org.ovirt.engine.core.utils

Class ReflectionUtils

java.lang.Object

org.ovirt.engine.core.utils.ReflectionUtils

public class ReflectionUtils
extends Object

General utilities for using Java's reflection mechanism.

Constructor Summary

Constructors

Constructor and Description
ReflectionUtils()

Method Summary

Methods

Modifier and Type	Method and Description
static <T> Constructor<T>	findConstructor(Class<T> type, Class<?>... expectedParams) Find the first constructor of the given type which matches the expected parameters, which is the one which has parameters that can be assigned from the expected parameters. Note: In case the type is a non-static inner class, then all it's constructors have the outer class as the first parameter. Warning: The returned constructor may not be normally visible to the calling class, so use it with care. For example, suppose we have a class A and a class B which extends it: If the class has 2 constructors accepting A and B (respectfully), and we look for one accepting A, then the A constructor is returned. If the class has 2 constructors accepting A and B (respectfully), and we look for one accepting B, then the first matching constructor is returned (not guaranteed to be the same each time). If the class has only a constructor accepting B, and we look for one accepting B, then the B constructor is returned. If the class has only a constructor accepting B, and we look for one accepting A, then null is returned. If the class has a default constructor and we don't expect any arguments, then it is returned.
static Class<?>	getClassFor(String className)
static Annotation	getColumnAnnotation(Field f) Get a Field Column annotation
static Annotation	getSizeAnnotation(Field f) Get a Field Size annotation
static Annotation	getTableAnnotation(Class c)

Methods inherited from class java.lang.Object

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

Constructor Detail

ReflectionUtils

public ReflectionUtils()

Method Detail

findConstructor

public static <T> Constructor<T> findConstructor(Class<T> type,
                                 Class<?>... expectedParams)

Find the first constructor of the given type which matches the expected parameters, which is the one which has parameters that can be assigned from the expected parameters.
Note: In case the type is a non-static inner class, then all it's constructors have the outer class as the first parameter.
Warning: The returned constructor may not be normally visible to the calling class, so use it with care.

For example, suppose we have a class A and a class B which extends it:

• If the class has 2 constructors accepting A and B (respectfully), and we look for one accepting A, then the A constructor is returned.
• If the class has 2 constructors accepting A and B (respectfully), and we look for one accepting B, then the first matching constructor is returned (not guaranteed to be the same each time).
• If the class has only a constructor accepting B, and we look for one accepting B, then the B constructor is returned.
• If the class has only a constructor accepting B, and we look for one accepting A, then null is returned.
• If the class has a default constructor and we don't expect any arguments, then it is returned.

Parameters:

type - The type to look up the constructor for.

expectedParams - The expected parameters for the constructor.

Returns:

The right constructor, or null in none found.

getClassFor

public static Class<?> getClassFor(String className)

Parameters:

className - The class to load.

Returns:

The class corresponding to the given classname.

getTableAnnotation

public static Annotation getTableAnnotation(Class c)

Parameters:

c - the class

Returns:

the Table annotation of the class if exists, otherwise null.

getColumnAnnotation

public static Annotation getColumnAnnotation(Field f)

Get a Field Column annotation

Parameters:

f - the field in the class

Returns:

the Column annotation of the given Field

getSizeAnnotation

public static Annotation getSizeAnnotation(Field f)

Get a Field Size annotation

Parameters:

f -

Returns: