Reflection (yop-reflection 0.9.0 API)

java.lang.Object
- org.yop.reflection.Reflection

```
public class Reflection
extends Object
```
Utility class for reflection-based method.
YOP mostly relies on reflection to get the field values to persist.

Field Summary

Fields
Modifier and Type	Field and Description
`private static org.slf4j.Logger`	`logger`
`private static boolean`	`TEST_BOOL`
`private static byte`	`TEST_BYTE`
`private static char`	`TEST_CHAR`
`private static double`	`TEST_DOUBLE`
`private static float`	`TEST_FLOAT`
`private static int`	`TEST_INT`
`private static long`	`TEST_LONG`
`private static short`	`TEST_SHORT`

Constructor Summary

Constructors
Constructor and Description

Reflection()

Constructors
Constructor and Description
`Reflection()`

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`private static String`	`concat(Object... objects)` Concat objects as Strings using an underlying StringBuilder.
`static String`	`fieldToString(Field field)` A 'toString' method for logging a field with its source class.
`static <T,R> Field`	`findField(Class<T> clazz, BiConsumer<T,R> setter)` Find a field on a class whose value is returned by the given getter operation.
`static <T,R> Field`	`findField(Class<T> clazz, Function<T,R> getter)` Find a field on a class whose value is returned by the given getter operation.
`static <T> Class<T>`	`forName(String name, ClassLoader... classLoaders)` Find a class for a given class name.
`static Field`	`get(Class type, String name)` Get a field from a class or superclass using the field name.
`static Type`	`get1ArgParameter(Field field)` Return the type parameter for a 1-arg generic field.
`static <A extends Annotation> A`	`getAnnotation(Class target, Class<A> annotation)` Find the given annotation instance on the given target class or from its class hierarchy.
`static <T> Class<T>`	`getCollectionTarget(Field field)` Find the target class of a field which is a collection.
`static <T> Constructor<T>`	`getConstructor(Class<T> on, Class<?> withParameter)` Get the constructor for the given class with the given other class as single parameter.
`static List<Field>`	`getFields(Class type)` Get all the non synthetic fields of a class.
`static List<Field>`	`getFields(Class type, Class<? extends Annotation> withAnnotation)` Get all non synthetic fields of a class, with a given annotation.
`static <S,T> Class<T>`	`getGetterCollectionTarget(Class<S> source, Function<S,? extends Collection<T>> getter)` Find the target class of a getter when the field is a collection.
`static <S,T> Class<T>`	`getGetterTarget(Class<S> source, Function<S,T> getter)` Find the target class of a getter.
`static Method`	`getMethod(Class<?> clazz, String name, Class<?>... parameterTypes)` Get an existing method on a given class, with the given parameters.
`static Set<Method>`	`getMethods(Class<?> target)` Gets an array of all methods in a class hierarchy walking up recursively to parent classes.
`static <S,T> Class<T>`	`getSetterCollectionTarget(Class<S> source, BiConsumer<S,? extends Collection<T>> setter)` Find the target class of a setter when the field is a collection.
`static <S,T> Class<T>`	`getSetterTarget(Class<S> source, BiConsumer<S,T> setter)` Find the target class of a setter.
`static <T> Class<T>`	`getTarget(Field field)` Find the target class of a field be it a collection or not.
`private static <T> Class<? extends T>`	`implementationOf(Class<T> clazz)` Returns the first known implementation of a class.
`(package private) static <T> boolean`	`isConcrete(Class<T> clazz)` Check if a type is concrete (a.k.a can be instantiated)
`static <T> T`	`newInstanceNoArgs(Class<T> clazz)` Instantiate a new object using 0-arg constructor.
`private static <T> T`	`newInstanceUnsafe(Class<T> clazz)` Return a new instance of a given class, for field testing purposes (see `findField(Class, Function)`.
`static String`	`packageName(Class<?> clazz)` Read the package name of a class.
`private static <T,R> boolean`	`primitiveCheck(Field field, Function<T,R> getter, T instance, Object testValue, R fieldValue)` Check a primitive field value against a setter, twice, using `primitiveTestValue(Class, short)` with a salt of 1.
`private static Object`	`primitiveTestValue(Class<?> primitive, short salt)` Returns a test value (see `TEST_LONG` for instance) for the given primitive type.
`static Object`	`readField(Field field, Object onto)` Read the value of a field on a target object.
`static Object`	`readField(String fieldName, Object onto)` Read the value of a field on a target object.
`static void`	`set(Field field, Object onto, Object value)` Set the value value of a field for a given instance.
`static void`	`setFrom(Field field, Object from, Object onto)` Set the value value of a field for a given instance, from another instance.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - logger
```
private static final org.slf4j.Logger logger
```
  - TEST_BOOL
```
private static final boolean TEST_BOOL
```
    See Also:
    
    Constant Field Values
  - TEST_BYTE
```
private static final byte TEST_BYTE
```
    See Also:
    
    Constant Field Values
  - TEST_CHAR
```
private static final char TEST_CHAR
```
    See Also:
    
    Constant Field Values
  - TEST_SHORT
```
private static final short TEST_SHORT
```
    See Also:
    
    Constant Field Values
  - TEST_INT
```
private static final int TEST_INT
```
    See Also:
    
    Constant Field Values
  - TEST_LONG
```
private static final long TEST_LONG
```
    See Also:
    
    Constant Field Values
  - TEST_FLOAT
```
private static final float TEST_FLOAT
```
    See Also:
    
    Constant Field Values
  - TEST_DOUBLE
```
private static final double TEST_DOUBLE
```
    See Also:
    
    Constant Field Values
- Constructor Detail
  - Reflection
```
public Reflection()
```
- Method Detail
  - forName
```
public static <T> Class<T> forName(String name,
                                   ClassLoader... classLoaders)
```
    Find a class for a given class name. Do not throw checked exception.
    
    Type Parameters:
    
    T - the target type
    
    Parameters:
    
    name - the class name
    
    classLoaders - the class loaders to use. First match returns. Use Class.forName(String) if no match.
    
    Returns:
    
    the class name
    
    Throws:
    
    ReflectionException - instead of ClassNotFoundException
  - packageName
```
public static String packageName(Class<?> clazz)
```
    Read the package name of a class. Never return null.
    
    Parameters:
    
    clazz - the class whose package is to read
    
    Returns:
    
    the package name or an empty string if either clazz or its package is null
  - getMethod
```
public static Method getMethod(Class<?> clazz,
                               String name,
                               Class<?>... parameterTypes)
```
    Get an existing method on a given class, with the given parameters.
    This is a call to Class.getDeclaredMethod(String, Class...).
    If the method does not exist, simply return null, do not throw any NoSuchMethodException.
    
    Parameters:
    
    clazz - the class of the target method
    
    name - the name of the method
    
    parameterTypes - the method parameter types.
    
    Returns:
    
    the target method, accessible for your convenience, or null if no method found
  - getMethods
```
public static Set<Method> getMethods(Class<?> target)
```
    Gets an array of all methods in a class hierarchy walking up recursively to parent classes.
    
    Parameters:
    
    target - the class
    
    Returns:
    
    the methods array
  - getAnnotation
```
public static <A extends Annotation> A getAnnotation(Class target,
                                                     Class<A> annotation)
```
    Find the given annotation instance on the given target class or from its class hierarchy.
    
    Type Parameters:
    
    A - the annotation type
    
    Parameters:
    
    target - the target class
    
    annotation - the annotation class
    
    Returns:
    
    the annotation instance or null if no annotation found on target class or any of its superclasses.
  - getFields
```
public static List<Field> getFields(Class type)
```
    Get all the non synthetic fields of a class.
    Also retrieve the non synthetic fields from superclasses.
    
    Parameters:
    
    type - the target class
    
    Returns:
    
    the field list
  - getFields
```
public static List<Field> getFields(Class type,
                                    Class<? extends Annotation> withAnnotation)
```
    Get all non synthetic fields of a class, with a given annotation.
    Also retrieve non synthetic fields from superclasses.
    
    Parameters:
    
    type - the class
    
    withAnnotation - the annotation the field must declare to be eligible
    
    Returns:
    
    the field list
  - fieldToString
```
public static String fieldToString(Field field)
```
    A 'toString' method for logging a field with its source class.
    e.g : Field from SomeClass → com.package.SomeClass#fieldName
    
    Parameters:
    
    field - the field to use. Can be null.
    
    Returns:
    
    [fullyQualifiedClassName]#[fieldName] or "null" if the field is null.
  - readField
```
public static Object readField(Field field,
                               Object onto)
```
    Read the value of a field on a target object.
    This method does not throw any IllegalAccessException !
    
    Parameters:
    
    field - the field to read
    
    onto - the target object where to read the field
    
    Returns:
    
    the field value
    
    Throws:
    
    ReflectionException - if the field could not be read for any reason.
  - readField
```
public static Object readField(String fieldName,
                               Object onto)
```
    Read the value of a field on a target object.
    This method does not throw any IllegalAccessException !
    
    Parameters:
    
    fieldName - the name of the field to read
    
    onto - the target object where to read the field
    
    Returns:
    
    the field value
    
    Throws:
    
    ReflectionException - if the field could not be read or does not exist.
  - get
```
public static Field get(Class type,
                        String name)
```
    Get a field from a class or superclass using the field name.
    
    Parameters:
    
    type - the class
    
    name - the field name
    
    Returns:
    
    the found field or null.
  - set
```
public static void set(Field field,
                       Object onto,
                       Object value)
```
    Set the value value of a field for a given instance.
    This method only throws RuntimeException exceptions.
    
    Parameters:
    
    field - the field to set
    
    onto - the target instance
    
    value - the field value to set
    
    Throws:
    
    ReflectionException - exception with context, if any exception (Illegal Access or Runtime) occurs.
  - setFrom
```
public static void setFrom(Field field,
                           Object from,
                           Object onto)
```
    Set the value value of a field for a given instance, from another instance.
    This method only throws RuntimeException exceptions.
    
    Parameters:
    
    field - the field to set
    
    from - the source instance
    
    onto - the target instance
    
    Throws:
    
    ReflectionException - exception with context, if any exception (Illegal Access or Runtime) occurs.
  - get1ArgParameter
```
public static Type get1ArgParameter(Field field)
```
    Return the type parameter for a 1-arg generic field.
    Throws an exception if not a 1-arg generic field.
    
    Parameters:
    
    field - the generic field.
    
    Returns:
    
    the type.
  - newInstanceNoArgs
```
public static <T> T newInstanceNoArgs(Class<T> clazz)
```
    Instantiate a new object using 0-arg constructor.
    
    Type Parameters:
    
    T - the object type
    
    Parameters:
    
    clazz - the object class to instantiate
    
    Returns:
    
    a new instance of the object
  - findField
```
public static <T,R> Field findField(Class<T> clazz,
                                    Function<T,R> getter)
```
    Find a field on a class whose value is returned by the given getter operation.
    The field can be transient !
    
    Type Parameters:
    
    T - the class type
    
    R - the field type
    
    Parameters:
    
    clazz - the class holding the field and getter
    
    getter - the getter operation
    
    Returns:
    
    the field found.
    
    Throws:
    
    ReflectionException - if no field matches the getter
  - primitiveCheck
```
private static <T,R> boolean primitiveCheck(Field field,
                                            Function<T,R> getter,
                                            T instance,
                                            Object testValue,
                                            R fieldValue)
```
    Check a primitive field value against a setter, twice, using primitiveTestValue(Class, short) with a salt of 1.
    
    Type Parameters:
    
    T - the type holding the setter
    
    R - the target type
    
    Parameters:
    
    field - the field to check
    
    getter - the getter to use
    
    instance - the instance holding the field
    
    testValue - the test value, from the setter
    
    fieldValue - the actual field value
    
    Returns:
    
    true if the getter actually returned the field value, twice
    
    Throws:
    
    ReflectionException - could not read the field
  - findField
```
public static <T,R> Field findField(Class<T> clazz,
                                    BiConsumer<T,R> setter)
```
    Find a field on a class whose value is returned by the given getter operation.
    The field can be transient !
    
    Type Parameters:
    
    T - the class type
    
    R - the field type
    
    Parameters:
    
    clazz - the class holding the field and getter
    
    setter - the setter operation
    
    Returns:
    
    the field found.
    
    Throws:
    
    ReflectionException - if no field matches the getter
  - getCollectionTarget
```
public static <T> Class<T> getCollectionTarget(Field field)
```
    Find the target class of a field which is a collection.
    
    Type Parameters:
    
    T - target type
    
    Parameters:
    
    field - the (collection) field
    
    Returns:
    
    the field target for the given collection field
  - getTarget
```
public static <T> Class<T> getTarget(Field field)
```
    Find the target class of a field be it a collection or not.
    
    Type Parameters:
    
    T - target type
    
    Parameters:
    
    field - the field
    
    Returns:
    
    the field target
  - getGetterTarget
```
public static <S,T> Class<T> getGetterTarget(Class<S> source,
                                             Function<S,T> getter)
```
    Find the target class of a getter.
    
    Type Parameters:
    
    S - source type
    
    T - target type
    
    Parameters:
    
    source - the source class, holding the field
    
    getter - the getter (lambda function)
    
    Returns:
    
    the field type for the given getter
  - getSetterTarget
```
public static <S,T> Class<T> getSetterTarget(Class<S> source,
                                             BiConsumer<S,T> setter)
```
    Find the target class of a setter.
    
    Type Parameters:
    
    S - source type
    
    T - target type
    
    Parameters:
    
    source - the source class, holding the field
    
    setter - the setter (lambda bi consumer)
    
    Returns:
    
    the field type for the given setter
  - getGetterCollectionTarget
```
public static <S,T> Class<T> getGetterCollectionTarget(Class<S> source,
                                                       Function<S,? extends Collection<T>> getter)
```
    Find the target class of a getter when the field is a collection. Example :
    Considering Set<Pojo> getChildren() this function will return the Pojo class for the lambda ::getChildren
    
    Type Parameters:
    
    S - source type
    
    T - target type
    
    Parameters:
    
    source - the source class, holding the field
    
    getter - the getter (lambda function)
    
    Returns:
    
    the field type for the given getter
  - getSetterCollectionTarget
```
public static <S,T> Class<T> getSetterCollectionTarget(Class<S> source,
                                                       BiConsumer<S,? extends Collection<T>> setter)
```
    Find the target class of a setter when the field is a collection. Example :
    Considering void setChildren(Set<Pojo>) this function will return the Pojo class for the lambda ::setChildren
    
    Type Parameters:
    
    S - source type
    
    T - target type
    
    Parameters:
    
    source - the source class, holding the field
    
    setter - the setter (lambda function)
    
    Returns:
    
    the field type for the given setter
  - newInstanceUnsafe
```
private static <T> T newInstanceUnsafe(Class<T> clazz)
```
    Return a new instance of a given class, for field testing purposes (see findField(Class, Function).
    - Check if primitive or Wrapper → return test value (e.g TEST_LONG
    - Find a concrete implementation of T if required (T is interface or abstract)
    - No arg constructor → new instance
    - Use the infamous Unsafe → new instance
    Type Parameters:
    
    T - the type to instantiate
    
    Parameters:
    
    clazz - the class of the type to instantiate
    
    Returns:
    
    a new instance of the type T
    
    Throws:
    
    ReflectionException - fake primitive or Wrapper
    
    ReflectionException - Unsafe was not able to instantiate the type T.
  - primitiveTestValue
```
private static Object primitiveTestValue(Class<?> primitive,
                                         short salt)
```
    Returns a test value (see TEST_LONG for instance) for the given primitive type.
    
    Parameters:
    
    primitive - the primitive type or Wrapper.
    
    salt - the amount to add to the reference test value (e.g. second test)
    
    Returns:
    
    the test value for the primitive type
  - isConcrete
```
static <T> boolean isConcrete(Class<T> clazz)
```
    Check if a type is concrete (a.k.a can be instantiated)
    
    Type Parameters:
    
    T - the type to check
    
    Parameters:
    
    clazz - the class object of the type to check
    
    Returns:
    
    true if clazz is neither an interface nor an abstract class
  - implementationOf
```
private static <T> Class<? extends T> implementationOf(Class<T> clazz)
```
    Returns the first known implementation of a class.
    It can be itself if the class isConcrete(Class).
    
    Type Parameters:
    
    T - the class generic type
    
    Parameters:
    
    clazz - the class whose implementation is sought
    
    Returns:
    
    the first implementation found, self if concrete, null if no known implementation
  - getConstructor
```
public static <T> Constructor<T> getConstructor(Class<T> on,
                                                Class<?> withParameter)
```
    Get the constructor for the given class with the given other class as single parameter.
    This method does not throw NoSuchMethodException. It returns null if no match.
    This method does not wrap/unwrap primitive types : withParameter must be the exact type !
    
    Type Parameters:
    
    T - the constructor target type
    
    Parameters:
    
    on - which class whose constructor we search
    
    withParameter - the constructor single parameter class
    
    Returns:
    
    the constructor, set accessible, or null if no constructor matches.
  - concat
```
private static String concat(Object... objects)
```
    Concat objects as Strings using an underlying StringBuilder.
    
    Parameters:
    
    objects - the strings to concat.
    
    Returns:
    
    the resulting string.

Class Reflection

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

logger

TEST_BOOL

TEST_BYTE

TEST_CHAR

TEST_SHORT

TEST_INT

TEST_LONG

TEST_FLOAT

TEST_DOUBLE

Constructor Detail

Reflection

Method Detail

forName

packageName

getMethod

getMethods

getAnnotation

getFields

getFields

fieldToString

readField

readField

get

set

setFrom

get1ArgParameter

newInstanceNoArgs

findField

primitiveCheck

findField

getCollectionTarget

getTarget

getGetterTarget

getSetterTarget

getGetterCollectionTarget

getSetterCollectionTarget

newInstanceUnsafe

primitiveTestValue

isConcrete

implementationOf

getConstructor

concat