Widget (Apache Juneau 7.1.1)

java.lang.Object
- org.apache.juneau.rest.widget.Widget

Direct Known Subclasses:

MenuItemWidget, PoweredByApache, PoweredByJuneau
```
public abstract class Widget
extends Object
```
Defines an interface for resolvers of "$W{...}" string variables.
Widgets are associated with resources through the following
Widgets allow you to add arbitrary HTML, CSS, and Javascript to the page.
The HTML content returned by the getHtml(RestRequest) method is added where the "$W{...}" is referenced in the page. The Javascript and stylesheet content is added to the header of the page. They allow you to control the look and behavior of your widgets.
The following examples shows how to associate a widget with a REST method and then have it rendered in the links and aside section of the page:
@RestMethod( widgets={ MyWidget.class } htmldoc=@HtmlDoc( navlinks={ "$W{MyWidget}" }, aside={ "Check out this widget: $W{MyWidget}" } ) )

The following shows an example of a widget that renders an image located in the htdocs static files directory in your classpath (see @RestResource.staticFiles()):
public class MyWidget extends Widget { @Override public String getHtml(RestRequest req) throws Exception { UriResolver r = req.getUriResolver(); return "<img class='myimage' onclick='myalert(this)' src='"+r.resolve("servlet:/htdocs/myimage.png")+"'>"; } @Override public String getScript(RestRequest req) throws Exception { return "" + "\n function myalert(imageElement) {" + "\n alert('cool!');" + "\n }"; } @Override public String getStyle(RestRequest req) throws Exception { return "" + "\n .myimage {" + "\n border: 10px solid red;" + "\n }"; } }

Note the getClasspathResourceAsString(String) and getClasspathResourceAsString(String, Locale) convenience methods provided for quickly loading javascript and css files from the classpath or file system. These are useful if your script or styles are complex and you want them loaded from files.

public class MyWidget extends Widget { ... @Override public String getScript(RestRequest req) throws Exception { return getResourceAsString("MyWidget.js"); } @Override public String getStyle(RestRequest req) throws Exception { return getResourceAsString("MyWidget.css"); } }

Widgets must provide one of the following public constructors:
- public Widget();
- public Widget(PropertyStore);
Widgets can be defined as inner classes of REST resource classes.
See Also:
- Overview > juneau-rest-server > Widgets

Constructor Summary

Constructors
Constructor and Description

Widget()

Constructors
Constructor and Description
`Widget()`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`protected String`	`getClasspathResourceAsString(String name)` Retrieves the specified classpath resource and returns the contents as a string.
`protected String`	`getClasspathResourceAsString(String name, Locale locale)` Same as `getClasspathResourceAsString(String)` except also looks for localized-versions of the file.
`String`	`getHtml(RestRequest req)` Resolves the HTML content for this widget.
`String`	`getName()` The widget key.
`String`	`getScript(RestRequest req)` Resolves any Javascript that should be added to the <head>/<script> element.
`String`	`getStyle(RestRequest req)` Resolves any CSS styles that should be added to the <head>/<style> element.
`protected String`	`loadHtml(String name)` Convenience method for calling `getClasspathResourceAsString(String)` except also strips HTML comments from the file.
`protected String`	`loadScript(String name)` Convenience method for calling `getClasspathResourceAsString(String)` except also strips Javascript comments from the file.
`protected String`	`loadStyle(String name)` Convenience method for calling `getClasspathResourceAsString(String)` except also strips CSS comments from the file.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - Widget
```
public Widget()
```
- Method Detail
  - getName
```
public String getName()
```
    The widget key.
    (i.e. The variable name inside the "$W{...}" variable).
    The returned value must not be null.
    If not overridden, the default value is the class simple name.
    
    Returns:
    
    The widget key.
  - getHtml
```
public String getHtml(RestRequest req)
               throws Exception
```
    Resolves the HTML content for this widget.
    A returned value of null will cause nothing to be added to the page.
    
    Parameters:
    
    req - The HTTP request object.
    
    Returns:
    
    The HTML content of this widget.
    
    Throws:
    
    Exception
  - getScript
```
public String getScript(RestRequest req)
                 throws Exception
```
    Resolves any Javascript that should be added to the <head>/<script> element.
    A returned value of null will cause nothing to be added to the page.
    
    Parameters:
    
    req - The HTTP request object.
    
    Returns:
    
    The Javascript needed by this widget.
    
    Throws:
    
    Exception
  - getStyle
```
public String getStyle(RestRequest req)
                throws Exception
```
    Resolves any CSS styles that should be added to the <head>/<style> element.
    A returned value of null will cause nothing to be added to the page.
    
    Parameters:
    
    req - The HTTP request object.
    
    Returns:
    
    The CSS styles needed by this widget.
    
    Throws:
    
    Exception
  - getClasspathResourceAsString
```
protected String getClasspathResourceAsString(String name)
                                       throws IOException
```
    Retrieves the specified classpath resource and returns the contents as a string.
    Same as Class.getResourceAsStream(String) except if it doesn't find the resource on this class, searches up the parent hierarchy chain.
    If the resource cannot be found in the classpath, then an attempt is made to look relative to the JVM working directory.
    Path traversals outside the working directory are not allowed for security reasons.
    
    Parameters:
    
    name - Name of the desired resource.
    
    Returns:
    
    The resource converted to a string, or null if the resource could not be found.
    
    Throws:
    
    IOException
  - getClasspathResourceAsString
```
protected String getClasspathResourceAsString(String name,
                                              Locale locale)
                                       throws IOException
```
    Same as getClasspathResourceAsString(String) except also looks for localized-versions of the file.
    If the locale is specified, then we look for resources whose name matches that locale.
    For example, if looking for the resource "MyResource.txt" for the Japanese locale, we will look for files in the following order:
    1. "MyResource_ja_JP.txt"
    2. "MyResource_ja.txt"
    3. "MyResource.txt"
    Parameters:
    
    name - Name of the desired resource.
    
    locale - The locale. Can be null.
    
    Returns:
    
    The resource converted to a string, or null if the resource could not be found.
    
    Throws:
    
    IOException
  - loadScript
```
protected String loadScript(String name)
                     throws IOException
```
    Convenience method for calling getClasspathResourceAsString(String) except also strips Javascript comments from the file.
    Comments are assumed to be Java-style block comments: "/*".
    
    Parameters:
    
    name - Name of the desired resource.
    
    Returns:
    
    The resource converted to a string, or null if the resource could not be found.
    
    Throws:
    
    IOException
  - loadStyle
```
protected String loadStyle(String name)
                    throws IOException
```
    Convenience method for calling getClasspathResourceAsString(String) except also strips CSS comments from the file.
    Comments are assumed to be Java-style block comments: "/*".
    
    Parameters:
    
    name - Name of the desired resource.
    
    Returns:
    
    The resource converted to a string, or null if the resource could not be found.
    
    Throws:
    
    IOException
  - loadHtml
```
protected String loadHtml(String name)
                   throws IOException
```
    Convenience method for calling getClasspathResourceAsString(String) except also strips HTML comments from the file.
    Comment are assumed to be "" code blocks.
    
    Parameters:
    
    name - Name of the desired resource.
    
    Returns:
    
    The resource converted to a string, or null if the resource could not be found.
    
    Throws:
    
    IOException

Class Widget

See Also:

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Widget

Method Detail

getName

getHtml

getScript

getStyle

getClasspathResourceAsString

getClasspathResourceAsString

loadScript

loadStyle

loadHtml