org.springframework.expression.spel.support

Class ReflectionHelper

java.lang.Object

org.springframework.expression.spel.support.ReflectionHelper

public abstract 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, Sam Brannen

Constructor Summary

Constructors

Constructor and Description
ReflectionHelper()

Method Summary

Modifier and Type	Method and Description
static boolean	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 requiredParameterTypes.

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 boolean 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 - a subsequent call to setupArgumentsForVarargsInvocation handles that.

Parameters:

converter - the converter to use for type conversions

arguments - the arguments to convert to the requested parameter types

method - the target Method

Returns:

true if some kind of conversion occurred on the argument

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 requiredParameterTypes.

For example, if requiredParameterTypes 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 types.

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