/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package org.hibernate.proxy;

import java.lang.reflect.Method;

import net.bytebuddy.implementation.bind.annotation.AllArguments;
import net.bytebuddy.implementation.bind.annotation.FieldValue;
import net.bytebuddy.implementation.bind.annotation.Origin;
import net.bytebuddy.implementation.bind.annotation.RuntimeType;
import net.bytebuddy.implementation.bind.annotation.StubValue;
import net.bytebuddy.implementation.bind.annotation.This;

A proxy configuration allows the definition of an interceptor object that decides on the behavior of a proxy.
This interface is meant for internal use but is in a public package in order to provide code generation.

While this interface depends on Byte Buddy types, this is only true for annotation types which are silently
suppressed by the runtime if they are not available on a class loader. This allows using this interceptor
and configuration with for example OSGi without any export of Byte Buddy when using Hibernate.
/**
 * A proxy configuration allows the definition of an interceptor object that decides on the behavior of a proxy.
 * This interface is meant for internal use but is in a public package in order to provide code generation.
 * <p>
 * While this interface depends on Byte Buddy types, this is only true for annotation types which are silently
 * suppressed by the runtime if they are not available on a class loader. This allows using this interceptor
 * and configuration with for example OSGi without any export of Byte Buddy when using Hibernate.
 */
public interface ProxyConfiguration {

	
The canonical field name for an interceptor object stored in a proxied object.
/**
	 * The canonical field name for an interceptor object stored in a proxied object.
	 */
	String INTERCEPTOR_FIELD_NAME = "$$_hibernate_interceptor";

	
Defines an interceptor object that specifies the behavior of the proxy object.
Params:
interceptor – The interceptor object./**
	 * Defines an interceptor object that specifies the behavior of the proxy object.
	 *
	 * @param interceptor The interceptor object.
	 */
	void $$_hibernate_set_interceptor(Interceptor interceptor);

	
An interceptor object that is responsible for invoking a proxy's method.
/**
	 * An interceptor object that is responsible for invoking a proxy's method.
	 */
	interface Interceptor {

		
Intercepts a method call to a proxy.
Params:
instance – The proxied instance.
method – The invoked method.
arguments – The intercepted method arguments.
Throws:
Throwable – If the intercepted method raises an exception.
Returns:
The method's return value./**
		 * Intercepts a method call to a proxy.
		 *
		 * @param instance The proxied instance.
		 * @param method The invoked method.
		 * @param arguments The intercepted method arguments.
		 *
		 * @return The method's return value.
		 *
		 * @throws Throwable If the intercepted method raises an exception.
		 */
		@RuntimeType
		Object intercept(@This Object instance, @Origin Method method, @AllArguments Object[] arguments) throws Throwable;
	}

	
A static interceptor that guards against method calls before the interceptor is set.
/**
	 * A static interceptor that guards against method calls before the interceptor is set.
	 */
	class InterceptorDispatcher {

		
Intercepts a method call to a proxy.
Params:
instance – The proxied instance.
method – The invoked method.
arguments – The method arguments.
stubValue – The intercepted method's default value.
interceptor – The proxy object's interceptor instance.
Throws:
Throwable – If the intercepted method raises an exception.
Returns:
The intercepted method's return value./**
		 * Intercepts a method call to a proxy.
		 *
		 * @param instance The proxied instance.
		 * @param method The invoked method.
		 * @param arguments The method arguments.
		 * @param stubValue The intercepted method's default value.
		 * @param interceptor The proxy object's interceptor instance.
		 *
		 * @return The intercepted method's return value.
		 *
		 * @throws Throwable If the intercepted method raises an exception.
		 */
		@RuntimeType
		public static Object intercept(
				@This final Object instance,
				@Origin final Method method,
				@AllArguments final Object[] arguments,
				@StubValue final Object stubValue,
				@FieldValue(INTERCEPTOR_FIELD_NAME) Interceptor interceptor
		) throws Throwable {
			if ( interceptor == null ) {
				if ( method.getName().equals( "getHibernateLazyInitializer" ) ) {
					return instance;
				}
				else {
					return stubValue;
				}
			}
			else {
				return interceptor.intercept( instance, method, arguments );
			}
		}
	}
}