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  • How can I connect to a mail server using SMTP over SSL using Python?

    - by jakecar
    Hello, So I have been having a hard time sending email from my school's email address. It is SSL and I could only find this code online by Matt Butcher that works with SSL: import smtplib, socket version = "1.00" all = ['SMTPSSLException', 'SMTP_SSL'] SSMTP_PORT = 465 class SMTPSSLException(smtplib.SMTPException): """Base class for exceptions resulting from SSL negotiation.""" class SMTP_SSL (smtplib.SMTP): """This class provides SSL access to an SMTP server. SMTP over SSL typical listens on port 465. Unlike StartTLS, SMTP over SSL makes an SSL connection before doing a helo/ehlo. All transactions, then, are done over an encrypted channel. This class is a simple subclass of the smtplib.SMTP class that comes with Python. It overrides the connect() method to use an SSL socket, and it overrides the starttles() function to throw an error (you can't do starttls within an SSL session). """ certfile = None keyfile = None def __init__(self, host='', port=0, local_hostname=None, keyfile=None, certfile=None): """Initialize a new SSL SMTP object. If specified, `host' is the name of the remote host to which this object will connect. If specified, `port' specifies the port (on `host') to which this object will connect. `local_hostname' is the name of the localhost. By default, the value of socket.getfqdn() is used. An SMTPConnectError is raised if the SMTP host does not respond correctly. An SMTPSSLError is raised if SSL negotiation fails. Warning: This object uses socket.ssl(), which does not do client-side verification of the server's cert. """ self.certfile = certfile self.keyfile = keyfile smtplib.SMTP.__init__(self, host, port, local_hostname) def connect(self, host='localhost', port=0): """Connect to an SMTP server using SSL. `host' is localhost by default. Port will be set to 465 (the default SSL SMTP port) if no port is specified. If the host name ends with a colon (`:') followed by a number, that suffix will be stripped off and the number interpreted as the port number to use. This will override the `port' parameter. Note: This method is automatically invoked by __init__, if a host is specified during instantiation. """ # MB: Most of this (Except for the socket connection code) is from # the SMTP.connect() method. I changed only the bare minimum for the # sake of compatibility. if not port and (host.find(':') == host.rfind(':')): i = host.rfind(':') if i >= 0: host, port = host[:i], host[i+1:] try: port = int(port) except ValueError: raise socket.error, "nonnumeric port" if not port: port = SSMTP_PORT if self.debuglevel > 0: print>>stderr, 'connect:', (host, port) msg = "getaddrinfo returns an empty list" self.sock = None for res in socket.getaddrinfo(host, port, 0, socket.SOCK_STREAM): af, socktype, proto, canonname, sa = res try: self.sock = socket.socket(af, socktype, proto) if self.debuglevel > 0: print>>stderr, 'connect:', (host, port) self.sock.connect(sa) # MB: Make the SSL connection. sslobj = socket.ssl(self.sock, self.keyfile, self.certfile) except socket.error, msg: if self.debuglevel > 0: print>>stderr, 'connect fail:', (host, port) if self.sock: self.sock.close() self.sock = None continue break if not self.sock: raise socket.error, msg # MB: Now set up fake socket and fake file classes. # Thanks to the design of smtplib, this is all we need to do # to get SSL working with all other methods. self.sock = smtplib.SSLFakeSocket(self.sock, sslobj) self.file = smtplib.SSLFakeFile(sslobj); (code, msg) = self.getreply() if self.debuglevel > 0: print>>stderr, "connect:", msg return (code, msg) def setkeyfile(self, keyfile): """Set the absolute path to a file containing a private key. This method will only be effective if it is called before connect(). This key will be used to make the SSL connection.""" self.keyfile = keyfile def setcertfile(self, certfile): """Set the absolute path to a file containing a x.509 certificate. This method will only be effective if it is called before connect(). This certificate will be used to make the SSL connection.""" self.certfile = certfile def starttls(): """Raises an exception. You cannot do StartTLS inside of an ssl session. Calling starttls() will return an SMTPSSLException""" raise SMTPSSLException, "Cannot perform StartTLS within SSL session." And then my code: import ssmtplib conn = ssmtplib.SMTP_SSL('HOST') conn.login('USERNAME','PW') conn.ehlo() conn.sendmail('FROM_EMAIL', 'TO_EMAIL', "MESSAGE") conn.close() And got this error: /Users/Jake/Desktop/Beth's Program/ssmtplib.py:116: DeprecationWarning: socket.ssl() is deprecated. Use ssl.wrap_socket() instead. sslobj = socket.ssl(self.sock, self.keyfile, self.certfile) Traceback (most recent call last): File "emailer.py", line 5, in conn = ssmtplib.SMTP_SSL('HOST') File "/Users/Jake/Desktop/Beth's Program/ssmtplib.py", line 79, in init smtplib.SMTP.init(self, host, port, local_hostname) File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/smtplib.py", line 239, in init (code, msg) = self.connect(host, port) File "/Users/Jake/Desktop/Beth's Program/ssmtplib.py", line 131, in connect self.sock = smtplib.SSLFakeSocket(self.sock, sslobj) AttributeError: 'module' object has no attribute 'SSLFakeSocket' Thank you!

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  • Authlogic Facebook Connect and cucumber

    - by jspooner
    I added the authlogic_facebook_connect plugin to my project and I'm now having problem running my cucumber test because of a NoMethodError. undefined method `set_facebook_session' for nil:NilClass (NoMethodError) In authlogic_facebook_connect/Session.rb the method "authenticating_with_facebook_connect?" is called as some sort of callback and the controller is defined but is missing the 'set_facebook_session' method. def authenticating_with_facebook_connect? controller.set_facebook_session attempted_record.nil? && errors.empty? && controller.facebook_session end I don't understand why the cucumber test is not loading the controller with this method. I also test the app in development and cucumber environments and everything works perfect. Here is the full cucumber output. Feature: Authentication In order to keep security a user should only be able to edit their own profile Background: # features/authorization.feature:4 Given a valid user record for joe_runner # features/step_definitions/user_steps.rb:4 undefined method `set_facebook_session' for nil:NilClass (NoMethodError) ./vendor/plugins/authlogic/lib/authlogic/controller_adapters/abstract_adapter.rb:63:in `send' ./vendor/plugins/authlogic/lib/authlogic/controller_adapters/abstract_adapter.rb:63:in `method_missing' ./vendor/plugins/authlogic_facebook_connect/lib/authlogic_facebook_connect/session.rb:132:in `authenticating_with_facebook_connect?' ./vendor/plugins/authlogic/lib/authlogic/session/callbacks.rb:83:in `validate' ./vendor/plugins/authlogic/lib/authlogic/session/validation.rb:64:in `valid?' ./vendor/plugins/authlogic/lib/authlogic/session/existence.rb:65:in `save' ./vendor/plugins/authlogic/lib/authlogic/session/existence.rb:30:in `create' ./vendor/plugins/authlogic/lib/authlogic/acts_as_authentic/session_maintenance.rb:113:in `create_session' ./vendor/plugins/authlogic/lib/authlogic/acts_as_authentic/session_maintenance.rb:103:in `maintain_sessions' ./features/step_definitions/user_steps.rb:5:in `/^a valid user record for ([\w]*)$/' features/authorization.feature:5:in `Given a valid user record for joe_runner' Scenario: Jonathan can edit his profile but not other users profiles # features/authorization.feature:7 Given jonathan is logged in as an user # features/step_definitions/user_steps.rb:13 When I go to my user edit page # features/step_definitions/web_steps.rb:18 And I press "Update" # features/step_definitions/web_steps.rb:22 Then I should see "Account updated!" # features/step_definitions/web_steps.rb:142 When I go to joe_runner's user edit page # features/step_definitions/web_steps.rb:18 Then I should see "You do not allowed to access to view that page" # features/step_definitions/web_steps.rb:142 Failing Scenarios: cucumber features/authentication.feature:9 # Scenario: Signup cucumber features/authorization.feature:7 # Scenario: Jonathan can edit his profile but not other users profiles 2 scenarios (2 failed) 15 steps (2 failed, 13 skipped) 0m0.173s rake aborted! Command failed with status (1): [/System/Library/Frameworks/Ruby.framework/...] /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:995:in `sh' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:1010:in `call' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:1010:in `sh' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:1094:in `sh' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:1029:in `ruby' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:1094:in `ruby' /Library/Ruby/Gems/1.8/gems/cucumber-0.6.4/lib/cucumber/rake/task.rb:68:in `run' /Library/Ruby/Gems/1.8/gems/cucumber-0.6.4/lib/cucumber/rake/task.rb:138:in `define_task' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `call' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `execute' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `each' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `execute' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:597:in `invoke_with_call_chain' /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/monitor.rb:242:in `synchronize' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:607:in `invoke_prerequisites' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:604:in `each' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:604:in `invoke_prerequisites' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:596:in `invoke_with_call_chain' /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/monitor.rb:242:in `synchronize' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:583:in `invoke' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2051:in `invoke_task' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `each' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2023:in `top_level' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2001:in `run' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:1998:in `run' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/bin/rake:31 /usr/bin/rake:19:in `load' /usr/bin/rake:19 activespoon:base_project jspooner$ There are a couple of blogs that give examples on how to test facebook apps with cucumber but they didn't help because my error comes before these. http://opensoul.org/2009/3/6/testing-facebook-with-cucumber http://ryanbigg.com/2010/03/testing-facebook/

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  • Custom View embed in Gallery crashes while key press

    - by tao
    Hi there, I'd like to find some stuff to replace the Tab component, so I'd make a custom View named StringView, which has the ability to display text, and to embed it into a Gallery. But it always crashes with error "NullPointerException at InputMethodManager". I have no idea about this, any help&tip&suggest are appreciate. Detail of my issue: First I'd created a class StringView extends View: public class StringView extends View { protected final Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG); protected String mString; protected int mAscent; // Constructor public StringView(Context context, String string) { super(context); mPaint.setARGB(255, 255, 60, 10); mPaint.setTextSize(30); //mPaint.setFakeBoldText(true); mString = string; setPadding(20,15,20,15); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); int w = this.getPaddingLeft(); int h = this.getPaddingTop() - mAscent; canvas.drawText(mString, w, h, mPaint); } public void setString(String str) { mString = str; this.requestLayout(); this.invalidate(); } public String getString() { return mString; } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { setMeasuredDimension(measureWidth(widthMeasureSpec), measureHeight(heightMeasureSpec)); } /** * Determines the width of this view * @param measureSpec A measureSpec packed into an int * @return The width of the view, honoring constraints from measureSpec */ private int measureWidth(int measureSpec) { int result = 0; int specMode = MeasureSpec.getMode(measureSpec); int specSize = MeasureSpec.getSize(measureSpec); if (specMode == MeasureSpec.EXACTLY) { // We were told how big to be result = specSize; } else { // Measure the text result = (int) mPaint.measureText(mString) + getPaddingLeft() + getPaddingRight(); if (specMode == MeasureSpec.AT_MOST) { // Respect AT_MOST value if that was what is called for by measureSpec result = Math.min(result, specSize); } } return result; } /** * Determines the height of this view * @param measureSpec A measureSpec packed into an int * @return The height of the view, honoring constraints from measureSpec */ private int measureHeight(int measureSpec) { int result = 0; int specMode = MeasureSpec.getMode(measureSpec); int specSize = MeasureSpec.getSize(measureSpec); mAscent = (int) mPaint.ascent(); if (specMode == MeasureSpec.EXACTLY) { // We were told how big to be result = specSize; } else { // Measure the text (beware: ascent is a negative number) result = (int) (-mAscent + mPaint.descent()) + getPaddingTop() + getPaddingBottom(); if (specMode == MeasureSpec.AT_MOST) { // Respect AT_MOST value if that was what is called for by measureSpec result = Math.min(result, specSize); } } return result; } } Second I put it in to Gallery through Adapter Gallery gallery = (Gallery) findViewById(R.id.gallery); gallery.setAdapter(new ImageAdapter(this)); ImageAdapter: public class ImageAdapter extends BaseAdapter { int mGalleryItemBackground; private Context mContext; private View[] mImages = genSerielImageViews(); public ImageAdapter(Context c) { mContext = c; TypedArray a = obtainStyledAttributes(R.styleable.Gallery); mGalleryItemBackground = a.getResourceId( R.styleable.Gallery_android_galleryItemBackground, 0); a.recycle(); } private View[] genSerielImageViews() { if (true) { int N = 6; StringView[] views = new StringView[N]; for (int i=0; i<N; i++) { views[i] = new StringView(mContext, "ITEM #" + Integer.toString(i) ); } return views; } else { int N = 6; TextView[] views = new TextView[N]; for (int i=0; i<N; i++) { views[i] = new TextView( mContext ); views[i].setText("CCTV #" + Integer.toString(i) ); } return views; } } public int getCount() { return mImages.length; } public Object getItem(int position) { return position; } public long getItemId(int position) { return position; } public View getView(int position, View convertView, ViewGroup parent) { return mImages[position]; } } Then Compile&Run, press keypad RIGHT and I got a crash, It's turns out a weird InputMethodManager error: 03-18 07:22:33.568: ERROR/AndroidRuntime(958): Uncaught handler: thread main exiting due to uncaught exception 03-18 07:22:33.648: ERROR/AndroidRuntime(958): java.lang.NullPointerException 03-18 07:22:33.648: ERROR/AndroidRuntime(958): at android.view.inputmethod.InputMethodManager.startInputInner(InputMethodManager.java:940) 03-18 07:22:33.648: ERROR/AndroidRuntime(958): at android.view.inputmethod.InputMethodManager.checkFocus(InputMethodManager.java:1114) 03-18 07:22:33.648: ERROR/AndroidRuntime(958): at android.view.ViewRoot.handleMessage(ViewRoot.java:1869) 03-18 07:22:33.648: ERROR/AndroidRuntime(958): at android.os.Handler.dispatchMessage(Handler.java:99) 03-18 07:22:33.648: ERROR/AndroidRuntime(958): at android.os.Looper.loop(Looper.java:123) 03-18 07:22:33.648: ERROR/AndroidRuntime(958): at android.app.ActivityThread.main(ActivityThread.java:4310) 03-18 07:22:33.648: ERROR/AndroidRuntime(958): at java.lang.reflect.Method.invokeNative(Native Method) 03-18 07:22:33.648: ERROR/AndroidRuntime(958): at java.lang.reflect.Method.invoke(Method.java:521) 03-18 07:22:33.648: ERROR/AndroidRuntime(958): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) 03-18 07:22:33.648: ERROR/AndroidRuntime(958): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 03-18 07:22:33.648: ERROR/AndroidRuntime(958): at dalvik.system.NativeStart.main(Native Method) Thanks.

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  • ASP.NET MVC: Using ProfileRequiredAttribute to restrict access to pages

    - by DigiMortal
    If you are using AppFabric Access Control Services to authenticate users when they log in to your community site using Live ID, Google or some other popular identity provider, you need more than AuthorizeAttribute to make sure that users can access the content that is there for authenticated users only. In this posting I will show you hot to extend the AuthorizeAttribute so users must also have user profile filled. Semi-authorized users When user is authenticated through external identity provider then not all identity providers give us user name or other information we ask users when they join with our site. What all identity providers have in common is unique ID that helps you identify the user. Example. Users authenticated through Windows Live ID by AppFabric ACS have no name specified. Google’s identity provider is able to provide you with user name and e-mail address if user agrees to publish this information to you. They both give you unique ID of user when user is successfully authenticated in their service. There is logical shift between ASP.NET and my site when considering user as authorized. For ASP.NET MVC user is authorized when user has identity. For my site user is authorized when user has profile and row in my users table. Having profile means that user has unique username in my system and he or she is always identified by this username by other users. My solution is simple: I created my own action filter attribute that makes sure if user has profile to access given method and if user has no profile then browser is redirected to join page. Illustrating the problem Usually we restrict access to page using AuthorizeAttribute. Code is something like this. [Authorize] public ActionResult Details(string id) {     var profile = _userRepository.GetUserByUserName(id);     return View(profile); } If this page is only for site users and we have user profiles then all users – the ones that have profile and all the others that are just authenticated – can access the information. It is okay because all these users have successfully logged in in some service that is supported by AppFabric ACS. In my site the users with no profile are in grey spot. They are on half way to be users because they have no username and profile on my site yet. So looking at the image above again we need something that adds profile existence condition to user-only content. [ProfileRequired] public ActionResult Details(string id) {     var profile = _userRepository.GetUserByUserName(id);     return View(profile); } Now, this attribute will solve our problem as soon as we implement it. ProfileRequiredAttribute: Profiles are required to be fully authorized Here is my implementation of ProfileRequiredAttribute. It is pretty new and right now it is more like working draft but you can already play with it. public class ProfileRequiredAttribute : AuthorizeAttribute {     private readonly string _redirectUrl;       public ProfileRequiredAttribute()     {         _redirectUrl = ConfigurationManager.AppSettings["JoinUrl"];         if (string.IsNullOrWhiteSpace(_redirectUrl))             _redirectUrl = "~/";     }              public override void OnAuthorization(AuthorizationContext filterContext)     {         base.OnAuthorization(filterContext);           var httpContext = filterContext.HttpContext;         var identity = httpContext.User.Identity;           if (!identity.IsAuthenticated || identity.GetProfile() == null)             if(filterContext.Result == null)                 httpContext.Response.Redirect(_redirectUrl);          } } All methods with this attribute work as follows: if user is not authenticated then he or she is redirected to AppFabric ACS identity provider selection page, if user is authenticated but has no profile then user is by default redirected to main page of site but if you have application setting with name JoinUrl then user is redirected to this URL. First case is handled by AuthorizeAttribute and the second one is handled by custom logic in ProfileRequiredAttribute class. GetProfile() extension method To get user profile using less code in places where profiles are needed I wrote GetProfile() extension method for IIdentity interface. There are some more extension methods that read out user and identity provider identifier from claims and based on this information user profile is read from database. If you take this code with copy and paste I am sure it doesn’t work for you but you get the idea. public static User GetProfile(this IIdentity identity) {     if (identity == null)         return null;       var context = HttpContext.Current;     if (context.Items["UserProfile"] != null)         return context.Items["UserProfile"] as User;       var provider = identity.GetIdentityProvider();     var nameId = identity.GetNameIdentifier();       var rep = ObjectFactory.GetInstance<IUserRepository>();     var profile = rep.GetUserByProviderAndNameId(provider, nameId);       context.Items["UserProfile"] = profile;       return profile; } To avoid round trips to database I cache user profile to current request because the chance that profile gets changed meanwhile is very minimal. The other reason is maybe more tricky – profile objects are coming from Entity Framework context and context has also HTTP request as lifecycle. Conclusion This posting gave you some ideas how to finish user profiles stuff when you use AppFabric ACS as external authentication provider. Although there was little shift between us and ASP.NET MVC with interpretation of “authorized” we were easily able to solve the problem by extending AuthorizeAttribute to get all our requirements fulfilled. We also write extension method for IIdentity that returns as user profile based on username and caches the profile in HTTP request scope.

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  • No NFC for the iPhone, and here's why

    - by David Dorf
    I, like many others in the retail industry, was hoping the iPhone 5 would include an NFC chip that enabled a mobile wallet.  In previous postings I've discussed the possible business case and the foreshadowing of Passbook, but it wasn't meant to be.  A few weeks ago I was considering all the rumors, and it suddenly occurred to me that it wasn't in Apple's best interest to support an NFC chip.  Yes they have patents in this area, but perhaps they are more defensive than indicating new development. Steve Jobs wanted to always win, but more importantly he didn't want others to win at his expense.  It drove him nuts that Windows was more successful than MacOS, and clearly he was bothered by Samsung and other handset manufacturers copying the iPhone.  But he was most angry at Google for their stewardship of Android. If the iPhone 5 had an NFC chip, who would benefit most?  Google Wallet is far and away the leader in NFC-based payments via mobile phones in the US.  Even without Steve at the helm, Apple isn't going to do anything to help Google.  Plus Apple doesn't like to do things in an open way -- then they lose control.  For example, you don't see iPhones with expandable memory, replaceable batteries, or USB connectors.  Adding a standards-based NFC chip just isn't in their nature. So I don't think Apple is holding back on the NFC chip for the 5S or 6.  It just isn't going to happen unless they can figure out how to prevent others from benefiting from it. All the other handset manufacturers will use NFC as a differentiator, which may be enough to keep Google and Isis afloat, and of course Square and PayPal aren't betting on NFC anyway.  This isn't the end of alternative payments, its just a major speed bump.

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  • Extreme Optimization –Mathematical Constants and Basic Functions

    - by JoshReuben
    Machine constants The MachineConstants class - contains constants for floating-point arithmetic because the CLS System.Single and Double floating-point types do not follow the standard conventions and are useless. machine constants for the Double type: machine precision: Epsilon , SqrtEpsilon CubeRootEpsilon largest possible value: MaxDouble , SqrtMaxDouble, LogMaxDouble smallest Double-precision floating point number that is greater than zero: MinDouble , SqrtMinDouble , LogMinDouble A similar set of constants is available for the Single Datatype  Mathematical Constants The Constants class contains static fields for many mathematical constants and common expressions involving small integers – if you are doing thousands of iterations, you wouldn't want to calculate OneOverSqrtTwoPi , Sqrt17 or Log17 !!! Fundamental constants E - The base for the natural logarithm, e (2.718...). EulersConstant - (0.577...). GoldenRatio - (1.618...). Pi - the ratio between the circumference and the diameter of a circle (3.1415...). Expressions involving fundamental constants: TwoPi, PiOverTwo, PiOverFour, LogTwoPi, PiSquared, SqrPi, SqrtTwoPi, OneOverSqrtPi, OneOverSqrtTwoPi Square roots of small integers: Sqrt2, Sqrt3, Sqrt5, Sqrt7, Sqrt17 Logarithms of small integers: Log2, Log3, Log10, Log17, InvLog10  Elementary Functions The IterativeAlgorithm<T> class in the Extreme.Mathematics namespace defines many elementary functions that are missing from System.Math. Hyperbolic Trig Functions: Cosh, Coth, Csch, Sinh, Sech, Tanh Inverse Hyperbolic Trig Functions: Acosh, Acoth, Acsch, Asinh, Asech, Atanh Exponential, Logarithmic and Miscellaneous Functions: ExpMinus1 - The exponential function minus one, ex-1. Hypot - The hypotenuse of a right-angled triangle with specified sides. LambertW - Lambert's W function, the (real) solution W of x=WeW. Log1PlusX - The natural logarithm of 1+x. Pow - A number raised to an integer power.

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  • Unable to Start Activity ComponentInfo when Starting a New Activity

    - by Timtim17
    {I know there's already a whole bunch of questions like this, but I can't see any problems that related to my program.} I have an Android App that is supposed to take a name from a EditText and put it in a TextView in another activity. It previously worked, but then I wanted it to start another activity if the EditText's value was equal to "ANDROID". However, now the app crashes whenever I try to start either activity. First Activity: package net.timtim17.dev.android.fun.nametag; import android.os.Bundle; import android.app.Activity; import android.content.Intent; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.EditText; public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); final EditText et = (EditText) findViewById(R.id.editText1); Button submit = (Button) findViewById(R.id.button1); submit.setOnClickListener(new OnClickListener(){ @Override public void onClick(View v) { String text = et.getText().toString(); if(text.equals("ANDROID")){ Intent android = new Intent(MainActivity.this, AndroidNameTag.class); startActivity(android); }else{ Intent intent = new Intent(MainActivity.this, NameTag.class); intent.putExtra("name", text); startActivity(intent); } } }); } } NameTag Activity: package net.timtim17.dev.android.fun.nametag; import android.app.Activity; import android.os.Bundle; import android.widget.TextView; public class NameTag extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_tag); TextView tv = (TextView) findViewById(R.id.textView2); tv.setText(getIntent().getExtras().getString("name")); } } AndroidNameTag Activity: package net.timtim17.dev.android.fun.nametag; import android.app.Activity; import android.graphics.drawable.AnimationDrawable; import android.os.Bundle; import android.widget.ImageView; public class AndroidNameTag extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_android); ImageView iv = (ImageView) findViewById(R.id.imageView1); iv.setBackgroundResource(R.anim.animation); AnimationDrawable anim = (AnimationDrawable) iv.getBackground(); anim.start(); } } LogCat Error: 10-26 11:26:35.602: E/AndroidRuntime(2900): FATAL EXCEPTION: main 10-26 11:26:35.602: E/AndroidRuntime(2900): java.lang.RuntimeException: Unable to start activity ComponentInfo{net.timtim17.dev.android.fun.nametag/net.timtim17.dev.android.fun.nametag.NameTag}: java.lang.NullPointerException 10-26 11:26:35.602: E/AndroidRuntime(2900): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211) 10-26 11:26:35.602: E/AndroidRuntime(2900): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261) 10-26 11:26:35.602: E/AndroidRuntime(2900): at android.app.ActivityThread.access$600(ActivityThread.java:141) 10-26 11:26:35.602: E/AndroidRuntime(2900): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256) 10-26 11:26:35.602: E/AndroidRuntime(2900): at android.os.Handler.dispatchMessage(Handler.java:99) 10-26 11:26:35.602: E/AndroidRuntime(2900): at android.os.Looper.loop(Looper.java:137) 10-26 11:26:35.602: E/AndroidRuntime(2900): at android.app.ActivityThread.main(ActivityThread.java:5103) 10-26 11:26:35.602: E/AndroidRuntime(2900): at java.lang.reflect.Method.invokeNative(Native Method) 10-26 11:26:35.602: E/AndroidRuntime(2900): at java.lang.reflect.Method.invoke(Method.java:525) 10-26 11:26:35.602: E/AndroidRuntime(2900): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737) 10-26 11:26:35.602: E/AndroidRuntime(2900): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 10-26 11:26:35.602: E/AndroidRuntime(2900): at dalvik.system.NativeStart.main(Native Method) 10-26 11:26:35.602: E/AndroidRuntime(2900): Caused by: java.lang.NullPointerException 10-26 11:26:35.602: E/AndroidRuntime(2900): at net.timtim17.dev.android.fun.nametag.NameTag.onCreate(NameTag.java:15) 10-26 11:26:35.602: E/AndroidRuntime(2900): at android.app.Activity.performCreate(Activity.java:5133) 10-26 11:26:35.602: E/AndroidRuntime(2900): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087) 10-26 11:26:35.602: E/AndroidRuntime(2900): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175) 10-26 11:26:35.602: E/AndroidRuntime(2900): ... 11 more MainActivity Layout: <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context=".MainActivity" > <TextView android:id="@+id/textView1" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignParentLeft="true" android:layout_alignParentTop="true" android:layout_marginTop="16dp" android:text="@string/main_text" android:textAppearance="?android:attr/textAppearanceMedium" /> <Button android:id="@+id/button1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignRight="@+id/textView1" android:layout_below="@+id/textView1" android:layout_marginTop="14dp" android:text="@string/submit_button" /> <EditText android:id="@+id/editText1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignLeft="@+id/textView1" android:layout_alignTop="@+id/button1" android:ems="10" android:inputType="textPersonName" > <requestFocus /> </EditText>

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  • Inconsistent movement / line-of-sight around obstacles on a hexagonal grid

    - by Darq
    In a roguelike game I've been working on, one of my core design goals has been to allow the player to "Play the game, not the grid." In essence, I want the player's positioning to be tactical because of elements in the game world, not simply because some grid tiles are more advantageous than others, in relation to enemies. I am fine with world geometry not being realistic, but it needs to be consistent. In this process I have ran into most of the common problems (Square tiles? Diagonal movement, LOS, corner cases, etc.) and have moved to a hexagonal tile grid. For the most part this has been great, and I've not had too many inconsistencies. Recently however I have been stumped by the following: Points A and B are both distance 4 from the player (red lines). Line-of-sight to both are blocked by walls (black tiles). However, due to the hexagonal grid, A can be reached in 4 moves, whereas B requires 5 moves (blue lines). On a hex grid, "shortest path" seems divorced from "direct path", there may be multiple shortest paths to any point, but there is only one direct path (or two in some situations). This is fine, geometry need not be realistic. However this also seems inconsistent, similar obstacles are more effective in some positions than in others. A player running away from an enemy should be able to run in any direction, increasing the distance between the two actors. However when placing obstacles or traps between themselves and enemies, the player is best served by running in one of the six directions that don't have multiple shortest paths. Is there a way to rationalise this? Am I missing something that makes this behaviour consistent? Or is there a way to make this behaviour consistent? I am most certainly over-thinking this, but as it is one of my goals, I should do it due diligence.

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  • Problem with custom Dialog Android

    - by Nanis
    Hi, I have a custom Dialog on my app and I have a problem to do what I would like. I explain. My Dialog have had 4 Buttons. (Back, Valid, Modify and Restore) When user click on Modify or Valid I would like to call another activity. So I use Intent but it crash. The error Log : 05-19 13:29:21.495: ERROR/DEBUGTAG(974): java.lang.NullPointerException 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.content.ComponentName.(ComponentName.java:75) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.content.Intent.(Intent.java:2551) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at com.android.booztermobile.activity.HeaderMailDisplayActivity.onClick(HeaderMailDisplayActivity.java:571) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.view.View.performClick(View.java:2364) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.view.View.onTouchEvent(View.java:4179) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.widget.TextView.onTouchEvent(TextView.java:6540) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.view.View.dispatchTouchEvent(View.java:3709) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1659) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1107) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.app.Dialog.dispatchTouchEvent(Dialog.java:643) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1643) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.view.ViewRoot.handleMessage(ViewRoot.java:1691) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.os.Handler.dispatchMessage(Handler.java:99) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.os.Looper.loop(Looper.java:123) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.app.ActivityThread.main(ActivityThread.java:4363) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at java.lang.reflect.Method.invokeNative(Native Method) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at java.lang.reflect.Method.invoke(Method.java:521) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at dalvik.system.NativeStart.main(Native Method) My custom Dialog : package com.android.booztermobile.services; import com.android.booztermobile.R; import android.app.Dialog; import android.content.Context; import android.os.Bundle; import android.util.Log; import android.widget.Button; public class MailDialog extends Dialog { private Button btnValid; private Button btnBack; private Button btnRestore; private Button btnModify; private Context context; public MailDialog(Context cont) { super(cont); context = cont; } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); Log.d("TestApp", "Dialog created"); setContentView(R.layout.dialog_classement); btnValid = (Button) findViewById(R.id.btnValidClassement); btnBack = (Button) findViewById(R.id.btnBackClassement); btnRestore = (Button) findViewById(R.id.btnRestoreClassement); btnModify = (Button) findViewById(R.id.btnModifyClassement); } } and the activity (cut because too long): //create dialog public void getMailInformations(View v, Context context){ currentMail = (MailHeader) v.getTag(); dial = new MailDialog(context); dial.setTitle("Classement"); dial.show(); btnValidClassement = (Button) dial.findViewById(R.id.btnValidClassement); btnValidClassement.setOnClickListener(this); } /** the Onclick : */ public void onClick(View view) { if(view == btnValidClassement){ try{ ClassementHandlerCall classement = new ClassementHandlerCall(); boolean mailClassify = classement.classifyMail(AuthentificationActivity.uidh, String.valueOf(currentMail.getSeqnum()), null, null); dial.dismiss(); if (mailClassify == true){ // create Intent Intent defineIntentDisplayPreviousMails = new Intent(HeaderMailDisplayActivity.this, ClassementActivity.class); } }catch(Exception e){ // TODO Auto-generated catch block Log.e("DEBUGTAG","Error occured", e); e.printStackTrace(); } } }

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  • Making a 2D game with responsive resolution

    - by alexandervrs
    I am making a 2D game, however I wish for it to be resolution agnostic. My target resolution i.e. where things look as intended is 1600 x 900. My ideas are: Make the HUD stay fixed to the sides no matter what resolution, use different size for HUD graphics under a certain resolution and another under a certain large one. Use large HD PNG sprites/backgrounds which are a power of 2, so they scale nicely. No vectors. Use the player's native resolution. Scale the game area (not the HUD) to fit (resulting zooming in some and cropping the game area sides if necessary for widescreen, no stretch), but always fill the screen. Have a min and max resolution limit for small and very large displays where you will just change the resolution(?) or scale up/down to fit. What I am a bit confused though is what math formula I would use to scale the game area correctly based on the resolution no matter the aspect ratio, fully fit in a square screen and with some clip to the sides for widescreen. Pseudocode would help as well. :)

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  • Pathfinding and BSP with Box2D

    - by Amplify91
    I'm looking into implementing AI in my 2D side-scrolling platformer, and I'm looking into using algorithms such as A*. For many kinds of pathfinding, we need some sort of grid or systems of nodes or polygon areas. My problem is that I am using Box2d for physics and I am not sure how best to create a structure that my AI can use besides placing individual nodes manually (something I really want to avoid) and using some sort of steering behavior. My level design is tile-based with each tile being about half of the height/width of my main character. The tiles are not all square (some are sloped). I'd like to have a system that can see what the terrain looks like for pathfinding and also keep track of the positions of other actors such as enemies. I'd like to avoid directly placing any nodes into my level design except for possible endpoints or goals. This question is related: How do you do AI path following within a 2d physics engine like farseer/box2d?, but it doesn't specify what kind of structure I could use instead of a list of nodes. I'm looking for some kind of grid or type of BSP that I can query for algorithms like A*.

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  • Use a Fake Http Channel to Unit Test with HttpClient

    - by Steve Michelotti
    Applications get data from lots of different sources. The most common is to get data from a database or a web service. Typically, we encapsulate calls to a database in a Repository object and we create some sort of IRepository interface as an abstraction to decouple between layers and enable easier unit testing by leveraging faking and mocking. This works great for database interaction. However, when consuming a RESTful web service, this is is not always the best approach. The WCF Web APIs that are available on CodePlex (current drop is Preview 3) provide a variety of features to make building HTTP REST services more robust. When you download the latest bits, you’ll also find a new HttpClient which has been updated for .NET 4.0 as compared to the one that shipped for 3.5 in the original REST Starter Kit. The HttpClient currently provides the best API for consuming REST services on the .NET platform and the WCF Web APIs provide a number of extension methods which extend HttpClient and make it even easier to use. Let’s say you have a client application that is consuming an HTTP service – this could be Silverlight, WPF, or any UI technology but for my example I’ll use an MVC application: 1: using System; 2: using System.Net.Http; 3: using System.Web.Mvc; 4: using FakeChannelExample.Models; 5: using Microsoft.Runtime.Serialization; 6:   7: namespace FakeChannelExample.Controllers 8: { 9: public class HomeController : Controller 10: { 11: private readonly HttpClient httpClient; 12:   13: public HomeController(HttpClient httpClient) 14: { 15: this.httpClient = httpClient; 16: } 17:   18: public ActionResult Index() 19: { 20: var response = httpClient.Get("Person(1)"); 21: var person = response.Content.ReadAsDataContract<Person>(); 22:   23: this.ViewBag.Message = person.FirstName + " " + person.LastName; 24: 25: return View(); 26: } 27: } 28: } On line #20 of the code above you can see I’m performing an HTTP GET request to a Person resource exposed by an HTTP service. On line #21, I use the ReadAsDataContract() extension method provided by the WCF Web APIs to serialize to a Person object. In this example, the HttpClient is being passed into the constructor by MVC’s dependency resolver – in this case, I’m using StructureMap as an IoC and my StructureMap initialization code looks like this: 1: using StructureMap; 2: using System.Net.Http; 3:   4: namespace FakeChannelExample 5: { 6: public static class IoC 7: { 8: public static IContainer Initialize() 9: { 10: ObjectFactory.Initialize(x => 11: { 12: x.For<HttpClient>().Use(() => new HttpClient("http://localhost:31614/")); 13: }); 14: return ObjectFactory.Container; 15: } 16: } 17: } My controller code currently depends on a concrete instance of the HttpClient. Now I *could* create some sort of interface and wrap the HttpClient in this interface and use that object inside my controller instead – however, there are a few why reasons that is not desirable: For one thing, the API provided by the HttpClient provides nice features for dealing with HTTP services. I don’t really *want* these to look like C# RPC method calls – when HTTP services have REST features, I may want to inspect HTTP response headers and hypermedia contained within the message so that I can make intelligent decisions as to what to do next in my workflow (although I don’t happen to be doing these things in my example above) – this type of workflow is common in hypermedia REST scenarios. If I just encapsulate HttpClient behind some IRepository interface and make it look like a C# RPC method call, it will become difficult to take advantage of these types of things. Second, it could get pretty mind-numbing to have to create interfaces all over the place just to wrap the HttpClient. Then you’re probably going to have to hard-code HTTP knowledge into your code to formulate requests rather than just “following the links” that the hypermedia in a message might provide. Third, at first glance it might appear that we need to create an interface to facilitate unit testing, but actually it’s unnecessary. Even though the code above is dependent on a concrete type, it’s actually very easy to fake the data in a unit test. The HttpClient provides a Channel property (of type HttpMessageChannel) which allows you to create a fake message channel which can be leveraged in unit testing. In this case, what I want is to be able to write a unit test that just returns fake data. I also want this to be as re-usable as possible for my unit testing. I want to be able to write a unit test that looks like this: 1: [TestClass] 2: public class HomeControllerTest 3: { 4: [TestMethod] 5: public void Index() 6: { 7: // Arrange 8: var httpClient = new HttpClient("http://foo.com"); 9: httpClient.Channel = new FakeHttpChannel<Person>(new Person { FirstName = "Joe", LastName = "Blow" }); 10:   11: HomeController controller = new HomeController(httpClient); 12:   13: // Act 14: ViewResult result = controller.Index() as ViewResult; 15:   16: // Assert 17: Assert.AreEqual("Joe Blow", result.ViewBag.Message); 18: } 19: } Notice on line #9, I’m setting the Channel property of the HttpClient to be a fake channel. I’m also specifying the fake object that I want to be in the response on my “fake” Http request. I don’t need to rely on any mocking frameworks to do this. All I need is my FakeHttpChannel. The code to do this is not complex: 1: using System; 2: using System.IO; 3: using System.Net.Http; 4: using System.Runtime.Serialization; 5: using System.Threading; 6: using FakeChannelExample.Models; 7:   8: namespace FakeChannelExample.Tests 9: { 10: public class FakeHttpChannel<T> : HttpClientChannel 11: { 12: private T responseObject; 13:   14: public FakeHttpChannel(T responseObject) 15: { 16: this.responseObject = responseObject; 17: } 18:   19: protected override HttpResponseMessage Send(HttpRequestMessage request, CancellationToken cancellationToken) 20: { 21: return new HttpResponseMessage() 22: { 23: RequestMessage = request, 24: Content = new StreamContent(this.GetContentStream()) 25: }; 26: } 27:   28: private Stream GetContentStream() 29: { 30: var serializer = new DataContractSerializer(typeof(T)); 31: Stream stream = new MemoryStream(); 32: serializer.WriteObject(stream, this.responseObject); 33: stream.Position = 0; 34: return stream; 35: } 36: } 37: } The HttpClientChannel provides a Send() method which you can override to return any HttpResponseMessage that you want. You can see I’m using the DataContractSerializer to serialize the object and write it to a stream. That’s all you need to do. In the example above, the only thing I’ve chosen to do is to provide a way to return different response objects. But there are many more features you could add to your own re-usable FakeHttpChannel. For example, you might want to provide the ability to add HTTP headers to the message. You might want to use a different serializer other than the DataContractSerializer. You might want to provide custom hypermedia in the response as well as just an object or set HTTP response codes. This list goes on. This is the just one example of the really cool features being added to the next version of WCF to enable various HTTP scenarios. The code sample for this post can be downloaded here.

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  • Implementation question involving implementing an interface

    - by Vivin Paliath
    I'm writing a set of collection classes for different types of Trees. I'm doing this as a learning exercise and I'm also hoping it turns out to be something useful. I really want to do this the right way and so I've been reading Effective Java and I've also been looking at the way Joshua Bloch implemented the collection classes by looking at the source. I seem to have a fair idea of what is being done, but I still have a few things to sort out. I have a Node<T> interface and an AbstractNode<T> class that implements the Node interface. I then created a GenericNode<T> (a node that can have 0 to n children, and that is part of an n-ary tree) class that extends AbstractNode<T> and implements Node<T>. This part was easy. Next, I created a Tree<T> interface and an AbstractTree<T> class that implements the Tree<T> interface. After that, I started writing a GenericTree<T> class that extends AbstractTree<T> and implements Tree<T>. This is where I started having problems. As far as the design is concerned, a GenericTree<T> can only consist of nodes of type GenericTreeNode<T>. This includes the root. In my Tree<T> interface I have: public interface Tree<T> { void setRoot(Node<T> root); Node<T> getRoot(); List<Node<T>> postOrder(); ... rest omitted ... } And, AbstractTree<T> implements this interface: public abstract class AbstractTree<T> implements Tree<T> { protected Node<T> root; protected AbstractTree() { } protected AbstractTree(Node<T> root) { this.root = root; } public void setRoot(Node<T> root) { this.root = root; } public Node<T> getRoot() { return this.root; } ... rest omitted ... } In GenericTree<T>, I can have: public GenericTree(Node<T> root) { super(root); } But what this means is that you can create a generic tree using any subtype of Node<T>. You can also set the root of a tree to any subtype of Node<T>. I want to be able to restrict the type of the node to the type of the tree that it can represent. To fix this, I can do this: public GenericTree(GenericNode<T> root) { super(root); } However, setRoot still accepts a parameter of type Node<T>. Which means a user can still create a tree with the wrong type of root node. How do I enforce this constraint? The only way I can think of doing is either: Do an instanceof which limits the check to runtime. I'm not a huge fan of this. Remove setRoot from the interface and have the base class implement this method. This means that it is not part of the contract and anyone who wants to make a new type of tree needs to remember to implement this method. Is there a better way? The second question I have concerns the return type of postOrder which is List<Node<T>>. This means that if a user is operating on a GenericTree<T> object and calls postOrder, he or she receives a list that consists of Node<T> objects. This means when iterating through (using a foreach construct) they would have perform an explicit cast to GenericNode<T> if they want to use methods that are only defined in that class. I don't like having to place this burden on the user. What are my options in this case? I can only think of removing the method from the interface and have the subclass implement this method making sure that it returns a list of appropriate subtype of Node<T>. However, this once again removes it from the contract and it's anyone who wants to create a new type of tree has to remember to implement this method. Is there a better way?

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  • Jquery Live Function

    - by marharépa
    Hi! I want to make this script to work as LIVE() function. Please help me! $(".img img").each(function() { $(this).cjObjectScaler({ destElem: $(this).parent(), method: "fit" }); }); the cjObjectScaler script (called in the html header) is this: (thanks for Doug Jones) (function ($) { jQuery.fn.imagesLoaded = function (callback) { var elems = this.filter('img'), len = elems.length; elems.bind('load', function () { if (--len <= 0) { callback.call(elems, this); } }).each(function () { // cached images don't fire load sometimes, so we reset src. if (this.complete || this.complete === undefined) { var src = this.src; // webkit hack from http://groups.google.com/group/jquery-dev/browse_thread/thread/eee6ab7b2da50e1f this.src = '#'; this.src = src; } }); }; })(jQuery); /* CJ Object Scaler */ (function ($) { jQuery.fn.cjObjectScaler = function (options) { /* user variables (settings) ***************************************/ var settings = { // must be a jQuery object method: "fill", // the parent object to scale our object into destElem: null, // fit|fill fade: 0 // if positive value, do hide/fadeIn }; /* system variables ***************************************/ var sys = { // function parameters version: '2.1.1', elem: null }; /* scale the image ***************************************/ function scaleObj(obj) { // declare some local variables var destW = jQuery(settings.destElem).width(), destH = jQuery(settings.destElem).height(), ratioX, ratioY, scale, newWidth, newHeight, borderW = parseInt(jQuery(obj).css("borderLeftWidth"), 10) + parseInt(jQuery(obj).css("borderRightWidth"), 10), borderH = parseInt(jQuery(obj).css("borderTopWidth"), 10) + parseInt(jQuery(obj).css("borderBottomWidth"), 10), objW = jQuery(obj).width(), objH = jQuery(obj).height(); // check for valid border values. IE takes in account border size when calculating width/height so just set to 0 borderW = isNaN(borderW) ? 0 : borderW; borderH = isNaN(borderH) ? 0 : borderH; // calculate scale ratios ratioX = destW / jQuery(obj).width(); ratioY = destH / jQuery(obj).height(); // Determine which algorithm to use if (!jQuery(obj).hasClass("cf_image_scaler_fill") && (jQuery(obj).hasClass("cf_image_scaler_fit") || settings.method === "fit")) { scale = ratioX < ratioY ? ratioX : ratioY; } else if (!jQuery(obj).hasClass("cf_image_scaler_fit") && (jQuery(obj).hasClass("cf_image_scaler_fill") || settings.method === "fill")) { scale = ratioX < ratioY ? ratioX : ratioY; } // calculate our new image dimensions newWidth = parseInt(jQuery(obj).width() * scale, 10) - borderW; newHeight = parseInt(jQuery(obj).height() * scale, 10) - borderH; // Set new dimensions & offset jQuery(obj).css({ "width": newWidth + "px", "height": newHeight + "px"//, // "position": "absolute", // "top": (parseInt((destH - newHeight) / 2, 10) - parseInt(borderH / 2, 10)) + "px", // "left": (parseInt((destW - newWidth) / 2, 10) - parseInt(borderW / 2, 10)) + "px" }).attr({ "width": newWidth, "height": newHeight }); // do our fancy fade in, if user supplied a fade amount if (settings.fade > 0) { jQuery(obj).fadeIn(settings.fade); } } /* set up any user passed variables ***************************************/ if (options) { jQuery.extend(settings, options); } /* main ***************************************/ return this.each(function () { sys.elem = this; // if they don't provide a destObject, use parent if (settings.destElem === null) { settings.destElem = jQuery(sys.elem).parent(); } // need to make sure the user set the parent's position. Things go bonker's if not set. // valid values: absolute|relative|fixed if (jQuery(settings.destElem).css("position") === "static") { jQuery(settings.destElem).css({ "position": "relative" }); } // if our object to scale is an image, we need to make sure it's loaded before we continue. if (typeof sys.elem === "object" && typeof settings.destElem === "object" && typeof settings.method === "string") { // if the user supplied a fade amount, hide our image if (settings.fade > 0) { jQuery(sys.elem).hide(); } if (sys.elem.nodeName === "IMG") { // to fix the weird width/height caching issue we set the image dimensions to be auto; jQuery(sys.elem).width("auto"); jQuery(sys.elem).height("auto"); // wait until the image is loaded before scaling jQuery(sys.elem).imagesLoaded(function () { scaleObj(this); }); } else { scaleObj(jQuery(sys.elem)); } } else { console.debug("CJ Object Scaler could not initialize."); return; } }); }; })(jQuery);

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  • Securing WebSocket applications on Glassfish

    - by Pavel Bucek
    Today we are going to cover deploying secured WebSocket applications on Glassfish and access to these services using WebSocket Client API. WebSocket server application setup Our server endpoint might look as simple as this: @ServerEndpoint("/echo") public class EchoEndpoint { @OnMessage   public String echo(String message) {     return message + " (from your server)";   } } Everything else must be configured on container level. We can start with enabling SSL, which will require web.xml to be added to your project. For starters, it might look as following: <web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee">   <security-constraint>     <web-resource-collection>       <web-resource-name>Protected resource</web-resource-name>       <url-pattern>/*</url-pattern>       <http-method>GET</http-method>     </web-resource-collection>     <!-- https -->     <user-data-constraint>       <transport-guarantee>CONFIDENTIAL</transport-guarantee>     </user-data-constraint>   </security-constraint> </web-app> This is minimal web.xml for this task - web-resource-collection just defines URL pattern and HTTP method(s) we want to put a constraint on and user-data-constraint defines that constraint, which is in our case transport-guarantee. More information about these properties and security settings for web application can be found in Oracle Java EE 7 Tutorial. I have some simple webpage attached as well, so I can test my endpoint right away. You can find it (along with complete project) in Tyrus workspace: [webpage] [whole project]. After deploying this application to Glassfish Application Server, you should be able to hit it using your favorite browser. URL where my application resides is https://localhost:8181/sample-echo-https/ (may be different, depends on other configuration). My browser warns me about untrusted certificate (I use what freshly built Glassfish provides - self signed certificates) and after adding an exception for this site, I can see my webpage and I am able to securely connect to wss://localhost:8181/sample-echo-https/echo. WebSocket client Already mentioned demo application also contains test client, but execution of this is skipped for normal build. Reason for this is that Glassfish uses these self-signed "random" untrusted certificates and you are (in most cases) not able to connect to these services without any additional settings. Creating test WebSocket client is actually quite similar to server side, only difference is that you have to somewhere create client container and invoke connect with some additional info. Java API for WebSocket allows you to use annotated and programmatic way to construct endpoints. Server side shows the annotated case, so let's see how the programmatic approach will look. final WebSocketContainer client = ContainerProvider.getWebSocketContainer(); client.connectToServer(new Endpoint() {   @Override   public void onOpen(Session session, EndpointConfig EndpointConfig) {     try {       // register message handler - will just print out the       // received message on standard output.       session.addMessageHandler(new MessageHandler.Whole<String>() {       @Override         public void onMessage(String message) {          System.out.println("### Received: " + message);         }       });       // send a message       session.getBasicRemote().sendText("Do or do not, there is no try.");     } catch (IOException e) {       // do nothing     }   } }, ClientEndpointConfig.Builder.create().build(),    URI.create("wss://localhost:8181/sample-echo-https/echo")); This client should work with some secured endpoint with valid certificated signed by some trusted certificate authority (you can try that with wss://echo.websocket.org). Accessing our Glassfish instance will require some additional settings. You can tell Java which certificated you trust by adding -Djavax.net.ssl.trustStore property (and few others in case you are using linked sample). Complete command line when you are testing your service might need to look somewhat like: mvn clean test -Djavax.net.ssl.trustStore=$AS_MAIN/domains/domain1/config/cacerts.jks\ -Djavax.net.ssl.trustStorePassword=changeit -Dtyrus.test.host=localhost\ -DskipTests=false Where AS_MAIN points to your Glassfish instance. Note: you might need to setup keyStore and trustStore per client instead of per JVM; there is a way how to do it, but it is Tyrus proprietary feature: http://tyrus.java.net/documentation/1.2.1/user-guide.html#d0e1128. And that's it! Now nobody is able to "hear" what you are sending to or receiving from your WebSocket endpoint. There is always room for improvement, so the next step you might want to take is introduce some authentication mechanism (like HTTP Basic or Digest). This topic is more about container configuration so I'm not going to go into details, but there is one thing worth mentioning: to access services which require authorization, you might need to put this additional information to HTTP headers of first (Upgrade) request (there is not (yet) any direct support even for these fundamental mechanisms, user need to register Configurator and add headers in beforeRequest method invocation). I filed related feature request as TYRUS-228; feel free to comment/vote if you need this functionality.

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  • Managed Service Architectures Part I

    - by barryoreilly
    Instead of thinking about service oriented architecture, a concept that is continually defined, redefined, abused and mistreated, perhaps it is time to drop the acronym and consider what we actually need to get the job done.   ‘Pure’ SOA involves the modeling of an organisation’s processes, the so called ‘Top Down’ approach, followed by the implementation of these processes as services.     Another approach, more commonly seen in the wild, is the bottom up approach. This usually involves services that simply start popping up in the organization, and SOA in this case is often just an attempt to rein in these services. Such projects, although described as SOA projects for a variety of reasons, have clearly little relation to process driven architecture. Much has been written about these two approaches, with many deciding that a hybrid of both methods is needed to succeed with SOA.   These hybrid methods are a sensible compromise, but one gets the feeling that there is too much focus on ‘Succeeding with SOA’. Organisations who focus too much on bottom up development, or who waste too much time and money on top down approaches that don’t produce results, are often recommended to attempt an ‘agile’(Erl) or ‘middle-out’ (Microsoft) approach in order to succeed with SOA.  The problem with recommending this approach is that, in most cases, succeeding with SOA isn’t the aim of the project. If a project is started with the simple aim of ‘Succeeding with SOA’ then the reasons for the projects existence probably need to be questioned.   There are a number of things we can be sure of: ·         An organisation will have a number of disparate IT systems ·         Some of these systems will have redundant data and functionality ·         Integration will give considerable ROI ·         Integration will already be under way. ·         Services will already exist in the organisation ·         These services will be inconsistent in their implementation and in their governance   So there are three goals here: 1.       Alignment between the business and IT 2.     Integration of disparate systems 3.     Management of services.   2 and 3 are going to happen,  in fact they must happen if any degree of return is expected from the IT department. Ignoring 1 is considered a typical mistake in SOA implementations, as it ignores the business implications. However, the business implication of this approach is the money saved in more efficient IT processes. 2 and 3 are ongoing, and they will continue happening, even if a large project to produce a SOA metamodel is started. The result will then be an unstructured cackle of services, and a metamodel that is already going out of date. So we get stuck in and rebuild our services so that they match the metamodel, with the far reaching consequences that this will have on all our LOB systems are current. Lets imagine that this actually works ( how often do we rip and replace working software because it doesn't fit a certain pattern? Never -that's the point of integration), we will now be working with a metamodel that is out of date, and most likely incomplete if the organisation is large.      Accepting that an object can have more than one model over time, with perhaps more than one model being  at any given time will help us realise the limitations of the top down model. It is entirely normal , and perhaps necessary, for an organisation to be able to view an entity from different perspectives.   So, instead of trying to constantly force these goals in a straight line, why not let them happen in parallel, and manage the changes in each layer.     If  company A has chosen to model their business processes and create a business architecture, there will be a reason behind this. Often the aim is to make the business more flexible and able to cope with change, through alignment between the business and the IT department.   If company B’s IT department recognizes the problem of wild services springing up everywhere, and decides to do something about it, by designing a platform and processes for the introduction of services, is this not a valid approach?   With the hybrid approach, it is recommended that company A begin deploying services as quickly as possible. Based on models that are clearly incomplete, and which will therefore change rapidly and often in the near future. Natural business evolution will also mean that the models can be guaranteed to change in the not so near future. To ‘Succeed with SOA’ Company B needs to go back to the drawing board and start modeling processes and objects. So, in effect, we are telling business analysts to start developing code based on a model they are unsure of, and telling programmers to ignore the obvious and growing problems in their IT department and start drawing lines and boxes.     Could the problem be that there are two different problem domains? And the whole concept of SOA as it being described by clever salespeople today creates an example of oft dreaded ‘tight coupling’ between these two domains?   Could it be that we have taken two large problem areas, and bundled the solution together in order to create a magic bullet? And then convinced ourselves that the bullet actually exists?   Company A wants to have a closer relationship between the business and its IT department, in order to become a more flexible organization. Company B wants to decrease the maintenance costs of its IT infrastructure. If both companies focus on succeeding with SOA, then they aren’t focusing on their actual goals.   If Company A starts building services from incomplete models, without a gameplan, they will end up in the same situation as company B, with wild services. If company B focuses on modeling, they could easily end up with the same problems as company A.   Now we have two companies, who a short while ago had one problem each, that now have two problems each. This has happened because of a focus on ‘Succeeding with SOA’, rather than solving the problem at hand.   This is not to suggest that the two problem domains are unrelated, a strategy that encompasses both will obviously be good for the organization. But only if the organization realizes this and can develop such a strategy. This strategy cannot be bought in a box.       Anyone who has worked with SOA for a while will be used to analyzing the solutions to a problem and judging the solution’s level of coupling. If we have two applications that each perform separate functions, but need to communicate with each other, we create a integration layer between them, perhaps with a service, but we do all we can to reduce the dependency between the two systems. Using the same approach, we can separate the modeling (business architecture) and the service hosting (technical architecture).     The business architecture describes the processes and business objects in the business domain.   The technical architecture describes the hosting and management and implementation of services.   The glue that binds these together, the integration layer in our analogy, is the service contract, where the operations map the processes to their technical implementation, and the messages map business concepts to software objects in the implementation.   If we reduce the coupling between these layers, we should be able to allow developers to develop services, and business analysts to develop models, without the changes rippling through from one side to the other.   This would allow company A to carry on modeling, and company B to develop a service platform, each achieving their intended goal, without necessarily creating the problems seen in pure top down or bottom up approaches. Company B could then at a later date map their service infrastructure to a unified model, and company A could carry on modeling, insulating deployed services from changes in the ongoing modeling.   How do we do this?  The concept of service virtualization has been around for a while, and is instantly realizable in Microsoft’s Managed Services Engine. Here we can create a layer of virtual services, which represent the business analyst’s view, presenting uniform contracts to the outside world. These services can then transform and route messages to the actual service implementations. I like to think of the virtual services with their beautifully modeled interfaces as ‘SOA services’, and the implementations as simple integration ‘adapter’ services providing an interface to a technical implementation. The Managed Services Engine also provides policy based control over services, regardless of where they are deployed, simplifying handling of security, logging, exception handling etc.   This solves a big problem. The pressure to deliver services quickly is always there in projects. It is very important to quickly show value when implementing service architectures. There is also pressure to deliver quality, and you can’t easily do both at the same time. This approach allows quick delivery with quality increasing over time, allowing modeling and service development to occur in parallel and independent of each other. The link between business modeling and service implementation is not one that is obvious to many organizations, and requires a certain maturity to realize and drive forward. It is also completely possible that a company can benefit from one without the other, even if this approach is frowned upon today, there are many companies doing so and seeing ROI.   Of course there are disadvantages to this. The biggest one being the transformations necessary between the virtual interfaces and the service implementations. Bad choices in developing the services in the service implementation could mean that it is impossible to map the modeled processes to the implementation with redevelopment of the service. In many cases the architect will not have a choice here anyway, as proprietary systems are often delivered with predeveloped services. The alternative is to wait until the model is finished and then build the service according the model. However, if that approach worked we wouldn’t be having this discussion! And even when it does work, natural business evolution will mean that the two concepts (model and implementation) will immediately start to drift away from each other, so coupling them tightly together so that they are forever bound to the model that only applies at the time of the modeling work will not really achieve a great deal. Architecture is all about trade offs, and here a choice has to be made. The choice is between something will initially be of low quality but will work, or something that may well be impossible to achieve in most situations.         In conclusion, top-down is a natural approach for business analysts, and bottom-up  is a natural approach for developers. Instead of trying to force something on both that neither want, and which has not shown itself to be successful,  why not let them get on with their jobs, and let an enterprise architect coordinate the processes?

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  • Why does this game loop stop my process from responding?

    - by Ben
    I implemented a fixed time step loop for my C# game. All it does at the moment is make a square bounce around the screen. The problem I'm having is that when I execute the program, I can't close it from the window's close button and the cursor is stuck on the "busy" icon. I have to go into Visual Studio and stop the program manually. Here's the loop at the moment: public void run() { int updates = 0; int frames = 0; double msPerTick = 1000.0 / 60.0; double threshhold = 0; long lastTime = getCurrentTime(); long lastTimer = getCurrentTime(); while (true) { long currTime = getCurrentTime(); threshhold += (currTime - lastTime) / msPerTick; lastTime = currTime; while (threshhold >= 1) { update(); updates++; threshhold -= 1; } this.Refresh(); frames++; if ((getCurrentTime() - lastTimer) >= 1000) { this.Text = updates + " updates and " + frames + " frames per second"; updates = 0; frames = 0; lastTimer += 1000; } } } Why is this happening?

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  • GetContactList stops reporting collisions on welded bodies

    - by Henrique Jung
    I have some strange problem with my game which uses Box2D as physics engine and I'm out of ideas on what I can do to solve it. My game is a class assignment where I need to build a simple game where the main character moves in a 2D environment while square blocks comes from below him. Each time a collision occurs, that block is attached to the character using a weld joint, when three blocks of the same colors are together, they annihilate themselves(an effect similar to Bejeweled). I'm using a recursive function to iterate through all the attached blocks of a given block to see if there are enough blocks for them to be deleted. I'm using GetContactList function to iterate through the list of contacts to see which blocks are adjacent to each other. The results are quite disappointing, the blocks only get annihilated in few cases. After a lot of debugging, I found the issue, but I still don't know how to solve. My issue is: after some time, GetContactList STOPS returning contacts (return NULL) to blocks that were already attached for some time. I spent some time reading the Box2D manual as well as some tutorials and still didn't find any clue of what is happening. Below there's some simplified version of the code that I wrote. for(int a = 0; a < blocksList.size(); a++) { blocksList[a].BuildConnections(); } And on BuildConnections b2ContactEdge* edge = body->GetContactList(); while(edge != NULL) { if (long_check_to_see_if_there's_a_block_nearby) { // add itself to the list to be anihilated globalList.push_back(this); //if there's, call BuildConnections again on the adjacent block adjacentBody->GetUserData()->BuildConnections; } edge = edge->next; } I know that there's another issue related to circular inclusions, but I fairly sure that this problem isn't causing the problem with the collisions. You can download my entire code from this page if you'd like http://code.google.com/p/fellz/source/list

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  • Meaning of offset in pygame Mask.overlap methods

    - by Alan
    I have a situation in which two rectangles collide, and I have to detect how much did they collide so so I can redraw the objects in a way that they are only touching each others edges. It's a situation in which a moving ball should hit a completely unmovable wall and instantly stop moving. Since the ball sometimes moves multiple pixels per screen refresh, it it possible that it enters the wall with more that half its surface when the collision is detected, in which case i want to shift it position back to the point where it only touches the edges of the wall. Here is the conceptual image it: I decided to implement this with masks, and thought that i could supply the masks of both objects (wall and ball) and get the surface (as a square) of their intersection. However, there is also the offset parameter which i don't understand. Here are the docs for the method: Mask.overlap Returns the point of intersection if the masks overlap with the given offset - or None if it does not overlap. Mask.overlap(othermask, offset) -> x,y The overlap tests uses the following offsets (which may be negative): +----+----------.. |A | yoffset | +-+----------.. +--|B |xoffset | | : :

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  • Prim's MST algorithm implementation with Java

    - by user1290164
    I'm trying to write a program that'll find the MST of a given undirected weighted graph with Kruskal's and Prim's algorithms. I've successfully implemented Kruskal's algorithm in the program, but I'm having trouble with Prim's. To be more precise, I can't figure out how to actually build the Prim function so that it'll iterate through all the vertices in the graph. I'm getting some IndexOutOfBoundsException errors during program execution. I'm not sure how much information is needed for others to get the idea of what I have done so far, but hopefully there won't be too much useless information. This is what I have so far: I have a Graph, Edge and a Vertex class. Vertex class mostly just an information storage that contains the name (number) of the vertex. Edge class can create a new Edge that has gets parameters (Vertex start, Vertex end, int edgeWeight). The class has methods to return the usual info like start vertex, end vertex and the weight. Graph class reads data from a text file and adds new Edges to an ArrayList. The text file also tells us how many vertecis the graph has, and that gets stored too. In the Graph class, I have a Prim() -method that's supposed to calculate the MST: public ArrayList<Edge> Prim(Graph G) { ArrayList<Edge> edges = G.graph; // Copies the ArrayList with all edges in it. ArrayList<Edge> MST = new ArrayList<Edge>(); Random rnd = new Random(); Vertex startingVertex = edges.get(rnd.nextInt(G.returnVertexCount())).returnStartingVertex(); // This is just to randomize the starting vertex. // This is supposed to be the main loop to find the MST, but this is probably horribly wrong.. while (MST.size() < returnVertexCount()) { Edge e = findClosestNeighbour(startingVertex); MST.add(e); visited.add(e.returnStartingVertex()); visited.add(e.returnEndingVertex()); edges.remove(e); } return MST; } The method findClosesNeighbour() looks like this: public Edge findClosestNeighbour(Vertex v) { ArrayList<Edge> neighbours = new ArrayList<Edge>(); ArrayList<Edge> edges = graph; for (int i = 0; i < edges.size() -1; ++i) { if (edges.get(i).endPoint() == s.returnVertexID() && !visited(edges.get(i).returnEndingVertex())) { neighbours.add(edges.get(i)); } } return neighbours.get(0); // This is the minimum weight edge in the list. } ArrayList<Vertex> visited and ArrayList<Edges> graph get constructed when creating a new graph. Visited() -method is simply a boolean check to see if ArrayList visited contains the Vertex we're thinking about moving to. I tested the findClosestNeighbour() independantly and it seemed to be working but if someone finds something wrong with it then that feedback is welcome also. Mainly though as I mentioned my problem is with actually building the main loop in the Prim() -method, and if there's any additional info needed I'm happy to provide it. Thank you. Edit: To clarify what my train of thought with the Prim() method is. What I want to do is first randomize the starting point in the graph. After that, I will find the closest neighbor to that starting point. Then we'll add the edge connecting those two points to the MST, and also add the vertices to the visited list for checking later, so that we won't form any loops in the graph. Here's the error that gets thrown: Exception in thread "main" java.lang.IndexOutOfBoundsException: Index: 0, Size: 0 at java.util.ArrayList.rangeCheck(Unknown Source) at java.util.ArrayList.get(Unknown Source) at Graph.findClosestNeighbour(graph.java:203) at Graph.Prim(graph.java:179) at MST.main(MST.java:49) Line 203: return neighbour.get(0); in findClosestNeighbour() Line 179: Edge e = findClosestNeighbour(startingVertex); in Prim()

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  • Why does my system use so much cache?

    - by Dave M G
    Previously, on my desktop computer running Ubuntu 14.04, I had 4GB RAM, which I thought should be plenty. However, after being on for a while, my computer would seem to get slow. I have a system resource monitor app in my Gnome panel, which I assume represents the available RAM (?). It shows a dark green area as being "Memory", and a light green area as "Cache". The "Cache" would slowly grow until it filled the whole graph, and then programs would get slow to load, or it would take a while to switch programs. I could alleviate the problem somewhat with this command, but eventually the computer cache fills up again, so it's only a bandaid: sudo sh -c "sync; echo 3 > /proc/sys/vm/drop_caches" So, I figured I'd get more RAM, so I replaced one 2GB stick with an 8GB stick, and now I have 10 GB ram. And my "cache" still slowly maxes out and my computer slows as a result. Also, sometimes the computer starts out with "cache" maxed when I first boot and log in. Not always though, I don't know if there's a pattern that determines why it happens. Why is Ubuntu using up so much cache? Is 10GB not enough for Ubuntu? Here's what my system monitor looks like in my Gnome panel. The middle square shows RAM usage. The light green area is the "cache": This is my memory and swap history, which doesn't seem to include any information about "cache". I realize at this point I'm not totally clear on the difference between "cache" and "swap":

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  • ZIPLIB problem on opening zip files

    - by Ahmet vardar
    I am using this class to create zip <?php // vim: expandtab sw=4 ts=4 sts=4: class zipfile { var $datasec = array(); var $ctrl_dir = array(); var $eof_ctrl_dir = "\x50\x4b\x05\x06\x00\x00\x00\x00"; var $old_offset = 0; function unix2DosTime($unixtime = 0) { $timearray = ($unixtime == 0) ? getdate() : getdate($unixtime); if ($timearray['year'] < 1980) { $timearray['year'] = 1980; $timearray['mon'] = 1; $timearray['mday'] = 1; $timearray['hours'] = 0; $timearray['minutes'] = 0; $timearray['seconds'] = 0; } // end if return (($timearray['year'] - 1980) << 25) | ($timearray['mon'] << 21) | ($timearray['mday'] << 16) | ($timearray['hours'] << 11) | ($timearray['minutes'] << 5) | ($timearray['seconds'] >> 1); } // end of the 'unix2DosTime()' method function addFile($data, $name, $time = 0) { $name = str_replace('\\', '/', $name); $dtime = dechex($this->unix2DosTime($time)); $hexdtime = '\x' . $dtime[6] . $dtime[7] . '\x' . $dtime[4] . $dtime[5] . '\x' . $dtime[2] . $dtime[3] . '\x' . $dtime[0] . $dtime[1]; eval('$hexdtime = "' . $hexdtime . '";'); $fr = "\x50\x4b\x03\x04"; $fr .= "\x14\x00"; // ver needed to extract $fr .= "\x00\x00"; // gen purpose bit flag $fr .= "\x08\x00"; // compression method $fr .= $hexdtime; // last mod time and date // "local file header" segment $unc_len = strlen($data); $crc = crc32($data); $zdata = gzcompress($data); $zdata = substr(substr($zdata, 0, strlen($zdata) - 4), 2); // fix crc bug $c_len = strlen($zdata); $fr .= pack('V', $crc); // crc32 $fr .= pack('V', $c_len); // compressed filesize $fr .= pack('V', $unc_len); // uncompressed filesize $fr .= pack('v', strlen($name)); // length of filename $fr .= pack('v', 0); // extra field length $fr .= $name; // "file data" segment $fr .= $zdata; // "data descriptor" segment (optional but necessary if archive is not // served as file) $fr .= pack('V', $crc); // crc32 $fr .= pack('V', $c_len); // compressed filesize $fr .= pack('V', $unc_len); // uncompressed filesize // add this entry to array $this -> datasec[] = $fr; // now add to central directory record $cdrec = "\x50\x4b\x01\x02"; $cdrec .= "\x00\x00"; // version made by $cdrec .= "\x14\x00"; // version needed to extract $cdrec .= "\x00\x00"; // gen purpose bit flag $cdrec .= "\x08\x00"; // compression method $cdrec .= $hexdtime; // last mod time & date $cdrec .= pack('V', $crc); // crc32 $cdrec .= pack('V', $c_len); // compressed filesize $cdrec .= pack('V', $unc_len); // uncompressed filesize $cdrec .= pack('v', strlen($name) ); // length of filename $cdrec .= pack('v', 0 ); // extra field length $cdrec .= pack('v', 0 ); // file comment length $cdrec .= pack('v', 0 ); // disk number start $cdrec .= pack('v', 0 ); // internal file attributes $cdrec .= pack('V', 32 ); // external file attributes - 'archive' bit set $cdrec .= pack('V', $this -> old_offset ); // relative offset of local header $this -> old_offset += strlen($fr); $cdrec .= $name; // optional extra field, file comment goes here // save to central directory $this -> ctrl_dir[] = $cdrec; } // end of the 'addFile()' method function file() { $data = implode('', $this -> datasec); $ctrldir = implode('', $this -> ctrl_dir); return $data . $ctrldir . $this -> eof_ctrl_dir . pack('v', sizeof($this -> ctrl_dir)) . // total # of entries "on this disk" pack('v', sizeof($this -> ctrl_dir)) . // total # of entries overall pack('V', strlen($ctrldir)) . // size of central dir pack('V', strlen($data)) . // offset to start of central dir "\x00\x00"; // .zip file comment length } // end of the 'file()' method function addFiles($files ) { foreach($files as $file) { if (is_file($file)) //directory check { $data = implode("",file($file)); $this->addFile($data,$file); } } } function output($file) { $fp=fopen($file,"w"); fwrite($fp,$this->file()); fclose($fp); } } // end of the 'zipfile' class ?> It creates zip file but when i try to open it on Mac os x snow leopard and windows 7, it doesnt open. on mac i had this error: Error 1: operation not permitted Any idea ? thanks

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  • Roll a DIY Camera Jib for $25

    - by Jason Fitzpatrick
    Video gear is expensive; save your pennies by building a DIY camera jib for smooth camera movement on a budget. Over at Oliva tech they explain just how few parts you need to build their DIY jib: The guys here at the studio mocked up a simple DIY jib that is not only ridiculously inexpensive to piece together, but also very straight forward. The point of this jib was to get a very wide range of motion from top to bottom with only a few feet of 0.75? square tube, 1? angled aluminum, 1/4? nuts and bolts, and nylon washers is all you’ll need to put the jib together. This light weight jib can be used on small portable tripods, but will require a fluid head for panning left and right. Hit up the link below for a detailed parts list and build guide. How to Make a DIY Camera Jib [via Make] How to Own Your Own Website (Even If You Can’t Build One) Pt 1 What’s the Difference Between Sleep and Hibernate in Windows? Screenshot Tour: XBMC 11 Eden Rocks Improved iOS Support, AirPlay, and Even a Custom XBMC OS

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  • ORA-600 Troubleshooting

    - by [email protected]
    Have you observed an ORA-0600 or ORA-07445 reported in your alert log? The ORA-600 error is the generic internal error number for Oracle program exceptions. It indicates that a process has encountered a low-level, unexpected condition. The ORA-600 error statement includes a list of arguments in square brackets: ORA 600 "internal error code, arguments: [%s], [%s],[%s], [%s], [%s]" The first argument is the internal message number or character string. This argument and the database version number are critical in identifying the root cause and the potential impact to your system.  The remaining arguments in the ORA-600 error text are used to supply further information (e.g. values of internal variables etc).   Looking for the best way to diagnose? There is an ORA-600 Troubleshooter Tool available in My Oracle Support.  This tool will lead you to applicable content in My Oracle Support on the problem and can be used to investigate the problem with argument data from the error message or you can pull out the first 10 or 15 stack pointers from the associated trace file to match up against known bugs. Note 153788.1 ORA-600/ORA-7445 TroubleshooterNote 1082674.1 A Video To Demonstrate The Usage Of The ORA-600/ORA-7445 Lookup Tool [Video] Also, take a quick look at the Master Note for Diagnosing ORA-600 ( MasterNoteORA600.docx) for some tips on diagnosing.

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  • 2D/Isometric map algorithm

    - by Icarus Cocksson
    First of all, I don't have much experience on game development but I do have experience on development. I do know how to make a map, but I don't know if my solution is a normal or a hacky solution. I don't want to waste my time coding things, and realise they're utterly crap and lose my motivation. Let's imagine the following map. (2D - top view - A square) X: 0 to 500 Y: 0 to 500 My character currently stands at X:250,Y:400, somewhere near center of 100px above bottom and I can control him with my keyboard buttons. LEFT button does X--, UP button does Y-- etc. This one is kid's play. I'm asking this because I know there are some engines that automate this task. For example, games like Diablo 3 uses an engine. You can pretty much drag drop a rock to map, and it is automatically being placed here - making player unable to pass through/detect the collision. But what the engine exactly does in the background? Generates a map like mine, places a rock at the center, and checks it like: unmovableObjects = array('50,50'); //we placed a rock at 50,50 location if(Map.hasUnmovableObject(CurrentPlayerX, CurrentPlayerY)) { //unable to move } else { //able to move } My question is: Is this how 2D/Isometric maps are being generated or there is a different and more complex logic behind them?

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