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 specified by the supplied Method.

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

      If the method accepts varargs, the final entry in its parameterTypes array is going to be an array itself whose component type will be used as the conversion target for any additional 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(Class[], Object...) must be used for that.

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

    • convertAllMethodHandleArguments

      public static boolean convertAllMethodHandleArguments(TypeConverter converter, Object[] arguments, MethodHandle methodHandle, @Nullable Integer varargsPosition) throws EvaluationException
      Takes an input set of argument values and converts them to the parameter types of the supplied MethodHandle.

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

      Parameters:
      converter - the type converter to use for attempting conversions
      arguments - the actual arguments that need conversion
      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 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