Package org.javagi.gobject

Class JavaClosure

java.lang.Object

org.javagi.base.ProxyInstance

org.gnome.gobject.Closure

org.javagi.gobject.JavaClosure

All Implemented Interfaces:

Proxy

@NullMarked
public class JavaClosure
extends Closure

An implementation of Closure that can be used with Java callbacks. In most cases, the callback will be invoked using reflection. For two common cases (Runnable and BooleanSupplier), the callback will be invoked directly.

Nested Class Summary

Nested classes/interfaces inherited from class org.gnome.gobject.Closure

Closure.MarshalCallback

Constructor Summary

Constructors

Constructor	Description
JavaClosure(@Nullable Object instance, Method method)	Construct a Closure that will invoke the provided Java method using reflection.
JavaClosure(Object lambda)	Construct a Closure that will invoke the provided Java lambda using reflection.
JavaClosure(Runnable callback)	Construct a Closure for a method or lambda that takes no parameters and returns void.
JavaClosure(BooleanSupplier callback)	Construct a Closure for a method or lambda that takes no parameters and returns boolean.

Method Summary

Modifier and Type	Method	Description
static Method	getSingleMethod(Class<?> cls)	Get the single abstract method (SAM) implementation of a class that implements a functional interface.
JavaClosure	ignoreFirstParameter()	Ignore the first parameter of the closure.

Methods inherited from class org.gnome.gobject.Closure

addFinalizeNotifier, addInvalidateNotifier, addMarshalGuards, getMemoryLayout, getType, invalidate, invoke, object, overrideMarshal, readData, readNotifiers, ref, removeFinalizeNotifier, removeInvalidateNotifier, setMarshal, setMetaMarshal, simple, sink, unref, writeData, writeNotifiers

Methods inherited from class org.javagi.base.ProxyInstance

equals, handle, hashCode

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Details

JavaClosure

public JavaClosure(Runnable callback)

Construct a Closure for a method or lambda that takes no parameters and returns void.

Parameters:

callback - a callback with signature void run()

JavaClosure

public JavaClosure(BooleanSupplier callback)

Construct a Closure for a method or lambda that takes no parameters and returns boolean.

Parameters:

callback - a callback with signature boolean run()

JavaClosure

public JavaClosure(Object lambda)
            throws IllegalArgumentException

Construct a Closure that will invoke the provided Java lambda using reflection. The Closure function arguments are read from the argument-Value containers and passed to the lambda. The return value of the lambda is put in the Closure return-Value.

Parameters:

lambda - a lambda (instance of a functional interface)

Throws:

IllegalArgumentException - if the lambda is not an instance of a functional interface

JavaClosure

public JavaClosure(@Nullable Object instance,
 Method method)

Construct a Closure that will invoke the provided Java method using reflection. The Closure function arguments are read from the argument-Value containers and passed to the method. The return value of the method is put in the Closure return-Value.

Parameters:

instance - a class instance on which the provided method will be invoked. When the method is static, this parameter is ignored and and may be null.

method - the method to invoke. See Method.invoke(Object, Object...)

Method Details

ignoreFirstParameter

public JavaClosure ignoreFirstParameter()

Ignore the first parameter of the closure. This is often the source of an event, a property binding, or something else that is not included in the Java API, so this option specifies to ignore it.

Returns:

this JavaClosure

getSingleMethod

public static Method getSingleMethod(Class<?> cls)
                              throws IllegalArgumentException

Get the single abstract method (SAM) implementation of a class that implements a functional interface. A functional interface is an interface with exactly one abstract method.

Parameters:

cls - a functional interface

Returns:

the Method reference to the method that implements the SAM

Throws:

IllegalArgumentException - if cls is not a functional interface