Try this:

	//obtain Document somehow, doesn&#39;t matter how
	DocumentBuilder b = DocumentBuilderFactory.newInstance().newDocumentBuilder();
	org.w3c.dom.Document doc = b.parse(new FileInputStream(&quot;page.html&quot;));

	//Evaluate XPath against Document itself
	XPath xPath = XPathFactory.newInstance().newXPath();
	NodeList nodes = (NodeList)xPath.evaluate(&quot;/html/body/p/div[3]/a&quot;,
			doc, XPathConstants.NODESET);
	for (int i = 0; i &lt; nodes.getLength(); ++i) {
		Element e = (Element) nodes.item(i);
	}

With the following `page.html` file:

    &lt;html&gt;
      &lt;head&gt;
      &lt;/head&gt;
      &lt;body&gt;
      &lt;p&gt;
        &lt;div&gt;&lt;/div&gt;
        &lt;div&gt;&lt;/div&gt;
        &lt;div&gt;&lt;a&gt;link&lt;/a&gt;&lt;/div&gt;
      &lt;/p&gt;
      &lt;/body&gt;
    &lt;/html&gt;


I have a couple model classes like so:

    public class MyModelBase
    {
        public string Name { get; set; }
    }

    public class MyModel : MyModelBase
    {
        public string SomeOtherProperty { get; set; }
    }

How can MyModel add a [Required] attribute to the Name property?

How to add attributes to a base class&#39;s properties

Say, I got this code:

    &lt;figure&gt;
     &lt;img src=&quot;bunnyrabbit.jpg&quot; width=&quot;200&quot; height=&quot;150&quot; alt=&quot;An image of a bunny rabbit.&quot; /&gt;
     &lt;figcaption&gt;Bunny rabits are cuddly and fluffy creatures with big ears. They eat carrots.&lt;/figcaption&gt;
    &lt;/figure&gt;

If I don&#39;t use any CSS the figcaption will expand the width of the figure element beyond 200px. How can I prevent this?

I know I can force the text inside the figcaption to wrap by specifying the width of the figure element (`&lt;figure style=&quot;width:200px;&quot;&gt;`) but I don&#39;t really want to use this for each and every image.

How can I make the width of my &lt;figcaption&gt; match the width of the &lt;img&gt; inside its &lt;figure&gt; tag?

How do you quickly locate element/elements via xpath string on a given org.w3c.dom.document? there seems to be no `FindElementsByXpath()` method. For example

    /html/body/p/div[3]/a

I found that recursively iterating through all the child node levels to be quite slow when there are lot of elements of same name. Any suggestions?

I cannot use any parser or library, must work with w3c dom document only.

Java: how to locate an element via xpath string on org.w3c.dom.document

How do you quickly locate element/elements via xpath string on a given org.w3c.dom.document? there seems to be no <code>FindElementsByXpath()</code> method. For example
<pre><code class="hljs language-css">/html/body/p/div[3]/a
</code></pre>
I found that recursively iterating through all the child node levels to be quite slow when there are lot of elements of same name. Any suggestions?
I cannot use any parser or library, must work with w3c dom document only.

I have an integer that was generated from an `android.graphics.Color`

The Integer has a value of -16776961

How do I convert this value into a hex string with the format #RRGGBB

Simply put: I would like to output #0000FF from -16776961

**Note:** I do not want the output to contain an alpha and i have also tried [this example][1] without any success


  [1]: https://stackoverflow.com/questions/4506708/android-convert-color-int-to-hexa-string

How to convert a color integer to a hex String in Android?

I am trying to implement a simple `SQLite` export/import for backup purposes. Export is just a matter of storing a copy of the raw `current.db` file. What I want to do for import is to just delete the old `current.db` file and rename the `imported.db` file to `current.db`. Is this possible? When I try this solution, I get the following error:

    06-30 13:33:38.831: ERROR/SQLiteOpenHelper(23570):
        android.database.sqlite.SQLiteDatabaseCorruptException: error code 11: database disk image is malformed

If I look at the raw database file in a `SQLite` browser it looks fine.

Simple export and import of a SQLite database on Android

I have a String of a date and time like this: `2011-04-15T20:08:18Z`. I don&#39;t know much about date/time formats, but I think, and correct me if I&#39;m wrong, that&#39;s its UTC format. 

My question: what&#39;s the easiest way to parse this to a more normal format, in Java?

How can I parse UTC date/time (String) into something more readable?

I have Java main class, in the class, I start a new thread, in the main, it waits until the thread dies. At some moment, I throw a runtime exception from the thread, but I can&#39;t catch the exception thrown from the thread in the main class. 

Here is the code:

    public class Test extends Thread
    {
      public static void main(String[] args) throws InterruptedException
      {
        Test t = new Test();
        
        try
        {
          t.start();
          t.join();
        }
        catch(RuntimeException e)
        {
          System.out.println(&quot;** RuntimeException from main&quot;);
        }
        
        System.out.println(&quot;Main stoped&quot;);
      }
      
      @Override
      public void run()
      {
        try
        {
          while(true)
          {
            System.out.println(&quot;** Started&quot;);
            
            sleep(2000);
            
            throw new RuntimeException(&quot;exception from thread&quot;);
          }
        }
        catch (RuntimeException e)
        {
          System.out.println(&quot;** RuntimeException from thread&quot;);
          
          throw e;
        } 
        catch (InterruptedException e)
        {
          
        }
      }
    }

Anybody knows why?

How to catch an Exception from a thread

I want to write an `ArrayList&lt;String&gt;` into a text file. 

The `ArrayList` is created with the code:

    ArrayList arr = new ArrayList();
    
    StringTokenizer st = new StringTokenizer(
        line, &quot;:Mode set - Out of Service In Service&quot;);

    while(st.hasMoreTokens()){
        arr.add(st.nextToken());	
    }

How to write an ArrayList of Strings into a text file?

When I discovered that **Node.js was built using the V8 JavaScript engine**, I thought: 

&gt; Great, web scraping will be easier as the page 
  will be rendered like in the browser, with a 
  &quot;native&quot; DOM supporting XPath and any AJAX calls on 
  the page executed.

1. Why doesn&#39;t it have a native DOM when it uses the same JavaScript engine as Chrome?
2. Why doesn&#39;t it have a mode to run JavaScript in retrieved pages?
3. What am I not understanding about JavaScript engines vs the engine in a web browser?

Many thanks!

Why doesn&#39;t Node.js have a native DOM?

Why is the DOMSubtreeModified event [deprecated](http://www.w3.org/TR/DOM-Level-3-Events/#event-type-DOMSubtreeModified) and what are we supposed to use instead?

Why is the DOMSubtreeModified event deprecated in DOM level 3?

I am currently uploading images pasted from the clipboard with the following code:
        
    // Turns out getAsFile will return a blob, not a file
    var blob = event.clipboardData.items[0].getAsFile(), 
        form = new FormData(),
        request = new XMLHttpRequest();
    form.append(&quot;blob&quot;,blob);
    request.open(
                &quot;POST&quot;,
                &quot;/upload&quot;,
                true
            );
    request.send(form);

Turns out the uploaded form field with receive a name similar to this: Blob157fce71535b4f93ba92ac6053d81e3a

Is there any way to set this or receive this file name client side, without doing any server side communication?

How to give a Blob uploaded as FormData a file name?

Since [`element.classList`][1] is not supported in IE 9 and Safari-5, what&#39;s an alternative cross-browser solution?

[No-frameworks][2] please.

Solution **must** work in at least **IE 9**, **Safari 5**, FireFox 4, Opera 11.5, and Chrome.

Related posts (but does not contain solution):

 1. https://stackoverflow.com/questions/2170878/how-to-add-and-remove-css-class

 2. https://stackoverflow.com/questions/5084182/add-and-remove-a-class-with-animation

 3. https://stackoverflow.com/questions/3066692/add-remove-class


  [1]: https://developer.mozilla.org/en-US/docs/Web/API/Element.classList#Browser_compatibility
  [2]: http://vanilla-js.com/

How to add/remove a class in JavaScript?

The web browser DOM has been around since the late &#39;90s, but it remains one of the largest constraints in performance/speed. 

We have some of the world&#39;s most brilliant minds from Google, Mozilla, Microsoft, Opera, W3C, and various other organizations working on web technologies for all of us, so obviously this isn&#39;t a simple &quot;Oh, we didn&#39;t optimize it&quot; issue.

**My question is** if i were to work on the the part of a web browser that deals specifically with this, why would I have such a hard time making it run faster?

**My question is not** asking *[what][1]* makes it slow, it&#39;s asking **[why][2]** hasn&#39;t it become faster?

This seems to be against the grain of what&#39;s going on elsewhere, such as JS engines with performance near that of C++ code.


Example of quick script:

    for (var i=0;i&lt;=10000;i++){
        someString = &quot;foo&quot;;
    }


Example of slow because of DOM:

    for (var i=0;i&lt;=10000;i++){
        element.innerHTML = &quot;foo&quot;;
    }


-----

Some details as per request:

After bench marking, it looks like it&#39;s not an unsolvable slow issue, but often the wrong tool is used, and the tool used depends on what you&#39;re doing cross-browser.

It looks like the DOM efficiency varies greatly between browsers, but my original presumption that the dom is slow and unsolvable seems to be wrong.

I ran tests against Chrome, FF4, and IE 5-9, you can see the operations per second in this chart:

![enter image description here][3]


Chrome is lightning fast when you use the DOM API, but vastly slower using the .innerHTML operator (by a magnitude 1000-fold slower), however, FF is worse than Chrome in some areas (for instance, the append test is much slower than Chrome), but the InnerHTML test runs much faster than chrome.

IE seems to actually be getting worse at using DOM append and better at innerHTML as you progress through versions since 5.5 (ie, 73ops/sec in IE8 now at 51 ops/sec in IE9).

I have the test page over here:

http://jsperf.com/browser-dom-speed-tests2

What&#39;s interesting is that it seems different browsers seem to all be having different challenges when generating the DOM. Why is there such disparity here?


  [1]: http://www.merriam-webster.com/dictionary/what
  [2]: http://www.merriam-webster.com/dictionary/why?show=0&amp;t=1311602447
  [3]: http://i.stack.imgur.com/OjUXN.jpg

But why&#39;s the browser DOM still so slow after 10 years of effort?

I am using XPath to pull data off of a web page.

I have a link that I want to get the href value of. I can reference it through its unique id: `id(&#39;unique-id&#39;)`, but that gives me the string between the `&lt;a&gt;` tags. 

How do I get the value of the `href` attribute?

XPath to get another attribute by id attribute

I&#39;ve come up kinda dry as to **why** -- at least in the .Net Framework -- it is necessary to use an `XmlNamespaceManager` in order to handle namespaces (or the rather clunky and verbose `[local-name()=...` XPath predicate/function/whatever) when performing XPath queries. I **do** understand why namespaces are necessary or at least beneficial, but **why** is it so complex?

In order to query a simple XML Document (no namespaces)...

    &lt;?xml version=&quot;1.0&quot; encoding=&quot;ISO-8859-1&quot;?&gt;
    &lt;rootNode&gt;
       &lt;nodeName&gt;Some Text Here&lt;/nodeName&gt;
    &lt;/rootNode&gt;

...one can use something like `doc.SelectSingleNode(&quot;//nodeName&quot;)` (which would match `&lt;nodeName&gt;Some Text Here&lt;/nodeName&gt;`)

*Mystery #1*: **My first annoyance** -- If I understand correctly -- is that merely adding a namespace reference to the parent/root tag (whether used as part of a child node tag or not) like so:

    &lt;?xml version=&quot;1.0&quot; encoding=&quot;ISO-8859-1&quot;?&gt;
    &lt;rootNode xmlns=&quot;http://example.com/xmlns/foo&quot;&gt;
       &lt;nodeName&gt;Some Text Here&lt;/nodeName&gt;
    &lt;/rootNode&gt;

...requires several extra lines of code to get the same result:

    Dim nsmgr As New XmlNamespaceManager(doc.NameTable)
    nsmgr.AddNamespace(&quot;ab&quot;, &quot;http://example.com/xmlns/foo&quot;)
    Dim desiredNode As XmlNode = doc.SelectSingleNode(&quot;//ab:nodeName&quot;, nsmgr)
...essentially dreaming up a non-existent prefix (&quot;`ab`&quot;) to find a node that doesn&#39;t even use a prefix. *How does this make sense?* What is wrong (conceptually) with `doc.SelectSingleNode(&quot;//nodeName&quot;)`?

*Mystery #2*: So, say you&#39;ve got an XML document that uses prefixes:

    &lt;?xml version=&quot;1.0&quot; encoding=&quot;ISO-8859-1&quot;?&gt;
    &lt;rootNode xmlns:cde=&quot;http://example.com/xmlns/foo&quot; xmlns:feg=&quot;http://example.com/xmlns/bar&quot;&gt;
       &lt;cde:nodeName&gt;Some Text Here&lt;/cde:nodeName&gt;
       &lt;feg:nodeName&gt;Some Other Value&lt;/feg:nodeName&gt;
       &lt;feg:otherName&gt;Yet Another Value&lt;/feg:otherName&gt;
    &lt;/rootNode&gt;

... If I understand correctly, you would have to add both namespaces to the `XmlNamespaceManager`, in order to make a query for a single node...

    Dim nsmgr As New XmlNamespaceManager(doc.NameTable)
    nsmgr.AddNamespace(&quot;cde&quot;, &quot;http://example.com/xmlns/foo&quot;)
    nsmgr.AddNamespace(&quot;feg&quot;, &quot;http://example.com/xmlns/bar&quot;)
    Dim desiredNode As XmlNode = doc.SelectSingleNode(&quot;//feg:nodeName&quot;, nsmgr)

... Why, in this case, do I need (conceptually) a namespace manager? 

******REDACTED into comments below****

**Edit Added:**
My revised and refined question is based upon the apparent redundancy of the XmlNamespaceManager in what I believe to be the majority of cases and the use of the namespace manager to specify a mapping of prefix to URI:

When the direct mapping of the namespace prefix (&quot;cde&quot;) to the namespace URI (&quot;http://example.com/xmlns/foo&quot;) is explicitly stated in the source document: 

    ...&lt;rootNode xmlns:cde=&quot;http://example.com/xmlns/foo&quot;...

what is the conceptual need for a programmer to recreate that mapping before making a query?

Why is XmlNamespaceManager necessary?

Is there a way to define a XPath type query for nested python dictionaries.

Something like this:

    foo = {
      &#39;spam&#39;:&#39;eggs&#39;,
      &#39;morefoo&#39;: {
                   &#39;bar&#39;:&#39;soap&#39;,
                   &#39;morebar&#39;: {&#39;bacon&#39; : &#39;foobar&#39;}
                  }
       }

    print( foo.select(&quot;/morefoo/morebar&quot;) )
    
    &gt;&gt; {&#39;bacon&#39; : &#39;foobar&#39;}

I also needed to select nested lists ;)

This can be done easily with @jellybean&#39;s solution:

    def xpath_get(mydict, path):
        elem = mydict
        try:
            for x in path.strip(&quot;/&quot;).split(&quot;/&quot;):
                try:
                    x = int(x)
                    elem = elem[x]
                except ValueError:
                    elem = elem.get(x)
        except:
            pass
    
        return elem
    
    foo = {
      &#39;spam&#39;:&#39;eggs&#39;,
      &#39;morefoo&#39;: [{
                   &#39;bar&#39;:&#39;soap&#39;,
                   &#39;morebar&#39;: {
                               &#39;bacon&#39; : {
                                           &#39;bla&#39;:&#39;balbla&#39;
                                         }
                               }
                  },
                  &#39;bla&#39;
                  ]
       }
    
    print xpath_get(foo, &quot;/morefoo/0/morebar/bacon&quot;)

[EDIT 2016] This question and the accepted answer are ancient. The newer answers may do the job better than the original answer. However I did not test them so I won&#39;t change the accepted answer.

Xpath like query for nested python dictionaries

So, I was absolutely baffled as to how to do this in Selenium, and couldn&#39;t find the answer anywhere, so I&#39;m sharing my experience.

I was trying to select an iframe and having no luck (or not repeatably anyway). The HTML is:

    &lt;iframe&#160;id=&quot;upload_file_frame&quot;&#160;width=&quot;100%&quot;&#160;height=&quot;465px&quot;&#160;frameborder=&quot;0&quot;&#160;framemargin=&quot;0&quot;&#160;name=&quot;upload_file_frame&quot;&#160;src=&quot;/blah/import/&quot;&gt;
	&lt;html&gt;
		&lt;body&gt;
			&lt;div&#160;class=&quot;import_devices&quot;&gt;
				&lt;div&#160;class=&quot;import_type&quot;&gt;
					&lt;a&#160;class=&quot;secondary_button&quot;&#160;href=&quot;/blah/blah/?source=blah&quot;&gt;
						&lt;div&#160;class=&quot;import_choice_image&quot;&gt;
							&lt;img&#160;alt=&quot;blah&quot;&#160;src=&quot;/public/images/blah/import/blah.png&quot;&gt;
						&lt;/div&gt;
						&lt;div&#160;class=&quot;import_choice_text&quot;&gt;Blah Blah&lt;/div&gt;
					&lt;/a&gt;
				&lt;/div&gt;
			&lt;/div&gt;
		&lt;/body&gt;
	&lt;/html&gt;
&lt;/iframe&gt;

The Python code (using the selenium library) was trying to find this iframe using this:

        @timed(650)
    def test_pedometer(self):
        sel = self.selenium
        ...
        time.sleep(10)
        for i in range(5):
            try:
                if sel.select_frame(&quot;css=#upload_file_frame&quot;): break
            except: pass
            time.sleep(10)
        else: self.fail(&quot;Cannot find upload_file_frame, the iframe for the device upload image buttons&quot;)

Repeated fails with every combination of Selenium commands I could find. 

The occasional success would not be reproducible, so perhaps it was some sort of race condition or something? Never did find the right way to get it in selenium proper.

Select iframe using Python + Selenium

I&#39;m trying to query an xml file generated by adium. xmlwf says that it&#39;s well formed. By using xmllint&#39;s debug option i get the following:

    $ xmllint --debug doc.xml
    DOCUMENT
    version=1.0
    encoding=UTF-8
    URL=doc.xml
    standalone=true
      ELEMENT chat
        default namespace href=http://purl.org/net/ulf/ns/0.4-02
        ATTRIBUTE account
          TEXT
            content=foo@bar.com
        ATTRIBUTE service
          TEXT compact
            content=MSN
        TEXT compact
          content= 
        ELEMENT event
          ATTRIBUTE type

Everything seems to parse just fine. However, when I try to query even the simplest things, I don&#39;t get anything:

    $ xmllint --xpath &#39;/chat&#39; doc.xml 
    XPath set is empty

What&#39;s happening? Running that exact same query using xpath returns the correct results (however with no newline between results). Am I doing something wrong or is xmllint just not working properly?

Here&#39;s a shorter, anonymized version of the xml that shows the same behavior:

    &lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot; ?&gt;
    &lt;chat xmlns=&quot;http://purl.org/net/ulf/ns/0.4-02&quot; account=&quot;foo@bar.com&quot; service=&quot;MSN&quot;&gt;
    &lt;event type=&quot;windowOpened&quot; sender=&quot;foo@bar.com&quot; time=&quot;2011-11-22T00:34:43-03:00&quot;&gt;&lt;/event&gt;
    &lt;message sender=&quot;foo@bar.com&quot; time=&quot;2011-11-22T00:34:43-03:00&quot; alias=&quot;foo&quot;&gt;&lt;div&gt;&lt;span style=&quot;color: #000000; font-family: Helvetica; font-size: 12pt;&quot;&gt;hi&lt;/span&gt;&lt;/div&gt;&lt;/message&gt;
    &lt;/chat&gt;

Content Type	Original Author	Original Content on Stackoverflow
Question	KJW	View Question on Stackoverflow
Solution 1 - Java	Tomasz Nurkiewicz	View Answer on Stackoverflow

Java: how to locate an element via xpath string on org.w3c.dom.document

Java Problem Overview

Java Solutions

Solution 1 - Java

How can I make the width of my <figcaption> match the width of the <img> inside its <figure> tag?

How to add attributes to a base class's properties

Attributions