Fn (HTML APIs via Java 1.6 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(Fn.Presenter presenter)
Creates new function object and associates it with given presenter.

Constructors
Modifier	Constructor and Description
`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
```
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

Method Detail

isValid

isValid

define

define

preload

activePresenter

activate

invoke

invokeLater

presenter