org.apidesign.html.boot.spi

Class Fn

java.lang.Object

org.apidesign.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.Presenters that need to convert JavaScript object (usually array) to Java object when calling back from JavaScript to Java.
static interface	Fn.Presenter The representation of a presenter - usually a browser window.
static interface	Fn.ToJavaScript Additional interface to be implemented by Fn.Presenters 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(org.apidesign.html.boot.spi.Fn.Presenter) constructor
protected	Fn(Fn.Presenter presenter) Creates new function object and associates it with given presenter.

Method Summary

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, 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.
boolean	isValid() True, if currently active presenter is the same as presenter this function has been created for via Fn(org.apidesign.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 {@link #Fn(org.apidesign.html.boot.spi.Fn.Presenter) 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(org.apidesign.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(org.apidesign.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 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

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

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

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 by the code generated by JavaScriptBody annotation:

 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

presenter

protected final Fn.Presenter presenter()

Provides the function implementation access to the presenter provided in {@link #Fn(org.apidesign.html.boot.spi.Fn.Presenter) the constructor).

Returns:

presenter passed in in the constructor (may be, but should not be null)

Since:

0.7