Fn (HTML APIs via Java 1.5.1 API)

java.lang.Object
- org.netbeans.html.boot.spi.Fn

```
public abstract class Fn
extends Object
```
Represents single JavaScript function that can be invoked. Created via Fn.Presenter.defineFn(java.lang.String, java.lang.String...).

Author:

Jaroslav Tulach

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static interface`	`Fn.FromJavaScript` Additional interface to be implemented by `Fn.Presenter`s that need to convert JavaScript object (usually array) to Java object when calling back from JavaScript to Java.
`static interface`	`Fn.KeepAlive` Additional interface to `Fn.Presenter` to control more precisely garbage collection behavior of individual parameters.
`static interface`	`Fn.Presenter` The representation of a presenter - usually a browser window.
`static interface`	`Fn.ToJavaScript` Additional interface to be implemented by `Fn.Presenter`s that wish to control what objects are passed into the JavaScript virtual machine.

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`Fn()` Deprecated. Ineffective as of 0.6. Provide a presenter via `Fn.Fn(org.netbeans.html.boot.spi.Fn.Presenter)` constructor
`protected`	`Fn(Fn.Presenter presenter)` Creates new function object and associates it with given presenter.

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`static Closeable`	`activate(Fn.Presenter p)` Activates given presenter.
`static Fn.Presenter`	`activePresenter()` The currently active presenter.
`static Fn`	`define(Class<?> caller, boolean keepParametersAlive, String code, String... names)` Helper method to find current presenter and ask it to define new function.
`static Fn`	`define(Class<?> caller, String code, String... names)` Helper method to find current presenter and ask it to define new function by calling `Fn.Presenter.defineFn(java.lang.String, java.lang.String...)`.
`abstract Object`	`invoke(Object thiz, Object... args)` Invokes the defined function with specified `this` and appropriate arguments.
`void`	`invokeLater(Object thiz, Object... args)` Invokes the defined function with specified `this` and appropriate arguments asynchronously.
`boolean`	`isValid()` True, if currently active presenter is the same as presenter this function has been created for via `Fn.Fn(org.netbeans.html.boot.spi.Fn.Presenter)`.
`static boolean`	`isValid(Fn fnOrNull)` Helper method to check if the provided instance is valid function.
`static Fn`	`preload(Fn fn, Class<?> caller, String resource)` Wraps function to ensure that the script represented by `resource` gets loaded into the browser environment before the function `fn` is executed.
`protected Fn.Presenter`	`presenter()` Provides the function implementation access to the presenter provided in `the constructor`.

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

- Constructor Detail
  - Fn
```
@Deprecated
protected Fn()
```
    Deprecated. Ineffective as of 0.6. Provide a presenter via Fn.Fn(org.netbeans.html.boot.spi.Fn.Presenter) constructor
  - Fn
```
protected Fn(Fn.Presenter presenter)
```
    Creates new function object and associates it with given presenter.
    
    Parameters:
    
    presenter - the browser presenter associated with this function
    
    Since:
    
    0.6
- Method Detail
  - isValid
```
public final boolean isValid()
```
    True, if currently active presenter is the same as presenter this function has been created for via Fn.Fn(org.netbeans.html.boot.spi.Fn.Presenter).
    
    Returns:
    
    true, if proper presenter is used
  - isValid
```
public static boolean isValid(Fn fnOrNull)
```
    Helper method to check if the provided instance is valid function. Checks if the parameter is non-null and if so, does Fn.isValid() check.
    
    Parameters:
    
    fnOrNull - function or null
    
    Returns:
    
    true if the parameter is non-null and valid
    
    Since:
    
    0.7
  - define
```
public static Fn define(Class<?> caller,
                        String code,
                        String... names)
```
    Helper method to find current presenter and ask it to define new function by calling Fn.Presenter.defineFn(java.lang.String, java.lang.String...).
    
    Parameters:
    
    caller - the class who wishes to define the function
    
    code - the body of the function (can reference this and names variables)
    
    names - names of individual parameters
    
    Returns:
    
    the function object that can be invoked - can return null if there is no presenter
    
    Since:
    
    0.7
  - define
```
public static Fn define(Class<?> caller,
                        boolean keepParametersAlive,
                        String code,
                        String... names)
```
    Helper method to find current presenter and ask it to define new function.
    
    Parameters:
    
    caller - the class who wishes to define the function
    
    keepParametersAlive - whether Java parameters should survive in JavaScript after the method invocation is over
    
    code - the body of the function (can reference this and names variables)
    
    names - names of individual parameters
    
    Returns:
    
    the function object that can be invoked - can return null if there is no presenter
    
    Since:
    
    1.1
  - preload
```
public static Fn preload(Fn fn,
                         Class<?> caller,
                         String resource)
```
    Wraps function to ensure that the script represented by resource gets loaded into the browser environment before the function fn is executed.
    
    Parameters:
    
    fn - original function to call (if null returns null)
    
    caller - the class who wishes to define/call the function
    
    resource - resources (accessible via ClassLoader.getResource(java.lang.String)) with a JavaScript that is supposed to loaded into the browser environment
    
    Returns:
    
    function that ensures the script is loaded and then delegates to fn. Returns null if the input fn is null
    
    Since:
    
    0.7
  - activePresenter
```
public static Fn.Presenter activePresenter()
```
    The currently active presenter.
    
    Returns:
    
    the currently active presenter or null
    
    Since:
    
    0.7
  - activate
```
public static Closeable activate(Fn.Presenter p)
```
    Activates given presenter. Used to associate the native JavaScript code specified by JavaScriptBody annotation with certain presenter:
```
 try (Closeable c = Fn.activate(presenter)) {
   doCallsInPresenterContext();
 }
 
```
    Parameters:
    
    p - the presenter that should be active until closable is closed
    
    Returns:
    
    the closable to close
    
    Since:
    
    0.7
  - invoke
```
public abstract Object invoke(Object thiz,
                              Object... args)
                       throws Exception
```
    Invokes the defined function with specified this and appropriate arguments.
    
    Parameters:
    
    thiz - the meaning of this inside of the JavaScript function - can be null
    
    args - arguments for the function
    
    Returns:
    
    return value from the function
    
    Throws:
    
    Exception - if something goes wrong, as exception may be thrown
  - invokeLater
```
public void invokeLater(Object thiz,
                        Object... args)
                 throws Exception
```
    Invokes the defined function with specified this and appropriate arguments asynchronously. The invocation may be happen "later".
    
    Parameters:
    
    thiz - the meaning of this inside of the JavaScript function - can be null
    
    args - arguments for the function
    
    Throws:
    
    Exception - if something goes wrong, as exception may be thrown
    
    Since:
    
    0.7.6
  - presenter
```
protected final Fn.Presenter presenter()
```
    Provides the function implementation access to the presenter provided in the constructor.
    
    Returns:
    
    presenter passed in the constructor (may be, but should not be null)
    
    Since:
    
    0.7

Class Fn

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Fn

Fn

Method Detail

isValid

isValid

define

define

preload

activePresenter

activate

invoke

invokeLater

presenter