org.springframework.expression.spel.support
Class ReflectionHelper

java.lang.Object
  org.springframework.expression.spel.support.ReflectionHelper

public class ReflectionHelper
extends Object

Utility methods used by the reflection resolver code to discover the appropriate methods/constructors and fields that should be used in expressions.

Since:

3.0

Author:

Andy Clement, Juergen Hoeller

Nested Class Summary

static class	ReflectionHelper.ArgsMatchKind
static class	ReflectionHelper.ArgumentsMatchInfo An instance of ArgumentsMatchInfo describes what kind of match was achieved between two sets of arguments - the set that a method/constructor is expecting and the set that are being supplied at the point of invocation.

Constructor Summary

ReflectionHelper()

Method Summary

static void	convertAllArguments(TypeConverter converter, Object[] arguments, Method method) Convert a supplied set of arguments into the requested types.
static int	getTypeDifferenceWeight(List<TypeDescriptor> paramTypes, List<TypeDescriptor> argTypes) Based on MethodInvoker.getTypeDifferenceWeight(Class[], Object[]) but operates on TypeDescriptors.
static Object[]	setupArgumentsForVarargsInvocation(Class[] requiredParameterTypes, Object... args) Package up the arguments so that they correctly match what is expected in parameterTypes.

Methods inherited from class java.lang.Object

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

Constructor Detail

ReflectionHelper

public ReflectionHelper()

Method Detail

getTypeDifferenceWeight

public static int getTypeDifferenceWeight(List<TypeDescriptor> paramTypes,
                                          List<TypeDescriptor> argTypes)

Based on MethodInvoker.getTypeDifferenceWeight(Class[], Object[]) but operates on TypeDescriptors.

convertAllArguments

public static void convertAllArguments(TypeConverter converter,
                                       Object[] arguments,
                                       Method method)
                                throws SpelEvaluationException

Convert a supplied set of arguments into the requested types. If the parameterTypes are related to a varargs method then the final entry in the parameterTypes array is going to be an array itself whose component type should be used as the conversion target for extraneous arguments. (For example, if the parameterTypes are {Integer, String[]} and the input arguments are {Integer, boolean, float} then both the boolean and float must be converted to strings). This method does not repackage the arguments into a form suitable for the varargs invocation

Parameters:

converter - the converter to use for type conversions

arguments - the arguments to convert to the requested parameter types

method - the target Method

Throws:

SpelEvaluationException - if there is a problem with conversion

setupArgumentsForVarargsInvocation

public static Object[] setupArgumentsForVarargsInvocation(Class[] requiredParameterTypes,
                                                          Object... args)

Package up the arguments so that they correctly match what is expected in parameterTypes. For example, if parameterTypes is (int, String[]) because the second parameter was declared String... then if arguments is [1,"a","b"] then it must be repackaged as [1,new String[]{"a","b"}] in order to match the expected parameterTypes.

Parameters:

requiredParameterTypes - the types of the parameters for the invocation

args - the arguments to be setup ready for the invocation

Returns:

a repackaged array of arguments where any varargs setup has been done