org.springframework.web.method.HandlerMethod Maven / Gradle / Ivy
/*
* Copyright 2002-2017 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;
import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.core.BridgeMethodResolver;
import org.springframework.core.GenericTypeResolver;
import org.springframework.core.MethodParameter;
import org.springframework.core.annotation.AnnotatedElementUtils;
import org.springframework.core.annotation.SynthesizingMethodParameter;
import org.springframework.http.HttpStatus;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.web.bind.annotation.ResponseStatus;
/**
* Encapsulates information about a handler method consisting of a
* {@linkplain #getMethod() method} and a {@linkplain #getBean() bean}.
* Provides convenient access to method parameters, the method return value,
* method annotations, etc.
*
* The class may be created with a bean instance or with a bean name
* (e.g. lazy-init bean, prototype bean). Use {@link #createWithResolvedBean()}
* to obtain a {@code HandlerMethod} instance with a bean instance resolved
* through the associated {@link BeanFactory}.
*
* @author Arjen Poutsma
* @author Rossen Stoyanchev
* @author Juergen Hoeller
* @author Sam Brannen
* @since 3.1
*/
public class HandlerMethod {
/** Logger that is available to subclasses */
protected final Log logger = LogFactory.getLog(getClass());
private final Object bean;
@Nullable
private final BeanFactory beanFactory;
private final Class beanType;
private final Method method;
private final Method bridgedMethod;
private final MethodParameter[] parameters;
@Nullable
private HttpStatus responseStatus;
@Nullable
private String responseStatusReason;
@Nullable
private HandlerMethod resolvedFromHandlerMethod;
/**
* Create an instance from a bean instance and a method.
*/
public HandlerMethod(Object bean, Method method) {
Assert.notNull(bean, "Bean is required");
Assert.notNull(method, "Method is required");
this.bean = bean;
this.beanFactory = null;
this.beanType = ClassUtils.getUserClass(bean);
this.method = method;
this.bridgedMethod = BridgeMethodResolver.findBridgedMethod(method);
this.parameters = initMethodParameters();
evaluateResponseStatus();
}
/**
* Create an instance from a bean instance, method name, and parameter types.
* @throws NoSuchMethodException when the method cannot be found
*/
public HandlerMethod(Object bean, String methodName, Class... parameterTypes) throws NoSuchMethodException {
Assert.notNull(bean, "Bean is required");
Assert.notNull(methodName, "Method name is required");
this.bean = bean;
this.beanFactory = null;
this.beanType = ClassUtils.getUserClass(bean);
this.method = bean.getClass().getMethod(methodName, parameterTypes);
this.bridgedMethod = BridgeMethodResolver.findBridgedMethod(this.method);
this.parameters = initMethodParameters();
evaluateResponseStatus();
}
/**
* Create an instance from a bean name, a method, and a {@code BeanFactory}.
* The method {@link #createWithResolvedBean()} may be used later to
* re-create the {@code HandlerMethod} with an initialized bean.
*/
public HandlerMethod(String beanName, BeanFactory beanFactory, Method method) {
Assert.hasText(beanName, "Bean name is required");
Assert.notNull(beanFactory, "BeanFactory is required");
Assert.notNull(method, "Method is required");
this.bean = beanName;
this.beanFactory = beanFactory;
Class beanType = beanFactory.getType(beanName);
if (beanType == null) {
throw new IllegalStateException("Cannot resolve bean type for bean with name '" + beanName + "'");
}
this.beanType = ClassUtils.getUserClass(beanType);
this.method = method;
this.bridgedMethod = BridgeMethodResolver.findBridgedMethod(method);
this.parameters = initMethodParameters();
evaluateResponseStatus();
}
/**
* Copy constructor for use in subclasses.
*/
protected HandlerMethod(HandlerMethod handlerMethod) {
Assert.notNull(handlerMethod, "HandlerMethod is required");
this.bean = handlerMethod.bean;
this.beanFactory = handlerMethod.beanFactory;
this.beanType = handlerMethod.beanType;
this.method = handlerMethod.method;
this.bridgedMethod = handlerMethod.bridgedMethod;
this.parameters = handlerMethod.parameters;
this.responseStatus = handlerMethod.responseStatus;
this.responseStatusReason = handlerMethod.responseStatusReason;
this.resolvedFromHandlerMethod = handlerMethod.resolvedFromHandlerMethod;
}
/**
* Re-create HandlerMethod with the resolved handler.
*/
private HandlerMethod(HandlerMethod handlerMethod, Object handler) {
Assert.notNull(handlerMethod, "HandlerMethod is required");
Assert.notNull(handler, "Handler object is required");
this.bean = handler;
this.beanFactory = handlerMethod.beanFactory;
this.beanType = handlerMethod.beanType;
this.method = handlerMethod.method;
this.bridgedMethod = handlerMethod.bridgedMethod;
this.parameters = handlerMethod.parameters;
this.responseStatus = handlerMethod.responseStatus;
this.responseStatusReason = handlerMethod.responseStatusReason;
this.resolvedFromHandlerMethod = handlerMethod;
}
private MethodParameter[] initMethodParameters() {
int count = this.bridgedMethod.getParameterCount();
MethodParameter[] result = new MethodParameter[count];
for (int i = 0; i < count; i++) {
HandlerMethodParameter parameter = new HandlerMethodParameter(i);
GenericTypeResolver.resolveParameterType(parameter, this.beanType);
result[i] = parameter;
}
return result;
}
private void evaluateResponseStatus() {
ResponseStatus annotation = getMethodAnnotation(ResponseStatus.class);
if (annotation == null) {
annotation = AnnotatedElementUtils.findMergedAnnotation(getBeanType(), ResponseStatus.class);
}
if (annotation != null) {
this.responseStatus = annotation.code();
this.responseStatusReason = annotation.reason();
}
}
/**
* Return the bean for this handler method.
*/
public Object getBean() {
return this.bean;
}
/**
* Return the method for this handler method.
*/
public Method getMethod() {
return this.method;
}
/**
* This method returns the type of the handler for this handler method.
*
Note that if the bean type is a CGLIB-generated class, the original
* user-defined class is returned.
*/
public Class getBeanType() {
return this.beanType;
}
/**
* If the bean method is a bridge method, this method returns the bridged
* (user-defined) method. Otherwise it returns the same method as {@link #getMethod()}.
*/
protected Method getBridgedMethod() {
return this.bridgedMethod;
}
/**
* Return the method parameters for this handler method.
*/
public MethodParameter[] getMethodParameters() {
return this.parameters;
}
/**
* Return the specified response status, if any.
* @since 4.3.8
* @see ResponseStatus#code()
*/
@Nullable
protected HttpStatus getResponseStatus() {
return this.responseStatus;
}
/**
* Return the associated response status reason, if any.
* @since 4.3.8
* @see ResponseStatus#reason()
*/
@Nullable
protected String getResponseStatusReason() {
return this.responseStatusReason;
}
/**
* Return the HandlerMethod return type.
*/
public MethodParameter getReturnType() {
return new HandlerMethodParameter(-1);
}
/**
* Return the actual return value type.
*/
public MethodParameter getReturnValueType(@Nullable Object returnValue) {
return new ReturnValueMethodParameter(returnValue);
}
/**
* Return {@code true} if the method return type is void, {@code false} otherwise.
*/
public boolean isVoid() {
return Void.TYPE.equals(getReturnType().getParameterType());
}
/**
* Return a single annotation on the underlying method traversing its super methods
* if no annotation can be found on the given method itself.
*
Also supports merged composed annotations with attribute
* overrides as of Spring Framework 4.2.2.
* @param annotationType the type of annotation to introspect the method for
* @return the annotation, or {@code null} if none found
* @see AnnotatedElementUtils#findMergedAnnotation
*/
@Nullable
public A getMethodAnnotation(Class annotationType) {
return AnnotatedElementUtils.findMergedAnnotation(this.method, annotationType);
}
/**
* Return whether the parameter is declared with the given annotation type.
* @param annotationType the annotation type to look for
* @since 4.3
* @see AnnotatedElementUtils#hasAnnotation
*/
public boolean hasMethodAnnotation(Class annotationType) {
return AnnotatedElementUtils.hasAnnotation(this.method, annotationType);
}
/**
* Return the HandlerMethod from which this HandlerMethod instance was
* resolved via {@link #createWithResolvedBean()}.
*/
@Nullable
public HandlerMethod getResolvedFromHandlerMethod() {
return this.resolvedFromHandlerMethod;
}
/**
* If the provided instance contains a bean name rather than an object instance,
* the bean name is resolved before a {@link HandlerMethod} is created and returned.
*/
public HandlerMethod createWithResolvedBean() {
Object handler = this.bean;
if (this.bean instanceof String) {
Assert.state(this.beanFactory != null, "Cannot resolve bean name without BeanFactory");
String beanName = (String) this.bean;
handler = this.beanFactory.getBean(beanName);
}
return new HandlerMethod(this, handler);
}
/**
* Return a short representation of this handler method for log message purposes.
* @since 4.3
*/
public String getShortLogMessage() {
int args = this.method.getParameterCount();
return getBeanType().getName() + "#" + this.method.getName() + "[" + args + " args]";
}
@Override
public boolean equals(Object other) {
if (this == other) {
return true;
}
if (!(other instanceof HandlerMethod)) {
return false;
}
HandlerMethod otherMethod = (HandlerMethod) other;
return (this.bean.equals(otherMethod.bean) && this.method.equals(otherMethod.method));
}
@Override
public int hashCode() {
return (this.bean.hashCode() * 31 + this.method.hashCode());
}
@Override
public String toString() {
return this.method.toGenericString();
}
/**
* A MethodParameter with HandlerMethod-specific behavior.
*/
protected class HandlerMethodParameter extends SynthesizingMethodParameter {
public HandlerMethodParameter(int index) {
super(HandlerMethod.this.bridgedMethod, index);
}
protected HandlerMethodParameter(HandlerMethodParameter original) {
super(original);
}
@Override
public Class getContainingClass() {
return HandlerMethod.this.getBeanType();
}
@Override
public T getMethodAnnotation(Class annotationType) {
return HandlerMethod.this.getMethodAnnotation(annotationType);
}
@Override
public boolean hasMethodAnnotation(Class annotationType) {
return HandlerMethod.this.hasMethodAnnotation(annotationType);
}
@Override
public HandlerMethodParameter clone() {
return new HandlerMethodParameter(this);
}
}
/**
* A MethodParameter for a HandlerMethod return type based on an actual return value.
*/
private class ReturnValueMethodParameter extends HandlerMethodParameter {
@Nullable
private final Object returnValue;
public ReturnValueMethodParameter(@Nullable Object returnValue) {
super(-1);
this.returnValue = returnValue;
}
protected ReturnValueMethodParameter(ReturnValueMethodParameter original) {
super(original);
this.returnValue = original.returnValue;
}
@Override
public Class getParameterType() {
return (this.returnValue != null ? this.returnValue.getClass() : super.getParameterType());
}
@Override
public ReturnValueMethodParameter clone() {
return new ReturnValueMethodParameter(this);
}
}
}