/// <summary>
/// Produces an instance of the given single-method interface which redirects
/// its calls to the given method handle.
/// <para>
/// A single-method interface is an interface which declares a uniquely named method.
/// When determining the uniquely named method of a single-method interface,
/// the public {@code Object} methods ({@code toString}, {@code equals}, {@code hashCode})
/// are disregarded. For example, <seealso cref="java.util.Comparator"/> is a single-method interface,
/// even though it re-declares the {@code Object.equals} method.
/// </para>
/// <para>
/// The interface must be public. No additional access checks are performed.
/// </para>
/// <para>
/// The resulting instance of the required type will respond to
/// invocation of the type's uniquely named method by calling
/// the given target on the incoming arguments,
/// and returning or throwing whatever the target
/// returns or throws. The invocation will be as if by
/// {@code target.invoke}.
/// The target's type will be checked before the
/// instance is created, as if by a call to {@code asType},
/// which may result in a {@code WrongMethodTypeException}.
/// </para>
/// <para>
/// The uniquely named method is allowed to be multiply declared,
/// with distinct type descriptors. (E.g., it can be overloaded,
/// or can possess bridge methods.) All such declarations are
/// connected directly to the target method handle.
/// Argument and return types are adjusted by {@code asType}
/// for each individual declaration.
/// </para>
/// <para>
/// The wrapper instance will implement the requested interface
/// and its super-types, but no other single-method interfaces.
/// This means that the instance will not unexpectedly
/// pass an {@code instanceof} test for any unrequested type.
/// <p style="font-size:smaller;">
/// <em>Implementation Note:</em>
/// Therefore, each instance must implement a unique single-method interface.
/// Implementations may not bundle together
/// multiple single-method interfaces onto single implementation classes
/// in the style of <seealso cref="java.awt.AWTEventMulticaster"/>.
/// </para>
/// <para>
/// The method handle may throw an <em>undeclared exception</em>,
/// which means any checked exception (or other checked throwable)
/// not declared by the requested type's single abstract method.
/// If this happens, the throwable will be wrapped in an instance of
/// <seealso cref="java.lang.reflect.UndeclaredThrowableException UndeclaredThrowableException"/>
/// and thrown in that wrapped form.
/// </para>
/// <para>
/// Like <seealso cref="java.lang.Integer#valueOf Integer.valueOf"/>,
/// {@code asInterfaceInstance} is a factory method whose results are defined
/// by their behavior.
/// It is not guaranteed to return a new instance for every call.
/// </para>
/// <para>
/// Because of the possibility of <seealso cref="java.lang.reflect.Method#isBridge bridge methods"/>
/// and other corner cases, the interface may also have several abstract methods
/// with the same name but having distinct descriptors (types of returns and parameters).
/// In this case, all the methods are bound in common to the one given target.
/// The type check and effective {@code asType} conversion is applied to each
/// method type descriptor, and all abstract methods are bound to the target in common.
/// Beyond this type check, no further checks are made to determine that the
/// abstract methods are related in any way.
/// </para>
/// <para>
/// Future versions of this API may accept additional types,
/// such as abstract classes with single abstract methods.
/// Future versions of this API may also equip wrapper instances
/// with one or more additional public "marker" interfaces.
/// </para>
/// <para>
/// If a security manager is installed, this method is caller sensitive.
/// During any invocation of the target method handle via the returned wrapper,
/// the original creator of the wrapper (the caller) will be visible
/// to context checks requested by the security manager.
///
/// </para>
/// </summary>
/// @param <T> the desired type of the wrapper, a single-method interface </param>
/// <param name="intfc"> a class object representing {@code T} </param>
/// <param name="target"> the method handle to invoke from the wrapper </param>
/// <returns> a correctly-typed wrapper for the given target </returns>
/// <exception cref="NullPointerException"> if either argument is null </exception>
/// <exception cref="IllegalArgumentException"> if the {@code intfc} is not a
/// valid argument to this method </exception>
/// <exception cref="WrongMethodTypeException"> if the target cannot
/// be converted to the type required by the requested interface </exception>
// Other notes to implementors:
// <p>
// No stable mapping is promised between the single-method interface and
// the implementation class C. Over time, several implementation
// classes might be used for the same type.
// <p>
// If the implementation is able
// to prove that a wrapper of the required type
// has already been created for a given
// method handle, or for another method handle with the
// same behavior, the implementation may return that wrapper in place of
// a new wrapper.
// <p>
// This method is designed to apply to common use cases
// where a single method handle must interoperate with
// an interface that implements a function-like
// API. Additional variations, such as single-abstract-method classes with
// private constructors, or interfaces with multiple but related
// entry points, must be covered by hand-written or automatically
// generated adapter classes.
//
//JAVA TO C# CONVERTER TODO TASK: Most Java annotations will not have direct .NET equivalent attributes:
//ORIGINAL LINE: @CallerSensitive public static <T> T asInterfaceInstance(final Class intfc, final MethodHandle target)
//JAVA TO C# CONVERTER WARNING: 'final' parameters are not allowed in .NET:
public static T asInterfaceInstance <T>(Class intfc, MethodHandle target)
{
if (!intfc.Interface || !Modifier.IsPublic(intfc.Modifiers))
{
throw newIllegalArgumentException("not a public interface", intfc.Name);
}
//JAVA TO C# CONVERTER WARNING: The original Java variable was marked 'final':
//ORIGINAL LINE: final MethodHandle mh;
MethodHandle mh;
if (System.SecurityManager != null)
{
//JAVA TO C# CONVERTER WARNING: The original Java variable was marked 'final':
//ORIGINAL LINE: final Class caller = sun.reflect.Reflection.getCallerClass();
Class caller = Reflection.CallerClass;
//JAVA TO C# CONVERTER WARNING: The original Java variable was marked 'final':
//ORIGINAL LINE: final ClassLoader ccl = caller != null ? caller.getClassLoader() : null;
ClassLoader ccl = caller != null ? caller.ClassLoader : null;
ReflectUtil.checkProxyPackageAccess(ccl, intfc);
mh = ccl != null?BindCaller(target, caller) : target;
}
else
{
mh = target;
}
ClassLoader proxyLoader = intfc.ClassLoader;
if (proxyLoader == null)
{
ClassLoader cl = Thread.CurrentThread.ContextClassLoader; // avoid use of BCP
proxyLoader = cl != null ? cl : ClassLoader.SystemClassLoader;
}
//JAVA TO C# CONVERTER WARNING: The original Java variable was marked 'final':
//ORIGINAL LINE: final Method[] methods = getSingleNameMethods(intfc);
Method[] methods = GetSingleNameMethods(intfc);
if (methods == null)
{
throw newIllegalArgumentException("not a single-method interface", intfc.Name);
}
//JAVA TO C# CONVERTER WARNING: The original Java variable was marked 'final':
//ORIGINAL LINE: final MethodHandle[] vaTargets = new MethodHandle[methods.length];
MethodHandle[] vaTargets = new MethodHandle[methods.Length];
for (int i = 0; i < methods.Length; i++)
{
Method sm = methods[i];
MethodType smMT = MethodType.MethodType(sm.ReturnType, sm.ParameterTypes);
MethodHandle checkTarget = mh.AsType(smMT); // make throw WMT
checkTarget = checkTarget.AsType(checkTarget.Type().ChangeReturnType(typeof(Object)));
vaTargets[i] = checkTarget.AsSpreader(typeof(Object[]), smMT.ParameterCount());
}
//JAVA TO C# CONVERTER WARNING: The original Java variable was marked 'final':
//ORIGINAL LINE: final InvocationHandler ih = new InvocationHandler()
InvocationHandler ih = new InvocationHandlerAnonymousInnerClassHelper(intfc, target, methods, vaTargets);
//JAVA TO C# CONVERTER WARNING: The original Java variable was marked 'final':
//ORIGINAL LINE: final Object proxy;
Object proxy;
if (System.SecurityManager != null)
{
// sun.invoke.WrapperInstance is a restricted interface not accessible
// by any non-null class loader.
//JAVA TO C# CONVERTER WARNING: The original Java variable was marked 'final':
//ORIGINAL LINE: final ClassLoader loader = proxyLoader;
ClassLoader loader = proxyLoader;
proxy = AccessController.doPrivileged(new PrivilegedActionAnonymousInnerClassHelper(intfc, ih, loader));
}
else
{
proxy = Proxy.NewProxyInstance(proxyLoader, new Class[] { intfc, typeof(WrapperInstance) }, ih);
}
return(intfc.Cast(proxy));
}
