Synthetic variable or method in Java
While working I found one keyword Synthetic variable or method in java. Never heard of this before.I found some information on net and thought of sharing knowledge with everyone. If you want add something in this ,it would be really great.
“Synthetic” attribute means a variable introduced by the compiler that doesn’t appear in the actual code. It is a compiler-created field that links a local inner class to a block’s local variable or reference type parameter. Synthetic members are only meant to be accessed by trusted code generated by the compiler. Compiler synthesizes certain hidden fields and methods in order to implement the scoping of names. Any constructs introduced by the compiler that do not have a corresponding construct in the source code must be marked as synthetic, except for default constructors and the class initialization method.[1]
it means when there is a field or method introduced into a class file by the compiler and we can not find the primary declaration in the source file, it will marked as synthetic
A synthetic field pointing to the outermost enclosing instance is named this$0. The next-outermost enclosing instance is this$1, and so forth. All these synthetic fields are initialized by constructor parameters, which have the same names as the fields they initialize. If one of the parameters is the innermost enclosing instance, it is the first. All such constructor parameters are deemed to be synthetic. If the compiler determines that the synthetic field’s value is used only in the code of the constructor, it may omit the field itself, and use only the parameter to implement variable references. A non-private final synthetic method which grants access to a private member or constructor has a name of the form access$N, where N is a decimal numeral.
when an inner class has access to an instance of an outer class, this is implemented by creating a synthetic field in the inner class, generally named this$0, which holds a reference to the outer class instance.
According to Java 6 spec – Any constructs introduced by the compiler that do not have a corresponding construct in the source code must be marked as synthetic, except for default constructors and the class initialization method.
Nested classes are sometimes implemented using synthetic fields and synthetic contructors, e.g. an inner class may use a synthetic field to save a reference to its outer class instance, and it may generate a synthetic constructor to set that field correctly.
Synthetic members are how the compiler deals with the fact that nested classes are actually compiled into top-level classes
if a static member type uses a private member of its containing type (or vice versa), the compiler generates synthetic non-private access methods and converts the expressions that access the private methods into expressions that invoke these specially generated methods. These methods are given the default package access which is sufficient, as the member class and its containing class are guaranteed to be in the same package.
Synthetic class is derived from Attribute and declares this class as `synthetic’, i.e., it needs special handling. It is instantiated from the Attribute.readAttribute() method.
According to the JVM Spec: “A class member that does not appear in the source code must be marked using a Synthetic attribute.” Also, “The Synthetic attribute was introduced in JDK release 1.1 to support nested classes and interfaces.
We can check using isSynthetic() method whether variable is synthetic variable or not.
Examples include a static variable to hold a Class object if you’ve used the “Integer.class” notation, and the member variable in a non-static inner class that holds a reference to the enclosing class. Besides the fact that they are inserted by the compiler
See the java doc on – http://bcel.sourceforge.net/docs/de/fub/bytecode/classfile/Synthetic.html
Introduction to MVVM pattern in WPF
The Model View ViewModel (MVVM) is an architectural pattern used in software engineering that originated from Microsoft as a specialization of the Presentation Model design pattern introduced by Martin Fowler. Largely based on the Model-view-controller pattern (MVC), MVVM is targeted at modern UI development platforms (Windows Presentation Foundation and Silverlight) in which there is a UX developer who has different requirements than a more “traditional” developer (i.e. oriented toward business logic and back end development).
Model
The Model is defined as in MVC; it is the data or business logic, completely UI independent, that stores the state and does the processing of the problem domain. The Model is written in code or is represented by pure data encoded in relational tables or XML.
View
A View is defined in XAML and should not have any logic in the code-behind. It binds to the view-model by only using data binding.
In simple examples, the View is data bound directly to the Model. Parts of the Model are simply displayed in the view by one-way data binding. Other parts of the model can be edited by directly binding controls two-way to the data.
ViewModel
The term means “Model of a View”, and can be thought of as abstraction of the view, but it also provides a specialization of the Model that the View can use for data-binding. In this latter role the ViewModel contains data-transformers that convert Model types into View types, and it contains Commands the View can use to interact with the Model.
The ViewModel exposes public properties, commands, and abstractions. The ViewModel has been likened to a conceptual state of the data as opposed to the real state of the data in the Model.
References
Wikepedia
Tales from the Smart Client
Model-View-ViewModel Pattern
Introduction of DOJO
Dojo is the Open Source JavaScript Toolkit. It is tool for constructing dynamic web
user interfaces. Dojo offers various widgets, utilities, higher IO (AJAX) abstraction etc.It is based on HTML and javascript. Dojo ups abstraction layer in a higher level. Dojo is sometimes advertised as AJAX
framework. It is able to make AJAX requests with Dojo But the technique of binding is under
the abstraction layer that Dojo has. Even if Dojo is nice, beautiful etc, it is quite heavy
We can one use Dojo by :-
1. Include package
2. use widget/utility/…
Package System
• Dojo consists of JavaScript files
• Package system takes care that only needed
files are included
• Each JavaScript file can be named as
package
dojo.provide(dojo.string);
• By that name the package can be taken in
use
dojo.require(dojo.string);
One has not to remember any file or
directory names
• Only dojo.js has to be included into HTML
document
• That file takes care of initialization of Dojo
• There is a couple of pre packaged builds that
consist of different kinds of packages
e.g. Widget, event or IO builds.
DOJO have following Language Libraries
• dojo.lang.*
• Wrappers for common idioms
• Functional programming APIs
• For Example
– dojo.lang.forEach
– dojo.lang.map
– dojo.lang.assert
Widget toolkit-
• Widget toolkit is also a very noticeable part of
Dojo toolkit
• Widget is a user interface object that has a
layout and some properties
• In Dojo widgets are HTML+CSS bound by
JavaScript
• Dojo has lots of useful widgets
e.g. Tabs, sorting table, dialogs
<script> dojo.require(”dojo.widget.Editor2”); </script> <!-- ... --> <textarea dojoType=”Editor2”> ... </textarea>
For more info – www.dojotoolkit.org
Experience Space using Microsoft WorldWide Telescope
We already have been visualizing the earth on our desktops for quite a long time now. Thanks Google Earth and Bind maps.
Ever wondered if we could visualize space this way as well? Imagine taking a close look at a stars or galaxies like Milky way right from your desktop? Or even taking a view of Moon or Mars? Well Microsoft Research has come up with a solution to this.
Microsoft Research WorldWide Telescope
Yes that’s true we have a software from Microsoft which will soon be integrated into Bing maps and it enables us to view space with the help of images captured by telescopes all around the world.
What is WWT
The WorldWide Telescope (WWT) is a Web 2.0 visualization software environment that enables your computer to function as a virtual telescope—bringing together imagery from the best ground and space-based telescopes in the world for a seamless exploration of the universe.
Choose from a growing number of guided tours of the sky by astronomers and educators from some of the most famous observatories and planetariums in the country. Feel free at any time to pause the tour, explore on your own (with multiple information sources for objects at your fingertips), and rejoin the tour where you left off. Join Harvard Astronomer Alyssa Goodman on a journey showing how dust in the Milky Way Galaxy condenses into stars and planets. Take a tour with University of Chicago Cosmologist Mike Gladders two billion years into the past to see a gravitational lens bending the light from galaxies allowing you to see billions more years into the past.
Some of the Tours available at the website are as follows:
Search for Extra Solar Planets
Apollo Missions 15 to 17
Pluto
Aug 1, 2008 Eclipse
Orion Nebula – Hubble’s
The Ring Nebula
Beautiful Nebulas
Center of the Milky Way
Universal Beauty
Impact with M31
and many more….
So what are you waiting for? just visit the website and enjoy looking at stars even during day time 
