if (Modernizr.geolocation){
//...Your logic here
}

Here, I wrote a simple html page that locate your location using Geolocation and show it on the Google map.

http://just-thor.com/sample-works/geolocation.html

Happy coding.

After doing some searching on the internet, my problem seems like caused by incorrect API key. Obtaining Android Map API key is different from normal Google Map API key. I assume you are running Android emulator and also a beginner(like me ), first step is to find out the location of your keystore. In Eclipse, fire up the “Preferences” window, and locate the Android->Build settings, you should see the location of your keystore file in the “Default debug keystore” field.

Type the following command in your command line. By the way, I am using Mac, I think *Nix user should have no problem running the following command, but for Windows Users, I think you need to find a way to do it.

keytool -list -keystore ~/.android/debug.keystore

and when it prompts you for the password, just hit the Enter key, no need to enter any password.
And you will get something like this in the output

Certificate fingerprint (MD5): 8E:6F:5D:3F:A9:94:96:69:42:D2: and more

copy the value of it, and go to this URL
http://code.google.com/intl/sv-SE/android/maps-api-signup.html

Paste your value into the textbox and submit, and you should be able to get your API key. By using this Android Map API key, I was able to get the map working in my Android apps.

package com.justthor;

import java.util.Collections;
import java.util.List;
import java.util.Map;

import org.json.simple.JSONObject;
import org.json.simple.JSONValue;
import org.json.simple.parser.JSONParser;

public final class JsonUtil {
  private static final LoggingUtil logger = LoggingUtil.getInstance(JsonUtil.class);
  
  private static final JSONParser jsonParser = new JSONParser();

  @SuppressWarnings("unchecked")
  private static final Map EMPTY_MAP = Collections.EMPTY_MAP;
  
  @SuppressWarnings("unchecked")
  private static final List EMPTY_LIST = Collections.EMPTY_LIST;
  
  private final JSONObject obj;
  
  /**
   * Private constructor
   */
  private JsonUtil() {
    obj = new JSONObject();
  }
  
  /**
   * Encode object to JSON string. Object can be String, Integer etc.
   * @param Object 
   * @return String
   */
  public static String encode(final Object obj) {
    return JSONValue.toJSONString(obj);
  }
  
  /**
   * Decode string to raw object
   * @param String 
   * @return Object
   */
  public static Object decode(final String string) {
    Object result;
    try{
      result = jsonParser.parse(string);
    } catch (Exception e) {
      result = new Object();
      logger.error(e.getMessage(), e);
    }
    return result;
  }
  
  /**
   * Decode string to List
   * @param String 
   * @return List
   */
  @SuppressWarnings("unchecked")
  public static List decodeAsList(final String string) {
    List result = EMPTY_LIST;
    try{
      result = (List)jsonParser.parse(string);
    } catch (Exception e) {
      logger.error(e.getMessage(), e);
    }
    return result;
  }
  
  /**
   * Decode string to Map
   * @param String 
   * @return Map
   */
  @SuppressWarnings("unchecked")
  public static Map decodeAsMap(final String string) {
    Map result = EMPTY_MAP;
    try{
      result = (Map)jsonParser.parse(string);
    } catch (Exception e) {
      logger.error(e.getMessage(), e);
    }
    return result;
  }
  
  /**
   * Get an instance of JsonUtil.
   * @return JsonUtil
   */
  public static JsonUtil getInstance() {
    return new JsonUtil();
  }
  
  /**
   * Put a name and value. 
   * Example : 
   * JsonUtil.getInstance().put("name", "thor").put("vehicle", "none").put("height", 165).toJsonString();
   * @param Object
   * @param Object
   * @return JsonUtil
   */
  @SuppressWarnings("unchecked")
  public JsonUtil put(final Object name, final Object value) {
    obj.put(name, value);
    return this;
  }
  
  /**
   * Convert stored name and value into Json string.
   * @return String
   */
  public String toJsonString(){
    return obj.toString();
  }
}

You can use it as a static class, such as

List<String> list = new ArrayList<String>();
... your code to populate the list here...

// Encode!
String jsonEncodedString = JsonUtil.encode(list);

To decode, simply type the following

List decodedList = (List)JsonUtil.decode(jsonEncodedString);
// Or even easier, I wrote another method to decode JSON String as List
List decodedList = JsonUtil.decodeList(jsonEncodedString);

If you don’t feel like using Map, you can do this

String jsonEncodedString = JsonUtil.getInstance()
        .put("name", "Thor")
        .put("url", "www.just-thor.com")
        .toJsonString();

A wrapper is important to encapsulate how things actually works. When you using the wrapper I wrote, you don’t have to import or even know that I am using json-simple or whatsoever. I hope this example helps you to understand the importance of writing a wrapper class.

Happy programming

Here’s part of the code

//sample code taken from http://code.google.com/apis/ajaxlibs/
<script src="http://www.google.com/jsapi"></script>
<script>
  // Load jQuery
  google.load("jquery", "1");

  // on page load complete, fire off a jQuery json-p query
  // against Google web search
  google.setOnLoadCallback(function() {
    $.getJSON("http://ajax.googleapis.com/ajax/services/search/web?q=google&v=1.0&callback=?",

      // on search completion, process the results
      function (data) {
        if (data.responseData.results &&
            data.responseData.results.length > 0) {
          var results = data.responseData.results;
          
          for (var i=0; i < results.length; i++) {
            // Display each result however you wish
            alert(results[i].titleNoFormatting);
          }    
        }
        
      });
    });
</script>

//sample code taken from http://code.google.com/apis/ajaxlibs/
<script src="http://www.google.com/jsapi"></script>
<script>
  // Load jQuery
  google.load("jquery", "1");
</script>
<script>
  // on page load complete, fire off a jQuery json-p query
  // against Google web search
  google.setOnLoadCallback(function() {
    $.getJSON("http://ajax.googleapis.com/ajax/services/search/web?q=google&v=1.0&callback=?",

      // on search completion, process the results
      function (data) {
        if (data.responseData.results &&
            data.responseData.results.length > 0) {
          var results = data.responseData.results;
          
          for (var i=0; i < results.length; i++) {
            // Display each result however you wish
            alert(results[i].titleNoFormatting);
          }    
        }
        
      });
    });
</script>

Happy Coding

Happy coding

Here’s the code of it.

package com.justthor.reader

import scala.io.Source
import scala.xml._

object SimpleFeedReader {
  def main(args : Array[String]) : Unit = {
    val url = "http://just-thor.com/feed/"
    val data = XML.loadString( Source.fromURL(url).mkString )
    data \ "channel" \ "item" foreach(
      a => println((a \ "title" text) + " == "  + (a \ "link" text))
    )
  }
}

Ok,let’s go thru the code line by line.

At line 09, again we use Source to load content from url,by calling the method fromURL(quite obvious,right?).The mkString will create a String out of the content. Then, we use XML.loadString to parse the String into an XML object.

At line 10, we traverse the XML object with something like XQuery.
The RSS xml format is something like this

<channel>
<link>...</link>
<description>...</description>
<!-- item 1-->
<item>
  <title></title>
  <link></link>
</item>
<!-- item 2-->
<item>
  <title></title>
  <link></link>
</item>
<!-- and the rest goes here -->
</channel>

So when we write

data \ "channel" \ "item"

Here’s the output of the result

File Reading in Java and Scala == http://just-thor.com/2009/10/01/file-reading-in-java-and-scala/
PHP communicate with Java using JSON – Unicode Version == http://just-thor.com/2009/09/28/php-communicate-with-java-using-json-unicode-version/
Scala And JDBC == http://just-thor.com/2009/09/27/scala-and-jdbc/
A mistake or fate? == http://just-thor.com/2009/09/17/a-mistake-or-fate/
Women are weird == http://just-thor.com/2009/09/13/women-are-weird/
20 must visit sites for Java developer == http://just-thor.com/2009/09/12/20-must-visit-sites-for-java-developer/
Why do I practice pair programming? == http://just-thor.com/2009/09/08/why-do-i-practice-pair-programming/
Installing Scala on Windows == http://just-thor.com/2009/09/02/installing-scala-on-window/
Logging for different requested URI in Apache HTTP Server == http://just-thor.com/2009/09/01/logging-for-different-requested-uri-in-apache-http-server/
Say hello to Java and Scala == http://just-thor.com/2009/08/30/say-hello-to-java-and-scala/

And now we have a very simple yet functional RSS parser.

Happy coding,

This is normally how we read files in Java.First we open a reading stream, then read the content and process it,and at last we close the stream.

package com.justthor;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class SampleFileReader {

  /**
   * @param args
   */
  public static void main(String[] args) {
    BufferedReader in; 
    try {
      // Open file
      in = new BufferedReader(new FileReader("test.txt"));
          String str;
       
          // Start reading
          while ((str = in.readLine()) != null) {
        // Print the content
        System.out.println(str);
          }
          
          // Close the stream
          in.close();
      } catch (IOException e) {
        e.printStackTrace();
      }
  }
}

With some third party libraries, such as Apache Common Io, we can simplify the code to something like this.

package com.justthor;

import java.io.File;
import java.io.IOException;
import java.util.List;

import org.apache.commons.io.FileUtils;

public class SampleFileReader {

  /**
   * @param args
   */
  @SuppressWarnings("unchecked")
  public static void main(String[] args) {
    try {
      List<String> contents = FileUtils.readLines(new File("test.txt"));
      for ( String content : contents ) {
        System.out.println(content);
      }
    } catch (IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }
}

Well, it does look a bit simple now compare to the previous version. But we only manage to type 1 or 2 lines less than the previous version. This is due to we are force to handle the checked IOException. What if we try to achieve the same thing using Scala?

package com.justthor

import scala.io.Source

object SampleFileReader {
 def main(args : Array[String]) = {
  Source fromFile("test.txt") getLines foreach { println }
 }
}

Its much simple, right? Scala provides an util for IO named Source. This util read the file and get the contents by calling getLines method. This getLines method returns a Iterator[String]. And from there we can process the content by looping the returned iterator. We can use Source util to do more than reading files. I will provide more examples in the next few posts.

Happy coding.

For instance,we want to store a PHP array in database and later to be processed by Java,we can do something like

$aValue = array("key1"=>"value1","key2"=>"value2");
$sEncodedValue = json_encode($aValue)
//we will get something like {"key1":"value1","key2":"value2"}
//and then, we store the value to db

On the other hand,we use Java to read it and decode it.

//read from db and got the resultset,assuming we are using JDBC
while (rs.next()){
String rawValue = rs.getString("encodedValue");
// since we encoded an associative array,it will be translated to a Java Map object instance.
// we are using JSON-lib for JSON parsing the following example
JSONObject json = JSONObject.fromObject(jsonString);
Map decodedValue = (Map) JSONObject.toBean(json, Map.class);
String value1 = decodedValue.get("key1");
}

What if we are trying to store unicode value using JSON format in PHP?
For example,

$aValue = array("key1"=>"你好吗","key2"=>"value2");
$sEncodedValue = json_encode($aValue);
//This is what we get after encoded
//{"key1":"\u4f60\u597d\u5417","key2":"value2"}

If you decoded it back to Java,key1 value will return “u4f60u597du5417″ instead.This is so wrong.

How to solve it?
We can use mb_convert_encoding function in PHP.
Let’s make some changes to our code.

$aValue = array("key1"=>mb_convert_encoding("你好吗", "UTF-8"),"key2"=>"value2");
$sEncodedValue = json_encode($aValue);

By doing so,values are stored in database in unicode format,and you can decode it back in Java.

Happy coding.

Here’s the code

// Import JDBC package from standard Java SDK
import java.sql.{Connection, DriverManager, ResultSet};

class DataReader {
  // Load the driver
  Class.forName("com.mysql.jdbc.Driver").newInstance;

  val connection = DriverManager getConnection "jdbc:mysql://localhost:3306/mail?user=root&password=&characterEncoding=UTF8"

  def startReadingData(){
    try{

      // Create statement for readonly
      val statement = conn createStatement (ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY)

      val rs = statement executeQuery "select * from mail_queues order by id"

      // Looping resultset
      while (rs next) {
      println (rs getLong "id")
      }

      statement close
    }catch {
      case e => e printStackTrace
    }finally {
      connection close
    }
  }

}

Ok, you maybe wondering,why are so many dots(.) and parentheses missing?In Scala,when you are invoking one function with no or one parameter, you can omit the dot and parentheses. And Scala doesn’t have checked exception, which means you can write the above code without enclosed it with try…catch clause.I included it to make sure the DB connection is properly closed after use.

Happy coding.:)

1.http://www.javaalmanac.com

2.http://www.onjava.com

3.http://java.sun.com

4.http://www.developer.com/java

5.http://www.java.net

6.http://www.builder.com

7.http://www.ibm.com/developerworks/java

8.http://www.javaworld.com

9.http://www.devx.com/java

10.http://www.fawcette.com/javapro

11.http://www.sys-con.com/java

12.http://www.javadesktop.org

13.http://www.theserverside.com

14.http://www.jars.com

15.http://www.jguru.com

16.http://www.javaranch.com

17.http://www.ibiblio.org/javafaq/javafaq.html

18.http://java.sun.com/docs/books/tutorial/

19.http://www.javablogs.com

20.http://java.about.com/

Happy coding.