org.axonframework.common

Class ReflectionUtils

java.lang.Object

org.axonframework.common.ReflectionUtils

public abstract class ReflectionUtils
extends Object

Utility class for working with Java Reflection API.

Since:

0.7

Author:

Allard Buijze

Field Summary

Fields

Modifier and Type	Field and Description
static boolean	NOT_RECURSIVE Specifying a reflection operation should not be performed recursive.
static boolean	RECURSIVE Specifying a reflection operation should be performed recursive.

Method Summary

Modifier and Type	Method and Description
static Class<?>	declaringClass(Class<?> instanceClass, String methodName, Class<?>... parameterTypes) Returns the class on which the method with given methodName and parameters of type parameterTypes is declared.
static <T extends AccessibleObject> T	ensureAccessible(T member) Makes the given member accessible via reflection if it is not the case already.
static boolean	explicitlyUnequal(Object value, Object otherValue) Indicates whether the two given objects are not the same, override an equals method that indicates they are not equal, or implements Comparable which indicates the two are not equal.
static Iterable<Field>	fieldsOf(Class<?> clazz) Returns an Iterable of all the fields declared on the given class and its super classes.
static Iterable<Field>	fieldsOf(Class<?> clazz, boolean recursive) Returns an Iterable of all the fields declared on the given class.
static <R> R	getFieldValue(Field field, Object object) Returns the value of the given field in the given object.
static String	getMemberGenericString(Member member) Returns the generic string of the given member.
static Type	getMemberGenericType(Member member) Returns the generic type of value of the given member, either by returning the generic type of Field or generic return type of a Method.
static <R> R	getMemberValue(Member member, Object target) Returns the value of the given member in the given object, either by returning Field value or invoking the method.
static Class<?>	getMemberValueType(Member member) Returns the type of value of the given member, either by returning the type of Field or type of the return value of a Method.
static boolean	hasEqualsMethod(Class<?> type) Indicates whether the given class implements a customized equals method.
static <R> R	invokeAndGetMethodValue(Method method, Object object) Invokes and returns the return value of the given method in the given object.
static boolean	isAccessible(AccessibleObject member) Indicates whether the given member is accessible.
static boolean	isNonFinalPublicMember(Member member) Checks whether the given member is public and non-final.
static boolean	isTransient(Field field) Indicates whether the given field has the "transient" modifier
static Method	methodOf(Class<?> clazz, String methodName, Class<?>... parameterTypes) Utility function which returns a Method matching the given methodName and parameterTypes in the clazz.
static Iterable<Method>	methodsOf(Class<?> clazz) Returns an Iterable of all the methods declared on the given class and its super classes.
static Iterable<Method>	methodsOf(Class<?> clazz, boolean recursive) Returns an Iterable of all the methods declared on the given class.
static Optional<Class<?>>	resolveGenericType(Field field, int genericTypeIndex) Resolve a generic type parameter from a field declaration
static Optional<Class<?>>	resolveMemberGenericType(Member member, int genericTypeIndex) Resolve a generic type parameter from a member declaration.
static Class<?>	resolvePrimitiveWrapperType(Class<?> primitiveType) Returns the boxed wrapper type for the given primitiveType.
static Type	resolvePrimitiveWrapperTypeIfPrimitive(Type type) Returns the boxed wrapper type for the given type if it is primitive.
static <T> void	setFieldValue(Field field, Object object, T value) Set the field of object to a certain value.
static String	toDiscernibleSignature(Executable executable) Returns a discernible signature without including the classname.
static Type	unwrapIfType(Type type, Class<?>... wrapperTypes) Unwrap the given type if is wrapped by any of the given wrapperTypes.

Methods inherited from class java.lang.Object

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

Field Detail

RECURSIVE

public static final boolean RECURSIVE

Specifying a reflection operation should be performed recursive.

See Also:

Constant Field Values

NOT_RECURSIVE

public static final boolean NOT_RECURSIVE

Specifying a reflection operation should not be performed recursive.

See Also:

Constant Field Values

Method Detail

getFieldValue

public static <R> R getFieldValue(Field field,
                                  Object object)

Returns the value of the given field in the given object. If necessary, the field is made accessible, assuming the security manager allows it.

Parameters:

field - The field containing the value

object - The object to retrieve the field's value from

Returns:

the value of the field in the object

Throws:

IllegalStateException - if the field is not accessible and the security manager doesn't allow it to be made accessible

setFieldValue

public static <T> void setFieldValue(Field field,
                                     Object object,
                                     T value)

Set the field of object to a certain value. If necessary, the field is made accessible, assuming the security manager allows it.

Type Parameters:

T - The type of the value

Parameters:

field - The field to set value on

object - The object to set the value on field

value - The value to set on field

declaringClass

public static Class<?> declaringClass(Class<?> instanceClass,
                                      String methodName,
                                      Class<?>... parameterTypes)

Returns the class on which the method with given methodName and parameters of type parameterTypes is declared. The given instanceClass is the instance on which the method can be called. If the method is not available on the given instanceClass, null is returned.

Parameters:

instanceClass - The class on which to look for the method

methodName - The name of the method

parameterTypes - The parameter types of the method

Returns:

The class on which the method is declared, or null if not found

hasEqualsMethod

public static boolean hasEqualsMethod(Class<?> type)

Indicates whether the given class implements a customized equals method. This methods returns true if the declaring type of the equals method is not Object.

Parameters:

type - The type to inspect

Returns:

true if the given type overrides the equals method, otherwise false

explicitlyUnequal

public static boolean explicitlyUnequal(Object value,
                                        Object otherValue)

Indicates whether the two given objects are not the same, override an equals method that indicates they are not equal, or implements Comparable which indicates the two are not equal. If this method cannot safely indicate two objects are not equal, it returns false.

Parameters:

value - One of the values to compare

otherValue - other value to compare

Returns:

true if these objects explicitly indicate they are not equal, false otherwise.

ensureAccessible

public static <T extends AccessibleObject> T ensureAccessible(T member)

Makes the given member accessible via reflection if it is not the case already.

Type Parameters:

T - The type of member to make accessible

Parameters:

member - The member (field, method, constructor, etc) to make accessible

Returns:

the given member, for easier method chaining

Throws:

IllegalStateException - if the member is not accessible and the security manager doesn't allow it to be made accessible

isAccessible

public static boolean isAccessible(AccessibleObject member)

Indicates whether the given member is accessible. It does so by checking whether the member is non-final and public, or made accessible via reflection.

Parameters:

member - The member (field, method, constructor, etc) to check for accessibility

Returns:

true if the member is accessible, otherwise false.

isNonFinalPublicMember

public static boolean isNonFinalPublicMember(Member member)

Checks whether the given member is public and non-final. These members do no need to be set accessible using reflection.

Parameters:

member - The member to check

Returns:

true if the member is public and non-final, otherwise false.

See Also:

isAccessible(java.lang.reflect.AccessibleObject), ensureAccessible(java.lang.reflect.AccessibleObject)

fieldsOf

public static Iterable<Field> fieldsOf(Class<?> clazz)

Returns an Iterable of all the fields declared on the given class and its super classes. The iterator will always return fields declared in a subtype before returning fields declared in a super type.

Parameters:

clazz - the class to return fields for

Returns:

an Iterable providing access to all declared fields in the class hierarchy

fieldsOf

public static Iterable<Field> fieldsOf(Class<?> clazz,
                                       boolean recursive)

Returns an Iterable of all the fields declared on the given class.

Will include the given clazz' super classes if recursive has been set. The iterator will always return fields declared in a subtype before returning fields declared in a super type.

Parameters:

clazz - the class to return fields for

recursive - defining whether fields should be found recursively on super classes as well

Returns:

an Iterable providing access to all declared fields in the class, including the hierarchy if recursive was set

methodOf

public static Method methodOf(Class<?> clazz,
                              String methodName,
                              Class<?>... parameterTypes)
                       throws NoSuchMethodException

Utility function which returns a Method matching the given methodName and parameterTypes in the clazz.

Parameters:

clazz - The Class to return a method for

methodName - A String for the simple name of the method to return

parameterTypes - An array of type Class for all the parameters which are part of the Method being searched for

Returns:

a Method object from the given clazz matching the specified methodName

Throws:

NoSuchMethodException - if no Method can be found matching the methodName in clazz

methodsOf

public static Iterable<Method> methodsOf(Class<?> clazz)

Returns an Iterable of all the methods declared on the given class and its super classes. The iterator will always return methods declared in a subtype before returning methods declared in a super type.

Parameters:

clazz - the class to return methods for

Returns:

an Iterable providing access to all declared methods in the class hierarchy

methodsOf

public static Iterable<Method> methodsOf(Class<?> clazz,
                                         boolean recursive)

Returns an Iterable of all the methods declared on the given class.

Will include the given clazz' super classes if recursive has been set. The iterator will always return fields declared in a subtype before returning fields declared in a super type.

Parameters:

clazz - the class to return methods for

recursive - defining whether methods should be found recursively on super classes as well

Returns:

an Iterable providing access to all declared methods in the class, including the hierarchy if recursive was set

resolvePrimitiveWrapperType

public static Class<?> resolvePrimitiveWrapperType(Class<?> primitiveType)

Returns the boxed wrapper type for the given primitiveType.

Parameters:

primitiveType - The primitive type to return boxed wrapper type for

Returns:

the boxed wrapper type for the given primitiveType

Throws:

IllegalArgumentException - will be thrown instead of returning null if no wrapper class was found.

resolvePrimitiveWrapperTypeIfPrimitive

public static Type resolvePrimitiveWrapperTypeIfPrimitive(Type type)

Returns the boxed wrapper type for the given type if it is primitive.

Parameters:

type - a Type to return boxed wrapper type for

Returns:

the boxed wrapper type for the give type, or type if no wrapper class was found.

unwrapIfType

public static Type unwrapIfType(Type type,
                                Class<?>... wrapperTypes)

Unwrap the given type if is wrapped by any of the given wrapperTypes. This method assumes that the wrapperTypes have a single generic argument, which identifies the type they wrap.

For example, if invoked with Future.class and Optional.class as wrapperTypes:

• Future<String> resolves to String
• Optional<String> resolves to String
• Optional<Future<List<String>>> resolves to List<String>

Parameters:

type - The type to unwrap, if wrapped

wrapperTypes - The wrapper types to unwrap

Returns:

the unwrapped Type, or the original if it wasn't wrapped in any of the given wrapper types

isTransient

public static boolean isTransient(Field field)

Indicates whether the given field has the "transient" modifier

Parameters:

field - the field to inspect

Returns:

true if the field is marked transient, otherwise false

resolveGenericType

public static Optional<Class<?>> resolveGenericType(Field field,
                                                    int genericTypeIndex)

Resolve a generic type parameter from a field declaration

Parameters:

field - The field to find generic parameters for

genericTypeIndex - The index of the type

Returns:

an optional that contains the resolved type, if found

resolveMemberGenericType

public static Optional<Class<?>> resolveMemberGenericType(Member member,
                                                          int genericTypeIndex)

Resolve a generic type parameter from a member declaration.

Parameters:

member - the member to find generic parameters for

genericTypeIndex - the index of the type

Returns:

an optional that contains the resolved type, if found

invokeAndGetMethodValue

public static <R> R invokeAndGetMethodValue(Method method,
                                            Object object)

Invokes and returns the return value of the given method in the given object. If necessary, the method is made accessible, assuming the security manager allows it.

Parameters:

method - the method to invoke

object - the target object the given method is invoked on

Returns:

the resulting value of invocation of the method in the object

Throws:

IllegalStateException - if the method is not accessible and the security manager doesn't allow it to be made accessible

getMemberValue

public static <R> R getMemberValue(Member member,
                                   Object target)

Returns the value of the given member in the given object, either by returning Field value or invoking the method. If necessary, the member is made accessible, assuming the security manager allows it. Supported members are Field and non-void Method without parameters.

Parameters:

member - the member containing or returning the value

target - the object to retrieve the member's value from

Returns:

the value of the member in the object

Throws:

IllegalStateException - if the member is not supported

getMemberValueType

public static Class<?> getMemberValueType(Member member)

Returns the type of value of the given member, either by returning the type of Field or type of the return value of a Method.

Parameters:

member - the member to get the value type from

Returns:

the type of value of the member

Throws:

IllegalStateException - if the member is not supported

getMemberGenericType

public static Type getMemberGenericType(Member member)

Returns the generic type of value of the given member, either by returning the generic type of Field or generic return type of a Method.

Parameters:

member - the member to get generic type of

Returns:

the generic type of value of the member

Throws:

IllegalStateException - if the member is not supported

getMemberGenericString

public static String getMemberGenericString(Member member)

Returns the generic string of the given member.

Parameters:

member - the member to get the generic string for

Returns:

the generic string of the member

Throws:

IllegalStateException - if the member is not supported

toDiscernibleSignature

public static String toDiscernibleSignature(Executable executable)

Returns a discernible signature without including the classname. This will contain the method name and the parameter types, such as: thisIfMyMethod(java.lang.String myString, com.acme.MyGreatObject).

Parameters:

executable - The executable to make a signature of.

Returns:

The discernible signature.