io.opsit.explang

Class BetterMethodFinder

java.lang.Object

io.opsit.explang.BetterMethodFinder

public final class BetterMethodFinder
extends Object

Finds methods and constructors that can be invoked reflectively. Attempts to address some of the limitations of the JDK's Class.getMethod() and Class.getConstructor(), and other JDK reflective facilities.

Constructor Summary

Constructors

Constructor and Description
BetterMethodFinder(Class<?> clazz) Create instance for given class.

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object obj)
Constructor<?>	findConstructor(Class<?>[] parameterTypes) Returns the most specific public constructor in my target class that accepts the number and type of parameters in the given Class array in a reflective invocation.
Method	findMethod(String methodName, Class<?>[] parameterTypes) Returns the most specific public method in my target class that has the given name and accepts the number and type of parameters in the given Class array in a reflective invocation.
static Class<?>[]	getParameterTypesFrom(Object[] args) Return an array of Class objects for the objects in the given array.
static Class<?>[]	getParameterTypesFrom(String[] classNames) Return an array of Class objects named by the FQNs in the given String array.
static Class<?>[]	getParameterTypesFrom(String[] classNames, ClassLoader loader) Return an array of Class objects named by the FQNs in the given String array.
int	hashCode()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

BetterMethodFinder

public BetterMethodFinder(Class<?> clazz)

Create instance for given class.

Parameters:

clazz - Class in which I will look for methods and constructors

Throws:

IllegalArgumentException - if clazz is null, or represents a primitive, or represents an array type

Method Detail

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

findConstructor

public Constructor<?> findConstructor(Class<?>[] parameterTypes)
                               throws NoSuchMethodException

Returns the most specific public constructor in my target class that accepts the number and type of parameters in the given Class array in a reflective invocation.

A null value or Void.TYPE in parameterTypes matches a corresponding Object or array reference in a constructor's formal parameter list, but not a primitive formal parameter.

Parameters:

parameterTypes - array representing the number and types of parameters to look for in the constructor's signature. A null array is treated as a zero-length array.

Returns:

Constructor object satisfying the conditions

Throws:

NoSuchMethodException - if no constructors match the criteria, or if the reflective call is ambiguous based on the parameter types

findMethod

public Method findMethod(String methodName,
                         Class<?>[] parameterTypes)
                  throws NoSuchMethodException

Returns the most specific public method in my target class that has the given name and accepts the number and type of parameters in the given Class array in a reflective invocation.

A null value or Void.TYPE in parameterTypes will match a corresponding Object or array reference in a method's formal parameter list, but not a primitive formal parameter.

Parameters:

methodName - name of the method to search for

parameterTypes - array representing the number and types of parameters to look for in the method's signature. A null array is treated as a zero-length array.

Returns:

Method object satisfying the conditions

Throws:

NoSuchMethodException - if no methods match the criteria, or if the reflective call is ambiguous based on the parameter types, or if methodName is null

getParameterTypesFrom

public static Class<?>[] getParameterTypesFrom(Object[] args)

Return an array of Class objects for the objects in the given array.

Parameters:

args - an Object array

Returns:

an array of Class objects representing the classes of the objects in the given Object array. If args is null, a zero-length Class array is returned. If an element in args is null, then Void.TYPE is the corresponding Class in the return array.

getParameterTypesFrom

public static Class<?>[] getParameterTypesFrom(String[] classNames)
                                        throws ClassNotFoundException

Return an array of Class objects named by the FQNs in the given String array.

Parameters:

classNames - String array of fully qualified names (FQNs) of classes or primitives. Represent an array type by using its JVM type descriptor, with dots instead of slashes (e.g. represent the type int[] with "[I", and Object[][] with "[[Ljava.lang.Object;").

Returns:

an array of Class objects representing the classes or primitives named by the FQNs in the given String array. If the String array is null, a zero-length Class array is returned. If an element in classNames is null, the empty string, "void", or "null", then Void.TYPE is the corresponding Class in the return array. If any classes require loading because of this operation, the loading is done by the ClassLoader that loaded this class. Such classes are not initialized, however.

Throws:

ClassNotFoundException - if any of the FQNs name an unknown class

getParameterTypesFrom

public static Class<?>[] getParameterTypesFrom(String[] classNames,
                                               ClassLoader loader)
                                        throws ClassNotFoundException

Return an array of Class objects named by the FQNs in the given String array.

Parameters:

classNames - String array of fully qualified names (FQNs) of classes or primitives. Represent an array type by using its JVM type descriptor, with dots instead of slashes (e.g. represent the type int[] with "[I", and Object[][] with "[[Ljava.lang.Object;").

loader - a ClassLoader

Returns:

an array of Class objects representing the classes or primitives named by the FQNs in the given String array. If the String array is null, a zero-length Class array is returned. If an element in classNames is null, the empty string, "void", or "null", then Void.TYPE is the corresponding Class in the return array. If any classes require loading because of this operation, the loading is done by the given ClassLoader. Such classes are not initialized, however.

Throws:

ClassNotFoundException - if any of the FQNs name an unknown class

hashCode

public int hashCode()

Overrides:

hashCode in class Object