach (T cachedDelegate in Rules) { callSite._match = true; cachedDelegate(); // sets _match to false if restrictions do not pass if (callSite._match) { // passed restrictions, and the cached method was invoked // set this delegate as the primary target to invoke next time callSite.Target = cachedDelegate; return; } // no luck, try the next one... } Level 3 cache: all methods that have ever been invoked on any callsite with the same signature The reason for this cache should be clear – if a method has been invoked through a callsite in one place, then it is likely to be invoked on other callsites in the codebase with the same signature. Rather than living in the callsite, the ‘global’ cache for callsite delegates lives in the CallSiteBinder class, in the Cache field. This is a dictionary, typed on the callsite delegate signature, providing a RuleCache<T> instance for each delegate signature. This is accessed in the same way as the level 2 callsite cache, by the UpdateAndExecute methods. When a method is matched in the global cache, it is copied into the callsite and Target cache before being executed. Putting it all together So, how does this all fit together? Like so (I’ve omitted some implementation & performance details): That, in essence, is how the DLR performs its dynamic calls nearly as fast as statically compiled IL code. Extensive use of expression trees, compiled to IL and then into native code. Multiple levels of caching, the first of which executes immediately when the dynamic callsite is invoked. And a clever re-use of compiled expression trees that can be used in completely different contexts without being recompiled. All in all, a very fast and very clever reflection caching mechanism.

  Read the article

• Farseer tutorial for the absolute beginners

  - by Bil Simser

  This post is inspired (and somewhat a direct copy) of a couple of posts Emanuele Feronato wrote back in 2009 about Box2D (his tutorial was ActionScript 3 based for Box2D, this is C# XNA for the Farseer Physics Engine). Here’s what we’re building: What is Farseer The Farseer Physics Engine is a collision detection system with realistic physics responses to help you easily create simple hobby games or complex simulation systems. Farseer was built as a .NET version of Box2D (based on the Box2D.XNA port of Box2D). While the constructs and syntax has changed over the years, the principles remain the same. This tutorial will walk you through exactly what Emanuele create for Flash but we’ll be doing it using C#, XNA and the Windows Phone platform. The first step is to download the library from its home on CodePlex. If you have NuGet installed, you can install the library itself using the NuGet package that but we’ll also be using some code from the Samples source that can only be obtained by downloading the library. Once you download and unpacked the zip file into a folder and open the solution, this is what you will get: The Samples XNA WP7 project (and content) have all the demos for Farseer. There’s a wealth of info here and great examples to look at to learn. The Farseer Physics XNA WP7 project contains the core libraries that do all the work. DebugView XNA contains an XNA-ready class to let you view debug data and information in the game draw loop (which you can copy into your project or build the source and reference the assembly). The downloaded version has to be compiled as it’s only available in source format so you can do that now if you want (open the solution file and rebuild everything). If you’re using the NuGet package you can just install that. We only need the core library and we’ll be copying in some code from the samples later. Your first Farseer experiment Start Visual Studio and create a new project using the Windows Phone template can call it whatever you want. It’s time to edit Game1.cs 1 public class Game1 : Game 2 { 3 private readonly GraphicsDeviceManager _graphics; 4 private DebugViewXNA _debugView; 5 private Body _floor; 6 private SpriteBatch _spriteBatch; 7 private float _timer; 8 private World _world; 9 10 public Game1() 11 { 12 _graphics = new GraphicsDeviceManager(this) 13 { 14 PreferredBackBufferHeight = 800, 15 PreferredBackBufferWidth = 480, 16 IsFullScreen = true 17 }; 18 19 Content.RootDirectory = "Content"; 20 21 // Frame rate is 30 fps by default for Windows Phone. 22 TargetElapsedTime = TimeSpan.FromTicks(333333); 23 24 // Extend battery life under lock. 25 InactiveSleepTime = TimeSpan.FromSeconds(1); 26 } 27 28 protected override void LoadContent() 29 { 30 // Create a new SpriteBatch, which can be used to draw textures. 31 _spriteBatch = new SpriteBatch(_graphics.GraphicsDevice); 32 33 // Load our font (DebugViewXNA needs it for the DebugPanel) 34 Content.Load<SpriteFont>("font"); 35 36 // Create our World with a gravity of 10 vertical units 37 if (_world == null) 38 { 39 _world = new World(Vector2.UnitY*10); 40 } 41 else 42 { 43 _world.Clear(); 44 } 45 46 if (_debugView == null) 47 { 48 _debugView = new DebugViewXNA(_world); 49 50 // default is shape, controller, joints 51 // we just want shapes to display 52 _debugView.RemoveFlags(DebugViewFlags.Controllers); 53 _debugView.RemoveFlags(DebugViewFlags.Joint); 54 55 _debugView.LoadContent(GraphicsDevice, Content); 56 } 57 58 // Create and position our floor 59 _floor = BodyFactory.CreateRectangle( 60 _world, 61 ConvertUnits.ToSimUnits(480), 62 ConvertUnits.ToSimUnits(50), 63 10f); 64 _floor.Position = ConvertUnits.ToSimUnits(240, 775); 65 _floor.IsStatic = true; 66 _floor.Restitution = 0.2f; 67 _floor.Friction = 0.2f; 68 } 69 70 protected override void Update(GameTime gameTime) 71 { 72 // Allows the game to exit 73 if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed) 74 Exit(); 75 76 // Create a random box every second 77 _timer += (float) gameTime.ElapsedGameTime.TotalSeconds; 78 if (_timer >= 1.0f) 79 { 80 // Reset our timer 81 _timer = 0f; 82 83 // Determine a random size for each box 84 var random = new Random(); 85 var width = random.Next(20, 100); 86 var height = random.Next(20, 100); 87 88 // Create it and store the size in the user data 89 var box = BodyFactory.CreateRectangle( 90 _world, 91 ConvertUnits.ToSimUnits(width), 92 ConvertUnits.ToSimUnits(height), 93 10f, 94 new Point(width, height)); 95 96 box.BodyType = BodyType.Dynamic; 97 box.Restitution = 0.2f; 98 box.Friction = 0.2f; 99 100 // Randomly pick a location along the top to drop it from 101 box.Position = ConvertUnits.ToSimUnits(random.Next(50, 400), 0); 102 } 103 104 // Advance all the elements in the world 105 _world.Step(Math.Min((float) gameTime.ElapsedGameTime.TotalMilliseconds*0.001f, (1f/30f))); 106 107 // Clean up any boxes that have fallen offscreen 108 foreach (var box in from box in _world.BodyList 109 let pos = ConvertUnits.ToDisplayUnits(box.Position) 110 where pos.Y > _graphics.GraphicsDevice.Viewport.Height 111 select box) 112 { 113 _world.RemoveBody(box); 114 } 115 116 base.Update(gameTime); 117 } 118 119 protected override void Draw(GameTime gameTime) 120 { 121 GraphicsDevice.Clear(Color.FromNonPremultiplied(51, 51, 51, 255)); 122 123 _spriteBatch.Begin(); 124 125 var projection = Matrix.CreateOrthographicOffCenter( 126 0f, 127 ConvertUnits.ToSimUnits(_graphics.GraphicsDevice.Viewport.Width), 128 ConvertUnits.ToSimUnits(_graphics.GraphicsDevice.Viewport.Height), 0f, 0f, 129 1f); 130 _debugView.RenderDebugData(ref projection); 131 132 _spriteBatch.End(); 133 134 base.Draw(gameTime); 135 } 136 } 137 Lines 4: Declare the debug view we’ll use for rendering (more on that later). Lines 8: Declare _world variable of type class World. World is the main object to interact with the Farseer engine. It stores all the joints and bodies, and is responsible for stepping through the simulation. Lines 12-17: Create the graphics device we’ll be rendering on. This is an XNA component and we’re just setting it to be the same size as the phone and toggling it to be full screen (no system tray). Lines 34: We create a SpriteFont here by adding it to the project. It’s called “font” because that’s what the DebugView uses but you can name it whatever you want (and if you’re not using DebugView for your production app you might have several fonts). Lines 37-44: We create the physics environment that Farseer uses to contain all the objects by specifying it here. We’re using Vector2.UnitY*10 to represent the gravity to be used in the environment. In other words, 10 units going in a downward motion. Lines 46-56: We create the DebugViewXNA here. This is copied from the […] from the code you downloaded and provides the ability to render all entities onto the screen. In a production release you’ll be doing the rendering yourself of each object but we cheat a bit for the demo and let the DebugView do it for us. The other thing it can provide is to render out a panel of debugging information while the simulation is going on. This is useful in tracking down objects, figuring out how something works, or just keeping track of what’s in the engine. Lines 49-67: Here we create a rigid body (Farseer only supports rigid bodies) to represent the floor that we’ll drop objects onto. We create it by using one of the Farseer factories and specifying the width and height. The ConvertUnits class is copied from the samples code as-is and lets us toggle between display units (pixels) and simulation units (usually metres). We’re creating a floor that’s 480 pixels wide and 50 pixels high (converting them to SimUnits for the engine to understand). We also position it near the bottom of the screen. Values are in metres and when specifying values they refer to the centre of the body object. Lines 77-78: The game Update method fires 30 times a second, too fast to be creating objects this quickly. So we use a variable to track the elapsed seconds since the last update, accumulate that value, then create a new box to drop when 1 second has passed. Lines 89-94: We create a box the same way we created our floor (coming up with a random width and height for the box). Lines 96-101: We set the box to be Dynamic (rather than Static like the floor object) and position it somewhere along the top of the screen. And now you created the world. Gravity does the rest and the boxes fall to the ground. Here’s the result: Farseer Physics Engine Demo using XNA Lines 105: We must update the world at every frame. We do this with the Step method which takes in the time interval. [more] Lines 108-114: Body objects are added to the world but never automatically removed (because Farseer doesn’t know about the display world, it has no idea if an item is on the screen or not). Here we just loop through all the entities and anything that’s dropped off the screen (below the bottom) gets removed from the World. This keeps our entity count down (the simulation never has more than 30 or 40 objects in the world no matter how long you run it for). Too many entities and the app will grind to a halt. Lines 125-130: Farseer knows nothing about the UI so that’s entirely up to you as to how to draw things. Farseer is just tracking the objects and moving them around using the physics engine and it’s rules. You’ll still use XNA to draw items (using the SpriteBatch.Draw method) so you can load up your usual textures and draw items and pirates and dancing zombies all over the screen. Instead in this demo we’re going to cheat a little. In the sample code for Farseer you can download there’s a project called DebugView XNA. This project contains the DebugViewXNA class which just handles iterating through all the bodies in the world and drawing the shapes. So we call the RenderDebugData method here of that class to draw everything correctly. In the case of this demo, we just want to draw Shapes so take a look at the source code for the DebugViewXNA class as to how it extracts all the vertices for the shapes created (in this case simple boxes) and draws them. You’ll learn a *lot* about how Farseer works just by looking at this class. That’s it, that’s all. Simple huh? Hope you enjoy the code and library. Physics is hard and requires some math skills to really grok. The Farseer Physics Engine makes it pretty easy to get up and running and start building games. In future posts we’ll get more in-depth with things you can do with the engine so this is just the beginning. Enjoy!

  Read the article

• Animating the offset of the scrollView in a UICollectionView/UITableView causes prematurely disappearing cells

  - by radutzan

  We have a UICollectionView with a custom layout very similar to UITableView (it scrolls vertically). The UICollectionView displays only 3 cells simultaneously, with one of them being the currently active cell: [ 1 ] [*2*] [ 3 ] (The active cell here is #2.) The cells are roughly 280 points high, so only the active cell is fully visible on the screen. The user doesn't directly scroll the view to navigate, instead, she swipes the active cell horizontally to advance to the next cell. We then do some fancy animations and scroll the UICollectionView so the next cell is in the "active" position, thus making it the active one, moving the old one away and bringing up the next cell in the queue: [ 2 ] [*3*] [ 4 ] The problem here is setting the UICollectionView's offset. We currently set it in a UIView animation block (self.collectionView.contentOffset = targetOffset;) along with three other animating properties, which mostly works great, but causes the first cell (the previously active one, in the latter case, #2) to vanish as soon as the animation starts running, even before the delay interval completes. This is definitely not ideal. I've thought of some solutions, but can't figure out the best one: Absurdly enlarge the UICollectionView's frame to fit five cells instead of three, thus forcing it to keep the cells in memory even if they are offscreen. I've tried this and it works, but it sounds like an awfully dirty hack. Take a snapshot of the rendered content of the vanishing cell, put it in a UIImageView, add the UIImageView as a subview of the scrollView just before the cell goes away in the exact same position of the old cell, removing it once the animation ends. Sounds less sucky than the previous option (memory-wise, at least), but still kinda hacky. I also don't know the best way to accomplish this, please point me in the right direction. Switch to UIScrollView's setContentOffset:animated:. We actually used to have this, and it fixed the disappearing cell issue, but running this in parallel with the other UIView animations apparently competes for the attention of the main thread, thus creating a terribly choppy animation on single-core devices (iPhone 3GS/4). It also doesn't allow us to change the duration or easing of the animation, so it feels out of sync with the rest. Still an option if we can find a way to make it work in harmony with the UIView block animations. Switch to UICollectionView's scrollToItemAtIndexPath:atScrollPosition:animated:. Haven't tried this, but it has a big downside: it only takes 3 possible constants (that apply to this case, at least) for the target scroll position: UICollectionViewScrollPositionTop, UICollectionViewScrollPositionCenteredVertically and UICollectionViewScrollPositionBottom. The active cell could vary its height, but it always has to be 35 points from the top of the window, and these options don't provide enough control to accomplish the design. It could also potentially be just as problematic as 3.1. Still an option because there might be a way to go around the scroll position thing that I don't know of, and it might not have the same issue with the main thread, which seems unlikely. Any help will be greatly appreciated. Please ask if you need clarification. Thanks a lot!

  Read the article

• calculater by using reverse polish notation and using a stack

  - by programmer

  hello everyone I have a segmentation fault ,can you help please? if i have this operater "3 5 +" that mean 3+5 and like "9 8 * 5 + 4 + sin", "sin(((9*8)+5)+4)" so my idea is check if the first and second are numbers and push theem in the stack then when i have operator i pop the numbers and make the calculation then push the answer again. ` typedef struct st_node { float val; struct st_node *next; } t_node; typedef t_node t_stack; // a function to allocate memory for a stack and returns the stack t_stack* fnewCell() { t_stack* ret; ret = (t_stack*) malloc(sizeof(t_stack)); return ret; } // a function to allocate memory for a stack, fills it with value v and pointer n , and returns the stack t_stack* fnewCellFilled(float v, t_stack* n) { t_stack* ret; ret = fnewCell(); ret->val = v; ret->next =n; return ret; } //function to initialize stack void initstack(t_stack** stack) { fnewCellFilled(0,NULL); } // add new cell void insrtHead(t_stack** head,float val) { *head = fnewCellFilled(val,*head); } //function to push the value v into the stack s void push(t_stack **s, float val) { insrtHead(s,val); } //function to pop a value from the stack and returns it int pop(t_stack **s) { t_stack* tmp; int ret; tmp = (*s)->next; ret = (*s)->val; free(*s); (*s) = tmp; return ret; } int isempty (t_stack *t) { return t == NULL; } //function to transfer a string(str) to int (value) //returns -1 when success , i otherwise int str2int(char *str,int *value) { int i; *value = 0; int sign=(str[0]=='-' ? -1 : 1); for(i=(str[0]=='-' ? 1 : 0);str[i]!=0;i++) { if(!(str[i]>=48 && str[i]<=57)) // Ascii char 0 to 9 return i; *value= *value*10+(str[i]-48); } *value = *value * sign; return -1; } //a function that takes a string, transfer it into integer and make operation using a stack void function(t_stack *stack, char *str) { char x[10]=" "; int y,j,i=0,z; printf("++\n"); if(str[i] != '\0') { strcpy(x, strtok(str, " ")); z= str2int(x, &y); if(z == -1) { push(&stack,y); i=i+2; } } while(str[i] != '\0') { strcpy(x, strtok(NULL, " ")); z= str2int(x, &y); if(z == -1) { printf("yes %d",y); push(&stack,y); i=i+2; } else { y=pop(&stack); j=pop(&stack); if(x[0] == '+' ) push(&stack,y+j); else if (x[0] == '-' ) push(&stack,j-y); else if(x[0] == '*' ) push(&stack,j*y); else if(x[0] == '/') push (&stack ,j/y); } } } int main() { t_stack *s; initstack(&s); char *str="3 5 +"; function(s,str); return 0; } `

  Read the article

• Mercurial hg clone on Windows via ssh with copSSH issue

  - by Kyle Tolle

  I have a Windows Server 2008 machine (iis7) that has CopSSH set up on it. To connect to it, I have a Windows 7 machine with Mercurial 1.5.1 (and TortoiseHg) installed. I can connect to the server using PuTTY with a non-standard ssh port and a .ppk file just fine. So I know the server can be SSH'd into. Next, I wanted to use the CLI to connect via hg clone to get a private repo. I've seen elsewhere that you need to have ssh configured in your mercurial.ini file, so my mercurial.ini has a line: ssh = plink.exe -ssh -C -l username -P #### -i "C:/Program Files/PuTTY/Key Files/KyleKey.ppk" Note: username is filled in with the username I set up via copSSH. #### is filled in with the non-standard ssh port I've defined for copSSH. I try to do the command hg clone ssh://inthom.com but I get this error: remote: bash: inthom.com: command not found abort: no suitable response from remote hg! It looks like hg or plink parses the hostname such that it thinks that inthom.com is a command instead of the server to ssh to. That's really odd. Next, I tried to just use plink to connect by plink -P #### ssh://inthom.com, and I am then prompted for my username, and next password. I enter them both and then I get this error: bash: ssh://inthom.com: No such file or directory So now it looks like plink doesn't parse the hostname correctly. I fiddled around for a while trying to figure out how to do call hg clone with an empty ssh:// field and eventually figured out that this command allows me to reach the server and clone a test repo on the inthom.com server: hg clone ssh://!/Repos/test ! is the character I've found that let's me leave the hostname blank, but specify the repo folder to clone. What I really don't understand is how plink knows what server to ssh to at all. neither my mercurial.ini nor the command specify a server. None of the hg clone examples I've seen have a ! character. They all use an address, which makes sense, so you can connect to any repo via ssh that you want to clone. My only guess is that it somehow defaults to the last server I used PuTTY to SSH to, but I SSH'd into another server, and then tried to use plink to get to it, but plink still defaults to inthom.com (verified with the -v arg to plink). So I am at a loss as to how plink gets this server value at all. For "fun", I tried using TortoiseHg and can only clone a repo when I use ssh://!/Repos/test as the Source. Now, you can see that, since plink doesn't parse the hostname correctly, I had to specify the port number and username in the mercurial.ini file, instead of in the hostname like [email protected]:#### like you'd expect to. Trying to figure this out at first drove me insane, because I would get errors that the host couldn't be reached, which I knew shouldn't be the case. My question is how can I configure my setup so that ssh://[email protected]:####/Repos/test is parsed correctly as the username, hostname, port number, and repo to copy? Is it something wrong with the version of plink that I'm using, or is there some setting I may have messed up? If it is plink's fault, is there an alternative tool I can use? I'm going to try to get my friend set up to connect to this same repo, so I'd like to have a clean solution instead of this ! business. Especially when I have no idea how plink gets this default server, so I'm not sure if he'd even be able to get to inthom.com correctly. PS. I've had to use a ton of different tutorials to even get to this stage. Therefore, I haven't tried pushing any changes to the server yet. Hopefully I'll get this figured out and then I can try pushing changes to the repo.

  Read the article

• BlackBerry - Facebook extended permissions

  - by Max Gontar

  Hi! I've just found a great sample of Facebook Connect on Blackberry by Eki Y. Baskoro, The following is a short HOWTO on using Facebook Connect on Blackberry. I created a simple Facade encapsulating the Facebook REST API as well as added 'rough' MVC approach for screen navigation. I have tested on JDE 4.5 using 8320 simulator. This is still work in progress and all work is GPLed. It works great for reading stuff. NB Don't forget to get Facebook App Key and set it in TestBB class. But now I want to post something on my wall. So I've add new method to FacebookFacade class using Stream.publish API: /*** * Publishes message to the stream. * @param message - message that will appear on the facebook stream * @param targetId - The ID of the user, Page, group, or event where * you are publishing the content. */ public void streamPublish(String message, String targetId) { Hashtable arguments = new Hashtable(); arguments.put("method", "stream.publish"); arguments.put("message", message); arguments.put("target_id", targetId); try { JSONObject result = new JSONObject( int new JSONTokener(sendRequest(arguments))); int errorCode = result.getInt("error_code"); if (errorCode != 0) System.out.println("Error Code: "+errorCode); } catch (Exception e) { System.out.println(e); } } /*** * Publishes message on current user wall. * @param message - message that will appear on the facebook stream */ public void postOnTheWall(String message) { String targetId = String.valueOf(getLoggedInUserId()); streamPublish(message, targetId); } This will return Error code 200, "The user hasn't authorized the application to perform this action" First I thought it's related with Facebook - Application Settings - Additional Permissions - Publish recent activity (one line stories) to my wall but even checked, no difference... Then I've found this post explains that issue related with extended permissions. This in turn should be fixed by modifying url a little in LoginScreen class : public LoginScreen(FacebookFacade facebookFacade) { this.facebookFacade = facebookFacade; StringBuffer data = new StringBuffer(); data.append("api_key=" + facebookFacade.getApplicationKey()); data.append("&connect_display=popup"); data.append("&v=1.0"); //revomed //data.append("&next=http://www.facebook.com/connect/login_success.html"); //added data.append("&next=http://www.facebook.com/connect/prompt_permissions.php?" + "api_key="+facebookFacade.getApplicationKey()+"&display=popup&v=1.0"+ "&next=http://www.facebook.com/connect/login_success.html?"+ "xxRESULTTOKENxx&fbconnect=true" + "&ext_perm=read_stream,publish_stream,offline_access"); data.append("&cancel_url=http://www.facebook.com/connect/login_failure.html"); data.append("&fbconnect=true"); data.append("&return_session=true"); (new FetchThread("http://m.facebook.com/login.php?" + data.toString())).start(); } Unfortunately it's not working. Still Error Code 200 in return to stream.publish request... Do you have any suggestions how to resolve this? Thank you!

  Read the article

• Getting an Access 2007 table (.accdb extension) in ArcMap programmatically

  - by Adrian

  I have recently found a script from ArcScripts on how to get an Access table in ArcGIS programmatically and it works well. But this is for Access 2003 (.mdb extension) and earlier. The code is posted below, and I want to know how to modify it for using Access 2007 (.accdb extension) and later databases. Attribute VB_Name = "Access_connect" Sub Open_Access_Connect() 'V. Guissard Jan. 2007 On Error GoTo EH Dim data_source As String Dim pTable As ITable Dim TableName As String Dim pFeatWorkspace As IFeatureWorkspace Dim pMap As IMap Dim mxDoc As IMxDocument Dim pPropset As IPropertySet Dim pStTab As IStandaloneTable Dim pStTabColl As IStandaloneTableCollection Dim pWorkspace As IWorkspace Dim pWorkspaceFact As IWorkspaceFactory Set pPropset = New PropertySet ' Get MDB file name data_source = GetFolder("mdb") ' Connect to the MDB database pPropset.SetProperty "CONNECTSTRING", "Provider=Microsoft.Jet.OLEDB.4.0;" _ & "Data source=" & data_source & ";User ID=Admin;Password=" Set pWorkspaceFact = New OLEDBWorkspaceFactory Set pWorkspace = pWorkspaceFact.Open(pPropset, 0) Set pFeatWorkspace = pWorkspace ' Get table name TableName = SelectDataSet(pFeatWorkspace, "Table") ' Open the table Set pTable = pFeatWorkspace.OpenTable(TableName) 'Create Table collection and add the table to ArcMap Set mxDoc = ThisDocument Set pMap = mxDoc.FocusMap Set pStTab = New StandaloneTable Set pStTab.Table = pTable Set pStTabColl = pMap pStTabColl.AddStandaloneTable pStTab ' Update ArcMap Source TOC mxDoc.UpdateContents Exit Sub EH: MsgBox "Access connect: " & Err.Number & " " & Err.Description End Sub Public Function GetFolder(Optional aFilter As String) As String ' Open a GUI to let the user select a Folder path name (by default) or : ' Set aFilter = "shp" to get a shapefile name ' Set aFilter = "mdb" to get an MS Access file name ' Return the Folder Path or phath & file name As String ' V. Guissard Jan. 2007 Dim pGxDialog As IGxDialog Dim pFilterCol As IGxObjectFilterCollection Dim pCurrentFilter As IGxObjectFilter Dim pEnumGx As IEnumGxObject Select Case aFilter Case "shp" Set pCurrentFilter = New GxFilterShapefiles aTitle = "Select Shapefile" Case "mdb" Set pCurrentFilter = New GxFilterContainers aTitle = "Select MS Access database" Case Else Set pCurrentFilter = New GxFilterBasicTypes aTitle = "Select Folder" End Select Set pGxDialog = New GxDialog Set pFilterCol = pGxDialog With pFilterCol .AddFilter pCurrentFilter, True End With With pGxDialog .Title = aTitle .ButtonCaption = "Select" End With If Not pGxDialog.DoModalOpen(0, pEnumGx) Then Smp = MsgBox("No selection : Exit", vbCritical) End 'Exit Function 'Exit if user press Cancel End If GetFolder = pEnumGx.Next.FullName End Function Public Function SelectDataSet(pWorkspace As IWorkspace, Optional theDataType As String) As String ' Open a GUI to let the user select a DataSet into a Workspace ' (Table or Request into an MS Access Database or a Geodatabase File) ' Set pWorkspace to the DataSet IWorkspace ' Set theDataType = "Table" to select a Table name of the DataSet ' Return the selected Table or Request Table name As String ' V. Guissard Jan. 2007 Dim aDataset As Boolean Dim boolOK As Boolean Dim DataSetList As New Collection Dim datasetType As Integer Dim n As Integer Dim pDataSetName As IDatasetName Dim pListDlg As IListDialog Dim pEnumDatasetName As IEnumDatasetName ' Set the Dataset Type Select Case theDataType Case "Table" datasetType = 10 Case Else Answ = MsgBox("Need a Dataset Type : Exit", vbCritical, "SelectDataset") End End Select ' Get the Dataset Names included in the workspace Set pEnumDatasetName = pWorkspace.DatasetNames(datasetType) ' Create the Dataset Names List Dialog aDataset = False Set pListDlg = New ListDialog pEnumDatasetName.Reset Set pDataSetName = pEnumDatasetName.Next Do While Not pDataSetName Is Nothing pListDlg.AddString pDataSetName.name DataSetList.Add (pDataSetName.name) Set pDataSetName = pEnumDatasetName.Next aDataset = True Loop ' Open a GUI for the user to select a dataset If aDataset Then boolOK = pListDlg.DoModal("Select a " & theDataType, 0, Application.hwnd) n = pListDlg.choice If (n <> -1) Then SelectDataSet = DataSetList(n + 1) Else Sup = MsgBox("No DataSet selected : EXIT", vbCritical, "SelectDataset") End End If End If End Function Here is the link to the ArcScript: http://arcscripts.esri.com/Data/AS14882.bas PS I know this code is written in VBA and I don't know if a modified version is in VB.NET or whatever else language. Thanks, Adrian

  Read the article

• JAXB + JAK java.lang.ClassCastException

  - by Ivansek

  Hi, I read page about JAK implementation where is a piece of code from pom.xml file (Listing 1). This piece of code is actually commented in pom.xml file so i uncommented it in order to add my own schema to compile. After that i run command mvn -e clean install, and i get this error: ivansek ~/Sites/Xlab/KMLTest/javaapiforkml-read-only $ mvn -e clean install + Error stacktraces are turned on. [INFO] Scanning for projects... [INFO] ------------------------------------------------------------------------ [INFO] Building a Java API for Kml [INFO] task-segment: [clean, install] [INFO] ------------------------------------------------------------------------ [INFO] [clean:clean {execution: default-clean}] [INFO] [antrun:run {execution: xjc-invocation}] [INFO] Executing tasks [INFO] ------------------------------------------------------------------------ [ERROR] BUILD ERROR [INFO] ------------------------------------------------------------------------ [INFO] An Ant BuildException has occured: java.util.ServiceConfigurationError: com.sun.tools.xjc.Plugin: Provider org.jvnet.jaxb2_commons.javaforkmlapi.XJCJavaForKmlApiPlugin could not be instantiated: java.lang.ClassCastException [INFO] ------------------------------------------------------------------------ [INFO] Trace org.apache.maven.lifecycle.LifecycleExecutionException: An Ant BuildException has occured: java.util.ServiceConfigurationError: com.sun.tools.xjc.Plugin: Provider org.jvnet.jaxb2_commons.javaforkmlapi.XJCJavaForKmlApiPlugin could not be instantiated: java.lang.ClassCastException at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:719) at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoalWithLifecycle(DefaultLifecycleExecutor.java:556) at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoal(DefaultLifecycleExecutor.java:535) at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoalAndHandleFailures(DefaultLifecycleExecutor.java:387) at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeTaskSegments(DefaultLifecycleExecutor.java:348) at org.apache.maven.lifecycle.DefaultLifecycleExecutor.execute(DefaultLifecycleExecutor.java:180) at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:328) at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:138) at org.apache.maven.cli.MavenCli.main(MavenCli.java:362) at org.apache.maven.cli.compat.CompatibleMain.main(CompatibleMain.java:60) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.codehaus.classworlds.Launcher.launchEnhanced(Launcher.java:315) at org.codehaus.classworlds.Launcher.launch(Launcher.java:255) at org.codehaus.classworlds.Launcher.mainWithExitCode(Launcher.java:430) at org.codehaus.classworlds.Launcher.main(Launcher.java:375) Caused by: org.apache.maven.plugin.MojoExecutionException: An Ant BuildException has occured: java.util.ServiceConfigurationError: com.sun.tools.xjc.Plugin: Provider org.jvnet.jaxb2_commons.javaforkmlapi.XJCJavaForKmlApiPlugin could not be instantiated: java.lang.ClassCastException at org.apache.maven.plugin.antrun.AbstractAntMojo.executeTasks(AbstractAntMojo.java:131) at org.apache.maven.plugin.antrun.AntRunMojo.execute(AntRunMojo.java:98) at org.apache.maven.plugin.DefaultPluginManager.executeMojo(DefaultPluginManager.java:490) at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:694) ... 17 more Caused by: java.util.ServiceConfigurationError: com.sun.tools.xjc.Plugin: Provider org.jvnet.jaxb2_commons.javaforkmlapi.XJCJavaForKmlApiPlugin could not be instantiated: java.lang.ClassCastException at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:116) at org.apache.tools.ant.Task.perform(Task.java:348) at org.apache.tools.ant.Target.execute(Target.java:357) at org.apache.maven.plugin.antrun.AbstractAntMojo.executeTasks(AbstractAntMojo.java:118) ... 20 more Caused by: java.util.ServiceConfigurationError: com.sun.tools.xjc.Plugin: Provider org.jvnet.jaxb2_commons.javaforkmlapi.XJCJavaForKmlApiPlugin could not be instantiated: java.lang.ClassCastException at java.util.ServiceLoader.fail(ServiceLoader.java:207) at java.util.ServiceLoader.access$100(ServiceLoader.java:164) at java.util.ServiceLoader$LazyIterator.next(ServiceLoader.java:353) at java.util.ServiceLoader$1.next(ServiceLoader.java:421) at com.sun.tools.xjc.Options.findServices(Options.java:910) at com.sun.tools.xjc.Options.getAllPlugins(Options.java:351) at com.sun.tools.xjc.Options.parseArgument(Options.java:650) at com.sun.tools.xjc.Options.parseArguments(Options.java:760) at com.sun.tools.xjc.XJC2Task._doXJC(XJC2Task.java:453) at com.sun.tools.xjc.XJC2Task.doXJC(XJC2Task.java:443) at com.sun.tools.xjc.XJC2Task.execute(XJC2Task.java:369) at com.sun.istack.tools.ProtectedTask.execute(ProtectedTask.java:55) at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:288) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106) ... 23 more Caused by: java.lang.ClassCastException at java.lang.Class.cast(Class.java:2990) at java.util.ServiceLoader$LazyIterator.next(ServiceLoader.java:345) ... 38 more [INFO] ------------------------------------------------------------------------ [INFO] Total time: 3 seconds [INFO] Finished at: Thu May 13 09:53:19 CEST 2010 [INFO] Final Memory: 16M/79M [INFO] ------------------------------------------------------------------------ Any suggestions?

  Read the article

• Quartz Thread Execution Parallel or Sequential?

  - by vikas

  We have a quartz based scheduler application which runs about 1000 jobs per minute which are evenly distributed across seconds of each minute i.e. about 16-17 jobs per second. Ideally, these 16-17 jobs should fire at same time, however our first statement, which simply logs the time of execution, of execute method of the job is being called very late. e.g. let us assume we have 1000 jobs scheduled per minute from 05:00 to 05:04. So, ideally the job which is scheduled at 05:03:50 should have logged the first statement of the execute method at 05:03:50, however, it is doing it at about 05:06:38. I have tracked down the time taken by the scheduled job which comes around 15-20 milliseconds. This scheduled job is fast enough because we just send a message on an ActiveMQ queue. We have specified the number of threads of quartz to be 100 and even tried with increasing it to 200 and more, but no gain. One more thing we noticed is that logs from scheduler are coming sequential after first 1 minute i.e. [Quartz_Worker_28] <Some log statement> .. .. [Quartz_Worker_29] <Some log statement> .. .. [Quartz_Worker_30] <Some log statement> .. .. So it suggesting that after some time quartz is running threads almost sequential. May be this is happening due to the time taken in notifying the job completion to persistence store (which is a separate postgres database in this case) and/or context switching. What can be the reason behind this strange behavior? EDIT: More detailed Log [06/07/12 10:08:37:192][QuartzScheduler_Worker-34][INFO] org.quartz.plugins.history.LoggingTriggerHistoryPlugin - Trigger [<trigger_name>] fired job [<job_name>] scheduled at: 06-07-2012 10:08:33.458, next scheduled at: 06-07-2012 10:34:53.000 [06/07/12 10:08:37:192][QuartzScheduler_Worker-34][INFO] <my_package>.scheduler.quartz.ScheduledLocateJob - execute begin--------- ScheduledLocateJob with key: <job_name> started at Fri Jul 06 10:08:37 EDT 2012 [06/07/12 10:08:37:192][QuartzScheduler_Worker-34][INFO] <my_package>.scheduler.quartz.ScheduledLocateJob <some log statement> [06/07/12 10:08:37:192][QuartzScheduler_Worker-34][INFO] <my_package>.scheduler.quartz.ScheduledLocateJob <some log statement> [06/07/12 10:08:37:192][QuartzScheduler_Worker-34][INFO] <my_package>.scheduler.quartz.ScheduledLocateJob <some log statement> [06/07/12 10:08:37:220][QuartzScheduler_Worker-34][INFO] <my_package>.scheduler.quartz.ScheduledLocateJob - execute end--------- ScheduledLocateJob with key: <job_name> ended at Fri Jul 06 10:08:37 EDT 2012 [06/07/12 10:08:37:220][QuartzScheduler_Worker-34][INFO] org.quartz.plugins.history.LoggingTriggerHistoryPlugin - Trigger [<trigger_name>] completed firing job [<job_name>] with resulting trigger instruction code: DO NOTHING. Next scheduled at: 06-07-2012 10:34:53.000 I am doubting on this section of the above log scheduled at: 06-07-2012 10:08:33.458, next scheduled at: 06-07-2012 10:34:53.000 because this job was scheduled for 10:04:53, but it fired at 10:08:33 and still quartz didn't consider it as misfire. Shouldn't it be a misfire?

  Read the article

• Mercurial "hg clone" on Windows via ssh with plink issue

  - by Kyle Tolle

  I have a Windows Server 2008 machine (iis7) that has CopSSH set up on it. To connect to it, I have a Windows 7 machine with Mercurial 1.5.1 (and TortoiseHg) installed. I can connect to the server using PuTTY with a non-standard ssh port and a .ppk file just fine. So I know the server can be SSH'd into. Next, I wanted to use the CLI to connect via hg clone to get a private repo. I've seen elsewhere that you need to have ssh configured in your mercurial.ini file, so my mercurial.ini has a line: ssh = plink.exe -ssh -C -l username -P #### -i "C:/Program Files/PuTTY/Key Files/KyleKey.ppk" Note: username is filled in with the username I set up via copSSH. #### is filled in with the non-standard ssh port I've defined for copSSH. I try to do the command hg clone ssh://inthom.com but I get this error: remote: bash: inthom.com: command not found abort: no suitable response from remote hg! It looks like hg or plink parses the hostname such that it thinks that inthom.com is a command instead of the server to ssh to. That's really odd. Next, I tried to just use plink to connect by plink -P #### ssh://inthom.com, and I am then prompted for my username, and next password. I enter them both and then I get this error: bash: ssh://inthom.com: No such file or directory So now it looks like plink doesn't parse the hostname correctly. I fiddled around for a while trying to figure out how to do call hg clone with an empty ssh:// field and eventually figured out that this command allows me to reach the server and clone a test repo on the inthom.com server: hg clone ssh://!/Repos/test ! is the character I've found that let's me leave the hostname blank, but specify the repo folder to clone. What I really don't understand is how plink knows what server to ssh to at all. neither my mercurial.ini nor the command specify a server. None of the hg clone examples I've seen have a ! character. They all use an address, which makes sense, so you can connect to any repo via ssh that you want to clone. My only guess is that it somehow defaults to the last server I used PuTTY to SSH to, but I SSH'd into another server, and then tried to use plink to get to it, but plink still defaults to inthom.com (verified with the -v arg to plink). So I am at a loss as to how plink gets this server value at all. For "fun", I tried using TortoiseHg and can only clone a repo when I use ssh://!/Repos/test as the Source. Now, you can see that, since plink doesn't parse the hostname correctly, I had to specify the port number and username in the mercurial.ini file, instead of in the hostname like [email protected]:#### like you'd expect to. Trying to figure this out at first drove me insane, because I would get errors that the host couldn't be reached, which I knew shouldn't be the case. My question is how can I configure my setup so that ssh://[email protected]:####/Repos/test is parsed correctly as the username, hostname, port number, and repo to copy? Is it something wrong with the version of plink that I'm using, or is there some setting I may have messed up? If it is plink's fault, is there an alternative tool I can use? I'm going to try to get my friend set up to connect to this same repo, so I'd like to have a clean solution instead of this ! business. Especially when I have no idea how plink gets this default server, so I'm not sure if he'd even be able to get to inthom.com correctly. PS. I've had to use a ton of different tutorials to even get to this stage. Therefore, I haven't tried pushing any changes to the server yet. Hopefully I'll get this figured out and then I can try pushing changes to the repo.

  Read the article

• passing folder path from an asp file

  - by sushant

  i am using this code to navigate through the folders available on a remote computer. <%@ Language=VBScript %><% option explicit dim sRoot, sDir, sParent, objFSO, objFolder, objFile, objSubFolder, sSize %> <META content="Microsoft Visual Studio 6.0" name=GENERATOR><!-- Author: Adrian Forbes --> <% sRoot = "\\iflblw-bpd-12\Vercon_IP-BPD-01\SOFT" sDir = Request("Dir") sDir = sDir & "\" Response.Write "<h1>" & sDir & "</h1>" & vbCRLF Set objFSO = CreateObject("Scripting.FileSystemObject") on error resume next Set objFolder = objFSO.GetFolder(sRoot & sDir) if err.number <> 0 then Response.Write "Could not open folder" Response.End end if on error goto 0 sParent = objFSO.GetParentFolderName(objFolder.Path) ' Remove the contents of sRoot from the front. This gives us the parent ' path relative to the root folder ' eg. if parent folder is "c:webfilessubfolder1subfolder2" then we just want "subfolder1subfolder2" sParent = mid(sParent, len(sRoot) + 1) Response.Write "<table border=""1"">" ' Give a link to the parent folder. This is just a link to this page only pssing in ' the new folder as a parameter Response.Write "<tr><td colspan=3><a href=""browse.asp?dir=" & Server.URLEncode(sParent) & """>Parent folder</a></td></tr>" & vbCRLF ' Now we want to loop through the subfolders in this folder For Each objSubFolder In objFolder.SubFolders ' And provide a link to them Response.Write "<tr><td colspan=3><a href=""browse.asp?dir=" & Server.URLEncode(sDir & objSubFolder.Name) & """>" & objSubFolder.Name & "</a></td></tr>" & vbCRLF Next ' Now we want to loop through the files in this folder 'For Each objFile In objFolder.Files ' if Clng(objFile.Size) < 1024 then ' sSize = objFile.Size & " bytes" ' else ' sSize = Clng(objFile.Size / 1024) & " KB" 'end if ' And provide a link to view them. This is a link to show.asp passing in the directory and the file ' as parameters ' Response.Write "<tr><td><a href=""show.asp?file=" & server.URLEncode(objFile.Name) & "&dir=" & server.URLEncode (sDir) & """>" & objFile.Name & "</a></td><td>" & sSize & "</td><td>" & objFile.Type & "</td></tr>" & vbCRLF 'Next Response.Write "</table>" %> i want to pass the folder path to a form on another page. actually while filling the form, this page should be called. how to pass the path? for ex: what i need is that when a user wants to select a folder, he clicks a button which calls this page. and on selecting the folder , the folder path should be returned to the form. any help is really appreciated. and sorry for the formatting issue.

  Read the article

• Why does vbkeyup produce different results than vbkeydown does in this Code.

  - by Joshua Rhoads

  I have a VB6 app. It consists of a flexgrid. I have code to allow the user to press the up or down arrow key to switch rows in the grid. When the down arrow key is pressed the cursor is placed at the end of the text in the next row, but when the Up arrow key is pressed the cursor is placed in the middle of the text of the previous row. Anybody have any explantion for this. Private Sub Command1_Click() With MSFlexGrid1 .Cols = 4 .Rows = 5 .FixedCols = 1 .FixedRows = 1 MSFlexGrid1.TextMatrix(0, 1) = "FROM" MSFlexGrid1.TextMatrix(0, 2) = "THRU" MSFlexGrid1.TextMatrix(0, 3) = "PAGE" MSFlexGrid1.TextMatrix(1, 1) = "Aa" MSFlexGrid1.TextMatrix(1, 2) = "Az" MSFlexGrid1.TextMatrix(1, 3) = "-" MSFlexGrid1.TextMatrix(2, 1) = "Ba" MSFlexGrid1.TextMatrix(2, 2) = "Bz" MSFlexGrid1.TextMatrix(2, 3) = "-" MSFlexGrid1.TextMatrix(3, 1) = "Ca" MSFlexGrid1.TextMatrix(3, 2) = "Cz" MSFlexGrid1.TextMatrix(3, 3) = "-" MSFlexGrid1.TextMatrix(4, 1) = "Da" MSFlexGrid1.TextMatrix(4, 2) = "Dz" MSFlexGrid1.TextMatrix(4, 3) = "-" End With End Sub Private Sub Command2_Click() End End Sub Private Sub Form_Load() Text1.Visible = False End Sub Private Sub MSFlexGrid1_DblClick() FlexGridEdit Asc(" ") Exit Sub End Sub Private Sub FlexGridEdit(KeyAscii As Integer) Text1.Left = MSFlexGrid1.CellLeft + MSFlexGrid1.Left Text1.Top = MSFlexGrid1.CellTop + MSFlexGrid1.Top Text1.Width = MSFlexGrid1.ColWidth(MSFlexGrid1.Col) - 2 * (MSFlexGrid1.ColWidth (MSFlexGrid1.Col) - MSFlexGrid1.CellWidth) Text1.Height = MSFlexGrid1.RowHeight(MSFlexGrid1.Row) - 2 * (MSFlexGrid1.RowHeight(MSFlexGrid1.Row) - MSFlexGrid1.CellHeight) Text1.MaxLength = 2 Text1.Visible = True Text1.SetFocus Select Case KeyAscii Case 0 To Asc(" ") Text1.Text = MSFlexGrid1.Text Text1.SelStart = Len(Text1.Text) Case Else Text1.Text = Chr$(KeyAscii) Text1.SelStart = 1 End Select Exit Sub End Sub Function ValidateFlexGrid1() As Boolean Dim llCntrRow As Integer Dim llCntrCol As Integer Dim max_len As Single Dim new_len As Single Dim liCntr As Integer Dim lsCheck As String With MSFlexGrid1 If Text1.Visible Then .Text = Text1.Text If .Rows = .FixedRows Then ValidateFlexGrid1 = False End If For llCntrCol = .FixedCols To MSFlexGrid1.Cols - 1 For llCntrRow = .FixedRows To MSFlexGrid1.Rows - 1 If .TextMatrix(llCntrRow, llCntrCol) = "" Then ValidateFlexGrid1 = False Exit Function End If Next llCntrRow Next llCntrCol End With ValidateFlexGrid1 = True Exit Function End Function Private Sub Text1_Keydown(KeyCode As Integer, Shift As Integer) Select Case KeyCode Case vbKeyRight, vbKeyLeft, vbKeyReturn If Text1.Visible = True Then If Text1.Text = "/" Then If MSFlexGrid1.Row > 1 Then Text1.Text = MSFlexGrid1.TextMatrix(MSFlexGrid1.Row - 1, MSFlexGrid1.Col) Text1.SelStart = Len(Text1.Text) End If End If MSFlexGrid1.Text = Text1.Text If KeyCode = vbKeyRight Or KeyCode = vbKeyReturn Then If Text1.SelStart = Len(Text1.Text) Then FlexGridChkPos KeyCode FlexGridEdit Asc(" ") End If Else If Text1.SelStart = 0 Then FlexGridChkPos KeyCode FlexGridEdit Asc(" ") End If End If End If Case vbKeyDown, vbKeyUp If Text1.Visible = True Then MSFlexGrid1.Text = Text1.Text FlexGridChkPos KeyCode FlexGridEdit Asc(" ") End If End Select Exit Sub End Sub Function FlexGridChkPos(KeyCode As Integer) As Boolean Dim llNextRow As Long Dim llNextCol As Long Dim llCurrCol As Long Dim llCurrRow As Long Dim llTotCols As Long Dim llTotRows As Long Dim llBegRow As Long Dim llBegCol As Long Dim llCntrCol As Long Dim lsText As String With MSFlexGrid1 llCurrRow = .Row + 1 llCurrCol = .Col + 1 llTotRows = .Rows llTotCols = .Cols llBegRow = .FixedRows llBegCol = .FixedCols If KeyCode = vbKeyRight Or KeyCode = vbKeyReturn Then llNextCol = llCurrCol + 1 If llNextCol > llTotCols Then llNextRow = llCurrRow + 1 If llNextRow > llTotRows Then .Rows = .Rows + 1 llCurrRow = llCurrRow + 1 llCurrCol = 1 + llBegCol Else llCurrRow = llNextRow llCurrCol = 1 + llBegCol End If Else llCurrCol = llNextCol End If End If If KeyCode = vbKeyLeft Then llNextCol = llCurrCol - 1 If llNextCol = llBegCol Then llNextRow = llCurrRow - 1 If llNextRow = llBegRow Then llCurrRow = llTotRows Else llCurrRow = llNextRow End If llCurrCol = llTotCols Else llCurrCol = llNextCol End If End If If KeyCode = vbKeyUp Then llNextRow = llCurrRow - 1 If llNextRow = llBegRow Then llCurrRow = llTotRows Else llCurrRow = llNextRow End If End If If KeyCode = vbKeyDown Then llNextRow = llCurrRow + 1 If llNextRow > llTotRows Then llCurrRow = llBegRow + 1 Else llCurrRow = llNextRow End If End If .Col = llCurrCol - 1 .Row = llCurrRow - 1 End With Exit Function End Function

  Read the article

• Python: Memory usage and optimization when modifying lists

  - by xApple

  The problem My concern is the following: I am storing a relativity large dataset in a classical python list and in order to process the data I must iterate over the list several times, perform some operations on the elements, and often pop an item out of the list. It seems that deleting one item out of a Python list costs O(N) since Python has to copy all the items above the element at hand down one place. Furthermore, since the number of items to delete is approximately proportional to the number of elements in the list this results in an O(N^2) algorithm. I am hoping to find a solution that is cost effective (time and memory-wise). I have studied what I could find on the internet and have summarized my different options below. Which one is the best candidate ? Keeping a local index: while processingdata: index = 0 while index < len(somelist): item = somelist[index] dosomestuff(item) if somecondition(item): del somelist[index] else: index += 1 This is the original solution I came up with. Not only is this not very elegant, but I am hoping there is better way to do it that remains time and memory efficient. Walking the list backwards: while processingdata: for i in xrange(len(somelist) - 1, -1, -1): dosomestuff(item) if somecondition(somelist, i): somelist.pop(i) This avoids incrementing an index variable but ultimately has the same cost as the original version. It also breaks the logic of dosomestuff(item) that wishes to process them in the same order as they appear in the original list. Making a new list: while processingdata: for i, item in enumerate(somelist): dosomestuff(item) newlist = [] for item in somelist: if somecondition(item): newlist.append(item) somelist = newlist gc.collect() This is a very naive strategy for eliminating elements from a list and requires lots of memory since an almost full copy of the list must be made. Using list comprehensions: while processingdata: for i, item in enumerate(somelist): dosomestuff(item) somelist[:] = [x for x in somelist if somecondition(x)] This is very elegant but under-the-cover it walks the whole list one more time and must copy most of the elements in it. My intuition is that this operation probably costs more than the original del statement at least memory wise. Keep in mind that somelist can be huge and that any solution that will iterate through it only once per run will probably always win. Using the filter function: while processingdata: for i, item in enumerate(somelist): dosomestuff(item) somelist = filter(lambda x: not subtle_condition(x), somelist) This also creates a new list occupying lots of RAM. Using the itertools' filter function: from itertools import ifilterfalse while processingdata: for item in itertools.ifilterfalse(somecondtion, somelist): dosomestuff(item) This version of the filter call does not create a new list but will not call dosomestuff on every item breaking the logic of the algorithm. I am including this example only for the purpose of creating an exhaustive list. Moving items up the list while walking while processingdata: index = 0 for item in somelist: dosomestuff(item) if not somecondition(item): somelist[index] = item index += 1 del somelist[index:] This is a subtle method that seems cost effective. I think it will move each item (or the pointer to each item ?) exactly once resulting in an O(N) algorithm. Finally, I hope Python will be intelligent enough to resize the list at the end without allocating memory for a new copy of the list. Not sure though. Abandoning Python lists: class Doubly_Linked_List: def __init__(self): self.first = None self.last = None self.n = 0 def __len__(self): return self.n def __iter__(self): return DLLIter(self) def iterator(self): return self.__iter__() def append(self, x): x = DLLElement(x) x.next = None if self.last is None: x.prev = None self.last = x self.first = x self.n = 1 else: x.prev = self.last x.prev.next = x self.last = x self.n += 1 class DLLElement: def __init__(self, x): self.next = None self.data = x self.prev = None class DLLIter: etc... This type of object resembles a python list in a limited way. However, deletion of an element is guaranteed O(1). I would not like to go here since this would require massive amounts of code refactoring almost everywhere.

  Read the article

• can't the asp file system object access shares server paths?

  - by sushant

  i am using this code to access files and folders. <%@ Language=VBScript %><% option explicit dim sRoot, sDir, sParent, objFSO, objFolder, objFile, objSubFolder, sSize %> <META content="Microsoft Visual Studio 6.0" name=GENERATOR><!-- Author: Adrian Forbes --> <% sRoot = "D:Raghu" sDir = Request("Dir") sDir = sDir & "\" Response.Write "<h1>" & sDir & "</h1>" & vbCRLF Set objFSO = CreateObject("Scripting.FileSystemObject") on error resume next Set objFolder = objFSO.GetFolder(sRoot & sDir) if err.number <> 0 then Response.Write "Could not open folder" Response.End end if on error goto 0 sParent = objFSO.GetParentFolderName(objFolder.Path) ' Remove the contents of sRoot from the front. This gives us the parent ' path relative to the root folder ' eg. if parent folder is "c:webfilessubfolder1subfolder2" then we just want "subfolder1subfolder2" sParent = mid(sParent, len(sRoot) + 1) Response.Write "<table border=""1"">" ' Give a link to the parent folder. This is just a link to this page only pssing in ' the new folder as a parameter Response.Write "<tr><td colspan=3><a href=""browse.asp?dir=" & Server.URLEncode(sParent) & """>Parent folder</a></td></tr>" & vbCRLF ' Now we want to loop through the subfolders in this folder For Each objSubFolder In objFolder.SubFolders ' And provide a link to them Response.Write "<tr><td colspan=3><a href=""browse.asp?dir=" & Server.URLEncode(sDir & objSubFolder.Name) & """>" & objSubFolder.Name & "</a></td></tr>" & vbCRLF Next ' Now we want to loop through the files in this folder For Each objFile In objFolder.Files if Clng(objFile.Size) < 1024 then sSize = objFile.Size & " bytes" else sSize = Clng(objFile.Size / 1024) & " KB" end if ' And provide a link to view them. This is a link to show.asp passing in the directory and the file ' as parameters Response.Write "<tr><td><a href=""show.asp?file=" & server.URLEncode(objFile.Name) & "&dir=" & server.URLEncode (sDir) & """>" & objFile.Name & "</a></td><td>" & sSize & "</td><td>" & objFile.Type & "</td></tr>" & vbCRLF Next Response.Write "</table>" %> it works fine. but when i try to access something on shred path like: "\\cvrdd0110:share" it gives error. how to access these files? and sorry for formatting issues.

  Read the article

• Deploying to a clustered weblogic application server or Red Hat Linux

  - by user510210

  I am developing an application with following software stack: XHTML / CSS / ExtJS / DWR / Javascript (Presentation Layer) EJB 3.0 / Spring MVC Hibernate / Hibernate Spatial My application works well in a single server development environment. But deploying to clustered weblogic environment on Red Hat does not work and results in the following exception: ============================================================================================ org.springframework.beans.factory.BeanDefinitionStoreException: Unexpected exception parsing XML document from ServletContext resource [/WEB-INF/applicationContext.xml]; nested exception is java.lang.NoSuchMethodError: Caused by: java.lang.NoSuchMethodError: at org.apache.xerces.impl.dv.xs.XSSimpleTypeDecl.applyFacets(Unknown Source) at org.apache.xerces.impl.dv.xs.XSSimpleTypeDecl.applyFacets1(Unknown Source) at org.apache.xerces.impl.dv.xs.BaseSchemaDVFactory.createBuiltInTypes(Unknown Source) at org.apache.xerces.impl.dv.xs.SchemaDVFactoryImpl.createBuiltInTypes(Unknown Source) at org.apache.xerces.impl.dv.xs.SchemaDVFactoryImpl.(Unknown Source) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) at java.lang.reflect.Constructor.newInstance(Constructor.java:513) at java.lang.Class.newInstance0(Class.java:355) at java.lang.Class.newInstance(Class.java:308) at org.apache.xerces.impl.dv.ObjectFactory.newInstance(Unknown Source) at org.apache.xerces.impl.dv.SchemaDVFactory.getInstance(Unknown Source) at org.apache.xerces.impl.dv.SchemaDVFactory.getInstance(Unknown Source) at org.apache.xerces.impl.xs.SchemaGrammar$BuiltinSchemaGrammar.(Unknown Source) at org.apache.xerces.impl.xs.SchemaGrammar.(Unknown Source) at org.apache.xerces.impl.xs.XMLSchemaValidator.(Unknown Source) at org.apache.xerces.parsers.XML11Configuration.configurePipeline(Unknown Source) at org.apache.xerces.parsers.XIncludeAwareParserConfiguration.configurePipeline(Unknown Source) at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source) at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source) at org.apache.xerces.parsers.XMLParser.parse(Unknown Source) at org.apache.xerces.parsers.DOMParser.parse(Unknown Source) at org.apache.xerces.jaxp.DocumentBuilderImpl.parse(Unknown Source) at org.springframework.beans.factory.xml.DefaultDocumentLoader.loadDocument(DefaultDocumentLoader.java:76) at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.doLoadBeanDefinitions(XmlBeanDefinitionReader.java:351) at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:303) at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:280) at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:131) at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:147) at org.springframework.web.context.support.XmlWebApplicationContext.loadBeanDefinitions(XmlWebApplicationContext.java:124) at org.springframework.web.context.support.XmlWebApplicationContext.loadBeanDefinitions(XmlWebApplicationContext.java:93) at org.springframework.context.support.AbstractRefreshableApplicationContext.refreshBeanFactory(AbstractRefreshableApplicationContext.java:101) at org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java:390) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:327) at org.springframework.web.context.ContextLoader.createWebApplicationContext(ContextLoader.java:244) at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:187) at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:50) at weblogic.servlet.internal.EventsManager$FireContextListenerAction.run(EventsManager.java:481) at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321) at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:121) at weblogic.servlet.internal.EventsManager.notifyContextCreatedEvent(EventsManager.java:181) at weblogic.servlet.internal.WebAppServletContext.preloadResources(WebAppServletContext.java:1801) at weblogic.servlet.internal.WebAppServletContext.start(WebAppServletContext.java:3042) at weblogic.servlet.internal.WebAppModule.startContexts(WebAppModule.java:1374) at weblogic.servlet.internal.WebAppModule.start(WebAppModule.java:455) at weblogic.application.internal.flow.ModuleStateDriver$3.next(ModuleStateDriver.java:205) at weblogic.application.utils.StateMachineDriver.nextState(StateMachineDriver.java:37) at weblogic.application.internal.flow.ModuleStateDriver.start(ModuleStateDriver.java:60) at weblogic.application.internal.flow.ScopedModuleDriver.start(ScopedModuleDriver.java:201) at weblogic.application.internal.flow.ModuleListenerInvoker.start(ModuleListenerInvoker.java:118) at weblogic.application.internal.flow.ModuleStateDriver$3.next(ModuleStateDriver.java:205) at weblogic.application.utils.StateMachineDriver.nextState(StateMachineDriver.java:37) at weblogic.application.internal.flow.ModuleStateDriver.start(ModuleStateDriver.java:60) at weblogic.application.internal.flow.StartModulesFlow.activate(StartModulesFlow.java:28) at weblogic.application.internal.BaseDeployment$2.next(BaseDeployment.java:630) at weblogic.application.utils.StateMachineDriver.nextState(StateMachineDriver.java:37) at weblogic.application.internal.BaseDeployment.activate(BaseDeployment.java:206) at weblogic.application.internal.EarDeployment.activate(EarDeployment.java:53) at weblogic.application.internal.DeploymentStateChecker.activate(DeploymentStateChecker.java:161) at weblogic.deploy.internal.targetserver.AppContainerInvoker.activate(AppContainerInvoker.java:79) at weblogic.deploy.internal.targetserver.BasicDeployment.activate(BasicDeployment.java:184) at weblogic.deploy.internal.targetserver.BasicDeployment.activateFromServerLifecycle(BasicDeployment.java:361) at weblogic.management.deploy.internal.DeploymentAdapter$1.doActivate(DeploymentAdapter.java:52) at weblogic.management.deploy.internal.DeploymentAdapter.activate(DeploymentAdapter.java:196) at weblogic.management.deploy.internal.AppTransition$2.transitionApp(AppTransition.java:31) at weblogic.management.deploy.internal.ConfiguredDeployments.transitionApps(ConfiguredDeployments.java:233) at weblogic.management.deploy.internal.ConfiguredDeployments.activate(ConfiguredDeployments.java:170) at weblogic.management.deploy.internal.ConfiguredDeployments.deploy(ConfiguredDeployments.java:124) at weblogic.management.deploy.internal.DeploymentServerService.resume(DeploymentServerService.java:174) at weblogic.management.deploy.internal.DeploymentServerService.start(DeploymentServerService.java:90) at weblogic.t3.srvr.SubsystemRequest.run(SubsystemRequest.java:64) at weblogic.work.ExecuteThread.execute(ExecuteThread.java:201) at weblogic.work.ExecuteThread.run(ExecuteThread.java:173) ============================================================================================ My initial thought is that there is a clash in the Xerces library being used. But I could use any feedback.

  Read the article

• Why is processing a sorted array faster than an unsorted array?

  - by GManNickG

  Here is a piece of code that shows some very peculiar performance. For some strange reason, sorting the data miraculously speeds up the code by almost 6x: #include <algorithm> #include <ctime> #include <iostream> int main() { // generate data const unsigned arraySize = 32768; int data[arraySize]; for (unsigned c = 0; c < arraySize; ++c) data[c] = std::rand() % 256; // !!! with this, the next loop runs faster std::sort(data, data + arraySize); // test clock_t start = clock(); long long sum = 0; for (unsigned i = 0; i < 100000; ++i) { // primary loop for (unsigned c = 0; c < arraySize; ++c) { if (data[c] >= 128) sum += data[c]; } } double elapsedTime = static_cast<double>(clock() - start) / CLOCKS_PER_SEC; std::cout << elapsedTime << std::endl; std::cout << "sum = " << sum << std::endl; } Without std::sort(data, data + arraySize);, the code runs in 11.54 seconds. With the sorted data, the code runs in 1.93 seconds. Initially I thought this might be just a language or compiler anomaly. So I tried it Java... import java.util.Arrays; import java.util.Random; public class Main { public static void main(String[] args) { // generate data int arraySize = 32768; int data[] = new int[arraySize]; Random rnd = new Random(0); for (int c = 0; c < arraySize; ++c) data[c] = rnd.nextInt() % 256; // !!! with this, the next loop runs faster Arrays.sort(data); // test long start = System.nanoTime(); long sum = 0; for (int i = 0; i < 100000; ++i) { // primary loop for (int c = 0; c < arraySize; ++c) { if (data[c] >= 128) sum += data[c]; } } System.out.println((System.nanoTime() - start) / 1000000000.0); System.out.println("sum = " + sum); } } with a similar but less extreme result. My first thought was that sorting brings the data into cache, but my next thought was how silly that is because the array was just generated. What is going on? Why is a sorted array faster than an unsorted array? The code is summing up some independent terms, the order should not matter.

  Read the article

• can't the asp file system object access shared server paths?

  - by sushant

  i am using this code to access files and folders. <%@ Language=VBScript %><% option explicit dim sRoot, sDir, sParent, objFSO, objFolder, objFile, objSubFolder, sSize %> <META content="Microsoft Visual Studio 6.0" name=GENERATOR><!-- Author: Adrian Forbes --> <% sRoot = "D:Raghu" sDir = Request("Dir") sDir = sDir & "\" Response.Write "<h1>" & sDir & "</h1>" & vbCRLF Set objFSO = CreateObject("Scripting.FileSystemObject") on error resume next Set objFolder = objFSO.GetFolder(sRoot & sDir) if err.number <> 0 then Response.Write "Could not open folder" Response.End end if on error goto 0 sParent = objFSO.GetParentFolderName(objFolder.Path) ' Remove the contents of sRoot from the front. This gives us the parent ' path relative to the root folder ' eg. if parent folder is "c:webfilessubfolder1subfolder2" then we just want "subfolder1subfolder2" sParent = mid(sParent, len(sRoot) + 1) Response.Write "<table border=""1"">" ' Give a link to the parent folder. This is just a link to this page only pssing in ' the new folder as a parameter Response.Write "<tr><td colspan=3><a href=""browse.asp?dir=" & Server.URLEncode(sParent) & """>Parent folder</a></td></tr>" & vbCRLF ' Now we want to loop through the subfolders in this folder For Each objSubFolder In objFolder.SubFolders ' And provide a link to them Response.Write "<tr><td colspan=3><a href=""browse.asp?dir=" & Server.URLEncode(sDir & objSubFolder.Name) & """>" & objSubFolder.Name & "</a></td></tr>" & vbCRLF Next ' Now we want to loop through the files in this folder For Each objFile In objFolder.Files if Clng(objFile.Size) < 1024 then sSize = objFile.Size & " bytes" else sSize = Clng(objFile.Size / 1024) & " KB" end if ' And provide a link to view them. This is a link to show.asp passing in the directory and the file ' as parameters Response.Write "<tr><td><a href=""show.asp?file=" & server.URLEncode(objFile.Name) & "&dir=" & server.URLEncode (sDir) & """>" & objFile.Name & "</a></td><td>" & sSize & "</td><td>" & objFile.Type & "</td></tr>" & vbCRLF Next Response.Write "</table>" %> it works fine. but when i try to access something on shared path like: "\\cvrdd0110:share" it gives error. how to access these files? and sorry for formatting issues.

  Read the article

• Using IF statements to find string length in array for alignment (Visual Basic)

  - by Brodoin

  My question is just as it says in the title. How would one use IF statements to find the string-length of content in an array, and then make it so that they show up in a Rich Text Box with the left sides aligned? Noting that one value in my array is a Decimal. Imports System.IO Imports System.Convert Public Class frmAll 'Declare Streamreader Private objReader As StreamReader 'Declare arrays to hold the information Private strNumber(24) As String Private strName(24) As String Private strSize(24) As String Private decCost(24) As Integer Private Sub frmAll_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 'Set objReader objReader = New StreamReader("products.csv") 'Call the FillArray sub to fill the array Call FillArray() End Sub Private Sub FillArray() 'Declare variables and arrays Dim decCost(24, 1) As Decimal Dim strFields() As String Dim strRec As String Dim intCount As Integer = 0 Dim chrdelim As Char = ToChar(",") 'Set strRec to read the lines strRec = objReader.ReadLine 'Do while loop to fill array. Do While strRec <> Nothing strFields = strRec.Split(chrdelim) strNumber(intCount) = strFields(0) strName(intCount) = strFields(1) strSize(intCount) = strFields(2) decCost(intCount, 0) = ToDecimal(strFields(3)) decCost(intCount, 1) = ToDecimal(strFields(4)) 'Set strRec to read the lines again strRec = objReader.ReadLine 'increment the index intCount += 1 Loop 'Call the Calculate sub for calculation Call Calculate(decCost) End Sub Private Sub Calculate(ByVal numIn(,) As Decimal) 'Define arrays to hold total cost Dim decRowTotal(24) As Decimal 'Define variables to hold the counters for rows and columns Dim intR As Integer Dim intC As Integer 'Calcualte total cost For intC = 0 To 1 For intR = 0 To 24 decRowTotal(intR) += numIn(intR, intC) * 1 Next Next 'Call the Output sub to configure the output. Call Output(numIn, decRowTotal) End Sub Private Sub Output(ByVal NumIn(,) As Decimal, _ ByVal RowTotalIn() As Decimal) 'Variables Dim strOut As String Dim intR As Integer = 0 Dim intC As Integer = 0 'Set header for output. strOut = "ID" & vbTab & "Item" & vbTab & vbTab & vbTab & "Size" & _ vbTab & vbTab & vbTab & vbTab & "Total Price" & _ vbCrLf & "---------- ... -------------------------" & vbCrLf 'For loop to add each line to strOut, setting 'the RowTotalIn to currency. For intC = 0 To 24 strOut &= strNumber(intC) & vbTab strOut &= strName(intC) & vbTab strOut &= strSize(intC) & vbTab strOut &= RowTotalIn(intC).ToString("c") & vbCrLf Next 'Add strOut to rbtAll rtbAll.Text = strOut End Sub End Class Output It shows up with vbTabs in my output, but still, it looks similar in that they are not aligned. The first two do, but after that they are not, and I am totally lost. P0001 Coffee - Colombian Supreme 24/Case: Pre-Ground 1.75 Oz Bags $16.50 P0002 Coffee - Hazelnut 24/Case: Pre-Ground 1.75 Oz Bags $24.00 P0003 Coffee - Mild Blend 24/Case: Pre-Ground 1.75 Oz Bags $20.50 P0004 Coffee - Assorted Flavors 18/Case. Pre-Ground 1.75 Oz Bags $23.50 P0005 Coffee - Decaf 24/Case: Pre-Ground 1.75 Oz Bags $20.50

  Read the article

• Running code when all threads are finished processing.

  - by rich97

  Quick note: Java and Android noob here, I'm open to you telling me I'm stupid (as long as you tell me why.) I have an android application which requires me start multiple threads originating from various classes and only advance to the next activity once all threads have done their job. I also want to add a "failsafe" timeout in case one the the threads takes too long (HTTP request taking too long or something.) I searched Stack Overflow and found a post saying that I should create a class to keep a running total of open threads and then use a timer to poll for when all the threads are completed. I think I've created a working class to do this for me, it's untested as of yet but has no errors showing in eclipse. Is this a correct implementation? Are there any APIs that I should be made aware of (such as classes in the Java or Android APIs that could be used in place of the abstract classes at the bottom of the class?) package com.dmp.geofix.libs; import java.util.ArrayList; import java.util.Iterator; import java.util.Timer; import java.util.TimerTask; public class ThreadMonitor { private Timer timer = null; private TimerTask timerTask = null; private OnSuccess onSuccess = null; private OnError onError = null; private static ArrayList<Thread> threads; private final int POLL_OPEN_THREADS = 100; private final int TIMEOUT = 10000; public ThreadMonitor() { timerTask = new PollThreadsTask(); } public ThreadMonitor(OnSuccess s) { timerTask = new PollThreadsTask(); onSuccess = s; } public ThreadMonitor(OnError e) { timerTask = new PollThreadsTask(); onError = e; } public ThreadMonitor(OnSuccess s, OnError e) { timerTask = new PollThreadsTask(); onSuccess = s; onError = e; } public void start() { Iterator<Thread> i = threads.iterator(); while (i.hasNext()) { i.next().start(); } timer = new Timer(); timer.schedule(timerTask, 0, POLL_OPEN_THREADS); } public void finish() { Iterator<Thread> i = threads.iterator(); while (i.hasNext()) { i.next().interrupt(); } threads.clear(); timer.cancel(); } public void addThread(Thread t) { threads.add(t); } public void removeThread(Thread t) { threads.remove(t); t.interrupt(); } class PollThreadsTask extends TimerTask { private int timeElapsed = 0; @Override public void run() { timeElapsed += POLL_OPEN_THREADS; if (timeElapsed <= TIMEOUT) { if (threads.isEmpty() == false) { if (onSuccess != null) { onSuccess.run(); } } } else { if (onError != null) { onError.run(); } finish(); } } } public abstract class OnSuccess { public abstract void run(); } public abstract class OnError { public abstract void run(); } }

  Read the article

< Previous Page | 138 139 140 141 142 143 144 145 146 147 148 149  | Next Page >