Class MethodInvoker

Field Detail

• targetClass

  @Nullable
  protected Class<?> targetClass

Constructor Detail

• MethodInvoker

  public MethodInvoker()

Method Detail

• setTargetClass

  public void setTargetClass​(@Nullable
                             Class<?> targetClass)

  Set the target class on which to call the target method. Only necessary when the target method is static; else, a target object needs to be specified anyway.

  See Also:

  setTargetObject(java.lang.Object), setTargetMethod(java.lang.String)

• getTargetClass

  @Nullable
  public Class<?> getTargetClass()

  Return the target class on which to call the target method.

• setTargetObject

  public void setTargetObject​(@Nullable
                              Object targetObject)

  Set the target object on which to call the target method. Only necessary when the target method is not static; else, a target class is sufficient.

  See Also:

  setTargetClass(java.lang.Class<?>), setTargetMethod(java.lang.String)

• getTargetObject

  @Nullable
  public Object getTargetObject()

  Return the target object on which to call the target method.

• setTargetMethod

  public void setTargetMethod​(@Nullable
                              String targetMethod)

  Set the name of the method to be invoked. Refers to either a static method or a non-static method, depending on a target object being set.

  See Also:

  setTargetClass(java.lang.Class<?>), setTargetObject(java.lang.Object)

• getTargetMethod

  @Nullable
  public String getTargetMethod()

  Return the name of the method to be invoked.

• setStaticMethod

  public void setStaticMethod​(String staticMethod)

  Set a fully qualified static method name to invoke, e.g. "example.MyExampleClass.myExampleMethod". Convenient alternative to specifying targetClass and targetMethod.

  See Also:

  setTargetClass(java.lang.Class<?>), setTargetMethod(java.lang.String)

• setArguments

  public void setArguments​(Object... arguments)

  Set arguments for the method invocation. If this property is not set, or the Object array is of length 0, a method with no arguments is assumed.

• getArguments

  public Object[] getArguments()

  Return the arguments for the method invocation.

• prepare

  public void prepare()
               throws ClassNotFoundException,
                      NoSuchMethodException

  Prepare the specified method. The method can be invoked any number of times afterwards.

  Throws:

  ClassNotFoundException

  NoSuchMethodException

  See Also:

  getPreparedMethod(), invoke()

• resolveClassName

  protected Class<?> resolveClassName​(String className)
                               throws ClassNotFoundException

  Resolve the given class name into a Class.

  The default implementations uses ClassUtils.forName, using the thread context class loader.

  Parameters:

  className - the class name to resolve

  Returns:

  the resolved Class

  Throws:

  ClassNotFoundException - if the class name was invalid

• findMatchingMethod

  @Nullable
  protected Method findMatchingMethod()

  Find a matching method with the specified name for the specified arguments.

  Returns:

  a matching method, or null if none

  See Also:

  getTargetClass(), getTargetMethod(), getArguments()

• getPreparedMethod

  public Method getPreparedMethod()
                           throws IllegalStateException

  Return the prepared Method object that will be invoked.

  Can for example be used to determine the return type.

  Returns:

  the prepared Method object (never null)

  Throws:

  IllegalStateException - if the invoker hasn't been prepared yet

  See Also:

  prepare(), invoke()

• isPrepared

  public boolean isPrepared()

  Return whether this invoker has been prepared already, i.e. whether it allows access to getPreparedMethod() already.

• invoke

  @Nullable
  public Object invoke()
                throws InvocationTargetException,
                       IllegalAccessException

  Invoke the specified method.

  The invoker needs to have been prepared before.

  Returns:

  the object (possibly null) returned by the method invocation, or null if the method has a void return type

  Throws:

  InvocationTargetException - if the target method threw an exception

  IllegalAccessException - if the target method couldn't be accessed

  See Also:

  prepare()

• getTypeDifferenceWeight

  public static int getTypeDifferenceWeight​(Class<?>[] paramTypes,
                                            Object[] args)

  Algorithm that judges the match between the declared parameter types of a candidate method and a specific list of arguments that this method is supposed to be invoked with.

  Determines a weight that represents the class hierarchy difference between types and arguments. A direct match, i.e. type Integer -> arg of class Integer, does not increase the result - all direct matches means weight 0. A match between type Object and arg of class Integer would increase the weight by 2, due to the superclass 2 steps up in the hierarchy (i.e. Object) being the last one that still matches the required type Object. Type Number and class Integer would increase the weight by 1 accordingly, due to the superclass 1 step up the hierarchy (i.e. Number) still matching the required type Number. Therefore, with an arg of type Integer, a constructor (Integer) would be preferred to a constructor (Number) which would in turn be preferred to a constructor (Object). All argument weights get accumulated.

  Note: This is the algorithm used by MethodInvoker itself and also the algorithm used for constructor and factory method selection in Spring's bean container (in case of lenient constructor resolution which is the default for regular bean definitions).

  Parameters:

  paramTypes - the parameter types to match

  args - the arguments to match

  Returns:

  the accumulated weight for all arguments