GWT applications are described as modules. A module ”modulename” is described by a configuration file ”modulename.gwt.xml”. Each module can define one or more Entry point classes.
An entry point is the starting point for a GWT application, similar to the main method in a standard Java program. A Java class which is an entry point must implement the interface ”com.google.gwt.core.client.EntryPoint” which defines the method onModuleLoad().
The module is connected to a HTML page, which is called ”host page”. The code for a GWT web application executes within this HTML document.
The HTML page can define ”div” containers to which the GWT application can assign UI components or the GWT UI components are simply assigned to the body tag of the HTML page.
DevelopmentModeLogHandler logs by calling method GWT.log. These messages can only be seen in Development Mode in the DevMode window.
A java data object should implement isSerializable interface so that it can be transferred over the wire in GWT RPC.
This widget represents a form of popup that has a caption area at the top and can be dragged by the user. Unlike a PopupPanel, calls to PopupPanel.setWidth(String) and PopupPanel.setHeight(String) will set the width and height of the dialog box itself, even if a widget has not been added as yet.
Following are the stairs of bootstrap proceure for GWT application whilst a browser loads the GWT application −Browser masses the host html page and .Nocache.Js document.
.Nocache.Js code resolves deferred binding configuarations (for example, browser detection) and use research desk generated by way of GWT compiler to locate one of the .Cache.Html.
.Nocache.Js code then creates a html hidden iframe, inserts that iframe into the host web page's DOM, and loads the .Cache.Html report into the identical iframe.
.Cache.Html contains the actual application of a GWT software and once loaded in iframe indicates the GWT utility in the browser.
CellBrowser widget represents a browsable view of a tree in which only a single node per level may be open at one time. This widget will only work in standards mode, which requires that the HTML page in which it is run have an explicit <!DOCTYPE> declaration.
FocusPanel widget represents a simple panel that makes its contents focusable, and adds the ability to catch mouse and keyboard events.
ScrollPanel widget represents a simple panel that wraps its contents in a scrollable area.
Following are the steps of bootstrap proceure for GWT application when a browser loads the GWT application −
Browser loads the host html page and .nocache.js file.
.nocache.js code resolves deferred binding configuarations (for example, browser detection) and use lookup table generated by GWT compiler to locate one of the .cache.html.
.nocache.js code then creates a html hidden iframe, inserts that iframe into the host page’s DOM, and loads the .cache.html file into the same iframe.
.cache.html contains the actual program of a GWT application and once loaded in iframe shows the GWT application in the browser.
Tree widget represents a standard hierarchical tree widget. The tree contains a hierarchy of TreeItems that the user can open, close, and select.
This widget represents a panel that lays its child widgets out "docked" at its outer edges, and allows its last widget to take up the remaining space in its center.
DeckPanel is a panel that displays all of its child widgets in a 'deck', where only one can be visible at a time. It is used by TabPanel.
Grid widget represents a rectangular grid that can contain text, html, or a child Widget within its cells. It must be resized explicitly to the desired number of rows and columns.
FlexTable widget represents a flexible table that creates cells on demand. It can be jagged (that is, each row can contain a different number of cells) and individual cells can be set to span multiple rows or columns.
HorizontalSplitPanel widget represents a panel that arranges two widgets in a single horizontal row and allows the user to interactively change the proportion of the width dedicated to each of the two widgets. Widgets contained within a HorizontalSplitPanel will be automatically decorated with scrollbars when necessary.
VerticalPanel widget represents a panel that lays all of its widgets out in a single vertical column.
HorizontalPanel widget represents a panel that lays all of its widgets out in a single horizontal column.
FlowPanel widget represents a panel that formats its child widgets using the default HTML layout behavior.
This widget displays an image at a given URL.
Like all AJAX tools, GWT’s HTTP client and RPC libraries are restricted to only accessing data from the same site where the application was loaded, due to the browser Same Origin Policy. If the application is using JSON, there is a work around to this limitation using a <script> tag (aka JSON-P).
First, we need an external JSON service which can invoke user defined callback functions with the JSON data as argument. An example of such a service is GData’s “alt=json-in-script& callback=myCallback” support. Then, we can use JsonpRequestBuilder to make our call, in a way similar to a RequestBuilder when we’re not making a cross-site request.
CellTable widget represents a tabular view that supports paging and columns.
CellList widget represents a single column list of cells.
CellTree widget represents a view of a tree. This widget will only work in standards mode, which requires that the HTML page in which it is run have an explicit <!DOCTYPE> declaration.
MenuBar widget represents a standard menu bar widget. A menu bar can contain any number of menu items, each of which can either fire a Command or open a cascaded menu bar.
Hidden widget represets a hidden field in an HTML form.
FileUpload widget wraps the HTML <input type='file'> element.
RichTextArea widget represents a rich text editor that allows complex styling and formatting.
TextArea widget represents a text box that allows multiple lines of text to be entered.
TextArea widget represents a text box that allows multiple lines of text to be entered.
PasswordTextBox widget represents a text box that visually masks its input to prevent eavesdropping.
By default, the class name for each component is gwt-<classname>. For example, the Button widget has a default style of gwt-Button and similar way TextBox widgest has a default style of gwt- TextBox.
The most important public resource is host page which is used to invoke actual GWT application. A typical HTML host page for an application might not include any visible HTML body content at all but it is always expected to include GWT application via a <script.../> tag.
GWT compiler generates .nocache.js file every time with the same name whenever a GWT application is compiled. So browser should always download the .nocache.js file to get the latest gwt application. gwt.js code actually appends a unique timestamp at the end of the file name so that browser always treat it a new file and should never cache it.
Automatically injects the external CSS file located at the location specified by src.
TextBox widget represents a single line text box.
SuggestBox widget represents a text box or text area which displays a pre-configured set of selections that match the user's input. Each SuggestBox is associated with a single SuggestOracle. The SuggestOracle is used to provide a set of selections given a specific query string.
ListBox widget represents a list of choices to the user, either as a list box or as a drop-down list.
RadioButton widget represents a mutually-exclusive selection radio button widget.
CheckBox widget represents a standard check box widget. This class also serves as a base class for RadioButton.
ToggleButton widget represents a stylish stateful button which allows the user to toggle between up and down states.
As of GWT 2.0, creating an application that fills the browser is easy using Layout Panels. LayoutPanels such as DockLayoutPanel and SplitLayoutPanel automatically resize to the size of the window when the browser resizes.
This specifies the names of source folders which GWT compiler will search for source compilation.
They are called sequentially in the order in which entry-point classes appear in the module file. So when the onModuleLoad of your first entry point finishes, the next entry point is called immediately.
onModuleLoad function gets called and acts similar to main method of a java application.
Button widget represents a standard push button.
This widget represents a simple <a> element.
This specifies the names of supply folders which GWT compiler will search for source compilation.
They are known as sequentially in the order in which entry-factor instructions appear in the module document. So while the onModuleLoad() of your first access point finishes, the next entry factor is called right now.
onModuleLoad() function receives known as and acts similar to important method of a java application.
Yes! Any range of entry-factor training may be introduced.