Java CallSite.getTarget方法代碼示例

import java.lang.invoke.CallSite; //導入方法依賴的package包/類
@Test
public void accessInstanceMethodWithFunction() throws Throwable {

    SimpleBean simpleBeanInstance = new SimpleBean();

    MethodHandles.Lookup caller = MethodHandles.lookup();
    MethodType getter = MethodType.methodType(Object.class);

    MethodHandle target = caller.findVirtual(SimpleBean.class, "getObj", getter);
    MethodType func = target.type();
    System.out.println(func);
    System.out.println(func.generic());
    CallSite site = LambdaMetafactory.metafactory(caller, "apply", MethodType.methodType(Function.class), func.generic(), target, func);

    MethodHandle factory = site.getTarget();
    Function r = (Function) factory.invoke();
    assertEquals("myCustomObject", r.apply(simpleBeanInstance));

}
 

import java.lang.invoke.CallSite; //導入方法依賴的package包/類
@Test
public void accessObjectInstanceMethod() throws Throwable {

    SimpleBean simpleBeanInstance = new SimpleBean();

    MethodHandles.Lookup caller = MethodHandles.lookup();

    Method reflected = SimpleBean.class.getDeclaredMethod("getObj");
    MethodHandle methodHandle = caller.unreflect(reflected);

    CallSite site = LambdaMetafactory.metafactory(caller, "get", MethodType.methodType(Supplier.class, SimpleBean.class),
            MethodType.methodType(Object.class), methodHandle, MethodType.methodType(Object.class));

    MethodHandle factory = site.getTarget();
    factory = factory.bindTo(simpleBeanInstance);
    Supplier r = (Supplier) factory.invoke();
    assertEquals(simpleBeanInstance.getObj(), r.get());
}
 

import java.lang.invoke.CallSite; //導入方法依賴的package包/類
public JavaConstant getCallSiteTarget(Assumptions assumptions) {
    if (object instanceof CallSite) {
        CallSite callSite = (CallSite) object;
        MethodHandle target = callSite.getTarget();
        if (!(callSite instanceof ConstantCallSite)) {
            if (assumptions == null) {
                return null;
            }
            assumptions.record(new Assumptions.CallSiteTargetValue(callSite, target));
        }
        return HotSpotObjectConstantImpl.forObject(target);
    }
    return null;
}
 

import java.lang.invoke.CallSite; //導入方法依賴的package包/類
private ParseFromBytes makeDeserializationFunc(Class<?> type, ParseFromBytes func) {
    try {
        MethodType originFuncArgs = MethodType.methodType(type, byte[].class);
        MethodType targetFuncArgs = MethodType.methodType(Object.class, byte[].class);
        MethodType targetClass = MethodType.methodType(ParseFromBytes.class);
        MethodHandle originFuncHandle = caller.findStatic(type, "parseFrom", originFuncArgs);
        CallSite callSite = LambdaMetafactory.metafactory(caller, "parseFormData", targetClass, targetFuncArgs,
                originFuncHandle, originFuncArgs);
        MethodHandle factory = callSite.getTarget();
        func = (ParseFromBytes) factory.invoke();
    } catch (Throwable e) {
        log.error("makeDeserializationFunc error ..", e);
    }
    return func;
}
 

import java.lang.invoke.CallSite; //導入方法依賴的package包/類
private void buildFunction(final MethodHandles.Lookup caller, final MethodHandle methodHandle) {
	try {
		final MethodType func = methodHandle.type();
		final CallSite site = LambdaMetafactory.metafactory(caller, "apply", MethodType.methodType(Function.class),
				MethodType.methodType(Object.class, Object.class), methodHandle, MethodType.methodType(func.returnType(), func.parameterArray()));

		final MethodHandle factory = site.getTarget();
		function = (Function<BEAN, R>) factory.invoke();

	} catch (final Throwable e) {
		throw new RuntimeException(e);
	}
}
 

import java.lang.invoke.CallSite; //導入方法依賴的package包/類
private void build(final MethodHandles.Lookup caller, final MethodHandle methodHandle) {
	try {
		final MethodType func = methodHandle.type();
		final CallSite site = LambdaMetafactory.metafactory(caller, "apply", MethodType.methodType(BiFunction.class),
				MethodType.methodType(Object.class, Object.class, Object.class), methodHandle, MethodType.methodType(func.returnType(), func.parameterArray()));

		final MethodHandle factory = site.getTarget();
		function = (BiFunction<BEAN, R, BEAN>) factory.invoke();

	} catch (final Throwable e) {
		throw new RuntimeException(e);
	}
}
 

import java.lang.invoke.CallSite; //導入方法依賴的package包/類
private void build(final MethodHandles.Lookup caller, final MethodHandle methodHandle) {
	try {
		final MethodType func = methodHandle.type();
		final CallSite site = LambdaMetafactory.metafactory(caller, "accept", MethodType.methodType(BiConsumer.class),
				MethodType.methodType(Void.TYPE, Object.class, Object.class), methodHandle, MethodType.methodType(Void.TYPE, func.parameterArray()));

		final MethodHandle factory = site.getTarget();
		consumer = (BiConsumer<BEAN, R>) factory.invoke();

	} catch (final Throwable e) {
		throw new RuntimeException(e);
	}
}
 

import java.lang.invoke.CallSite; //導入方法依賴的package包/類
@Test
public void accessStaticMethod() throws Throwable {
    MethodHandles.Lookup caller = MethodHandles.lookup();
    Method reflected = SimpleBean.class.getDeclaredMethod("getStaticObj");
    MethodHandle methodHandle = caller.unreflect(reflected);
    CallSite site = LambdaMetafactory.metafactory(caller, "get", MethodType.methodType(Supplier.class), MethodType.methodType(Object.class), methodHandle,
            MethodType.methodType(Object.class));
    MethodHandle factory = site.getTarget();
    Supplier r = (Supplier) factory.invoke();
    assertEquals(SimpleBean.getStaticObj(), r.get());
}
 

import java.lang.invoke.CallSite; //導入方法依賴的package包/類
@Test
public void accessStringInstanceSetterMethodAttemptTwo() throws Throwable {

    SimpleBean simpleBeanInstance = new SimpleBean();

    MethodHandles.Lookup caller = MethodHandles.lookup();

    MethodType setter = MethodType.methodType(Void.TYPE, Object.class);
    MethodHandle target = caller.findVirtual(SimpleBean.class, "setObj", setter);

    // target.invoke(simpleBeanInstance, "newStringValue");
    // assertEquals( "newStringValue" , simpleBeanInstance.getObj() );

    MethodType func = target.type(); // MethodType.methodType(Void.TYPE,
                                     // SimpleBean.class, String.class),
    System.out.println(func);
    System.out.println(func.generic());
    System.out.println(MethodType.methodType(Void.TYPE, SimpleBean.class, Object.class));

    CallSite site = LambdaMetafactory.metafactory(caller, "accept", MethodType.methodType(BiConsumer.class),
            MethodType.methodType(Void.TYPE, Object.class, Object.class), target, func);

    MethodHandle factory = site.getTarget();
    BiConsumer r = (BiConsumer) factory.invoke();
    r.accept(simpleBeanInstance, "newCustomObject");

    assertEquals("newCustomObject", simpleBeanInstance.getObj());

}
 

import java.lang.invoke.CallSite; //導入方法依賴的package包/類
@Test
public void accessPrimitiveInstanceMethod() throws Throwable {

    SimpleBean simpleBeanInstance = new SimpleBean();

    MethodHandles.Lookup caller = MethodHandles.lookup();

    Method reflected = SimpleBean.class.getDeclaredMethod("getIntPrimitive");
    MethodHandle methodHandle = caller.unreflect(reflected);

    CallSite site = LambdaMetafactory.metafactory(caller, "get", MethodType.methodType(Supplier.class, SimpleBean.class),
            MethodType.methodType(Object.class), methodHandle, MethodType.methodType(int.class));

    MethodHandle factory = site.getTarget();
    factory = factory.bindTo(simpleBeanInstance);
    Supplier r = (Supplier) factory.invoke();
    assertEquals(simpleBeanInstance.getIntPrimitive(), r.get());

}
 

import java.lang.invoke.CallSite; //導入方法依賴的package包/類
@Test
public void accessStringInstanceMethod() throws Throwable {

    SimpleBean simpleBeanInstance = new SimpleBean();

    MethodHandles.Lookup caller = MethodHandles.lookup();

    Method reflected = SimpleBean.class.getDeclaredMethod("getValue");
    MethodHandle methodHandle = caller.unreflect(reflected);

    CallSite site = LambdaMetafactory.metafactory(caller, "get", MethodType.methodType(Supplier.class, SimpleBean.class),
            MethodType.methodType(Object.class), methodHandle, MethodType.methodType(String.class));

    MethodHandle factory = site.getTarget();
    factory = factory.bindTo(simpleBeanInstance);
    Supplier r = (Supplier) factory.invoke();
    assertEquals(simpleBeanInstance.getValue(), r.get());

}
 

import java.lang.invoke.CallSite; //導入方法依賴的package包/類
private void buildFactory(String name, MethodHandles.Lookup caller, MethodType fact, MethodType getter) throws LambdaConversionException, IllegalAccessException {
	CallSite site = LambdaMetafactory.metafactory(caller, name, fact, getter, target, getter);
	factory = site.getTarget();
}
 

import java.lang.invoke.CallSite; //導入方法依賴的package包/類
/**
 * This method uses {@link LambdaMetafactory} to create a lambda. 
 * <br>
 * The lambda will implement the argument provided interface.
 * <br>
 * This interface is expected to contain a signature that matches the method, for which we are creating the lambda.
 * In the context of the lambda-factory project, this interface will always be the same, namely an auto-generate interface
 * with abstract methods for all combinations of primitives + Object (up until some max number of arguments.)
 * <p>
 * 
 * @param method The {@link Method} we are trying to create "direct invocation fast" access to.
 * @param setAccessible a boolean flag indicating whether or not the returned lambda shall force access private methods. 
 * This corresponds to {@link Method#setAccessible(boolean)}. 
 * @param interfaceClass The interface, which the created lambda will implement. 
 * In the context of the lambda-factory project this will always be the same, namely a compile time auto-generated interface. See {@link GenerateLambdaProcessor}.
 * @param the name of the method from the interface, which shall be implemented. This argument exists for the sake of jUnit testing.
 * @return An instance of the argument provided interface, which implements only 1 of the interface's methods, namely the one whose signature matches the methods, we are create fast access to.
 * @throws Throwable
 */
private static <T> T privateCreateLambda(Method method, MethodHandles.Lookup lookup, Class<T> interfaceClass, String signatureName, boolean createSpecial) throws Throwable {
	MethodHandle methodHandle = createSpecial? lookup.unreflectSpecial(method, method.getDeclaringClass()) : lookup.unreflect(method);
	MethodType instantiatedMethodType = methodHandle.type();
	MethodType signature = createLambdaMethodType(method, instantiatedMethodType);

	CallSite site = createCallSite(signatureName, lookup, methodHandle, instantiatedMethodType, signature,interfaceClass);
	MethodHandle factory = site.getTarget();
	return (T) factory.invoke();
}