/*
 * Copyright 2002-2020 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.web.method.support;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Arrays;

import org.springframework.core.CoroutinesUtils;
import org.springframework.core.DefaultParameterNameDiscoverer;
import org.springframework.core.KotlinDetector;
import org.springframework.core.MethodParameter;
import org.springframework.core.ParameterNameDiscoverer;
import org.springframework.lang.Nullable;
import org.springframework.util.ObjectUtils;
import org.springframework.util.ReflectionUtils;
import org.springframework.web.bind.WebDataBinder;
import org.springframework.web.bind.support.SessionStatus;
import org.springframework.web.bind.support.WebDataBinderFactory;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.method.HandlerMethod;

Extension of HandlerMethod that invokes the underlying method with argument values resolved from the current HTTP request through a list of HandlerMethodArgumentResolver. 
Author:
Rossen Stoyanchev, Juergen Hoeller, Sebastien Deleuze
Since:
3.1/**
 * Extension of {@link HandlerMethod} that invokes the underlying method with
 * argument values resolved from the current HTTP request through a list of
 * {@link HandlerMethodArgumentResolver}.
 *
 * @author Rossen Stoyanchev
 * @author Juergen Hoeller
 * @author Sebastien Deleuze
 * @since 3.1
 */
public class InvocableHandlerMethod extends HandlerMethod {

	private static final Object[] EMPTY_ARGS = new Object[0];


	private HandlerMethodArgumentResolverComposite resolvers = new HandlerMethodArgumentResolverComposite();

	private ParameterNameDiscoverer parameterNameDiscoverer = new DefaultParameterNameDiscoverer();

	@Nullable
	private WebDataBinderFactory dataBinderFactory;


	
Create an instance from a HandlerMethod. /**
	 * Create an instance from a {@code HandlerMethod}.
	 */
	public InvocableHandlerMethod(HandlerMethod handlerMethod) {
		super(handlerMethod);
	}

	
Create an instance from a bean instance and a method.
/**
	 * Create an instance from a bean instance and a method.
	 */
	public InvocableHandlerMethod(Object bean, Method method) {
		super(bean, method);
	}

	
Construct a new handler method with the given bean instance, method name and parameters.
Params:
bean – the object bean
methodName – the method name
parameterTypes – the method parameter types
Throws:
NoSuchMethodException – when the method cannot be found/**
	 * Construct a new handler method with the given bean instance, method name and parameters.
	 * @param bean the object bean
	 * @param methodName the method name
	 * @param parameterTypes the method parameter types
	 * @throws NoSuchMethodException when the method cannot be found
	 */
	public InvocableHandlerMethod(Object bean, String methodName, Class<?>... parameterTypes)
			throws NoSuchMethodException {

		super(bean, methodName, parameterTypes);
	}


	
Set HandlerMethodArgumentResolvers to use for resolving method argument values. /**
	 * Set {@link HandlerMethodArgumentResolver HandlerMethodArgumentResolvers}
	 * to use for resolving method argument values.
	 */
	public void setHandlerMethodArgumentResolvers(HandlerMethodArgumentResolverComposite argumentResolvers) {
		this.resolvers = argumentResolvers;
	}

	
Set the ParameterNameDiscoverer for resolving parameter names when needed
(e.g. default request attribute name).
Default is a DefaultParameterNameDiscoverer. /**
	 * Set the ParameterNameDiscoverer for resolving parameter names when needed
	 * (e.g. default request attribute name).
	 * <p>Default is a {@link org.springframework.core.DefaultParameterNameDiscoverer}.
	 */
	public void setParameterNameDiscoverer(ParameterNameDiscoverer parameterNameDiscoverer) {
		this.parameterNameDiscoverer = parameterNameDiscoverer;
	}

	
Set the WebDataBinderFactory to be passed to argument resolvers allowing them to create a WebDataBinder for data binding and type conversion purposes. /**
	 * Set the {@link WebDataBinderFactory} to be passed to argument resolvers allowing them
	 * to create a {@link WebDataBinder} for data binding and type conversion purposes.
	 */
	public void setDataBinderFactory(WebDataBinderFactory dataBinderFactory) {
		this.dataBinderFactory = dataBinderFactory;
	}


	
Invoke the method after resolving its argument values in the context of the given request.
Argument values are commonly resolved through HandlerMethodArgumentResolvers. The providedArgs parameter however may supply argument values to be used directly, i.e. without argument resolution. Examples of provided argument values include a WebDataBinder, a SessionStatus, or a thrown exception instance. Provided argument values are checked before argument resolvers. 
Delegates to getMethodArgumentValues and calls doInvoke with the resolved arguments. 
Params:
request – the current request
mavContainer – the ModelAndViewContainer for this request
providedArgs – "given" arguments matched by type, not resolved
Throws:
Exception – raised if no suitable argument resolver can be found,
or if the method raised an exception
See Also:
getMethodArgumentValues
doInvoke
Returns:
the raw value returned by the invoked method/**
	 * Invoke the method after resolving its argument values in the context of the given request.
	 * <p>Argument values are commonly resolved through
	 * {@link HandlerMethodArgumentResolver HandlerMethodArgumentResolvers}.
	 * The {@code providedArgs} parameter however may supply argument values to be used directly,
	 * i.e. without argument resolution. Examples of provided argument values include a
	 * {@link WebDataBinder}, a {@link SessionStatus}, or a thrown exception instance.
	 * Provided argument values are checked before argument resolvers.
	 * <p>Delegates to {@link #getMethodArgumentValues} and calls {@link #doInvoke} with the
	 * resolved arguments.
	 * @param request the current request
	 * @param mavContainer the ModelAndViewContainer for this request
	 * @param providedArgs "given" arguments matched by type, not resolved
	 * @return the raw value returned by the invoked method
	 * @throws Exception raised if no suitable argument resolver can be found,
	 * or if the method raised an exception
	 * @see #getMethodArgumentValues
	 * @see #doInvoke
	 */
	@Nullable
	public Object invokeForRequest(NativeWebRequest request, @Nullable ModelAndViewContainer mavContainer,
			Object... providedArgs) throws Exception {

		Object[] args = getMethodArgumentValues(request, mavContainer, providedArgs);
		if (logger.isTraceEnabled()) {
			logger.trace("Arguments: " + Arrays.toString(args));
		}
		return doInvoke(args);
	}

	
Get the method argument values for the current request, checking the provided
argument values and falling back to the configured argument resolvers.
The resulting array will be passed into doInvoke. 
Since:
5.1.2/**
	 * Get the method argument values for the current request, checking the provided
	 * argument values and falling back to the configured argument resolvers.
	 * <p>The resulting array will be passed into {@link #doInvoke}.
	 * @since 5.1.2
	 */
	protected Object[] getMethodArgumentValues(NativeWebRequest request, @Nullable ModelAndViewContainer mavContainer,
			Object... providedArgs) throws Exception {

		MethodParameter[] parameters = getMethodParameters();
		if (ObjectUtils.isEmpty(parameters)) {
			return EMPTY_ARGS;
		}

		Object[] args = new Object[parameters.length];
		for (int i = 0; i < parameters.length; i++) {
			MethodParameter parameter = parameters[i];
			parameter.initParameterNameDiscovery(this.parameterNameDiscoverer);
			args[i] = findProvidedArgument(parameter, providedArgs);
			if (args[i] != null) {
				continue;
			}
			if (!this.resolvers.supportsParameter(parameter)) {
				throw new IllegalStateException(formatArgumentError(parameter, "No suitable resolver"));
			}
			try {
				args[i] = this.resolvers.resolveArgument(parameter, mavContainer, request, this.dataBinderFactory);
			}
			catch (Exception ex) {
				// Leave stack trace for later, exception may actually be resolved and handled...
				if (logger.isDebugEnabled()) {
					String exMsg = ex.getMessage();
					if (exMsg != null && !exMsg.contains(parameter.getExecutable().toGenericString())) {
						logger.debug(formatArgumentError(parameter, exMsg));
					}
				}
				throw ex;
			}
		}
		return args;
	}

	
Invoke the handler method with the given argument values.
/**
	 * Invoke the handler method with the given argument values.
	 */
	@Nullable
	protected Object doInvoke(Object... args) throws Exception {
		Method method = getBridgedMethod();
		ReflectionUtils.makeAccessible(method);
		try {
			if (KotlinDetector.isSuspendingFunction(method)) {
				return CoroutinesUtils.invokeSuspendingFunction(method, getBean(), args);
			}
			return method.invoke(getBean(), args);
		}
		catch (IllegalArgumentException ex) {
			assertTargetBean(method, getBean(), args);
			String text = (ex.getMessage() != null ? ex.getMessage() : "Illegal argument");
			throw new IllegalStateException(formatInvokeError(text, args), ex);
		}
		catch (InvocationTargetException ex) {
			// Unwrap for HandlerExceptionResolvers ...
			Throwable targetException = ex.getTargetException();
			if (targetException instanceof RuntimeException) {
				throw (RuntimeException) targetException;
			}
			else if (targetException instanceof Error) {
				throw (Error) targetException;
			}
			else if (targetException instanceof Exception) {
				throw (Exception) targetException;
			}
			else {
				throw new IllegalStateException(formatInvokeError("Invocation failure", args), targetException);
			}
		}
	}

}