You should raise NotImplementedError

    raise NotImplementedError

[ruby-doc][1]

  [1]: http://ruby-doc.org/core-2.3.0/NotImplementedError.html

You may use the [todonotes-gem][1]

There is a [documentation][2] with some examples.


It doesn&#39;t implement an exception, but a logging mechanism and a possibility for temporary  solutions.

  [1]: https://rubygems.org/gems/todonotes
  [2]: http://gems.rubypla.net/todonotes/0.1.1/

Looks like the original answer, which suggested raising `NotImplementedError`, was removed. I&#39;ll take a crack at it: write documentation. 

Don&#39;t add code that&#39;s just a placeholder. You wouldn&#39;t want folks coding against that API so don&#39;t even give them a chance (yourself included). Instead, document the road map you are currently planning on in the class and/or README. Then be open to it changing. Odds are by the time you get around to solving whatever problem is in the road map you&#39;ll have new thoughts on what is the appropriate solution. I think this is the right course of action in any language/framework, but I think Ruby in particular encourages us to not write code that you don&#39;t plan on having executed.

Do not mention the unimplemented methods in the documents, or mention that they are not implemented yet. That is all.

Ruby will raise a `NoMethodError` for you anyway, when calling a non-existing method. That should be good enough for most cases.

I am writing a small Java program to get the amount of results for a given Google search term. For some reason, in Java I am getting a 403 Forbidden but I am getting the right results in web browsers. Code:

    import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStreamReader;
    import java.net.URL;
    
    
    public class DataGetter {
    
    	public static void main(String[] args) throws IOException {
    		getResultAmount(&quot;test&quot;);
    	}
    	
    	private static int getResultAmount(String query) throws IOException {
    		BufferedReader r = new BufferedReader(new InputStreamReader(new URL(&quot;https://www.google.com/search?q=&quot; + query).openConnection()
    				.getInputStream()));
            String line;
            String src = &quot;&quot;;
            while ((line = r.readLine()) != null) {
            	src += line;
            }
            System.out.println(src);
            return 1;
    	}
    
    }

And the error:

    Exception in thread &quot;main&quot; java.io.IOException: Server returned HTTP response code: 403 for URL: https://www.google.com/search?q=test
    	at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
    	at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(Unknown Source)
    	at DataGetter.getResultAmount(DataGetter.java:15)
    	at DataGetter.main(DataGetter.java:10)

Why is it doing this?

403 Forbidden with Java but not web browser?

What&#39;s the difference? Which is preferred, or when should I use each one respectively?

EXIT_FAILURE vs exit(1)?

In the initial drafting of a new gem I need to leave some method implementations empty ( to be implemented in the next )

Therefore, I would like to signal a &quot;not implemented yet&quot; exception

I&#39;m wondering if there is a *best practice* or *standard conventions* specific to the Ruby language to code this kind of placeholder / exception. 

i.e: something like: 

 - [UnsupportedOperationException](http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/UnsupportedOperationException.html) in Java
 - [NotImplementedException](http://msdn.microsoft.com/en-us/library/system.notimplementedexception.aspx) in .Net Framework (C#)

How to signal &quot;not implemented yet&quot;?

In the initial drafting of a new gem I need to leave some method implementations empty ( to be implemented in the next )
Therefore, I would like to signal a "not implemented yet" exception
I'm wondering if there is a best practice or standard conventions specific to the Ruby language to code this kind of placeholder / exception.
i.e: something like:
<ul>
<li><a href="http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/UnsupportedOperationException.html" target="_blank" rel="noopener noreferrer">UnsupportedOperationException</a> in Java</li>
<li><a href="http://msdn.microsoft.com/en-us/library/system.notimplementedexception.aspx" target="_blank" rel="noopener noreferrer">NotImplementedException</a> in .Net Framework (C#)</li>
</ul>

On server-side using Sinatra with a `stream` block.

    get &#39;/stream&#39;, :provides =&gt; &#39;text/event-stream&#39; do
      stream :keep_open do |out|
        connections &lt;&lt; out
        out.callback { connections.delete(out) }
      end
    end

On client side:

    var es = new EventSource(&#39;/stream&#39;);
    es.onmessage = function(e) { $(&#39;#chat&#39;).append(e.data + &quot;\n&quot;) };

When i using app directly, via `http://localhost:9292/`, everything works perfect. The connection is persistent and all messages are passed to all clients.

However when it goes through Nginx, `http://chat.dev`, the connection are dropped and a reconnection fires every second or so.

Nginx setup looks ok to me:

    upstream chat_dev_upstream {
      server 127.0.0.1:9292;
    }

    server {
      listen       80;
      server_name  chat.dev;

      location / {
        proxy_pass http://chat_dev_upstream;
        proxy_buffering off;
        proxy_cache off;
        proxy_set_header Host $host;
      }
    }

Tried `keepalive 1024` in `upstream` section as well as `proxy_set_header Connection keep-alive;`in `location`.

Nothing helps :(

No persistent connections and messages not passed to any clients.





EventSource / Server-Sent Events through Nginx

Can anyone explain to me what the meaning of adding `self` to the method definition is? Is it similar to the `this` keyword in java?  

What does `def self.function` name mean?

What is a good way to extract `filename.jpg` from:

    url = &#39;http://www.example.com/foo/bar/filename.jpg?2384973948743&#39;


I&#39;m using Ruby 1.9.3.

What is a good way to get the filename from a URL in Ruby?

I just want to know whether ruby regex has a not match operator just like `!~` in perl. I feel it&#39;s inconvenient to use `(?!xxx)`or `(?&lt;!xxxx)` because you cannot use regex patterns in the `xxx` part. 

Does Ruby regular expression have a not match operator like &quot;!~&quot; in Perl?

In Java I might do:

    public static void doSomething();

And then I can access the method statically without making an instance:

    className.doSomething(); 

How can I do that in Ruby? this is my class and from my understanding `self.` makes the method static:

    class Ask
    
      def self.make_permalink(phrase)
        phrase.strip.downcase.gsub! /\ +/, &#39;-&#39;
      end
    
    end

But when i try to call:

    Ask.make_permalink(&quot;make a slug out of this line&quot;)

I get:

    undefined method `make_permalink&#39; for Ask:Class

Why is that if i haven&#39;t declared the method to be private?  

 

Ruby: How to make a public static method?

Is it possible to construct a snippet of code in [Java][1] that would make a hypothetical `java.lang.ChuckNorrisException` uncatchable?

Thoughts that came to mind are using for example interceptors or [aspect-oriented programming][2].

  [1]: http://en.wikipedia.org/wiki/Java_%28programming_language%29
  [2]: http://en.wikipedia.org/wiki/Aspect-oriented_programming


Uncatchable ChuckNorrisException

I have the following code:

	catch(Exception ex)
	{
		throw new FatalException(&quot;An error occurred while trying to load the XSLT file.&quot;, ex);
	}

This unfortunately just swallows up the Exception.  I can fix this by doing the following:

	catch(Exception ex)
	{
		throw;
	}

But I would still like to include the custom message for help with event logging.

How do I add this message to the exception without losing any information?  (stack trace/debug symbols, etc.)

How can I add a message to an exception without losing any information in C#?

I&#39;m trying to assert the equality of two `System.Drawing.Size` structures, and I&#39;m getting a format exception instead of the expected assert failure.

    [TestMethod]
    public void AssertStructs()
    {
    	var struct1 = new Size(0, 0);
    	var struct2 = new Size(1, 1);

    	//This throws a format exception, &quot;System.FormatException: Input string was not in a correct format.&quot;
    	Assert.AreEqual(struct1, struct2, &quot;Failed. Expected {0}, actually it is {1}&quot;, struct1, struct2); 

    	//This assert fails properly, &quot;Failed. Expected {Width=0, Height=0}, actually it is {Width=1, Height=1}&quot;.
    	Assert.AreEqual(struct1, struct2, &quot;Failed. Expected &quot; + struct1 + &quot;, actually it is &quot; + struct2); 
    }
    
Is this intended behavior? Am I doing something wrong here?


Why does this assert throw a format exception when comparing structures?

Is there any resource (web or book) describing exception handling / error handling design patterns?

There is a lot of literature on how to write clean code, and there are a lot of books covering design patterns. I have, however, never seen any design pattern covering the issue of where and how best to handle errors and how best to propagate an error appearing in a low-level function up the levels of abstraction.

Design patterns: exception / error handling

Please correct me if this is wrong:  In Java 7&#39;s try-with-resources statement, any exceptions thrown by the resource&#39;s `close()` method must be either declared as thrown by my method or I must wrap the whole try in another `try` which catches any exceptions thrown by `close()`.

If so, I have to wonder if I will make much use of it.  I certainly don&#39;t want to `throw` the exceptions thrown by `close()`, the caller won&#39;t know what to do with that.  And a `try` wrapping another `try` just to handle `close()` would not look very elegant, to me at least.

&lt;b&gt;EDIT:&lt;/b&gt;  I think I accidentally asked two questions, one of which was a duplicate.

Question 1.  Do I have to declare that my method throws the exception from the `close()` method or wrap the try-with-resources in another try?  (Not answered in proposed duplicate.)

Question 2.  Is there a way to close the resource silently?  (Clearly a duplicate, so I am taking that sentence out of the question.  Hopefully this makes the question satisfactorily unique.)

Try-with-resources: Must I throw or catch the close() method&#39;s exceptions?

I&#39;m a fairly rookie C++ programmer, but in my limited experience with the language, most standard C++ style guidelines (e.g. [Google C++ Style Guidelines][1]) go against what is implemented in the stl and boost libraries.

For example, class names in the C++ standard library and Boost are always lower case, with underscores separating words (e.g. `std::vector`, `boost::unordered_map`, `std::map::const_iterator`), whereas most style guides I&#39;ve seen for C++ tend towards a CamelCase style (e.g. `TcpConnection` or `Int32`).

The same applies to methods too. The standard library and Boost use the same style for methods and functions as they do for classes (e.g. `std::map&lt;&gt;::get_equal(&quot;foo&quot;)`), whereas most style guides advocate pascalCase or CamelCase.

If we contrast this with a language like Ruby, where most users will adhere to the conventions used in the core libraries, it seems odd that there&#39;d be such a difference between the standard C++ libraries and everyone else&#39;s code.

**Does anyone know why this is?**

EDIT: Just to clarify, I&#39;m talking simply about the superficial textual style (casing, use of underscores, etc) rather than actual implementation style.

  [1]: https://google.github.io/styleguide/cppguide.html

Why does the STL/Boost C++ coding style differ so much from everyone elses?

Reading online some programmers use `sys.exit`, others use `SystemExit`.  
Sorry for the basic question:

 1. What is the difference?
 2. When do I need to use SystemExit or sys.exit inside a function?

Example

    ref = osgeo.ogr.Open(reference)
    if ref is None:
        raise SystemExit(&#39;Unable to open %s&#39; % reference)

or

    ref = osgeo.ogr.Open(reference)
    if ref is None:
        print(&#39;Unable to open %s&#39; % reference)
        sys.exit(-1)

Python: using sys.exit or SystemExit differences and suggestions

I was thinking: they say if you&#39;re calling destructor manually - you&#39;re doing something wrong. But is it always the case? Are there any counter-examples? Situations where it is neccessary to call it manually or where it is hard/impossible/impractical to avoid it?

Is calling destructor manually always a sign of bad design?

I know there are tools which validate whether your Python code is compliant with PEP8,  for example there is both [an online service](http://pep8online.com/) and [a python module](https://github.com/jcrocholl/pep8/).

However, I cannot find a service or module which can *convert* my Python file to a self-contained, PEP8 valid Python file. Does anyone know if there are any?  
*I assume it&#39;s feasible since PEP8 is all about the appearance of the code, right?*

Tool to convert Python code to be PEP8 compliant

I have a strange habit it seems... according to my co-worker at least. We&#39;ve been working on a small project together. The way I wrote the classes is (simplified example):

    [Serializable()]
    public class Foo
    {
        public Foo()
        { }

        private Bar _bar;

        public Bar Bar
        {
            get
            {
                if (_bar == null)
                    _bar = new Bar();

                return _bar;
            }
            set { _bar = value; }
        }
    }

So, basically, I only initialize any field when a getter is called and the field is still null. I figured this would reduce overload by not initializing any properties that aren&#39;t used anywhere.

ETA: The reason I did this is that my class has several properties that return an instance of another class, which in turn also have properties with yet more classes, and so on. Calling the constructor for the top class would subsequently call all constructors for all these classes, when they are not _always_ all needed.

Are there any objections against this practice, other than personal preference?

UPDATE: I have considered the many differing opinions in regards to this question and I will stand by my accepted answer. However, I have now come to a much better understanding of the concept and I&#39;m able to decide when to use it and when not.

Cons:

- Thread safety issues
- Not obeying a &quot;setter&quot; request when the value passed is null
- Micro-optimizations
- Exception handling should take place in a constructor
- Need to check for null in class&#39; code

Pros:

- Micro-optimizations
- Properties never return null
- Delay or avoid loading &quot;heavy&quot; objects

Most of the cons are not applicable to my current library, however I would have to test to see if the &quot;micro-optimizations&quot; are actually optimizing anything at all.

LAST UPDATE:

Okay, I changed my answer. My original question was whether or not this is a good habit. And I&#39;m now convinced that it&#39;s not. Maybe I will still use it in some parts of my current code, but not unconditionally and definitely not all the time. So I&#39;m going to lose my habit and think about it before using it. Thanks everyone!

Good or bad practice? Initializing objects in getter

As far as I know, one needs to use double or single quotes for fonts if they contain spaces, like:

    font-family: &quot;Times New Roman&quot;, Times; 
    font-family: &#39;Times New Roman&#39;, Times;

But on Google Fonts ([http://www.google.com/webfont][1]), I also see 

    font-family: &#39;Margarine&#39;, cursive;

Some even use it like so:

    font-family: &#39;Margarine&#39;, &#39;Helvetica&#39;, arial;

I find this weird, as the following works as well:

    font-family: Arial, Helvetica, sans-serif;
    font-family: Cambria, serif;

So what is the correct usage of quotes around font names in CSS?


  [1]: http://www.google.com/webfont

Why would font names need quotes?

In Python, I&#39;ve seen two variable values swapped using this syntax:

    left, right = right, left

Is this considered the standard way to swap two variable values or is there some other means by which two variables are by convention most usually swapped?

Is there a standardized method to swap two variables in Python?

When writing a python module and functions in it, I have some &quot;public&quot; functions that are supposed to be exposed to outsiders, but some other &quot;private&quot; functions that are only supposed to be seen and used locally and internally.

I understand in python there is no absolute private functions. But what is the best, most neat, or most used style to distinguish &quot;public&quot; functions and &quot;private&quot; functions?

I list some of the styles I know:

1. use `__all__` in module file to indicate its &quot;public&quot; functions (https://stackoverflow.com/questions/2187583/whats-the-python-all-module-level-variable-for)
2. use underscore at the beginning of name of &quot;private&quot; functions

Is there any other idea or convention that people use?

Thank you very much!


Python &quot;private&quot; function coding convention

NetBeans 7.4 **beta** is currently available for public download, and it introduces a weird warning rule by default:

&gt; Method length is 16 lines (10 allowed)

My question is: Is this an accepted code convention rule, that can be proven somehow, somewhere ? NetBeans support/devs say it&#39;s not a bug, but don&#39;t give a statement why they only allow 10 lines, and where exactly this rule has its origin.

Netbeans 7.4 introduces &quot;10 lines max&quot; per method rule. Where does this rule come from?

I&#39;ve seen this a couple of times recently in *high profile* code, where constant values are defined as variables, named after the value, then used only once. I wondered why it gets done?

E.g. Linux Source (resize.c)

    unsigned five = 5;
    unsigned seven = 7;

E.g. C#.NET Source (Quaternion.cs)

    double zero = 0;
    double one = 1;



Content Type	Original Author	Original Content on Stackoverflow
Question	Franco Rondini	View Question on Stackoverflow
Solution 1 - Ruby	pasha.zhukov	View Answer on Stackoverflow
Solution 2 - Ruby	knut	View Answer on Stackoverflow
Solution 3 - Ruby	Chris	View Answer on Stackoverflow
Solution 4 - Ruby	sawa	View Answer on Stackoverflow
Solution 5 - Ruby	Jörg W Mittag	View Answer on Stackoverflow

How to signal "not implemented yet"?

Ruby Problem Overview

Ruby Solutions

Solution 1 - Ruby

Solution 2 - Ruby

Solution 3 - Ruby

Solution 4 - Ruby

Solution 5 - Ruby

EXIT_FAILURE vs exit(1)?

403 Forbidden with Java but not web browser?

Attributions