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

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ReflectionUtils.AnnotationFieldFilter	A ReflectionUtils.FieldFilter for a given annotation.
static interface	ReflectionUtils.DescribedFieldFilter	A ReflectionUtils.FieldFilter that has a description.

Method Summary

Modifier and Type	Method	Description
static <T> @Nullable Constructor<T>	findConstructor(Class<T> type, Object... constructorArguments)	Finds a constructor on the given type that matches the given constructor arguments.
static @Nullable Field	findField(Class<?> type, ReflectionUtils.DescribedFieldFilter filter)	Finds the field matching the given ReflectionUtils.DescribedFieldFilter.
static @Nullable Field	findField(Class<?> type, ReflectionUtils.DescribedFieldFilter filter, boolean enforceUniqueness)	Finds the field matching the given ReflectionUtils.DescribedFieldFilter.
static @Nullable Field	findField(Class<?> type, ReflectionUtils.FieldFilter filter)	Finds the first field on the given class matching the given ReflectionUtils.FieldFilter.
static @Nullable Method	findMethod(Class<?> type, String name, ResolvableType... parameterTypes)	Returns the Method with the given name and parameters declared on the given type, if available.
static Method	findRequiredMethod(Class<?> type, String name, Class<?>... parameterTypes)	Deprecated. since 3.5, use getRequiredMethod(Class, String, Class[]) instead.
static int	getParameterCount(Method method, Predicate<Class<?>> predicate)	Returns the number of matching parameters Method for Predicate.
static Object	getPrimitiveDefault(Class<?> type)	Get default value for a primitive type.
static Field	getRequiredField(Class<?> type, String name)	Obtains the required field of the given name on the given type or throws IllegalArgumentException if the found could not be found.
static Method	getRequiredMethod(Class<?> type, String name, Class<?>... parameterTypes)	Returns the method with the given name of the given class and parameter types.
static boolean	hasParameterAssignableToType(Method method, Class<?> type)	Returns whether the given Method has a parameter that is assignable to the given type.
static boolean	hasParameterOfType(Method method, Class<?> type)	Returns whether the given Method has a parameter of the given type.
static boolean	isNullable(MethodParameter parameter)	Returns whether the given MethodParameter is nullable.
static boolean	isVoid(Class<?> type)	Check whether the given type represents a void type such as void, Void or Kotlin Unit.
static Stream<Class<?>>	returnTypeAndParameters(Method method)	Returns a Stream of the return and parameters types of the given Method.
static void	setField(Field field, Object target, @Nullable Object value)	Sets the given field on the given object to the given value.

Methods inherited from class java.lang.Object

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

Method Details

hasParameterOfType

public static boolean hasParameterOfType(Method method,
 Class<?> type)

Returns whether the given Method has a parameter of the given type.

Parameters:

method - the method to check, must not be null.

type - parameter type to query for, must not be null.

Returns:

true the given Method has a parameter of the given type.

Since:

3.5

hasParameterAssignableToType

public static boolean hasParameterAssignableToType(Method method,
 Class<?> type)

Returns whether the given Method has a parameter that is assignable to the given type.

Parameters:

method - the method to check, must not be null.

type - parameter type to query for, must not be null.

Returns:

true the given Method has a parameter that is assignable to the given type.

Since:

3.5

getParameterCount

public static int getParameterCount(Method method,
 Predicate<Class<?>> predicate)

Returns the number of matching parameters Method for Predicate.

Parameters:

method - Method to evaluate.

predicate - the predicate matching Method

Returns:

the resulting number of matching parameters.

Since:

3.5

See Also:

• Method.getParameterTypes()

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

public static @Nullable 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

public static @Nullable 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(Class, DescribedFieldFilter, boolean)

findField

public static @Nullable 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

getRequiredField

public static Field getRequiredField(Class<?> type,
 String name)

Obtains the required field of the given name on the given type or throws IllegalArgumentException if the found could not be found.

Parameters:

type - must not be null.

name - must not be null or empty.

Returns:

the required field.

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 <T> @Nullable Constructor<T> findConstructor(Class<T> 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

@Deprecated
public static Method findRequiredMethod(Class<?> type,
 String name,
 Class<?>... parameterTypes)

Deprecated.

since 3.5, use getRequiredMethod(Class, String, Class[]) instead.

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.

getRequiredMethod

public static Method getRequiredMethod(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.

Since:

3.5

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:

stream of return and parameter types.

Since:

2.0

findMethod

public static @Nullable Method findMethod(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:

the required method.

Since:

3.5

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