Syntax

$telnet HOST PORT

Example

$telnet 127.0.0.1 11211
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.
// now store some data and get it from memcached server
set tutorialspoint 0 900 9
memcached
STORED
get tutorialspoint
VALUE tutorialspoint 0 9
memcached
END

Connection from Java Application

Example

import net.spy.memcached.MemcachedClient;
import java.net.*;


public class MemcachedJava {
   public static void main(String[] args) {
      try{
         // Connecting to Memcached server on localhost
         MemcachedClient mcc = new MemcachedClient(new InetSocketAddress("127.0.0.1", 11211));
         System.out.println("Connection to server sucessful.");
         
         // Shutdowns the memcached client
         mcc.shutdown();
         
      }catch(Exception ex){
         System.out.println( ex.getMessage() );
      }
   }
}

Output

Connection to server successful.

• It is open source.
• Memcached server is a big hash table.
• It significantly reduces the database load.
• It is perfectly efficient for websites with high database load.
• It is distributed under Berkeley Software Distribution (BSD) license.
• It is a client-server application over TCP and/or UDP.

Memcached is not −

• a persistent data store
• a database
• application-specific
• a large object cache
• fault-tolerant or
• highly available

Installing Memcached on Ubuntu

$sudo apt-get update
$sudo apt-get install memcached

Confirming Memcached Installation

$ps aux | grep memcached

$memcached -p 11111 -U 11111 -u user -d

• -p is for TCP port number
• -U is for UDP port number
• -u is for user name
• -d runs memcached as daemon process

Offline App

Online App

Sign Your App

keytool -genkey -v -keystore my_keystore.keystore 
   -alias TutorialsPoint -keyalg RSA -keysize 2048 -validity 10000

• Configuration files
• Icons for app
• Information or content (built using web technologies)

Configuration

<?xml version = "1.0" encoding = "UTF-8"?>

<widget xmlns = "http://www.w3.org/ns/widgets" 
   xmlns:gap = "http://phonegap.com/ns/1.0" id = "com.tutorialspoint.onlineviewer" version = "1.0">
   
   <name>Tutorials Point</name>
   
   <description>
      Tutorials Point Online Viewer
   </description>
   
   <author href = "http://tutorialspoint.com" email = "contact@tutorialspoint.com">
      Tutorials Point
   </author>
   
   <preference name = "permissions" value = "none"/>
   
   <icon src = "res/icon/android/drawable-ldpi/tp_icon.png" 
      gap:platform = "android" gap:qualifier = "ldpi" />
  
   <icon src = "res/icon/android/drawable-mdpi/tp_icon.png" 
      gap:platform = "android" gap:qualifier = "mdpi" />
  
   <icon src = "res/icon/android/drawable-hdpi/tp_icon.png" 
      gap:platform = "android" gap:qualifier = "hdpi" />
  
   <icon src = "res/icon/android/drawable-xhdpi/tp_icon.png" 
      gap:platform = "android" gap:qualifier = "xhdpi" />
  
   <icon src = "res/icon/android/drawable-xxhdpi/tp_icon.png" 
      gap:platform = "android" gap:qualifier = "xxhdpi" />
   
   <icon src = "res/icon/ios/Icon-72.png" gap:platform = "ios" gap:qualifier = ""/>
   <icon src = "res/icon/ios/icon-57.png" gap:platform = "ios" width = "57" height = "57" />
   <icon src = "res/icon/ios/icon-72.png" gap:platform = "ios" width = "72" height = "72" />
   <icon src = "res/icon/ios/icon-57-2x.png" gap:platform = "ios" width = "114" height = "114" />
   <icon src = "res/icon/ios/icon-72-2x.png" gap:platform = "ios" width = "144" height = "144" />
   
</widget>

<widget id = ”app_id”>

<widget version = "x.y.z">

<name> App Name</name>

<description> My First Web App </description>

<author> Author_Name </author>

<preferences name = "permissions" value = "none">

<icon>

Icons

Audience

Prerequisites

It is mandatory that you have knowledge of HTML, CSS and JScript to create website that you might want to put on App. No other programming language is required to use PhoneGap.

Mobile, handhelds and easy-to-carry devices have started a new revolution in software engineering. These small but efficient devices are capable to run applications created with high-end programming languages. People who own these devices tend to use them at their maximum as these devices such as mobile phones, are very convenient to use anytime, anywhere.

The architecture of a mobile device is similar to that of a computer system. It has custom built hardware, firmware, and operating systems.

These three items are mostly proprietary and are engineered, developed, and assembled under one flagship organization. Apps (Application Software) are developed both by flagship organization and developers from outside the organization.

A number of well-recognized mobile operating systems are available in the market in both proprietary and open-source categories. Most widely used mobile operating systems are −

• Android
• IOS
• BlackBerry
• Windows

Every mobile operating system provides their own set of tools and environments to develop apps that will run on them. Application made for one operating system cannot run on any other platform as they are entirely different. Developers tend to cover all major mobile operating systems in order to increase reachability among their users.

Thus it becomes a tedious task to develop an application program that may run on all major OS platforms, keeping its look, feel, and functionality identical on all platforms. For this work, a developer needs to understand all platforms and should have a good understanding of major development tools for different operating systems.

PhoneGap

PhoneGap may be seen as a solution to all problems mentioned above. PhoneGap is a framework that makes the developers develop their apps using standard web APIs for all major mobile operating systems. It is open-source and free.

Developers only need to know web development using HTML, CSS and JavaScript. PhoneGap takes care of rest of the work, such as look and feel of the app and portability among various mobile operating systems.

Using PhoneGap, one can create apps for all major mobile operating systems like Apple iOS, Android, BlackBerry, Windows etc. This does not require the developer to have an expertise over any of the above mentioned platforms, neither the developer is required to know programming to code the app from scratch.

PhoneGap allows its users to upload the data contents on website and it automatically converts it to various App files.

In this tutorial, we shall see how to create an app for Apple, android, and windows platform online without using any offline tool.

RSS

Index.html

<html>
   <head>
      
      <script>
         function showRSS(str) {
            if (str.length==0) { 
               document.getElementById("output").innerHTML="";
               return;
            }
         
            if (window.XMLHttpRequest) {
               xmlhttp=new XMLHttpRequest();
            }
            else 
            {
               xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
            }
            xmlhttp.onreadystatechange=function() {
               if (xmlhttp.readyState==4 && xmlhttp.status==200) {
                  document.getElementById("output").innerHTML=xmlhttp.responseText;
               }
            }
            
            xmlhttp.open("GET","rss.php?q="+str,true);
            xmlhttp.send();
         }
      </script>
      
   </head>
   <body>
      <p>Please Select an option to get RSS:</p>
      
      <form>
         <select onchange="showRSS(this.value)">
            <option value="">Select an RSS-feed:</option>
            <option value="cnn">CNN</option>
            <option value="bbc">BBC News</option>
            <option value="pc">PC World</option>
         </select>
      </form>
      <br>
      
      <div id="output">RSS-feeds</div>
      
   </body>
</html>

rss.php

<?php
   $q=$_GET["q"];
   
   if($q=="cnn") {
      $xml=("http://rss.cnn.com/rss/cnn_topstories.rss");
   }
   
   elseif($q=="bbc") {
      $xml=("http://newsrss.bbc.co.uk/rss/newsonline_world_edition/americas/rss.xml");
   }
   
   elseif($q="pcw"){
      $xml=("http://www.pcworld.com/index.rss");
   }
   $xmlDoc = new DOMDocument();
   $xmlDoc->load($xml);
   
   $channel=$xmlDoc->getElementsByTagName('channel')->item(0);
   
   $channel_title = $channel->getElementsByTagName('title')
   ->item(0)->childNodes->item(0)->nodeValue;
   
   $channel_link = $channel->getElementsByTagName('link')
   ->item(0)->childNodes->item(0)->nodeValue;
   
   $channel_desc = $channel->getElementsByTagName('description')
   ->item(0)->childNodes->item(0)->nodeValue;
   
   echo("<p><a href='" . $channel_link . "'>" . $channel_title . "</a>");
   echo("<br>");
   echo($channel_desc . "</p>");
   
   $x=$xmlDoc->getElementsByTagName('item');
   
   for ($i=0; $i<=2; $i++) {
      $item_title=$x->item($i)->getElementsByTagName('title')
      ->item(0)->childNodes->item(0)->nodeValue;
      
      $item_link=$x->item($i)->getElementsByTagName('link')
      ->item(0)->childNodes->item(0)->nodeValue;
      
      $item_desc=$x->item($i)->getElementsByTagName('description')
      ->item(0)->childNodes->item(0)->nodeValue;
      
      echo ("<p><a href='" . $item_link . "'>" . $item_title . "</a>");
      echo ("<br>");
      echo ($item_desc . "</p>");
   }
?>