org.springframework.web.method

## Class HandlerMethod

- java.lang.Object
- - org.springframework.web.method.HandlerMethod

- Direct Known Subclasses:
    InvocableHandlerMethod

      public class HandlerMethod
      extends Object

  Encapsulates information about a bean method consisting of a method and a bean. Provides convenient access to method parameters, the method return value, method annotations.

  The class may be created with a bean instance or with a bean name (e.g. lazy bean, prototype bean). Use `createWithResolvedBean()` to obtain an `HandlerMethod` instance with a bean instance initialized through the bean factory.

  Since:
    3.1
  Author:
    Arjen Poutsma, Rossen Stoyanchev

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `protected Log` | `logger` Logger that is available to subclasses

  - ### Constructor Summary

    Constructors
    Modifier | Constructor and Description
    --- | ---
    `protected` | `HandlerMethod(HandlerMethod handlerMethod)` Copy constructor for use in sub-classes.
    `` | `HandlerMethod(Object bean, Method method)` Create an instance from a bean instance and a method.
    `` | `HandlerMethod(Object bean, String methodName, Class<?>... parameterTypes)` Create an instance from a bean instance, method name, and parameter types.
    `` | `HandlerMethod(String beanName, BeanFactory beanFactory, Method method)` Create an instance from a bean name, a method, and a `BeanFactory`.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `HandlerMethod` | `createWithResolvedBean()` If the provided instance contains a bean name rather than an object instance, the bean name is resolved before a `HandlerMethod` is created and returned.
    `boolean` | `equals(Object o)`
    `Object` | `getBean()` Returns the bean for this handler method.
    `Class<?>` | `getBeanType()` Returns the type of the handler for this handler method.
    `protected Method` | `getBridgedMethod()` If the bean method is a bridge method, this method returns the bridged (user-defined) method.
    `Method` | `getMethod()` Returns the method for this handler method.
    `<A extends Annotation> A` | `getMethodAnnotation(Class<A> annotationType)` Returns a single annotation on the underlying method traversing its super methods if no annotation can be found on the given method itself.
    `MethodParameter[]` | `getMethodParameters()` Returns the method parameters for this handler method.
    `MethodParameter` | `getReturnType()` Return the HandlerMethod return type.
    `MethodParameter` | `getReturnValueType(Object returnValue)` Return the actual return value type.
    `int` | `hashCode()`
    `boolean` | `isVoid()` Returns `true` if the method return type is void, `false` otherwise.
    `String` | `toString()`

    - ### Methods inherited from class java.lang.Object

      `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

- - ### Field Detail

    - #### logger

          protected final Log logger

      Logger that is available to subclasses

  - ### Constructor Detail

    - #### HandlerMethod

          public HandlerMethod(Object bean,
                       Method method)

      Create an instance from a bean instance and a method.

    - #### HandlerMethod

          public HandlerMethod(Object bean,
                       String methodName,
                       Class<?>... parameterTypes)
                        throws NoSuchMethodException

      Create an instance from a bean instance, method name, and parameter types.
      Throws:
        `NoSuchMethodException` - when the method cannot be found

    - #### HandlerMethod

          public HandlerMethod(String beanName,
                       BeanFactory beanFactory,
                       Method method)

      Create an instance from a bean name, a method, and a `BeanFactory`. The method `createWithResolvedBean()` may be used later to re-create the `HandlerMethod` with an initialized the bean.

    - #### HandlerMethod

          protected HandlerMethod(HandlerMethod handlerMethod)

      Copy constructor for use in sub-classes.

  - ### Method Detail

    - #### getBean

          public Object getBean()

      Returns the bean for this handler method.

    - #### getMethod

          public Method getMethod()

      Returns the method for this handler method.

    - #### getBeanType

          public Class<?> getBeanType()

      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.

    - #### getBridgedMethod

          protected Method getBridgedMethod()

      If the bean method is a bridge method, this method returns the bridged (user-defined) method. Otherwise it returns the same method as `getMethod()`.

    - #### getMethodParameters

          public MethodParameter[] getMethodParameters()

      Returns the method parameters for this handler method.

    - #### getReturnType

          public MethodParameter getReturnType()

      Return the HandlerMethod return type.

    - #### getReturnValueType

          public MethodParameter getReturnValueType(Object returnValue)

      Return the actual return value type.

    - #### isVoid

          public boolean isVoid()

      Returns `true` if the method return type is void, `false` otherwise.

    - #### getMethodAnnotation

          public <A extends Annotation> A getMethodAnnotation(Class<A> annotationType)

      Returns a single annotation on the underlying method traversing its super methods if no annotation can be found on the given method itself.
      Parameters:
        `annotationType` - the type of annotation to introspect the method for.
      Returns:
        the annotation, or `null` if none found

    - #### createWithResolvedBean

          public HandlerMethod createWithResolvedBean()

      If the provided instance contains a bean name rather than an object instance, the bean name is resolved before a `HandlerMethod` is created and returned.

    - #### equals

          public boolean equals(Object o)

      Overrides:
        `equals` in class `Object`

    - #### hashCode

          public int hashCode()

      Overrides:
        `hashCode` in class `Object`

    - #### toString

          public String toString()

      Overrides:
        `toString` in class `Object`