gobblin.util.reflection

Class GobblinConstructorUtils

java.lang.Object

gobblin.util.reflection.GobblinConstructorUtils

public class GobblinConstructorUtils
extends Object

Helper methods to instantiate classes

Constructor Summary

Constructors

Constructor and Description
GobblinConstructorUtils()

Method Summary

Modifier and Type	Method and Description
static <T> T	invokeConstructor(Class<T> superType, String clsName, Object... args) Utility method to create an instance of clsName using the constructor matching the arguments, args
static <T> T	invokeFirstConstructor(Class<T> cls, List<Object>... constructorArgs) Convenience method on top of ConstructorUtils.invokeConstructor(Class, Object[]) that returns a new instance of the cls based on a constructor priority order.
static <T> T	invokeLongestConstructor(Class<T> cls, Object... args) Returns a new instance of the cls based on a set of arguments.

Methods inherited from class java.lang.Object

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

Constructor Detail

GobblinConstructorUtils

public GobblinConstructorUtils()

Method Detail

invokeFirstConstructor

@SafeVarargs
public static <T> T invokeFirstConstructor(Class<T> cls,
                                                        List<Object>... constructorArgs)
                                                 throws NoSuchMethodException,
                                                        IllegalAccessException,
                                                        InvocationTargetException,
                                                        InstantiationException

Convenience method on top of ConstructorUtils.invokeConstructor(Class, Object[]) that returns a new instance of the cls based on a constructor priority order. Each List in the constructorArgs array contains the arguments for a constructor of cls. The first constructor whose signature matches the argument types will be invoked.

Parameters:

cls - the class to be instantiated

constructorArgs - An array of constructor argument list. Order defines the priority of a constructor.

Returns:

Throws:

NoSuchMethodException - if no constructor matched was found

IllegalAccessException

InvocationTargetException

InstantiationException

invokeLongestConstructor

public static <T> T invokeLongestConstructor(Class<T> cls,
                                             Object... args)
                                      throws ReflectiveOperationException

Returns a new instance of the cls based on a set of arguments. The method will search for a constructor accepting the first k arguments in args for every k from args.length to 0, and will invoke the first constructor found. For example, invokeLongestConstructor(java.lang.Class<T>, java.lang.Object...)(cls, myString, myInt) will first attempt to create an object with of class cls with constructor (String, int), if it fails it will attempt (String), and finally ().

Parameters:

cls - the class to instantiate.

args - the arguments to use for instantiation.

Throws:

ReflectiveOperationException

invokeConstructor

public static <T> T invokeConstructor(Class<T> superType,
                                      String clsName,
                                      Object... args)

Utility method to create an instance of clsName using the constructor matching the arguments, args

Parameters:

superType - of clsName. The new instance is cast to superType

clsName - complete cannonical name of the class to be instantiated

args - constructor args to be used

Returns:

A new instance of clsName

Throws:

IllegalArgumentException - if there was an issue creating the instance due to NoSuchMethodException, InvocationTargetException,InstantiationException, ClassNotFoundException