Package 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 Details

    • ReflectionHelper

      public ReflectionHelper()

  • Method Details

    • 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 the supplied set of arguments into the parameter types of the supplied Method.

      If the supplied method is a varargs method, the final parameter type must be an array whose component type should be used as the conversion target for extraneous arguments. For example, if the parameter types are {Integer, String[]} and the input arguments are {Integer, boolean, float}, then both the boolean and the 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(Class[], Object...) is required for that.

      Parameters:
      converter - the converter to use for type conversions
      arguments - the arguments to convert to the required parameter types
      method - the target Method
      Returns:
      true if some kind of conversion occurred on an argument
      Throws:
      SpelEvaluationException - if a problem occurs during conversion

    • convertAllMethodHandleArguments

      public static boolean convertAllMethodHandleArguments(TypeConverter converter, Object[] arguments, MethodHandle methodHandle, @Nullable Integer varargsPosition) throws EvaluationException
      Convert the supplied set of arguments into the parameter types of the supplied MethodHandle, taking the varargs position into account.

      The arguments are converted 'in-place' in the input array.

      Parameters:
      converter - the converter to use for type conversions
      arguments - the arguments to convert to the required parameter types
      methodHandle - the target MethodHandle
      varargsPosition - the known position of the varargs argument, if any (null if not varargs)
      Returns:
      true if some kind of conversion occurred on an argument
      Throws:
      EvaluationException - if a problem occurs during conversion
      Since:
      6.1

    • setupArgumentsForVarargsInvocation

      public static Object[] setupArgumentsForVarargsInvocation(Class<?>[] requiredParameterTypes, Object... args)
      Package up the supplied args so that they correctly match what is expected in requiredParameterTypes.

      For example, if requiredParameterTypes is (int, String[]) because the second parameter was declared as String..., then if args is [1, "a", "b"] 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 set up for the invocation
      Returns:
      a repackaged array of arguments where any varargs setup has been performed