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• java.lang.IllegalArgumentException: Method must not be null

  - by abc

  Nested in org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.beans.factory.config.PropertyPlaceholderConfigurer#0': Initialization of bean failed; nested exception is java.lang.IllegalArgumentException: Method must not be null:java.lang.IllegalArgumentException: Method must not be null i am getting this deployment error while deploying my application. java -version java version "1.6.0_20" Java(TM) SE Runtime Environment (build 1.6.0_20-b02) Java HotSpot(TM) Server VM (build 16.3-b01, mixed mode) while the same build gets deployed successfully in the same server jetty 6.1.3 with following conf. java version "1.6.0_17" spring version used is 2.5.6.SEC01 how to overcome, googling didnt work? 2010-05-13 15:53:20.903::WARN: Failed startup of context org.mortbay.jetty.webapp.WebAppContext@9ad840{/caw,jar:file:/home/jigar/jetty-6.1.3/webapps/caw.war!/} org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.beans.factory.config.PropertyPlaceholderConfigurer#0': Initialization of bean failed; nested exception is java.lang.IllegalArgumentException: Method must not be null at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:480) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory$1.run(AbstractAutowireCapableBeanFactory.java:409) at java.security.AccessController.doPrivileged(Native Method) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:380) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:264) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:261) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:185) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:164) at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:515) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:362) at org.springframework.web.context.ContextLoader.createWebApplicationContext(ContextLoader.java:255) at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:199) at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:45) at org.mortbay.jetty.handler.ContextHandler.startContext(ContextHandler.java:530) at org.mortbay.jetty.servlet.Context.startContext(Context.java:135) at org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1218) at org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:500) at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:448) at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:40) at org.mortbay.jetty.handler.HandlerCollection.doStart(HandlerCollection.java:147) at org.mortbay.jetty.handler.ContextHandlerCollection.doStart(ContextHandlerCollection.java:161) at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:40) at org.mortbay.jetty.handler.HandlerCollection.doStart(HandlerCollection.java:147) at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:40) at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:117) at org.mortbay.jetty.Server.doStart(Server.java:210) at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:40) at org.mortbay.xml.XmlConfiguration.main(XmlConfiguration.java:929) 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.mortbay.start.Main.invokeMain(Main.java:183) at org.mortbay.start.Main.start(Main.java:497) at org.mortbay.start.Main.main(Main.java:115) Caused by: java.lang.IllegalArgumentException: Method must not be null at org.springframework.util.Assert.notNull(Assert.java:112) at org.springframework.core.BridgeMethodResolver.findBridgedMethod(BridgeMethodResolver.java:63) at org.springframework.beans.GenericTypeAwarePropertyDescriptor.<init>(GenericTypeAwarePropertyDescriptor.java:58) at org.springframework.beans.CachedIntrospectionResults.<init>(CachedIntrospectionResults.java:250) at org.springframework.beans.CachedIntrospectionResults.forClass(CachedIntrospectionResults.java:144) at org.springframework.beans.BeanWrapperImpl.getCachedIntrospectionResults(BeanWrapperImpl.java:252) at org.springframework.beans.BeanWrapperImpl.getPropertyDescriptorInternal(BeanWrapperImpl.java:282) at org.springframework.beans.BeanWrapperImpl.isWritableProperty(BeanWrapperImpl.java:333) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1247) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1010) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:472) ... 35 more 2010-05-13 15:53:20.906::WARN: Nested in org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.beans.factory.config.PropertyPlaceholderConfigurer#0': Initialization of bean failed; nested exception is java.lang.IllegalArgumentException: Method must not be null: java.lang.IllegalArgumentException: Method must not be null at org.springframework.util.Assert.notNull(Assert.java:112) at org.springframework.core.BridgeMethodResolver.findBridgedMethod(BridgeMethodResolver.java:63) at org.springframework.beans.GenericTypeAwarePropertyDescriptor.<init>(GenericTypeAwarePropertyDescriptor.java:58) at org.springframework.beans.CachedIntrospectionResults.<init>(CachedIntrospectionResults.java:250) at org.springframework.beans.CachedIntrospectionResults.forClass(CachedIntrospectionResults.java:144) at org.springframework.beans.BeanWrapperImpl.getCachedIntrospectionResults(BeanWrapperImpl.java:252) at org.springframework.beans.BeanWrapperImpl.getPropertyDescriptorInternal(BeanWrapperImpl.java:282) at org.springframework.beans.BeanWrapperImpl.isWritableProperty(BeanWrapperImpl.java:333) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1247) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1010) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:472) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory$1.run(AbstractAutowireCapableBeanFactory.java:409) at java.security.AccessController.doPrivileged(Native Method) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:380) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:264) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:261) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:185) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:164) at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:515) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:362) at org.springframework.web.context.ContextLoader.createWebApplicationContext(ContextLoader.java:255) at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:199) at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:45) at org.mortbay.jetty.handler.ContextHandler.startContext(ContextHandler.java:530) at org.mortbay.jetty.servlet.Context.startContext(Context.java:135) at org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1218) at org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:500) at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:448) at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:40) at org.mortbay.jetty.handler.HandlerCollection.doStart(HandlerCollection.java:147) at org.mortbay.jetty.handler.ContextHandlerCollection.doStart(ContextHandlerCollection.java:161) at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:40) at org.mortbay.jetty.handler.HandlerCollection.doStart(HandlerCollection.java:147) at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:40) at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:117) at org.mortbay.jetty.Server.doStart(Server.java:210) at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:40) at org.mortbay.xml.XmlConfiguration.main(XmlConfiguration.java:929) 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.mortbay.start.Main.invokeMain(Main.java:183) at org.mortbay.start.Main.start(Main.java:497) at org.mortbay.start.Main.main(Main.java:115) 2010-05-13 15:53:20.964::INFO: Started SelectChannelConnector @ 0.0.0.0:8090

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• Using QT to build a WYSIWYG Editor for a Custom Markup Language

  - by Aaron

  I'm new to QT, and am trying to figure out the best means of creating a WYSIWYG editor widget for a custom markup language that displays simple text, images, and links. I need to be able to propagate changes from the WYSIWYG editor to the custom markup representation. As a concrete example of the problem domain, imagine that the custom markup might have a "player" tag which contains a player name and a team name. The markup could look like this: Last week, <player id="1234"><name>Aaron Rodgers</name><team>Packers</team></player> threw a pass. This text would display in the editor as: Last week, Aaron Rodgers of the Packers threw a pass. The player name and the team name would be editable directly within the editor in standard WYSIWYG fashion, so that my users do not have to learn any markup. Also, when the player name is moused-over, a details pop-up will appear about that player, and similarly for the team. With that long introduction, I'm trying to figure out where to start with QT. It seems that the most logical option would be the Rich Text API using a QTextDocument. This approach seems less than ideal given the limitations of a QTextDocument: I can't figure out how to capture navigation events from clicking on links. Following links on click seems to only be enabled when the QTextEdit is readonly. Custom objects that implement QTextObjectInterface are ignored in copy-and-paste operations Any HTML-based markup that is passed to it as Rich Text is retranslated into a series of span tags and lots of other junk, making it extremely difficult to propagate changes from the editor back to the original custom markup. A second option appears to be QWebKit, which allows for live editing of HTML5 markup, so I could specify a two-way translation between the custom markup and HTML5. I'm not clear on how one would propagate changes from the editor back to the original markup in real-time without re-translating the entire document on every text change. The QWebKit solutions looks like awfully bulky to me (Learning WebKit along with QT) to what should be a relatively simple problem. I have also considered implementing the WYSIWYG with a custom class using native QT containers, labels, images, and other widgets manually. This seems like the most flexible approach, and the one most likely not to run into unresolvable problems. However, I'm pretty sure that implementing all the details of a normal text editor (selecting text, font changes, cut-and-paste support, undo/redo, dragging of objects, cursor placement, etc.) will be incredibly time consuming. So, finally, my question: are there any QT gurus out there with some advice on where to start with this sort of project? BTW, I am using QT because the application is a desktop application that needs platform independence.

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• How to add a specific method to a particular scope in Visual Studion 2005

  - by pragadheesh

  Hi, In my visual studio project (C++), when i copy a method(meth1) of a particular scope say 'scope1' and paste it in the same code area, it is getting pasted in General Scope. i.e I want to add a method into a particular scope but when i try it is getting added in general scope. How can i solve this? For eg: There is an existing method: void add(int a, int b) { .... } This method is in File scope. i.e limited for that file. Now i want to add another method add2 in the same file scope. So I copied the existing add method and pasted it. void add2(int a, int b) { .... } But this method is getting added in the global scope and not in the file scope.

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• Call a macro every time any method is called - Objective C

  - by Jacob Relkin

  Hi, I wrote a debug macro that prints to the console the passed-in string whenever the global kDebug flag == YES. I need to print out the name of a method and it's classname whenever any method is called. That works fine when i painstakingly go through every method and write the name of the class and the method in a string. Is there any special handler that gets called when any method in Objective-C is called, and if so, is there a way i can somehow override it to call my debug macro?? The entire purpose of this is so that I don't have to go through every method in my code and hand-code the method signature in the debug macro call. Thanks

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• No-argument method on window.external is invoked when checking with typeof

  - by janko

  Hi, I am trying to display an HTML page with embedded JavaScript code inside a System.Windows.Forms.WebBrowser control. The JavaScript code is expected to interact with the embedding environment through the window.external object. Before invoking a method on window.external, JavaScript is supposed to check for the existance of the method. If it is not there, the code should invoke a generic fallback method. // basic idea if (typeof(window.external.MyMethod) != 'undefined') { window.external.MyMethod(args); } else { window.external.Generic("MyMethod", args); } However, checking for a no-argument method with typeof seems to invoke the method already. That is, if MyMethod accepts any positive number of arguments, the code above will work perfectly; but, if MyMethod is a no-argument method, then the expression typeof(window.external.MyMethod) will not check for its type but invoke it, too. Is there any work-around to this behavior? Can I somehow escape the expression window.external.MyMethod to prevent the method call from occurring?

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• Track user through Google Universal Analytics

  - by raygo

  I want to track a user from my site, give an id to Google Analytics and later be able to see which pages that id visited and for how long did that id view the pages. I've tried custom variables with the classic analytics. I tried enabling the User-ID feature in the Universal Analytics. Neither of these have given me what I want yet. Is there any way to accomplish this with Universal Analytics? UPDATE This is a sample code with a user whose id is 2. I try to set the userid in different ways to see if at least in one way it shows. <script> (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){ (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o), m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m) })(window,document,'script','//www.google-analytics.com/analytics.js','ga'); ga('create', 'UA-XXXXXXX-1', 'domain.com', { 'userId': '2' }); ga('set', '&uid', '2'); // Set the user ID using signed-in user_id. var dimensionValue = '2'; ga('set', 'dimension1', dimensionValue); ga('send', 'pageview'); </script>

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• Copy Ubuntu distro with all settings from one computer to a different one

  - by theFisher86

  I'd like to copy my exact setup from my computer at work to my computer at home. I'm trying to figure out how to go about doing that. So far I've figured this much out. On the source computer run dpkg --get-selections > installed-software and backup the installed-software file Backup /etc/apt/sources.list Backup /usr/share/applications/ to save all my custom Quicklists Backup /etc/fstab to save all my network mounts Backup /usr/share/themes/ to save the customization I've done to my themes I'm also going to backup my entire HOME directory. Once I get to the destination computer I'm going to first do just a fresh install of 11.10 Then I'll copy over my HOME directory, /etc/apt/sources.list, /usr/share/appications, /etc/fstab and /usr/share/themes/ Then I'm going to run dpkg --set-selections < installed-software Followed by dselect That should install all of my apps for me. I'm wondering if there's a way/need to backup dconf and gconf settings from the source computer? I guess that's my ultimate question. I'd also like any notes on anything else that might need backed up as well before I undertake this project. I hope this post is legit, I figured other people would be interested in knowing this process and I don't see any other questions that seem to really document this on here. I'd also like to further this project and have each computer routinely backup all the necessary files so that both computer are basically identical at all times. That's stage 2 though...

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• Android - creating a custom preferences activity screen

  - by Bill Osuch

  Android applications can maintain their own internal preferences (and allow them to be modified by users) with very little coding. In fact, you don't even need to write an code to explicitly save these preferences, it's all handled automatically! Create a new Android project, with an intial activity title Main. Create two more activities: ShowPrefs, which extends Activity Set Prefs, which extends PreferenceActivity Add these two to your AndroidManifest.xml file: <activity android:name=".SetPrefs"></activity> <activity android:name=".ShowPrefs"></activity> Now we'll work on fleshing out each activity. First, open up the main.xml layout file and add a couple of buttons to it: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="vertical"    android:layout_width="fill_parent"    android:layout_height="fill_parent"> <Button android:text="Edit Preferences"    android:id="@+id/prefButton"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:layout_gravity="center_horizontal"/> <Button android:text="Show Preferences"    android:id="@+id/showButton"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:layout_gravity="center_horizontal"/> </LinearLayout> Next, create a couple button listeners in Main.java to handle the clicks and start the other activities: Button editPrefs = (Button) findViewById(R.id.prefButton);       editPrefs.setOnClickListener(new View.OnClickListener() {              public void onClick(View view) {                  Intent myIntent = new Intent(view.getContext(), SetPrefs.class);                  startActivityForResult(myIntent, 0);              }      });           Button showPrefs = (Button) findViewById(R.id.showButton);      showPrefs.setOnClickListener(new View.OnClickListener() {              public void onClick(View view) {                  Intent myIntent = new Intent(view.getContext(), ShowPrefs.class);                  startActivityForResult(myIntent, 0);              }      }); Now, we'll create the actual preferences layout. You'll need to create a file called preferences.xml inside res/xml, and you'll likely have to create the xml directory as well. Add the following xml: <?xml version="1.0" encoding="utf-8"?> <PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android"> </PreferenceScreen> First we'll add a category, which is just a way to group similar preferences... sort of a horizontal bar. Add this inside the PreferenceScreen tags: <PreferenceCategory android:title="First Category"> </PreferenceCategory> Now add a Checkbox and an Edittext box (inside the PreferenceCategory tags): <CheckBoxPreference    android:key="checkboxPref"    android:title="Checkbox Preference"    android:summary="This preference can be true or false"    android:defaultValue="false"/> <EditTextPreference    android:key="editTextPref"    android:title="EditText Preference"    android:summary="This allows you to enter a string"    android:defaultValue="Nothing"/> The key is how you will refer to the preference in code, the title is the large text that will be displayed, and the summary is the smaller text (this will make sense when you see it). Let's say we've got a second group of preferences that apply to a different part of the app. Add a new category just below the first one: <PreferenceCategory android:title="Second Category"> </PreferenceCategory> In there we'll a list with radio buttons, so add: <ListPreference    android:key="listPref"    android:title="List Preference"    android:summary="This preference lets you select an item in a array"    android:entries="@array/listArray"    android:entryValues="@array/listValues" /> When complete, your full xml file should look like this: <?xml version="1.0" encoding="utf-8"?> <PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">  <PreferenceCategory android:title="First Category"> <CheckBoxPreference    android:key="checkboxPref"    android:title="Checkbox Preference"    android:summary="This preference can be true or false"    android:defaultValue="false"/> <EditTextPreference    android:key="editTextPref"    android:title="EditText Preference"    android:summary="This allows you to enter a string"    android:defaultValue="Nothing"/>  </PreferenceCategory>  <PreferenceCategory android:title="Second Category">   <ListPreference    android:key="listPref"    android:title="List Preference"    android:summary="This preference lets you select an item in a array"    android:entries="@array/listArray"    android:entryValues="@array/listValues" />  </PreferenceCategory> </PreferenceScreen> However, when you try to save it, you'll get an error because you're missing your array definition. To fix this, add a file called arrays.xml in res/values, and paste in the following: <?xml version="1.0" encoding="utf-8"?> <resources>  <string-array name="listArray">      <item>Value 1</item>      <item>Value 2</item>      <item>Value 3</item>  </string-array>  <string-array name="listValues">      <item>1</item>      <item>2</item>      <item>3</item>  </string-array> </resources> Finally (for the preferences screen at least...) add the code that will display the preferences layout to the SetPrefs.java file:  @Override     public void onCreate(Bundle savedInstanceState) {      super.onCreate(savedInstanceState);      addPreferencesFromResource(R.xml.preferences);      } OK, so now we've got an activity that will set preferences, and save them without the need to write custom save code. Let's throw together an activity to work with the saved preferences. Create a new layout called showpreferences.xml and give it three Textviews: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"     android:orientation="vertical"     android:layout_width="fill_parent"     android:layout_height="fill_parent"> <TextView   android:id="@+id/textview1"     android:layout_width="fill_parent"     android:layout_height="wrap_content"     android:text="textview1"/> <TextView   android:id="@+id/textview2"     android:layout_width="fill_parent"     android:layout_height="wrap_content"     android:text="textview2"/> <TextView   android:id="@+id/textview3"     android:layout_width="fill_parent"     android:layout_height="wrap_content"     android:text="textview3"/> </LinearLayout> Open up the ShowPrefs.java file and have it use that layout: setContentView(R.layout.showpreferences); Then add the following code to load the DefaultSharedPreferences and display them: SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);    TextView text1 = (TextView)findViewById(R.id.textview1); TextView text2 = (TextView)findViewById(R.id.textview2); TextView text3 = (TextView)findViewById(R.id.textview3);    text1.setText(new Boolean(prefs.getBoolean("checkboxPref", false)).toString()); text2.setText(prefs.getString("editTextPref", "<unset>"));; text3.setText(prefs.getString("listPref", "<unset>")); Fire up the application in the emulator and click the Edit Preferences button. Set various things, click the back button, then the Edit Preferences button again. Notice that your choices have been saved.   Now click the Show Preferences button, and you should see the results of what you set:   There are two more preference types that I did not include here: RingtonePreference - shows a radioGroup that lists your ringtones PreferenceScreen - allows you to embed a second preference screen inside the first - it opens up a new set of preferences when clicked

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• A Taxonomy of Numerical Methods v1

  - by JoshReuben

  Numerical Analysis – When, What, (but not how) Once you understand the Math & know C++, Numerical Methods are basically blocks of iterative & conditional math code. I found the real trick was seeing the forest for the trees – knowing which method to use for which situation. Its pretty easy to get lost in the details – so I’ve tried to organize these methods in a way that I can quickly look this up. I’ve included links to detailed explanations and to C++ code examples. I’ve tried to classify Numerical methods in the following broad categories: Solving Systems of Linear Equations Solving Non-Linear Equations Iteratively Interpolation Curve Fitting Optimization Numerical Differentiation & Integration Solving ODEs Boundary Problems Solving EigenValue problems Enjoy – I did ! Solving Systems of Linear Equations Overview Solve sets of algebraic equations with x unknowns The set is commonly in matrix form Gauss-Jordan Elimination http://en.wikipedia.org/wiki/Gauss%E2%80%93Jordan_elimination C++: http://www.codekeep.net/snippets/623f1923-e03c-4636-8c92-c9dc7aa0d3c0.aspx Produces solution of the equations & the coefficient matrix Efficient, stable 2 steps: · Forward Elimination – matrix decomposition: reduce set to triangular form (0s below the diagonal) or row echelon form. If degenerate, then there is no solution · Backward Elimination –write the original matrix as the product of ints inverse matrix & its reduced row-echelon matrix à reduce set to row canonical form & use back-substitution to find the solution to the set Elementary ops for matrix decomposition: · Row multiplication · Row switching · Add multiples of rows to other rows Use pivoting to ensure rows are ordered for achieving triangular form LU Decomposition http://en.wikipedia.org/wiki/LU_decomposition C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-lu-decomposition-for-solving.html Represent the matrix as a product of lower & upper triangular matrices A modified version of GJ Elimination Advantage – can easily apply forward & backward elimination to solve triangular matrices Techniques: · Doolittle Method – sets the L matrix diagonal to unity · Crout Method - sets the U matrix diagonal to unity Note: both the L & U matrices share the same unity diagonal & can be stored compactly in the same matrix Gauss-Seidel Iteration http://en.wikipedia.org/wiki/Gauss%E2%80%93Seidel_method C++: http://www.nr.com/forum/showthread.php?t=722 Transform the linear set of equations into a single equation & then use numerical integration (as integration formulas have Sums, it is implemented iteratively). an optimization of Gauss-Jacobi: 1.5 times faster, requires 0.25 iterations to achieve the same tolerance Solving Non-Linear Equations Iteratively find roots of polynomials – there may be 0, 1 or n solutions for an n order polynomial use iterative techniques Iterative methods · used when there are no known analytical techniques · Requires set functions to be continuous & differentiable · Requires an initial seed value – choice is critical to convergence à conduct multiple runs with different starting points & then select best result · Systematic - iterate until diminishing returns, tolerance or max iteration conditions are met · bracketing techniques will always yield convergent solutions, non-bracketing methods may fail to converge Incremental method if a nonlinear function has opposite signs at 2 ends of a small interval x1 & x2, then there is likely to be a solution in their interval – solutions are detected by evaluating a function over interval steps, for a change in sign, adjusting the step size dynamically. Limitations – can miss closely spaced solutions in large intervals, cannot detect degenerate (coinciding) solutions, limited to functions that cross the x-axis, gives false positives for singularities Fixed point method http://en.wikipedia.org/wiki/Fixed-point_iteration C++: http://books.google.co.il/books?id=weYj75E_t6MC&pg=PA79&lpg=PA79&dq=fixed+point+method++c%2B%2B&source=bl&ots=LQ-5P_taoC&sig=lENUUIYBK53tZtTwNfHLy5PEWDk&hl=en&sa=X&ei=wezDUPW1J5DptQaMsIHQCw&redir_esc=y#v=onepage&q=fixed%20point%20method%20%20c%2B%2B&f=false Algebraically rearrange a solution to isolate a variable then apply incremental method Bisection method http://en.wikipedia.org/wiki/Bisection_method C++: http://numericalcomputing.wordpress.com/category/algorithms/ Bracketed - Select an initial interval, keep bisecting it ad midpoint into sub-intervals and then apply incremental method on smaller & smaller intervals – zoom in Adv: unaffected by function gradient à reliable Disadv: slow convergence False Position Method http://en.wikipedia.org/wiki/False_position_method C++: http://www.dreamincode.net/forums/topic/126100-bisection-and-false-position-methods/ Bracketed - Select an initial interval , & use the relative value of function at interval end points to select next sub-intervals (estimate how far between the end points the solution might be & subdivide based on this) Newton-Raphson method http://en.wikipedia.org/wiki/Newton's_method C++: http://www-users.cselabs.umn.edu/classes/Summer-2012/csci1113/index.php?page=./newt3 Also known as Newton's method Convenient, efficient Not bracketed – only a single initial guess is required to start iteration – requires an analytical expression for the first derivative of the function as input. Evaluates the function & its derivative at each step. Can be extended to the Newton MutiRoot method for solving multiple roots Can be easily applied to an of n-coupled set of non-linear equations – conduct a Taylor Series expansion of a function, dropping terms of order n, rewrite as a Jacobian matrix of PDs & convert to simultaneous linear equations !!! Secant Method http://en.wikipedia.org/wiki/Secant_method C++: http://forum.vcoderz.com/showthread.php?p=205230 Unlike N-R, can estimate first derivative from an initial interval (does not require root to be bracketed) instead of inputting it Since derivative is approximated, may converge slower. Is fast in practice as it does not have to evaluate the derivative at each step. Similar implementation to False Positive method Birge-Vieta Method http://mat.iitm.ac.in/home/sryedida/public_html/caimna/transcendental/polynomial%20methods/bv%20method.html C++: http://books.google.co.il/books?id=cL1boM2uyQwC&pg=SA3-PA51&lpg=SA3-PA51&dq=Birge-Vieta+Method+c%2B%2B&source=bl&ots=QZmnDTK3rC&sig=BPNcHHbpR_DKVoZXrLi4nVXD-gg&hl=en&sa=X&ei=R-_DUK2iNIjzsgbE5ID4Dg&redir_esc=y#v=onepage&q=Birge-Vieta%20Method%20c%2B%2B&f=false combines Horner's method of polynomial evaluation (transforming into lesser degree polynomials that are more computationally efficient to process) with Newton-Raphson to provide a computational speed-up Interpolation Overview Construct new data points for as close as possible fit within range of a discrete set of known points (that were obtained via sampling, experimentation) Use Taylor Series Expansion of a function f(x) around a specific value for x Linear Interpolation http://en.wikipedia.org/wiki/Linear_interpolation C++: http://www.hamaluik.com/?p=289 Straight line between 2 points à concatenate interpolants between each pair of data points Bilinear Interpolation http://en.wikipedia.org/wiki/Bilinear_interpolation C++: http://supercomputingblog.com/graphics/coding-bilinear-interpolation/2/ Extension of the linear function for interpolating functions of 2 variables – perform linear interpolation first in 1 direction, then in another. Used in image processing – e.g. texture mapping filter. Uses 4 vertices to interpolate a value within a unit cell. Lagrange Interpolation http://en.wikipedia.org/wiki/Lagrange_polynomial C++: http://www.codecogs.com/code/maths/approximation/interpolation/lagrange.php For polynomials Requires recomputation for all terms for each distinct x value – can only be applied for small number of nodes Numerically unstable Barycentric Interpolation http://epubs.siam.org/doi/pdf/10.1137/S0036144502417715 C++: http://www.gamedev.net/topic/621445-barycentric-coordinates-c-code-check/ Rearrange the terms in the equation of the Legrange interpolation by defining weight functions that are independent of the interpolated value of x Newton Divided Difference Interpolation http://en.wikipedia.org/wiki/Newton_polynomial C++: http://jee-appy.blogspot.co.il/2011/12/newton-divided-difference-interpolation.html Hermite Divided Differences: Interpolation polynomial approximation for a given set of data points in the NR form - divided differences are used to approximately calculate the various differences. For a given set of 3 data points , fit a quadratic interpolant through the data Bracketed functions allow Newton divided differences to be calculated recursively Difference table Cubic Spline Interpolation http://en.wikipedia.org/wiki/Spline_interpolation C++: https://www.marcusbannerman.co.uk/index.php/home/latestarticles/42-articles/96-cubic-spline-class.html Spline is a piecewise polynomial Provides smoothness – for interpolations with significantly varying data Use weighted coefficients to bend the function to be smooth & its 1st & 2nd derivatives are continuous through the edge points in the interval Curve Fitting A generalization of interpolating whereby given data points may contain noise à the curve does not necessarily pass through all the points Least Squares Fit http://en.wikipedia.org/wiki/Least_squares C++: http://www.ccas.ru/mmes/educat/lab04k/02/least-squares.c Residual – difference between observed value & expected value Model function is often chosen as a linear combination of the specified functions Determines: A) The model instance in which the sum of squared residuals has the least value B) param values for which model best fits data Straight Line Fit Linear correlation between independent variable and dependent variable Linear Regression http://en.wikipedia.org/wiki/Linear_regression C++: http://www.oocities.org/david_swaim/cpp/linregc.htm Special case of statistically exact extrapolation Leverage least squares Given a basis function, the sum of the residuals is determined and the corresponding gradient equation is expressed as a set of normal linear equations in matrix form that can be solved (e.g. using LU Decomposition) Can be weighted - Drop the assumption that all errors have the same significance –-> confidence of accuracy is different for each data point. Fit the function closer to points with higher weights Polynomial Fit - use a polynomial basis function Moving Average http://en.wikipedia.org/wiki/Moving_average C++: http://www.codeproject.com/Articles/17860/A-Simple-Moving-Average-Algorithm Used for smoothing (cancel fluctuations to highlight longer-term trends & cycles), time series data analysis, signal processing filters Replace each data point with average of neighbors. Can be simple (SMA), weighted (WMA), exponential (EMA). Lags behind latest data points – extra weight can be given to more recent data points. Weights can decrease arithmetically or exponentially according to distance from point. Parameters: smoothing factor, period, weight basis Optimization Overview Given function with multiple variables, find Min (or max by minimizing –f(x)) Iterative approach Efficient, but not necessarily reliable Conditions: noisy data, constraints, non-linear models Detection via sign of first derivative - Derivative of saddle points will be 0 Local minima Bisection method Similar method for finding a root for a non-linear equation Start with an interval that contains a minimum Golden Search method http://en.wikipedia.org/wiki/Golden_section_search C++: http://www.codecogs.com/code/maths/optimization/golden.php Bisect intervals according to golden ratio 0.618.. Achieves reduction by evaluating a single function instead of 2 Newton-Raphson Method Brent method http://en.wikipedia.org/wiki/Brent's_method C++: http://people.sc.fsu.edu/~jburkardt/cpp_src/brent/brent.cpp Based on quadratic or parabolic interpolation – if the function is smooth & parabolic near to the minimum, then a parabola fitted through any 3 points should approximate the minima – fails when the 3 points are collinear , in which case the denominator is 0 Simplex Method http://en.wikipedia.org/wiki/Simplex_algorithm C++: http://www.codeguru.com/cpp/article.php/c17505/Simplex-Optimization-Algorithm-and-Implemetation-in-C-Programming.htm Find the global minima of any multi-variable function Direct search – no derivatives required At each step it maintains a non-degenerative simplex – a convex hull of n+1 vertices. Obtains the minimum for a function with n variables by evaluating the function at n-1 points, iteratively replacing the point of worst result with the point of best result, shrinking the multidimensional simplex around the best point. Point replacement involves expanding & contracting the simplex near the worst value point to determine a better replacement point Oscillation can be avoided by choosing the 2nd worst result Restart if it gets stuck Parameters: contraction & expansion factors Simulated Annealing http://en.wikipedia.org/wiki/Simulated_annealing C++: http://code.google.com/p/cppsimulatedannealing/ Analogy to heating & cooling metal to strengthen its structure Stochastic method – apply random permutation search for global minima - Avoid entrapment in local minima via hill climbing Heating schedule - Annealing schedule params: temperature, iterations at each temp, temperature delta Cooling schedule – can be linear, step-wise or exponential Differential Evolution http://en.wikipedia.org/wiki/Differential_evolution C++: http://www.amichel.com/de/doc/html/ More advanced stochastic methods analogous to biological processes: Genetic algorithms, evolution strategies Parallel direct search method against multiple discrete or continuous variables Initial population of variable vectors chosen randomly – if weighted difference vector of 2 vectors yields a lower objective function value then it replaces the comparison vector Many params: #parents, #variables, step size, crossover constant etc Convergence is slow – many more function evaluations than simulated annealing Numerical Differentiation Overview 2 approaches to finite difference methods: · A) approximate function via polynomial interpolation then differentiate · B) Taylor series approximation – additionally provides error estimate Finite Difference methods http://en.wikipedia.org/wiki/Finite_difference_method C++: http://www.wpi.edu/Pubs/ETD/Available/etd-051807-164436/unrestricted/EAMPADU.pdf Find differences between high order derivative values - Approximate differential equations by finite differences at evenly spaced data points Based on forward & backward Taylor series expansion of f(x) about x plus or minus multiples of delta h. Forward / backward difference - the sums of the series contains even derivatives and the difference of the series contains odd derivatives – coupled equations that can be solved. Provide an approximation of the derivative within a O(h^2) accuracy There is also central difference & extended central difference which has a O(h^4) accuracy Richardson Extrapolation http://en.wikipedia.org/wiki/Richardson_extrapolation C++: http://mathscoding.blogspot.co.il/2012/02/introduction-richardson-extrapolation.html A sequence acceleration method applied to finite differences Fast convergence, high accuracy O(h^4) Derivatives via Interpolation Cannot apply Finite Difference method to discrete data points at uneven intervals – so need to approximate the derivative of f(x) using the derivative of the interpolant via 3 point Lagrange Interpolation Note: the higher the order of the derivative, the lower the approximation precision Numerical Integration Estimate finite & infinite integrals of functions More accurate procedure than numerical differentiation Use when it is not possible to obtain an integral of a function analytically or when the function is not given, only the data points are Newton Cotes Methods http://en.wikipedia.org/wiki/Newton%E2%80%93Cotes_formulas C++: http://www.siafoo.net/snippet/324 For equally spaced data points Computationally easy – based on local interpolation of n rectangular strip areas that is piecewise fitted to a polynomial to get the sum total area Evaluate the integrand at n+1 evenly spaced points – approximate definite integral by Sum Weights are derived from Lagrange Basis polynomials Leverage Trapezoidal Rule for default 2nd formulas, Simpson 1/3 Rule for substituting 3 point formulas, Simpson 3/8 Rule for 4 point formulas. For 4 point formulas use Bodes Rule. Higher orders obtain more accurate results Trapezoidal Rule uses simple area, Simpsons Rule replaces the integrand f(x) with a quadratic polynomial p(x) that uses the same values as f(x) for its end points, but adds a midpoint Romberg Integration http://en.wikipedia.org/wiki/Romberg's_method C++: http://code.google.com/p/romberg-integration/downloads/detail?name=romberg.cpp&can=2&q= Combines trapezoidal rule with Richardson Extrapolation Evaluates the integrand at equally spaced points The integrand must have continuous derivatives Each R(n,m) extrapolation uses a higher order integrand polynomial replacement rule (zeroth starts with trapezoidal) à a lower triangular matrix set of equation coefficients where the bottom right term has the most accurate approximation. The process continues until the difference between 2 successive diagonal terms becomes sufficiently small. Gaussian Quadrature http://en.wikipedia.org/wiki/Gaussian_quadrature C++: http://www.alglib.net/integration/gaussianquadratures.php Data points are chosen to yield best possible accuracy – requires fewer evaluations Ability to handle singularities, functions that are difficult to evaluate The integrand can include a weighting function determined by a set of orthogonal polynomials. Points & weights are selected so that the integrand yields the exact integral if f(x) is a polynomial of degree <= 2n+1 Techniques (basically different weighting functions): · Gauss-Legendre Integration w(x)=1 · Gauss-Laguerre Integration w(x)=e^-x · Gauss-Hermite Integration w(x)=e^-x^2 · Gauss-Chebyshev Integration w(x)= 1 / Sqrt(1-x^2) Solving ODEs Use when high order differential equations cannot be solved analytically Evaluated under boundary conditions RK for systems – a high order differential equation can always be transformed into a coupled first order system of equations Euler method http://en.wikipedia.org/wiki/Euler_method C++: http://rosettacode.org/wiki/Euler_method First order Runge–Kutta method. Simple recursive method – given an initial value, calculate derivative deltas. Unstable & not very accurate (O(h) error) – not used in practice A first-order method - the local error (truncation error per step) is proportional to the square of the step size, and the global error (error at a given time) is proportional to the step size In evolving solution between data points xn & xn+1, only evaluates derivatives at beginning of interval xn à asymmetric at boundaries Higher order Runge Kutta http://en.wikipedia.org/wiki/Runge%E2%80%93Kutta_methods C++: http://www.dreamincode.net/code/snippet1441.htm 2nd & 4th order RK - Introduces parameterized midpoints for more symmetric solutions à accuracy at higher computational cost Adaptive RK – RK-Fehlberg – estimate the truncation at each integration step & automatically adjust the step size to keep error within prescribed limits. At each step 2 approximations are compared – if in disagreement to a specific accuracy, the step size is reduced Boundary Value Problems Where solution of differential equations are located at 2 different values of the independent variable x à more difficult, because cannot just start at point of initial value – there may not be enough starting conditions available at the end points to produce a unique solution An n-order equation will require n boundary conditions – need to determine the missing n-1 conditions which cause the given conditions at the other boundary to be satisfied Shooting Method http://en.wikipedia.org/wiki/Shooting_method C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-shooting-method-for-solving.html Iteratively guess the missing values for one end & integrate, then inspect the discrepancy with the boundary values of the other end to adjust the estimate Given the starting boundary values u1 & u2 which contain the root u, solve u given the false position method (solving the differential equation as an initial value problem via 4th order RK), then use u to solve the differential equations. Finite Difference Method For linear & non-linear systems Higher order derivatives require more computational steps – some combinations for boundary conditions may not work though Improve the accuracy by increasing the number of mesh points Solving EigenValue Problems An eigenvalue can substitute a matrix when doing matrix multiplication à convert matrix multiplication into a polynomial EigenValue For a given set of equations in matrix form, determine what are the solution eigenvalue & eigenvectors Similar Matrices - have same eigenvalues. Use orthogonal similarity transforms to reduce a matrix to diagonal form from which eigenvalue(s) & eigenvectors can be computed iteratively Jacobi method http://en.wikipedia.org/wiki/Jacobi_method C++: http://people.sc.fsu.edu/~jburkardt/classes/acs2_2008/openmp/jacobi/jacobi.html Robust but Computationally intense – use for small matrices < 10x10 Power Iteration http://en.wikipedia.org/wiki/Power_iteration For any given real symmetric matrix, generate the largest single eigenvalue & its eigenvectors Simplest method – does not compute matrix decomposition à suitable for large, sparse matrices Inverse Iteration Variation of power iteration method – generates the smallest eigenvalue from the inverse matrix Rayleigh Method http://en.wikipedia.org/wiki/Rayleigh's_method_of_dimensional_analysis Variation of power iteration method Rayleigh Quotient Method Variation of inverse iteration method Matrix Tri-diagonalization Method Use householder algorithm to reduce an NxN symmetric matrix to a tridiagonal real symmetric matrix vua N-2 orthogonal transforms     Whats Next Outside of Numerical Methods there are lots of different types of algorithms that I’ve learned over the decades: Data Mining – (I covered this briefly in a previous post: http://geekswithblogs.net/JoshReuben/archive/2007/12/31/ssas-dm-algorithms.aspx ) Search & Sort Routing Problem Solving Logical Theorem Proving Planning Probabilistic Reasoning Machine Learning Solvers (eg MIP) Bioinformatics (Sequence Alignment, Protein Folding) Quant Finance (I read Wilmott’s books – interesting) Sooner or later, I’ll cover the above topics as well.

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• Is your test method self-validating ?

  - by mehfuzh

  Writing state of art unit tests that can validate your every part of the framework is challenging and interesting at the same time, its like becoming a samurai. One of the key concept in this is to keep our test synced all the time as underlying code changes and thus breaking them to the furthest unit as possible.  This also means, we should avoid  multiple conditions embedded in a single test. Let’s consider the following example of transfer funds. [Fact] public void ShouldAssertTranserFunds() {     var currencyService = Mock.Create<ICurrencyService>();     //// current rate     Mock.Arrange(() => currencyService.GetConversionRate("AUS", "CAD")).Returns(0.88f);       Account to = new Account { Currency = "AUS", Balance = 120 };     Account from = new Account { Currency = "CAD" };       AccountService accService = new AccountService(currencyService);       Assert.Throws<InvalidOperationException>(() => accService.TranferFunds(to, from, 200f));       accService.TranferFunds(to, from, 100f);       Assert.Equal(from.Balance, 88);     Assert.Equal(20, to.Balance); } At first look,  it seems ok but as you look more closely , it is actually doing two tasks in one test. At line# 10 it is trying to validate the exception for invalid fund transfer and finally it is asserting if the currency conversion is successfully made. Here, the name of the test itself is pretty vague. The first rule for writing unit test should always reflect to inner working of the target code, where just by looking at their names it is self explanatory. Having a obscure name for a test method not only increase the chances of cluttering the test code, but it also gives the opportunity to add multiple paths into it and eventually makes things messy as possible. I would rater have two test methods that explicitly describes its intent and are more self-validating. ShouldThrowExceptionForInvalidTransferOperation ShouldAssertTransferForExpectedConversionRate Having, this type of breakdown also helps us pin-point reported bugs easily rather wasting any time on debugging for something more general and can minimize confusion among team members. Finally, we should always make our test F.I.R.S.T ( Fast.Independent.Repeatable.Self-validating.Timely) [ Bob martin – Clean Code]. Only this will be enough to ensure, our test is as simple and clean as possible.   Hope that helps

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• Advice for moving from custom domain hosted on blogspot to new custom domain on hosting provider [closed]

  - by Chan

  Need some advice :) a) Facts: 1. Currently, we have a blog www.thebigbigsky.net hosted on blogspot.com. The site has been up for around a year and google had cached some of the posts. 2. The idea for setting up the blog was to promote/share articles/write-up about personal development and self-growth, and also to offer counseling services related to them. 3. There is another subdomain - chinese.thebigbigsky.net hosting similar blog posts but in Chinese. This is hosted on blogspot as well. b) What we want to do: 1. We did some research on the internet and understood that, to make a website more popular, it is better to have a domain name that is related to the content of the site. Hence, in our case, a domain name containing "personal development" would be more ideal and easier for people to remember. 2. Hence, we are thinking to move away from blogspot to a meaningful new domain (example: personaldevelopmentwithxyz.com) and move all contents there. The new domain will be hosted on a hosting provider e.g. hostgator.com c) Here are the steps we have in mind: 1. Register the new domain (example: personaldevelopmentwithxyz.com) 2. Get a hosting provider hostgator.com 3. Setup a new site based on Wordpress, import all contents from existing blog to this new site - personaldevelopmentwithxyz.com. 4. Switch current blog back to thebigbigsky.blogspot.com 5. Switch DNS of www.thebigbigsky.net to point to the new site on hostgator.com 6. On hostgator.com, setup permanent redirect 301 of www.thebigbigsky.net to point to personaldevelopmetnwithxyz.com by following the tutorial mentioned here - http://www.blogbloke.com/migrating-redirecting-blogger-wordpress-htaccess-apache-best-method/ Questions: 1. Will it have major impact on the current google pagerank or SEO of thebigbigsky.net? As the site is not that popular, we assumed that the impact would not be a major one. 2. Is the domain personaldevelopmentwithxyz.com considered too long? (For SEO etc) 3. Steps c.4 and c.5 above - Will this work for our case? 4. How about the subdomain - chinese.thebigbigsky.net? We would like keep it as separate blog with the domain e.g. chinese.personaldevelopmentwithxyz.com 5. We added "facebook comments" to the existing post on www.thebigtbigsky.net and would not want to lose it. Will the comments still be there after we moved to the new domain? 6. Any better idea to do it? :) Thank you very much! regards, -chan

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• C#/.NET Little Wonders: The Generic Func Delegates

  - by James Michael Hare

  Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. Back in one of my three original “Little Wonders” Trilogy of posts, I had listed generic delegates as one of the Little Wonders of .NET.  Later, someone posted a comment saying said that they would love more detail on the generic delegates and their uses, since my original entry just scratched the surface of them. Last week, I began our look at some of the handy generic delegates built into .NET with a description of delegates in general, and the Action family of delegates.  For this week, I’ll launch into a look at the Func family of generic delegates and how they can be used to support generic, reusable algorithms and classes. Quick Delegate Recap Delegates are similar to function pointers in C++ in that they allow you to store a reference to a method.  They can store references to either static or instance methods, and can actually be used to chain several methods together in one delegate. Delegates are very type-safe and can be satisfied with any standard method, anonymous method, or a lambda expression.  They can also be null as well (refers to no method), so care should be taken to make sure that the delegate is not null before you invoke it. Delegates are defined using the keyword delegate, where the delegate’s type name is placed where you would typically place the method name: 1: // This delegate matches any method that takes string, returns nothing 2: public delegate void Log(string message); This delegate defines a delegate type named Log that can be used to store references to any method(s) that satisfies its signature (whether instance, static, lambda expression, etc.). Delegate instances then can be assigned zero (null) or more methods using the operator = which replaces the existing delegate chain, or by using the operator += which adds a method to the end of a delegate chain: 1: // creates a delegate instance named currentLogger defaulted to Console.WriteLine (static method) 2: Log currentLogger = Console.Out.WriteLine; 3:  4: // invokes the delegate, which writes to the console out 5: currentLogger("Hi Standard Out!"); 6:  7: // append a delegate to Console.Error.WriteLine to go to std error 8: currentLogger += Console.Error.WriteLine; 9:  10: // invokes the delegate chain and writes message to std out and std err 11: currentLogger("Hi Standard Out and Error!"); While delegates give us a lot of power, it can be cumbersome to re-create fairly standard delegate definitions repeatedly, for this purpose the generic delegates were introduced in various stages in .NET.  These support various method types with particular signatures. Note: a caveat with generic delegates is that while they can support multiple parameters, they do not match methods that contains ref or out parameters. If you want to a delegate to represent methods that takes ref or out parameters, you will need to create a custom delegate. We’ve got the Func… delegates Just like it’s cousin, the Action delegate family, the Func delegate family gives us a lot of power to use generic delegates to make classes and algorithms more generic.  Using them keeps us from having to define a new delegate type when need to make a class or algorithm generic. Remember that the point of the Action delegate family was to be able to perform an “action” on an item, with no return results.  Thus Action delegates can be used to represent most methods that take 0 to 16 arguments but return void.  You can assign a method The Func delegate family was introduced in .NET 3.5 with the advent of LINQ, and gives us the power to define a function that can be called on 0 to 16 arguments and returns a result.  Thus, the main difference between Action and Func, from a delegate perspective, is that Actions return nothing, but Funcs return a result. The Func family of delegates have signatures as follows: Func<TResult> – matches a method that takes no arguments, and returns value of type TResult. Func<T, TResult> – matches a method that takes an argument of type T, and returns value of type TResult. Func<T1, T2, TResult> – matches a method that takes arguments of type T1 and T2, and returns value of type TResult. Func<T1, T2, …, TResult> – and so on up to 16 arguments, and returns value of type TResult. These are handy because they quickly allow you to be able to specify that a method or class you design will perform a function to produce a result as long as the method you specify meets the signature. For example, let’s say you were designing a generic aggregator, and you wanted to allow the user to define how the values will be aggregated into the result (i.e. Sum, Min, Max, etc…).  To do this, we would ask the user of our class to pass in a method that would take the current total, the next value, and produce a new total.  A class like this could look like: 1: public sealed class Aggregator<TValue, TResult> 2: { 3: // holds method that takes previous result, combines with next value, creates new result 4: private Func<TResult, TValue, TResult> _aggregationMethod; 5:  6: // gets or sets the current result of aggregation 7: public TResult Result { get; private set; } 8:  9: // construct the aggregator given the method to use to aggregate values 10: public Aggregator(Func<TResult, TValue, TResult> aggregationMethod = null) 11: { 12: if (aggregationMethod == null) throw new ArgumentNullException("aggregationMethod"); 13:  14: _aggregationMethod = aggregationMethod; 15: } 16:  17: // method to add next value 18: public void Aggregate(TValue nextValue) 19: { 20: // performs the aggregation method function on the current result and next and sets to current result 21: Result = _aggregationMethod(Result, nextValue); 22: } 23: } Of course, LINQ already has an Aggregate extension method, but that works on a sequence of IEnumerable<T>, whereas this is designed to work more with aggregating single results over time (such as keeping track of a max response time for a service). We could then use this generic aggregator to find the sum of a series of values over time, or the max of a series of values over time (among other things): 1: // creates an aggregator that adds the next to the total to sum the values 2: var sumAggregator = new Aggregator<int, int>((total, next) => total + next); 3:  4: // creates an aggregator (using static method) that returns the max of previous result and next 5: var maxAggregator = new Aggregator<int, int>(Math.Max); So, if we were timing the response time of a web method every time it was called, we could pass that response time to both of these aggregators to get an idea of the total time spent in that web method, and the max time spent in any one call to the web method: 1: // total will be 13 and max 13 2: int responseTime = 13; 3: sumAggregator.Aggregate(responseTime); 4: maxAggregator.Aggregate(responseTime); 5:  6: // total will be 20 and max still 13 7: responseTime = 7; 8: sumAggregator.Aggregate(responseTime); 9: maxAggregator.Aggregate(responseTime); 10:  11: // total will be 40 and max now 20 12: responseTime = 20; 13: sumAggregator.Aggregate(responseTime); 14: maxAggregator.Aggregate(responseTime); The Func delegate family is useful for making generic algorithms and classes, and in particular allows the caller of the method or user of the class to specify a function to be performed in order to generate a result. What is the result of a Func delegate chain? If you remember, we said earlier that you can assign multiple methods to a delegate by using the += operator to chain them.  So how does this affect delegates such as Func that return a value, when applied to something like the code below? 1: Func<int, int, int> combo = null; 2:  3: // What if we wanted to aggregate the sum and max together? 4: combo += (total, next) => total + next; 5: combo += Math.Max; 6:  7: // what is the result? 8: var comboAggregator = new Aggregator<int, int>(combo); Well, in .NET if you chain multiple methods in a delegate, they will all get invoked, but the result of the delegate is the result of the last method invoked in the chain.  Thus, this aggregator would always result in the Math.Max() result.  The other chained method (the sum) gets executed first, but it’s result is thrown away: 1: // result is 13 2: int responseTime = 13; 3: comboAggregator.Aggregate(responseTime); 4:  5: // result is still 13 6: responseTime = 7; 7: comboAggregator.Aggregate(responseTime); 8:  9: // result is now 20 10: responseTime = 20; 11: comboAggregator.Aggregate(responseTime); So remember, you can chain multiple Func (or other delegates that return values) together, but if you do so you will only get the last executed result. Func delegates and co-variance/contra-variance in .NET 4.0 Just like the Action delegate, as of .NET 4.0, the Func delegate family is contra-variant on its arguments.  In addition, it is co-variant on its return type.  To support this, in .NET 4.0 the signatures of the Func delegates changed to: Func<out TResult> – matches a method that takes no arguments, and returns value of type TResult (or a more derived type). Func<in T, out TResult> – matches a method that takes an argument of type T (or a less derived type), and returns value of type TResult(or a more derived type). Func<in T1, in T2, out TResult> – matches a method that takes arguments of type T1 and T2 (or less derived types), and returns value of type TResult (or a more derived type). Func<in T1, in T2, …, out TResult> – and so on up to 16 arguments, and returns value of type TResult (or a more derived type). Notice the addition of the in and out keywords before each of the generic type placeholders.  As we saw last week, the in keyword is used to specify that a generic type can be contra-variant -- it can match the given type or a type that is less derived.  However, the out keyword, is used to specify that a generic type can be co-variant -- it can match the given type or a type that is more derived. On contra-variance, if you are saying you need an function that will accept a string, you can just as easily give it an function that accepts an object.  In other words, if you say “give me an function that will process dogs”, I could pass you a method that will process any animal, because all dogs are animals.  On the co-variance side, if you are saying you need a function that returns an object, you can just as easily pass it a function that returns a string because any string returned from the given method can be accepted by a delegate expecting an object result, since string is more derived.  Once again, in other words, if you say “give me a method that creates an animal”, I can pass you a method that will create a dog, because all dogs are animals. It really all makes sense, you can pass a more specific thing to a less specific parameter, and you can return a more specific thing as a less specific result.  In other words, pay attention to the direction the item travels (parameters go in, results come out).  Keeping that in mind, you can always pass more specific things in and return more specific things out. For example, in the code below, we have a method that takes a Func<object> to generate an object, but we can pass it a Func<string> because the return type of object can obviously accept a return value of string as well: 1: // since Func<object> is co-variant, this will access Func<string>, etc... 2: public static string Sequence(int count, Func<object> generator) 3: { 4: var builder = new StringBuilder(); 5:  6: for (int i=0; i<count; i++) 7: { 8: object value = generator(); 9: builder.Append(value); 10: } 11:  12: return builder.ToString(); 13: } Even though the method above takes a Func<object>, we can pass a Func<string> because the TResult type placeholder is co-variant and accepts types that are more derived as well: 1: // delegate that's typed to return string. 2: Func<string> stringGenerator = () => DateTime.Now.ToString(); 3:  4: // This will work in .NET 4.0, but not in previous versions 5: Sequence(100, stringGenerator); Previous versions of .NET implemented some forms of co-variance and contra-variance before, but .NET 4.0 goes one step further and allows you to pass or assign an Func<A, BResult> to a Func<Y, ZResult> as long as A is less derived (or same) as Y, and BResult is more derived (or same) as ZResult. Sidebar: The Func and the Predicate A method that takes one argument and returns a bool is generally thought of as a predicate.  Predicates are used to examine an item and determine whether that item satisfies a particular condition.  Predicates are typically unary, but you may also have binary and other predicates as well. Predicates are often used to filter results, such as in the LINQ Where() extension method: 1: var numbers = new[] { 1, 2, 4, 13, 8, 10, 27 }; 2:  3: // call Where() using a predicate which determines if the number is even 4: var evens = numbers.Where(num => num % 2 == 0); As of .NET 3.5, predicates are typically represented as Func<T, bool> where T is the type of the item to examine.  Previous to .NET 3.5, there was a Predicate<T> type that tended to be used (which we’ll discuss next week) and is still supported, but most developers recommend using Func<T, bool> now, as it prevents confusion with overloads that accept unary predicates and binary predicates, etc.: 1: // this seems more confusing as an overload set, because of Predicate vs Func 2: public static SomeMethod(Predicate<int> unaryPredicate) { } 3: public static SomeMethod(Func<int, int, bool> binaryPredicate) { } 4:  5: // this seems more consistent as an overload set, since just uses Func 6: public static SomeMethod(Func<int, bool> unaryPredicate) { } 7: public static SomeMethod(Func<int, int, bool> binaryPredicate) { } Also, even though Predicate<T> and Func<T, bool> match the same signatures, they are separate types!  Thus you cannot assign a Predicate<T> instance to a Func<T, bool> instance and vice versa: 1: // the same method, lambda expression, etc can be assigned to both 2: Predicate<int> isEven = i => (i % 2) == 0; 3: Func<int, bool> alsoIsEven = i => (i % 2) == 0; 4:  5: // but the delegate instances cannot be directly assigned, strongly typed! 6: // ERROR: cannot convert type... 7: isEven = alsoIsEven; 8:  9: // however, you can assign by wrapping in a new instance: 10: isEven = new Predicate<int>(alsoIsEven); 11: alsoIsEven = new Func<int, bool>(isEven); So, the general advice that seems to come from most developers is that Predicate<T> is still supported, but we should use Func<T, bool> for consistency in .NET 3.5 and above. Sidebar: Func as a Generator for Unit Testing One area of difficulty in unit testing can be unit testing code that is based on time of day.  We’d still want to unit test our code to make sure the logic is accurate, but we don’t want the results of our unit tests to be dependent on the time they are run. One way (of many) around this is to create an internal generator that will produce the “current” time of day.  This would default to returning result from DateTime.Now (or some other method), but we could inject specific times for our unit testing.  Generators are typically methods that return (generate) a value for use in a class/method. For example, say we are creating a CacheItem<T> class that represents an item in the cache, and we want to make sure the item shows as expired if the age is more than 30 seconds.  Such a class could look like: 1: // responsible for maintaining an item of type T in the cache 2: public sealed class CacheItem<T> 3: { 4: // helper method that returns the current time 5: private static Func<DateTime> _timeGenerator = () => DateTime.Now; 6:  7: // allows internal access to the time generator 8: internal static Func<DateTime> TimeGenerator 9: { 10: get { return _timeGenerator; } 11: set { _timeGenerator = value; } 12: } 13:  14: // time the item was cached 15: public DateTime CachedTime { get; private set; } 16:  17: // the item cached 18: public T Value { get; private set; } 19:  20: // item is expired if older than 30 seconds 21: public bool IsExpired 22: { 23: get { return _timeGenerator() - CachedTime > TimeSpan.FromSeconds(30.0); } 24: } 25:  26: // creates the new cached item, setting cached time to "current" time 27: public CacheItem(T value) 28: { 29: Value = value; 30: CachedTime = _timeGenerator(); 31: } 32: } Then, we can use this construct to unit test our CacheItem<T> without any time dependencies: 1: var baseTime = DateTime.Now; 2:  3: // start with current time stored above (so doesn't drift) 4: CacheItem<int>.TimeGenerator = () => baseTime; 5:  6: var target = new CacheItem<int>(13); 7:  8: // now add 15 seconds, should still be non-expired 9: CacheItem<int>.TimeGenerator = () => baseTime.AddSeconds(15); 10:  11: Assert.IsFalse(target.IsExpired); 12:  13: // now add 31 seconds, should now be expired 14: CacheItem<int>.TimeGenerator = () => baseTime.AddSeconds(31); 15:  16: Assert.IsTrue(target.IsExpired); Now we can unit test for 1 second before, 1 second after, 1 millisecond before, 1 day after, etc.  Func delegates can be a handy tool for this type of value generation to support more testable code.  Summary Generic delegates give us a lot of power to make truly generic algorithms and classes.  The Func family of delegates is a great way to be able to specify functions to calculate a result based on 0-16 arguments.  Stay tuned in the weeks that follow for other generic delegates in the .NET Framework!   Tweet Technorati Tags: .NET, C#, CSharp, Little Wonders, Generics, Func, Delegates

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• RemoveAll Dictionary Extension Method

  - by João Angelo

  Removing from a dictionary all the elements where the keys satisfy a set of conditions is something I needed to do more than once so I implemented it as an extension method to the IDictionary<TKey, TValue> interface. Here’s the code: public static class DictionaryExtensions { /// <summary> /// Removes all the elements where the key match the conditions defined by the specified predicate. /// </summary> /// <typeparam name="TKey"> /// The type of the dictionary key. /// </typeparam> /// <typeparam name="TValue"> /// The type of the dictionary value. /// </typeparam> /// <param name="dictionary"> /// A dictionary from which to remove the matched keys. /// </param> /// <param name="match"> /// The <see cref="Predicate{T}"/> delegate that defines the conditions of the keys to remove. /// </param> /// <exception cref="ArgumentNullException"> /// dictionary is null /// <br />-or-<br /> /// match is null. /// </exception> /// <returns> /// The number of elements removed from the <see cref="IDictionary{TKey, TValue}"/>. /// </returns> public static int RemoveAll<TKey, TValue>( this IDictionary<TKey, TValue> dictionary, Predicate<TKey> match) { if (dictionary == null) throw new ArgumentNullException("dictionary"); if (match == null) throw new ArgumentNullException("match"); var keysToRemove = dictionary.Keys.Where(k => match(k)).ToList(); if (keysToRemove.Count == 0) return 0; foreach (var key in keysToRemove) { dictionary.Remove(key); } return keysToRemove.Count; } }

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• Helper method to Replace/Remove characters that do not match the Regular Expression

  - by Michael Freidgeim

  I have a few fields, that use regEx for validation. In case if provided field has unaccepted characters, I don't want to reject the whole field, as most of validators do, but just remove invalid characters. I am expecting to keep only Character Classes for allowed characters and created a helper method to strip unaccepted characters. The allowed pattern should be in Regex format, expect them wrapped in square brackets. function will insert a tilde after opening squere bracket , according to http://stackoverflow.com/questions/4460290/replace-chars-if-not-match.  [^ ] at the start of a character class negates it - it matches characters not in the class.I anticipate that it could work not for all RegEx describing valid characters sets,but it works for relatively simple sets, that we are using.         /// <summary>               /// Replaces  not expected characters.               /// </summary>               /// <param name="text"> The text.</param>               /// <param name="allowedPattern"> The allowed pattern in Regex format, expect them wrapped in brackets</param>               /// <param name="replacement"> The replacement.</param>               /// <returns></returns>               /// //        http://stackoverflow.com/questions/4460290/replace-chars-if-not-match.               //http://stackoverflow.com/questions/6154426/replace-remove-characters-that-do-not-match-the-regular-expression-net               //[^ ] at the start of a character class negates it - it matches characters not in the class.               //Replace/Remove characters that do not match the Regular Expression               static public string ReplaceNotExpectedCharacters( this string text, string allowedPattern,string replacement )              {                     allowedPattern = allowedPattern.StripBrackets( "[", "]" );                      //[^ ] at the start of a character class negates it - it matches characters not in the class.                      var result = Regex .Replace(text, @"[^" + allowedPattern + "]", replacement);                      return result;              }static public string RemoveNonAlphanumericCharacters( this string text)              {                      var result = text.ReplaceNotExpectedCharacters(NonAlphaNumericCharacters, "" );                      return result;              }        public const string NonAlphaNumericCharacters = "[a-zA-Z0-9]";There are a couple of functions from my StringHelper class  http://geekswithblogs.net/mnf/archive/2006/07/13/84942.aspx , that are used here.    //                           /// <summary>               /// 'StripBrackets checks that starts from sStart and ends with sEnd (case sensitive).               ///           'If yes, than removes sStart and sEnd.               ///           'Otherwise returns full string unchanges               ///           'See also MidBetween               /// </summary>               /// <param name="str"></param>               /// <param name="sStart"></param>               /// <param name="sEnd"></param>               /// <returns></returns>               public static string StripBrackets( this string str, string sStart, string sEnd)              {                      if (CheckBrackets(str, sStart, sEnd))                     {                           str = str.Substring(sStart.Length, (str.Length - sStart.Length) - sEnd.Length);                     }                      return str;              }               public static bool CheckBrackets( string str, string sStart, string sEnd)              {                      bool flag1 = (str != null ) && (str.StartsWith(sStart) && str.EndsWith(sEnd));                      return flag1;              }               public static string WrapBrackets( string str, string sStartBracket, string sEndBracket)              {                      StringBuilder builder1 = new StringBuilder(sStartBracket);                     builder1.Append(str);                     builder1.Append(sEndBracket);                      return builder1.ToString();              }v

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• Software Architecture Analysis Method (SAAM)

  Software Architecture Analysis Method (SAAM) is a methodology used to determine how specific application quality attributes were achieved and how possible changes in the future will affect quality attributes based on hypothetical cases studies. Common quality attributes that can be utilized by this methodology include modifiability, robustness, portability, and extensibility. Quality Attribute: Application Modifiability The Modifiability quality attribute refers to how easy it changing the system in the future will be. This to me is a very open-ended attribute because a business could decide to transform a Point of Sale (POS) system in to a Lead Tracking system overnight. (Yes, this did actually happen to me) In order for SAAM to be properly applied for checking this attribute specific hypothetical case studies need to be created and review for the modifiability attribute due to the fact that various scenarios would return various results based on the amount of changes. In the case of the POS change out a payment gateway or adding an additional payment would have scored very high in comparison to changing the system over to a lead management system. I personally would evaluate this quality attribute based on the S.O.I.L.D Principles of software design. I have found from my experience the use of S.O.I.L.D in software design allows for the adoption of changes within a system. Quality Attribute: Application Robustness The Robustness quality attribute refers to how an application handles the unexpected. The unexpected can be defined but is not limited to anything not anticipated in the originating design of the system. For example: Bad Data, Limited to no network connectivity, invalid permissions, or any unexpected application exceptions. I would personally evaluate this quality attribute based on how the system handled the exceptions. Robustness Considerations Did the system stop or did it handle the unexpected error? Did the system log the unexpected error for future debugging? What message did the user receive about the error? Quality Attribute: Application Portability The Portability quality attribute refers to the ease of porting an application to run in a new operating system or device. For example, It is much easier to alter an ASP.net website to be accessible by a PC, Mac, IPhone, Android Phone, Mini PC, or Table in comparison to desktop application written in VB.net because a lot more work would be involved to get the desktop app to the point where it would be viable to port the application over to the various environments and devices. I would personally evaluate this quality attribute based on each new environment for which the hypothetical case study identifies. I would pay particular attention to the following items. Portability Considerations Hardware Dependencies Operating System Dependencies Data Source Dependencies Network Dependencies and Availabilities  Quality Attribute: Application Extensibility The Extensibility quality attribute refers to the ease of adding new features to an existing application without impacting existing functionality. I would personally evaluate this quality attribute based on each new environment for the following Extensibility  Considerations Hard coded Variables versus Configurable variables Application Documentation (External Documents and Codebase Documentation.) The use of Solid Design Principles

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• Adding and accessing custom sections in your C# App.config

  - by deadlydog

  So I recently thought I’d try using the app.config file to specify some data for my application (such as URLs) rather than hard-coding it into my app, which would require a recompile and redeploy of my app if one of our URLs changed.  By using the app.config it allows a user to just open up the .config file that sits beside their .exe file and edit the URLs right there and then re-run the app; no recompiling, no redeployment necessary. I spent a good few hours fighting with the app.config and looking at examples on Google before I was able to get things to work properly.  Most of the examples I found showed you how to pull a value from the app.config if you knew the specific key of the element you wanted to retrieve, but it took me a while to find a way to simply loop through all elements in a section, so I thought I would share my solutions here.   Simple and Easy The easiest way to use the app.config is to use the built-in types, such as NameValueSectionHandler.  For example, if we just wanted to add a list of database server urls to use in my app, we could do this in the app.config file like so: 1: <?xml version="1.0" encoding="utf-8" ?> 2: <configuration> 3: <configSections> 4: <section name="ConnectionManagerDatabaseServers" type="System.Configuration.NameValueSectionHandler" /> 5: </configSections> 6: <startup> 7: <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" /> 8: </startup> 9: <ConnectionManagerDatabaseServers> 10: <add key="localhost" value="localhost" /> 11: <add key="Dev" value="Dev.MyDomain.local" /> 12: <add key="Test" value="Test.MyDomain.local" /> 13: <add key="Live" value="Prod.MyDomain.com" /> 14: </ConnectionManagerDatabaseServers> 15: </configuration>   And then you can access these values in code like so: 1: string devUrl = string.Empty; 2: var connectionManagerDatabaseServers = ConfigurationManager.GetSection("ConnectionManagerDatabaseServers") as NameValueCollection; 3: if (connectionManagerDatabaseServers != null) 4: { 5: devUrl = connectionManagerDatabaseServers["Dev"].ToString(); 6: }   Sometimes though you don’t know what the keys are going to be and you just want to grab all of the values in that ConnectionManagerDatabaseServers section.  In that case you can get them all like this: 1: // Grab the Environments listed in the App.config and add them to our list. 2: var connectionManagerDatabaseServers = ConfigurationManager.GetSection("ConnectionManagerDatabaseServers") as NameValueCollection; 3: if (connectionManagerDatabaseServers != null) 4: { 5: foreach (var serverKey in connectionManagerDatabaseServers.AllKeys) 6: { 7: string serverValue = connectionManagerDatabaseServers.GetValues(serverKey).FirstOrDefault(); 8: AddDatabaseServer(serverValue); 9: } 10: }   And here we just assume that the AddDatabaseServer() function adds the given string to some list of strings.  So this works great, but what about when we want to bring in more values than just a single string (or technically you could use this to bring in 2 strings, where the “key” could be the other string you want to store; for example, we could have stored the value of the Key as the user-friendly name of the url).   More Advanced (and more complicated) So if you want to bring in more information than a string or two per object in the section, then you can no longer simply use the built-in System.Configuration.NameValueSectionHandler type provided for us.  Instead you have to build your own types.  Here let’s assume that we again want to configure a set of addresses (i.e. urls), but we want to specify some extra info with them, such as the user-friendly name, if they require SSL or not, and a list of security groups that are allowed to save changes made to these endpoints. So let’s start by looking at the app.config: 1: <?xml version="1.0" encoding="utf-8" ?> 2: <configuration> 3: <configSections> 4: <section name="ConnectionManagerDataSection" type="ConnectionManagerUpdater.Data.Configuration.ConnectionManagerDataSection, ConnectionManagerUpdater" /> 5: </configSections> 6: <startup> 7: <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" /> 8: </startup> 9: <ConnectionManagerDataSection> 10: <ConnectionManagerEndpoints> 11: <add name="Development" address="Dev.MyDomain.local" useSSL="false" /> 12: <add name="Test" address="Test.MyDomain.local" useSSL="true" /> 13: <add name="Live" address="Prod.MyDomain.com" useSSL="true" securityGroupsAllowedToSaveChanges="ConnectionManagerUsers" /> 14: </ConnectionManagerEndpoints> 15: </ConnectionManagerDataSection> 16: </configuration>   The first thing to notice here is that my section is now using the type “ConnectionManagerUpdater.Data.Configuration.ConnectionManagerDataSection” (the fully qualified path to my new class I created) “, ConnectionManagerUpdater” (the name of the assembly my new class is in).  Next, you will also notice an extra layer down in the <ConnectionManagerDataSection> which is the <ConnectionManagerEndpoints> element.  This is a new collection class that I created to hold each of the Endpoint entries that are defined.  Let’s look at that code now: 1: using System; 2: using System.Collections.Generic; 3: using System.Configuration; 4: using System.Linq; 5: using System.Text; 6: using System.Threading.Tasks; 7:  8: namespace ConnectionManagerUpdater.Data.Configuration 9: { 10: public class ConnectionManagerDataSection : ConfigurationSection 11: { 12: /// <summary> 13: /// The name of this section in the app.config. 14: /// </summary> 15: public const string SectionName = "ConnectionManagerDataSection"; 16: 17: private const string EndpointCollectionName = "ConnectionManagerEndpoints"; 18:  19: [ConfigurationProperty(EndpointCollectionName)] 20: [ConfigurationCollection(typeof(ConnectionManagerEndpointsCollection), AddItemName = "add")] 21: public ConnectionManagerEndpointsCollection ConnectionManagerEndpoints { get { return (ConnectionManagerEndpointsCollection)base[EndpointCollectionName]; } } 22: } 23:  24: public class ConnectionManagerEndpointsCollection : ConfigurationElementCollection 25: { 26: protected override ConfigurationElement CreateNewElement() 27: { 28: return new ConnectionManagerEndpointElement(); 29: } 30: 31: protected override object GetElementKey(ConfigurationElement element) 32: { 33: return ((ConnectionManagerEndpointElement)element).Name; 34: } 35: } 36: 37: public class ConnectionManagerEndpointElement : ConfigurationElement 38: { 39: [ConfigurationProperty("name", IsRequired = true)] 40: public string Name 41: { 42: get { return (string)this["name"]; } 43: set { this["name"] = value; } 44: } 45: 46: [ConfigurationProperty("address", IsRequired = true)] 47: public string Address 48: { 49: get { return (string)this["address"]; } 50: set { this["address"] = value; } 51: } 52: 53: [ConfigurationProperty("useSSL", IsRequired = false, DefaultValue = false)] 54: public bool UseSSL 55: { 56: get { return (bool)this["useSSL"]; } 57: set { this["useSSL"] = value; } 58: } 59: 60: [ConfigurationProperty("securityGroupsAllowedToSaveChanges", IsRequired = false)] 61: public string SecurityGroupsAllowedToSaveChanges 62: { 63: get { return (string)this["securityGroupsAllowedToSaveChanges"]; } 64: set { this["securityGroupsAllowedToSaveChanges"] = value; } 65: } 66: } 67: }   So here the first class we declare is the one that appears in the <configSections> element of the app.config.  It is ConnectionManagerDataSection and it inherits from the necessary System.Configuration.ConfigurationSection class.  This class just has one property (other than the expected section name), that basically just says I have a Collection property, which is actually a ConnectionManagerEndpointsCollection, which is the next class defined.  The ConnectionManagerEndpointsCollection class inherits from ConfigurationElementCollection and overrides the requied fields.  The first tells it what type of Element to create when adding a new one (in our case a ConnectionManagerEndpointElement), and a function specifying what property on our ConnectionManagerEndpointElement class is the unique key, which I’ve specified to be the Name field. The last class defined is the actual meat of our elements.  It inherits from ConfigurationElement and specifies the properties of the element (which can then be set in the xml of the App.config).  The “ConfigurationProperty” attribute on each of the properties tells what we expect the name of the property to correspond to in each element in the app.config, as well as some additional information such as if that property is required and what it’s default value should be. Finally, the code to actually access these values would look like this: 1: // Grab the Environments listed in the App.config and add them to our list. 2: var connectionManagerDataSection = ConfigurationManager.GetSection(ConnectionManagerDataSection.SectionName) as ConnectionManagerDataSection; 3: if (connectionManagerDataSection != null) 4: { 5: foreach (ConnectionManagerEndpointElement endpointElement in connectionManagerDataSection.ConnectionManagerEndpoints) 6: { 7: var endpoint = new ConnectionManagerEndpoint() { Name = endpointElement.Name, ServerInfo = new ConnectionManagerServerInfo() { Address = endpointElement.Address, UseSSL = endpointElement.UseSSL, SecurityGroupsAllowedToSaveChanges = endpointElement.SecurityGroupsAllowedToSaveChanges.Split(',').Where(e => !string.IsNullOrWhiteSpace(e)).ToList() } }; 8: AddEndpoint(endpoint); 9: } 10: } This looks very similar to what we had before in the “simple” example.  The main points of interest are that we cast the section as ConnectionManagerDataSection (which is the class we defined for our section) and then iterate over the endpoints collection using the ConnectionManagerEndpoints property we created in the ConnectionManagerDataSection class.   Also, some other helpful resources around using app.config that I found (and for parts that I didn’t really explain in this article) are: How do you use sections in C# 4.0 app.config? (Stack Overflow) <== Shows how to use Section Groups as well, which is something that I did not cover here, but might be of interest to you. How to: Create Custom Configuration Sections Using Configuration Section (MSDN) ConfigurationSection Class (MSDN) ConfigurationCollectionAttribute Class (MSDN) ConfigurationElementCollection Class (MSDN)   I hope you find this helpful.  Feel free to leave a comment.  Happy Coding!

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• Implementing a post-notification function to perform custom validation

  - by Alejandro Sosa

  Introduction Oracle Workflow Notification System can be extended to perform extra validation or processing via PLSQL procedures when the notification is being responded to. These PLSQL procedures are called post-notification functions since they are executed after a notification action such as Approve, Reject, Reassign or Request Information is performed. The standard signature for the post-notification function is     procedure <procedure_name> (itemtype  in varchar2,                                itemkey   in varchar2,                                actid     in varchar2,                                funcmode  in varchar2,                                resultout in out nocopy varchar2); Modes The post-notification function provides the parameter 'funcmode' which will have the following values: 'RESPOND', 'VALIDATE, and 'RUN' for a notification is responded to (Approve, Reject, etc) 'FORWARD' for a notification being forwarded to another user 'TRANSFER' for a notification being transferred to another user 'QUESTION' for a request of more information from one user to another 'QUESTION' for a response to a request of more information 'TIMEOUT' for a timed-out notification 'CANCEL' when the notification is being re-executed in a loop. Context Variables Oracle Workflow provides different context information that corresponds to the current notification being acted upon to the post-notification function. WF_ENGINE.context_nid - The notification ID  WF_ENGINE.context_new_role - The new role to which the action on the notification is directed WF_ENGINE.context_user_comment - Comments appended to the notification   WF_ENGINE.context_user - The user who is responsible for taking the action that updated the notification's state WF_ENGINE.context_recipient_role - The role currently designated as the recipient of the notification. This value may be the same as the value of WF_ENGINE.context_user variable, or it may be a group role of which the context user is a member. WF_ENGINE.context_original_recipient - The role that has ownership of and responsibility for the notification. This value may differ from the value of the WF_ENGINE.context_recipient_role variable if the notification has previously been reassigned.  Example Let us assume there is an EBS transaction that can only be approved by a certain people thus any attempt to transfer or delegate such notification should be allowed only to users SPIERSON or CBAKER. The way to implement this functionality would be as follows: Edit the corresponding workflow definition in Workflow Builder and open the notification. In the Function Name enter the name of the procedure where the custom code is handled, for instance, TEST_PACKAGE.Post_Notification In PLSQL create the corresponding package TEST_PACKAGE with a procedure named Post_Notification, as follows:     procedure Post_Notification (itemtype  in varchar2,                                  itemkey   in varchar2,                                  actid     in varchar2,                                  funcmode  in varchar2,                                  resultout in out nocopy varchar2) is     l_count number;     begin       if funcmode in ('TRANSFER','FORWARD') then         select count(1) into l_count         from WF_ROLES         where WF_ENGINE.context_new_role in ('SPIERSON','CBAKER');               --and/or any other conditions         if l_count<1 then           WF_CORE.TOKEN('ROLE', WF_ENGINE.context_new_role);           WF_CORE.RAISE('WFNTF_TRANSFER_FAIL');         end if;       end if;     end Post_Notification; Launch the workflow process with the changed notification and attempt to reassign or transfer it. When trying to reassign the notification to user CBROWN the screen would like like below: Check the Workflow API Reference Guide, section Post-Notification Functions, to see all the standard, seeded WF_ENGINE variables available for extending notifications processing. 

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• Best depth sorting method for a Top Down 2D game using a 3D physics engine

  - by Alic44

  I've spent many days googling this and still have issues with my game engine I'd like to ask about, which I haven't seen addressed before. I think the problem is that my game is an unusual combination of a completely 2D graphical approach using XNA's SpriteBatch, and a completely 3D engine (the amazing BEPU physics engine) with rotation mostly disabled. In essence, my question is similar to this one (the part about "faux 3D"), but the difference is that in my game, the player as well as every other creature is represented by 3D objects, and they can all jump, pick up other objects, and throw them around. What this means is that sorting by one value, such as a Z position (how far north/south a character is on the screen) won't work, because as soon as a smaller creature jumps on top of a larger creature, or a box, and walks backwards, the moment its z value is less than that other creature, it will appear to be behind the object it is actually standing on. I actually originally solved this problem by splitting every object in the game into physics boxes which MUST have a Y height equal to their Z depth. I then based the depth sorting value on the object's y position (how high it is off the ground) PLUS its z position (how far north or south it is on the screen). The problem with this approach is that it requires all moving objects in the game to be split graphically into chunks which match up with a physical box which has its y dimension equal to its z dimension. Which is stupid. So, I got inspired last night to rewrite with a fresh approach. My new method is a little more complex, but I think a little more sane: every object which needs to be sorted by depth in the game exposes the interface IDepthDrawable and is added to a list owned by the DepthDrawer object. IDepthDrawable contains: public interface IDepthDrawable { Rectangle Bounds { get; } //possibly change this to a class if struct copying of the xna Rectangle type becomes an issue DepthDrawShape DepthShape { get; } void Draw(SpriteBatch spriteBatch); } The Bounds Rectangle of each IDepthDrawable object represents the 2D Axis-Aligned Bounding Box it will take up when drawn to the screen. Anything that doesn't intersect the screen will be culled at this stage and the remaining on-screen IDepthDrawables will be Bounds tested for intersections with each other. This is where I get a little less sure of what I'm doing. Each group of collisions will be added to a list or other collection, and each list will sort itself based on its DepthShape property, which will have access to the object-to-be-drawn's physics information. For starting out, lets assume everything in the game is an axis aligned 3D Box shape. Boxes are pretty easy to sort. Something like: if (depthShape1.Back > depthShape2.Front) //if depthShape1 is in front of depthShape2. //depthShape1 goes on top. else if (depthShape1.Bottom > depthShape2.Top) //if depthShape1 is above depthShape2. //depthShape1 goes on top. //if neither of these are true, depthShape2 must be in front or above. So, by sorting draw order by several different factors from the physics engine, I believe I can get a really correct draw order. My question is, is this a good way of going about this, or is there some tried and true, tested way which is completely different and has somehow completely eluded me on the internets? And, if this does seem like a good way to remake my draw order sorting, what's the right sorting algorithm for reordering the Bounds Rectangle collision lists, and how do you deal with a Bounds Rectangle colliding with two different object which don't collide with eachother. I know these are solved problems, but I've only been programming for a year so any specific input here will be greatly appreciated. Thanks for reading this far, ye who made it -- sorry it was so long!

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• Knockoutjs - stringify to handling observables and custom events

  - by Renso

  Goal: Once you viewmodel has been built and populated with data, at some point it goal of it all is to persist the data to the database (or some other media). Regardless of where you want to save it, your client-side viewmodel needs to be converted to a JSON string and sent back to the server. Environment considerations: jQuery 1.4.3+ Knockoutjs version 1.1.2   How to: So let’s set the stage, you are using Knockoutjs and you have a viewmodel with some Knockout dependencies. You want to make sure it is in the proper JSON format and via ajax post it to the server for persistence.   First order of business is to deal with the viewmodel (JSON) object. To most the JSON stringifier sounds familiar. The JSON stringifier converts JavaScript data structures into JSON text. JSON does not support cyclic data structures, so be careful to not give cyclical structures to the JSON stringifier. You may ask, is this the best way to do it? What about those observables and other Knockout properties that I don’t want to persist or want their actual value persisted and not their function, etc. Not sure if you were aware, but KO already has a method; ko.utils.stringifyJson() - it's mostly just a wrapper around JSON.stringify. (which is native in some browsers, and can be made available by referencing json2.js in others). What does it do that the regular stringify does not is that it automatically converts observable, dependentObservable, or observableArray to their underlying value to JSON. Hold on! There is a new feature in this version of Knockout, the ko.toJSON. It is part of the core library and it will clone the view model’s object graph, so you don’t mess it up after you have stringified  it and unwrap all its observables. It's smart enough to avoid reference cycles. Since you are using the MVVM pattern it would assume you are not trying to reference DOM nodes from your view. Wait a minute. I can already see this info on the http://knockoutjs.com/examples/contactsEditor.html website, why mention it all here? First of this is a much nicer blog, no orange ? At this time, you may want to have a look at the blog and see what I am talking about. See the save event, how they stringify the view model’s contacts only? That’s cool but what if your view model is a representation of your object you want to persist, meaning it has no property that represents the json object you want to persist, it is the view model itself. The example in http://knockoutjs.com/examples/contactsEditor.html assumes you have a list of contacts you may want to persist. In the example here, you want to persist the view model itself. The viewmodel here looks something like this:     var myViewmodel = {         accountName: ko.observable(""),         accountType: ko.observable("Active")     };     myViewmodel.isItActive = ko.dependentObservable(function () {         return myViewmodel.accountType() == "Active";     });     myViewmodel.clickToSaveMe = function() {         SaveTheAccount();     }; Here is the function in charge of saving the account: Function SaveTheAccount() {     $.ajax({         data: ko.toJSON(viewmodel),         url: $('#ajaxSaveAccountUrl').val(),         type: "POST",         dataType: "json",         async: false,         success: function (result) {             if (result && result.Success == true) {                 $('#accountMessage').html('<span class="fadeMyContainerSlowly">The account has been saved</span>').show();                 FadeContainerAwaySlowly();             }         },         error: function (xmlHttpRequest, textStatus, errorThrown) {             alert('An error occurred: ' + errorThrown);         }     }); //ajax }; Try run this and your browser will eventually freeze up or crash. Firebug will tell you that you have a repetitive call to the first function call in your model that keeps firing infinitely.  What is happening is that Knockout serializes the view model to a JSON string by traversing the object graph and firing off the functions, again-and-again. Not sure why it does that, but it does. So what is the work around: Nullify your function calls and then post it:         var lightweightModel = viewmodel.clickToSaveMe = null;         data: ko.toJSON(lightweightModel), So then I traced the JSON string on the server and found it having issues with primitive types. C#, by the way. So I changed ko.toJSON(model) to ko.toJS(model), and that solved my problem. Of course you could just create a property on the viewmodel for the account itself, so you only have to serialize the property and not the entire viewmodel. If that is an option then that would be the way to go. If your view model contains other properties in the view model that you also want to post then that would not be an option and then you’ll know what to watch out for. Hope this helps.

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• A very useful custom component

  - by Kevin Smith

  Whenever I am debugging a problem in WebCenter Content (WCC) I often find it useful to see the contents of the internal data binder used by WCC when executing a service. I want to know the value of all parameters passed in by the caller, either a user in the web GUI or from an application calling the service via RIDC or web services. I also want to the know the value of binder variables calculated by WCC as it processes a service. What defaults has it applied based on configuration settings or profile rules? What values has it derived based on the user input? To help with this I created a  component that uses a java filter to dump out the contents of the internal data binder to the WCC trace file. It dumps the binder contents using the toString() method. You can register this filter code using many different filter hooks to see how the binder is updated as WCC processes the service. By default, it uses the validateStandard filter hook which is useful during a CHECKIN service. It uses the system trace section, so make sure that trace section is enabled before looking for the output from this component. Here is some sample output>system/6    10.09 09:57:40.648    IdcServer-1    filter: postParseDataForServiceRequest, binder start -- system/6    10.09 09:57:40.698    IdcServer-1    *** LocalData *** system/6    10.09 09:57:40.698    IdcServer-1    (10 keys + 0 defaults) system/6    10.09 09:57:40.698    IdcServer-1    ClientEncoding=UTF-8 system/6    10.09 09:57:40.698    IdcServer-1    IdcService=CHECKIN_UNIVERSAL system/6    10.09 09:57:40.698    IdcServer-1    NoHttpHeaders=0 system/6    10.09 09:57:40.698    IdcServer-1    UserDateFormat=iso8601 system/6    10.09 09:57:40.698    IdcServer-1    UserTimeZone=UTC system/6    10.09 09:57:40.698    IdcServer-1    dDocTitle=Check in from RIDC using Framework Folder system/6    10.09 09:57:40.698    IdcServer-1    dDocType=Document system/6    10.09 09:57:40.698    IdcServer-1    dSecurityGroup=Public system/6    10.09 09:57:40.698    IdcServer-1    parentFolderPath=/folder1/folder2 system/6    10.09 09:57:40.698    IdcServer-1    primaryFile=testfile5.bin     system/6    10.09 09:57:40.698    IdcServer-1    ***  RESULT SETS  ***>system/6    10.09 09:57:40.698    IdcServer-1    binder end -------------------------------------------- See the readme included in the component for more details. You can download the component from here.

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• Magento My Account Layout XML Problem

  - by Remy

  Hi there, I'm having issues getting the customer.xml layout file to work properly for the customer's "my account" pages. The navigation links and the previously ordered items that are usually on the left hand side of the page won't show up on the page, but if I change the reference name to "content" in the xml file, it shows up (except it's obviously then on the right hand side). I've checked the template it's referencing (2columns-left.phtml), and the getChildHtml('left') is there in the correct position. The block that's causing the problem: <customer_account> <!-- Mage_Customer --> <reference name="root"> <action method="setTemplate"><template>page/2columns-left.phtml</template></action> </reference> <reference name="left"> <action method="unsetChild"><name>catalog.navigation.all</name></action> <action method="unsetChild"><name>callout.sendcard</name></action> <action method="unsetChild"><name>callout.specialorder</name></action> <block type="customer/account_navigation" name="customer_account_navigation" before="-" template="customer/account/navigation.phtml"> <action method="addLink" translate="label" module="customer"><name>account</name><path>customer/account/</path><label>Account Dashboard</label></action> <action method="addLink" translate="label" module="customer"><name>account_edit</name><path>customer/account/edit/</path><label>Account Information</label></action> <action method="addLink" translate="label" module="customer"><name>address_book</name><path>customer/address/</path><label>Address Book</label></action> </block> <block type="sales/reorder_sidebar" name="sale.reorder.sidebar" as="reorder" template="sales/reorder/sidebar.phtml"/> <remove name="tags_popular"/> </reference> </customer_account> This was basically copied straight over from another one of our sites where this works 100%. I've tried everything I can think of (changing the name of the reference in both the template and the layout xml, for example) to no avail. The templates that the layout is referencing are obviously working because they do show up when put into the "content" area. This installation of magento is version 1.3.1.1. I appreciate any advice you have to give me... *Update: I tried changing the reference to "global_messages", and it doesn't show there either. It only seems to work in the "content" section.* Update 2: These are the results of using the "showLayout=page" query string on the page when used with Alan Storm's very handy debugging module (which you'll find in his answer below). <?xml version="1.0"?> <layout><block type="page/html" name="root" output="toHtml" template="page/3columns.phtml"> <block type="page/html_head" name="head" as="head"> <action method="addJs"> <script>prototype/prototype.js</script> </action> <action method="addJs"> <script>prototype/validation.js</script> </action> <action method="addJs"> <script>paypoint/validation.js</script> </action> <action method="addJs"> <script>scriptaculous/builder.js</script> </action> <action method="addJs"> <script>scriptaculous/effects.js</script> </action> <action method="addJs"> <script>scriptaculous/dragdrop.js</script> </action> <action method="addJs"> <script>scriptaculous/controls.js</script> </action> <action method="addJs"> <script>scriptaculous/slider.js</script> </action> <action method="addJs"> <script>varien/js.js</script> </action> <action method="addJs"> <script>varien/form.js</script> </action> <action method="addJs"> <script>varien/menu.js</script> </action> <action method="addJs"> <script>mage/translate.js</script> </action> <action method="addJs"> <script>mage/cookies.js</script> </action> <action method="addCss"> <stylesheet>css/reset.css</stylesheet> </action> <action method="addCss"> <stylesheet>css/boxes.css</stylesheet> </action> <action method="addCss"> <stylesheet>css/clears.css</stylesheet> </action> <action method="addCss"> <stylesheet>css/menu.css</stylesheet> </action> <action method="addCss"> <stylesheet>css/calendar-blue.css</stylesheet> </action> <action method="addCss"> <stylesheet>css/styles.css</stylesheet> </action> <action method="addItem"> <type>skin_css</type> <name>css/iestyles.css</name> <params/> <if>IE</if> </action> <action method="addItem"> <type>skin_css</type> <name>css/ie7.css</name> <params/> <if>IE 7</if> </action> <action method="addItem"> <type>skin_css</type> <name>css/ie7minus.css</name> <params/> <if>lt IE 7</if> </action> <action method="addItem"> <type>js</type> <name>lib/ds-sleight.js</name> <params/> <if>lt IE 7</if> </action> <action method="addItem"> <type>js</type> <name>varien/iehover-fix.js</name> <params/> <if>lt IE 7</if> </action> <action method="addCss"> <stylesheet>css/print.css</stylesheet> <params>media="print"</params> </action> </block> <block type="page/html_header" name="header" as="header"> <block type="page/template_links" name="top.links" as="topLinks"/> <block type="page/switch" name="store_language" as="store_language" template="page/switch/languages.phtml"/> <block type="core/template" name="top.nav" template="page/html/top.nav.phtml"/> </block> <block type="core/messages" name="global_messages" as="global_messages"/> <block type="core/messages" name="messages" as="messages"/> <block type="core/text_list" name="content" as="content"/> <block type="core/text_list" name="right" as="right"/> <block type="page/html_footer" name="footer" as="footer" template="page/html/footer.phtml"/> <block type="core/text_list" name="before_body_end" as="before_body_end"/> </block> <block type="core/profiler" output="toHtml"/> <reference name="top.links"> <action method="addLink" translate="label title" module="customer"> <label>My Account</label> <url helper="customer/getAccountUrl"/> <title>My Account</title> <prepare/> <urlParams/> <position>10</position> </action> </reference> <reference name="root"> <action method="setTemplate"> <template>page/2columns-left.phtml</template> </action> </reference> <reference name="top.menu"> <block type="catalog/navigation" name="catalog.topnav" template="catalog/navigation/top.phtml"/> </reference> <reference name="footer_links"> <action method="addLink" translate="label title" module="catalog" ifconfig="catalog/seo/site_map"> <label>Site Map</label> <url helper="catalog/map/getCategoryUrl"/> <title>Site Map</title> </action> </reference> <reference name="footer_links"> <action method="addLink" translate="label title" module="catalogsearch" ifconfig="catalog/seo/search_terms"> <label>Search Terms</label> <url helper="catalogsearch/getSearchTermUrl"/> <title>Search Terms</title> </action> <action method="addLink" translate="label title" module="catalogsearch"> <label>Advanced Search</label> <url helper="catalogsearch/getAdvancedSearchUrl"/> <title>Advanced Search</title> </action> </reference> <reference name="top.links"> <block type="checkout/links" name="checkout_cart_link"> <action method="addCartLink"/> <action method="addCheckoutLink"/> </block> </reference> <reference name="footer"> <block type="cms/block" name="cms_footer_links" before="footer_links"> <action method="setBlockId"> <block_id>footer_links</block_id> </action> </block> </reference> <reference name="left"> <block type="tag/popular" name="tags_popular" template="tag/popular.phtm" ignore="1"> <action method="setTemplate"> <template>tag/popular.phtml</template> </action> </block> </reference> <reference name="left"> </reference> <reference name="before_body_end"> <block type="googleanalytics/ga" name="google_analytics" as="google_analytics"/> </reference> <reference name="footer_links"> <action method="addLink" translate="label title" module="contacts" ifconfig="contacts/contacts/enabled"> <label>Contact Us</label> <url>contact-us</url> <title>Contact Us</title> <prepare>true</prepare> </action> </reference> <reference name="footer_links"> <action method="addLink" translate="label title" module="rss" ifconfig="rss/config/active"> <label>RSS</label> <url>rss</url> <title>RSS testing</title> <prepare>true</prepare> <urlParams/> <position/> <li/> <a>class="link-feed"</a> </action> </reference> <reference name="wishlist_sidebar"> <action method="addPriceBlockType"> <type>bundle</type> <block>bundle/catalog_product_price</block> <template>bundle/catalog/product/price.phtml</template> </action> </reference> <reference name="cart_sidebar"> <action method="addItemRender"> <type>bundle</type> <block>bundle/checkout_cart_item_renderer</block> <template>checkout/cart/sidebar/default.phtml</template> </action> </reference> <reference name="root"> <action method="setTemplate"> <template>page/2columns-left.phtml</template> </action> </reference> <reference name="left"> <action method="unsetChild"> <name>catalog.navigation.all</name> </action> <action method="unsetChild"> <name>callout.sendcard</name> </action> <action method="unsetChild"> <name>callout.specialorder</name> </action> <block type="customer/account_navigation" name="customer_account_navigation" before="-" template="customer/account/navigation.phtml"> <action method="addLink" translate="label" module="customer"> <name>account</name> <path>customer/account/</path> <label>Account Dashboard</label> </action> <action method="addLink" translate="label" module="customer"> <name>account_edit</name> <path>customer/account/edit/</path> <label>Account Information</label> </action> <action method="addLink" translate="label" module="customer"> <name>address_book</name> <path>customer/address/</path> <label>Address Book</label> </action> </block> <block type="sales/reorder_sidebar" name="sale.reorder.sidebar" as="reorder" template="sales/reorder/sidebar.phtml"/> <remove name="tags_popular"/> </reference> <reference name="customer_account_navigation"> <action method="addLink" translate="label" module="sales"> <name>orders</name> <path>sales/order/history/</path> <label>My Orders</label> </action> </reference> <reference name="customer_account_navigation"> <action method="addLink" translate="label" module="tag"> <name>tags</name> <path>tag/customer/</path> <label>My Tags</label> </action> </reference> <reference name="customer_account_navigation"> <action method="addLink" translate="label" module="newsletter"> <name>newsletter</name> <path>newsletter/manage/</path> <label>Newsletter Subscriptions</label> </action> </reference> <reference name="cart_sidebar"> <action method="addItemRender"> <type>bundle</type> <block>bundle/checkout_cart_item_renderer</block> <template>checkout/cart/sidebar/default.phtml</template> </action> </reference> <update handle="customer_account"/> <reference name="content"> <block type="customer/account_dashboard" name="customer_account_dashboard" template="customer/account/dashboard.phtml"> <block type="customer/account_dashboard_hello" name="customer_account_dashboard_hello" as="hello" template="customer/account/dashboard/hello.phtml"/> <block type="core/template" name="customer_account_dashboard_top" as="top"/> <block type="customer/account_dashboard_info" name="customer_account_dashboard_info" as="info" template="customer/account/dashboard/info.phtml"/> <block type="customer/account_dashboard_newsletter" name="customer_account_dashboard_newsletter" as="newsletter" template="customer/account/dashboard/newsletter.phtml"/> <block type="customer/account_dashboard_address" name="customer_account_dashboard_address" as="address" template="customer/account/dashboard/address.phtml"/> <block type="core/template" name="customer_account_dashboard_info1" as="info1"/> <block type="core/template" name="customer_account_dashboard_info2" as="info2"/> </block> </reference> <reference name="right"> <action method="unsetChild"> <name>catalog_compare_sidebar</name> </action> </reference> <reference name="customer_account_dashboard"> <action method="unsetChild"> <name>top</name> </action> <block type="sales/order_recent" name="customer_account_dashboard_top" as="top" template="sales/order/recent.phtml"/> </reference> <reference name="right"> <action method="unsetChild"> <name>right.poll</name> </action> </reference> <reference name="customer_account_dashboard"> <action method="unsetChild"> <name>customer_account_dashboard_info2</name> </action> <block type="tag/customer_recent" name="customer_account_dashboard_info2" as="info2" template="tag/customer/recent.phtml"/> </reference> <reference name="right"> <action method="unsetChild"> <name>right.newsletter</name> </action> </reference> <reference name="top.links"> <action method="addLink" translate="label title" module="customer"> <label>Log Out</label> <url helper="customer/getLogoutUrl"/> <title>Log Out</title> <prepare/> <urlParams/> <position>100</position> </action> </reference></layout>

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• Objective C: Initalizing static variable with static method call

  - by adranale

  The Compiler claims an error saying: "initializer element is not constant", when I try to initialize a static variable inside a method with a call to a static method (with + in its definition). Anyway I can tell him that this method always returns the same value. I know this is not the same as static method, but there seems to be no constant methods in Objective-C (other than macros which won't work here because I am calling UI_USER_INTERFACE_IDIOM() from inside the method).

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• How to check how many threads are waiting for a synchronized method to become unlocked

  - by MontyBongo

  Is there any way to check how many threads are waiting for a synchronized method to become unlocked? I would like to know when the thread calls a synchronized method: 1) How many threads are already waiting to call the method? 2) Once the method is called how long it needed to wait for the method to become unlocked?

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• Oracle HRMS API – Create Employee Payment Method

  - by PRajkumar

  API --  hr_personal_pay_method_api.create_personal_pay_method   Example -- DECLARE   ln_method_id  PAY_PERSONAL_PAYMENT_METHODS_F.PERSONAL_PAYMENT_METHOD_ID%TYPE; ln_ext_acc_id        PAY_EXTERNAL_ACCOUNTS.EXTERNAL_ACCOUNT_ID%TYPE; ln_obj_ver_num    PAY_PERSONAL_PAYMENT_METHODS_F.OBJECT_VERSION_NUMBER%TYPE; ld_eff_start_date   DATE;   ld_eff_end_date    DATE; ln_comment_id     NUMBER; BEGIN      -- Create Employee Payment Method      -- --------------------------------------------------       hr_personal_pay_method_api.create_personal_pay_method       (   -- Input data elements           -- ------------------------------           p_effective_date                                     => TO_DATE('21-JUN-2011'),           p_assignment_id                                   => 33561,           p_org_payment_method_id               => 2,           p_priority                                                 => 50,           p_percentage                                           => 100,           p_territory_code                                     => 'US',           p_segment1                                              => 'PRAJKUMAR',           p_segment2                                              => 'S',           p_segment3                                              => '100200300',           p_segment4                                              => '567',           p_segment5                                              => 'HDFC',           p_segment6                                              => 'INDIA',           -- Output data elements           -- --------------------------------           p_personal_payment_method_id   => ln_method_id,           p_external_account_id                       => ln_ext_acc_id,           p_object_version_number                  => ln_obj_ver_num,           p_effective_start_date                          => ld_eff_start_date,           p_effective_end_date                           => ld_eff_end_date,          p_comment_id                                        => ln_comment_id      );    COMMIT; EXCEPTION           WHEN OTHERS THEN                           ROLLBACK;                            dbms_output.put_line(SQLERRM); END; / SHOW ERR;    

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• Struct Method for Loops Problem

  - by Annalyne

  I have tried numerous times how to make a do-while loop using the float constructor for my code but it seems it does not work properly as I wanted. For summary, I am making a TBRPG in C++ and I encountered few problems. But before that, let me post my code. #include <iostream> #include <string> #include <ctime> #include <cstdlib> using namespace std; int char_level = 1; //the starting level of the character. string town; //town string town_name; //the name of the town the character is in. string charname; //holds the character's name upon the start of the game int gems = 0; //holds the value of the games the character has. const int MAX_ITEMS = 15; //max items the character can carry string inventory [MAX_ITEMS]; //the inventory of the character in game int itemnum = 0; //number of items that the character has. bool GameOver = false; //boolean intended for the game over scr. string monsterTroop [] = {"Slime", "Zombie", "Imp", "Sahaguin, Hounds, Vampire"}; //monster name float monsterTroopHealth [] = {5.0f, 10.0f, 15.0f, 20.0f, 25.0f}; // the health of the monsters int monLifeBox; //life carrier of the game's enemy troops int enemNumber; //enemy number //inventory[itemnum++] = "Sword"; class RPG_Game_Enemy { public: void enemyAppear () { srand(time(0)); enemNumber = 1+(rand()%3); if (enemNumber == 1) cout << monsterTroop[1]; //monster troop 1 else if (enemNumber == 2) cout << monsterTroop[2]; //monster troop 2 else if (enemNumber == 3) cout << monsterTroop[3]; //monster troop 3 else if (enemNumber == 4) cout << monsterTroop[4]; //monster troop 4 } void enemDefeat () { cout << "The foe has been defeated. You are victorious." << endl; } void enemyDies() { //if the enemy dies: //collapse declaration cout << "The foe vanished and you are victorious!" << endl; } }; class RPG_Scene_Battle { public: RPG_Scene_Battle(float ini_health) : health (ini_health){}; float getHealth() { return health; } void setHealth(float rpg_val){ health = rpg_val;}; private: float health; }; //---------------------------------------------------------------// // Conduct Damage for the Scene Battle's Damage //---------------------------------------------------------------// float conductDamage(RPG_Scene_Battle rpg_tr, float damage) { rpg_tr.setHealth(rpg_tr.getHealth() - damage); return rpg_tr.getHealth(); }; // ------------------------------------------------------------- // void RPG_Scene_DisplayItem () { cout << "Items: \n"; for (int i=0; i < itemnum; ++i) cout << inventory[i] <<endl; }; In this code I have so far, the problem I have is the battle scene. For example, the player battles a Ghost with 10 HP, when I use a do while loop to subtract the HP of the character and the enemy, it only deducts once in the do while. Some people said I should use a struct, but I have no idea how to make it. Is there a way someone can display a code how to implement it on my game? Edit: I made the do-while by far like this: do RPG_Scene_Battle (player, 20.0f); RPG_Scene_Battle (enemy, 10.0f); cout << "Battle starts!" <<endl; cout << "You used a blade skill and deducted 2 hit points to the enemy!" conductDamage (enemy, 2.0f); while (enemy!=0) also, I made something like this: #include <iostream> using namespace std; int gems = 0; class Entity { public: Entity(float startingHealth) : health(startingHealth){}; // initialize health float getHealth(){return health;} void setHealth(float value){ health = value;}; private: float health; }; float subtractHealthFrom(Entity& ent, float damage) { ent.setHealth(ent.getHealth() - damage); return ent.getHealth(); }; int main () { Entity character(10.0f); Entity enemy(10.0f); cout << "Hero Life: "; cout << subtractHealthFrom(character, 2.0f) <<endl; cout << "Monster Life: "; cout << subtractHealthFrom(enemy, 2.0f) <<endl; cout << "Hero Life: "; cout << subtractHealthFrom(character, 2.0f) <<endl; cout << "Monster Life: "; cout << subtractHealthFrom(enemy, 2.0f) <<endl; }; Struct method, they say, should solve this problem. How can I continously deduct hp from the enemy? Whenever I deduct something, it would return to its original value -_-

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