Spring Core 6.1.4 · org.springframework.util.MethodInvoker

Modifier and Type	Field and Description
private Object[]	arguments
private static final Object[]	EMPTY_ARGUMENTS
private Method	methodObject The method we will call.
private String	staticMethod
protected Class<?>	targetClass
private String	targetMethod
private Object	targetObject

Access	Constructor and Description
public	MethodInvoker()

Method Summary

Modifier and Type	Method and Description
protected Method	Returns: a matching method, or `null` if none findMatchingMethod() Find a matching method with the specified name for the specified arguments.
public Object[]	getArguments() Return the arguments for the method invocation.
public Method	Returns: the prepared Method object (never `null`) getPreparedMethod() Return the prepared Method object that will be invoked.
public Class<?>	getTargetClass() Return the target class on which to call the target method.
public String	getTargetMethod() Return the name of the method to be invoked.
public Object	getTargetObject() Return the target object on which to call the target method.
public static int	Returns: the accumulated weight for all arguments getTypeDifferenceWeight(Class<?>[] the parameter types to match paramTypes, Object[] the arguments to match 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.
public Object	Returns: the object (possibly null) returned by the method invocation, or `null` if the method has a void return type invoke() Invoke the specified method.
public boolean	isPrepared() Return whether this invoker has been prepared already, i.e. whether it allows access to `getPreparedMethod()` already.
public void	prepare() Prepare the specified method.
protected Class<?>	Returns: the resolved Class resolveClassName(String the class name to resolve className) Resolve the given class name into a Class.
public void	setArguments(Object... arguments) Set arguments for the method invocation.
public void	setStaticMethod(String staticMethod) Set a fully qualified static method name to invoke, e.g. "example.MyExampleClass.myExampleMethod".
public void	setTargetClass(Class<?> targetClass) Set the target class on which to call the target method.
public void	setTargetMethod(String targetMethod) Set the name of the method to be invoked.
public void	setTargetObject(Object targetObject) Set the target object on which to call the target method.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

arguments	back to summary
private Object[] arguments Annotations @Nullable

EMPTY_ARGUMENTS	back to summary
private static final Object[] EMPTY_ARGUMENTS

methodObject	back to summary
private Method methodObject The method we will call. Annotations @Nullable

staticMethod	back to summary
private String staticMethod Annotations @Nullable

targetClass	back to summary
protected Class<?> targetClass Annotations @Nullable

targetMethod	back to summary
private String targetMethod Annotations @Nullable

targetObject	back to summary
private Object targetObject Annotations @Nullable

MethodInvoker	back to summary
public MethodInvoker()

Method Detail

findMatchingMethod back to summary

findMatchingMethod	back to summary
protected Method findMatchingMethod() Find a matching method with the specified name for the specified arguments. Returns:Method a matching method, or `null` if none Annotations @Nullable See Also `getTargetClass()`, `getTargetMethod()`, `getArguments()`

protected Method findMatchingMethod()

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

Returns:Method

a matching method, or null if none

Annotations

@Nullable

getArguments	back to summary
public Object[] getArguments() Return the arguments for the method invocation.

getPreparedMethod back to summary

getPreparedMethod	back to summary
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:Method the prepared Method object (never `null`) Exceptions IllegalStateException: if the invoker hasn't been prepared yet See Also `prepare`, `invoke`

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:Method

the prepared Method object (never null)

Exceptions

IllegalStateException:: if the invoker hasn't been prepared yet

See Also

prepare, invoke

getTargetClass	back to summary
public Class<?> getTargetClass() Return the target class on which to call the target method. Annotations @Nullable

getTargetClass

back to summary

public Class<?> getTargetClass()

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

Annotations

@Nullable

getTargetMethod	back to summary
public String getTargetMethod() Return the name of the method to be invoked. Annotations @Nullable

getTargetMethod

back to summary

public String getTargetMethod()

Return the name of the method to be invoked.

Annotations

@Nullable

getTargetObject	back to summary
public Object getTargetObject() Return the target object on which to call the target method. Annotations @Nullable

getTargetObject

back to summary

public Object getTargetObject()

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

Annotations

@Nullable

getTypeDifferenceWeight	back to summary
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:Class<?>[] the parameter types to match args:Object[] the arguments to match Returns:int the accumulated weight for all arguments

getTypeDifferenceWeight

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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:Class<?>[]: the parameter types to match
args:Object[]: the arguments to match

Returns:int

the accumulated weight for all arguments

invoke back to summary

invoke	back to summary
public Object invoke() throws InvocationTargetException, IllegalAccessException Invoke the specified method. The invoker needs to have been prepared before. Returns:Object the object (possibly null) returned by the method invocation, or `null` if the method has a void return type Annotations @Nullable Exceptions InvocationTargetException: if the target method threw an exception IllegalAccessException: if the target method couldn't be accessed See Also `prepare`

public Object invoke() throws InvocationTargetException, IllegalAccessException

Invoke the specified method.

The invoker needs to have been prepared before.

Returns:Object

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

Annotations

@Nullable

Exceptions

InvocationTargetException:: if the target method threw an exception
IllegalAccessException:: if the target method couldn't be accessed

See Also

prepare

isPrepared	back to summary
public boolean isPrepared() Return whether this invoker has been prepared already, i.e. whether it allows access to `getPreparedMethod()` already.

prepare back to summary

prepare	back to summary
public void prepare() throws ClassNotFoundException, NoSuchMethodException Prepare the specified method. The method can be invoked any number of times afterwards. See Also `getPreparedMethod`, `invoke`

public void prepare() throws ClassNotFoundException, NoSuchMethodException

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

See Also: getPreparedMethod, invoke

resolveClassName back to summary

resolveClassName	back to summary
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:String the class name to resolve Returns:Class<?> the resolved Class Exceptions ClassNotFoundException: if the class name was invalid

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:String: the class name to resolve

Returns:Class<?>

the resolved Class

Exceptions

ClassNotFoundException:: if the class name was invalid

setArguments	back to summary
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.

setStaticMethod back to summary

setStaticMethod	back to summary
public void setStaticMethod(String staticMethod) Set a fully qualified static method name to invoke, e.g. "example.MyExampleClass.myExampleMethod". This is a convenient alternative to specifying targetClass and targetMethod. See Also `setTargetClass`, `setTargetMethod`

public void setStaticMethod(String staticMethod)

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

See Also: setTargetClass, setTargetMethod

setTargetClass back to summary

setTargetClass	back to summary
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. See Also `setTargetObject`, `setTargetMethod`

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.

See Also: setTargetObject, setTargetMethod

setTargetMethod back to summary

setTargetMethod	back to summary
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. See Also `setTargetClass`, `setTargetObject`

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.

See Also: setTargetClass, setTargetObject

setTargetObject back to summary

setTargetObject	back to summary
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. See Also `setTargetClass`, `setTargetMethod`

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.

See Also: setTargetClass, setTargetMethod

public Class MethodInvoker

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Field Detail

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