Package org.springframework.data.util

Class ReflectionUtils

java.lang.Object
org.springframework.data.util.ReflectionUtils
public final class ReflectionUtils extends Object
Spring Data specific reflection utility methods and classes.
Since:
1.5
Author:
Oliver Gierke, Thomas Darimont, Christoph Strobl, Mark Paluch, Johannes Englmeier

  • Method Details

    • createInstanceIfPresent

      public static <T> T createInstanceIfPresent(String classname, T defaultInstance)
      Creates an instance of the class with the given fully qualified name or returns the given default instance if the class cannot be loaded or instantiated.
      Parameters:
      classname - the fully qualified class name to create an instance for.
      defaultInstance - the instance to fall back to in case the given class cannot be loaded or instantiated.
      Returns:

    • isVoid

      public static boolean isVoid(Class<?> type)
      Check whether the given type represents a void type such as void, Void or Kotlin Unit.
      Parameters:
      type - must not be null.
      Returns:
      whether the given the type is a void type.
      Since:
      2.4

    • findField

      @Nullable public static Field findField(Class<?> type, ReflectionUtils.FieldFilter filter)
      Finds the first field on the given class matching the given ReflectionUtils.FieldFilter.
      Parameters:
      type - must not be null.
      filter - must not be null.
      Returns:
      the field matching the filter or null in case no field could be found.

    • findField

      @Nullable public static Field findField(Class<?> type, ReflectionUtils.DescribedFieldFilter filter)
      Finds the field matching the given ReflectionUtils.DescribedFieldFilter. Will make sure there's only one field matching the filter.
      Parameters:
      type - must not be null.
      filter - must not be null.
      Returns:
      the field matching the given ReflectionUtils.DescribedFieldFilter or null if none found.
      Throws:
      IllegalStateException - in case more than one matching field is found
      See Also:

    • findField

      @Nullable public static Field findField(Class<?> type, ReflectionUtils.DescribedFieldFilter filter, boolean enforceUniqueness)
      Finds the field matching the given ReflectionUtils.DescribedFieldFilter. Will make sure there's only one field matching the filter in case enforceUniqueness is true.
      Parameters:
      type - must not be null.
      filter - must not be null.
      enforceUniqueness - whether to enforce uniqueness of the field
      Returns:
      the field matching the given ReflectionUtils.DescribedFieldFilter or null if none found.
      Throws:
      IllegalStateException - if enforceUniqueness is true and more than one matching field is found

    • findRequiredField

      public static Field findRequiredField(Class<?> type, String name)
      Finds the field of the given name on the given type.
      Parameters:
      type - must not be null.
      name - must not be null or empty.
      Returns:
      Throws:
      IllegalArgumentException - in case the field can't be found.

    • setField

      public static void setField(Field field, Object target, @Nullable Object value)
      Sets the given field on the given object to the given value. Will make sure the given field is accessible.
      Parameters:
      field - must not be null.
      target - must not be null.
      value -

    • findConstructor

      public static Optional<Constructor<?>> findConstructor(Class<?> type, Object... constructorArguments)
      Finds a constructor on the given type that matches the given constructor arguments.
      Parameters:
      type - must not be null.
      constructorArguments - must not be null.
      Returns:
      a Constructor that is compatible with the given arguments.

    • findRequiredMethod

      public static Method findRequiredMethod(Class<?> type, String name, Class<?>... parameterTypes)
      Returns the method with the given name of the given class and parameter types. Prefers regular methods over bridge and synthetic ones.
      Parameters:
      type - must not be null.
      name - must not be null.
      parameterTypes - must not be null.
      Returns:
      the method object.
      Throws:
      IllegalArgumentException - in case the method cannot be resolved.

    • returnTypeAndParameters

      public static Stream<Class<?>> returnTypeAndParameters(Method method)
      Returns a Stream of the return and parameters types of the given Method.
      Parameters:
      method - must not be null.
      Returns:
      Since:
      2.0

    • getMethod

      public static Optional<Method> getMethod(Class<?> type, String name, ResolvableType... parameterTypes)
      Returns the Method with the given name and parameters declared on the given type, if available.
      Parameters:
      type - must not be null.
      name - must not be null or empty.
      parameterTypes - must not be null.
      Returns:
      Since:
      2.0

    • isNullable

      public static boolean isNullable(MethodParameter parameter)
      Returns whether the given MethodParameter is nullable. Nullable parameters are reference types and ones that are defined in Kotlin as such.
      Returns:
      true if MethodParameter is nullable.
      Since:
      2.0

    • getPrimitiveDefault

      public static Object getPrimitiveDefault(Class<?> type)
      Get default value for a primitive type.
      Parameters:
      type - must not be null.
      Returns:
      boxed primitive default value.
      Since:
      2.1

    • loadIfPresent

      @Nullable public static Class<?> loadIfPresent(String name, ClassLoader classLoader)
      Loads the class with the given name using the given ClassLoader.
      Parameters:
      name - the name of the class to be loaded.
      classLoader - the ClassLoader to use to load the class.
      Returns:
      the Class or null in case the class can't be loaded for any reason.
      Since:
      2.5