类 MethodInvoker
- java.lang.Object
- org.springframework.util.MethodInvoker
public class MethodInvoker extends Object
Helper class that allows for specifying a method to invoke in a declarative fashion, be it static or non-static.Usage: Specify "targetClass"/"targetMethod" or "targetObject"/"targetMethod", optionally specify arguments, prepare the invoker. Afterwards, you may invoke the method any number of times, obtaining the invocation result.
构造器概要
构造器 构造器 说明 MethodInvoker()
方法概要
所有方法 静态方法 实例方法 具体方法 修饰符和类型 方法 说明 protected Method
findMatchingMethod()
Find a matching method with the specified name for the specified arguments.Object[]
getArguments()
Return the arguments for the method invocation.Method
getPreparedMethod()
Return the prepared Method object that will be invoked.Class<?>
getTargetClass()
Return the target class on which to call the target method.String
getTargetMethod()
Return the name of the method to be invoked.Object
getTargetObject()
Return the target object on which to call the target method.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.Object
invoke()
Invoke the specified method.boolean
isPrepared()
Return whether this invoker has been prepared already, i.e. whether it allows access togetPreparedMethod()
already.void
prepare()
Prepare the specified method.protected Class<?>
resolveClassName(String className)
Resolve the given class name into a Class.void
setArguments(Object... arguments)
Set arguments for the method invocation.void
setStaticMethod(String staticMethod)
Set a fully qualified static method name to invoke, e.g.void
setTargetClass(Class<?> targetClass)
Set the target class on which to call the target method.void
setTargetMethod(String targetMethod)
Set the name of the method to be invoked.void
setTargetObject(Object targetObject)
Set the target object on which to call the target method.
构造器详细资料
MethodInvoker
public MethodInvoker()
方法详细资料
setTargetClass
public void setTargetClass(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.
getTargetClass
public Class<?> getTargetClass()
Return the target class on which to call the target method.
setTargetObject
public void setTargetObject(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.
getTargetObject
public Object getTargetObject()
Return the target object on which to call the target method.
setTargetMethod
public void setTargetMethod(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.
getTargetMethod
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.
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.
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.- 参数:
className
- the class name to resolve- 返回:
- the resolved Class
- 抛出:
ClassNotFoundException
- if the class name was invalid
findMatchingMethod
protected Method findMatchingMethod()
Find a matching method with the specified name for the specified arguments.- 返回:
- a matching method, or
null
if none - 另请参阅:
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.
- 返回:
- the prepared Method object (never
null
) - 抛出:
IllegalStateException
- if the invoker hasn't been prepared yet- 另请参阅:
prepare()
,invoke()
isPrepared
public boolean isPrepared()
Return whether this invoker has been prepared already, i.e. whether it allows access togetPreparedMethod()
already.
invoke
public Object invoke() throws InvocationTargetException, IllegalAccessException
Invoke the specified method.The invoker needs to have been prepared before.
- 返回:
- the object (possibly null) returned by the method invocation, or
null
if the method has a void return type - 抛出:
InvocationTargetException
- if the target method threw an exceptionIllegalAccessException
- if the target method couldn't be accessed- 另请参阅:
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).
- 参数:
paramTypes
- the parameter types to matchargs
- the arguments to match- 返回:
- the accumulated weight for all arguments