org.apache.beam.sdk.util.common

Class ReflectHelpers

java.lang.Object

org.apache.beam.sdk.util.common.ReflectHelpers

public class ReflectHelpers
extends java.lang.Object

Utilities for working with with Classes and Methods.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ReflectHelpers.ObjectsClassComparator A Comparator that uses the object's class' canonical name to compare them.

Constructor Summary

Constructors

Constructor and Description
ReflectHelpers()

Method Summary

Modifier and Type	Method and Description
static java.util.Collection<java.lang.reflect.Field>	declaredFieldsWithAnnotation(java.lang.Class<? extends java.lang.annotation.Annotation> anno, java.lang.Class<?> startClass, java.lang.Class<?> stopClass)
static java.util.Collection<java.lang.reflect.Method>	declaredMethodsWithAnnotation(java.lang.Class<? extends java.lang.annotation.Annotation> anno, java.lang.Class<?> startClass, java.lang.Class<?> stopClass)
static java.lang.ClassLoader	findClassLoader() Finds the appropriate ClassLoader to be used by the ServiceLoader.load(java.lang.Class<S>, java.lang.ClassLoader) call, which by default would use the context ClassLoader, which can be null.
static java.lang.ClassLoader	findClassLoader(java.lang.Class<?>... classes) Find the common classloader of all these classes.
static java.lang.ClassLoader	findClassLoader(java.lang.ClassLoader proposed) Finds the appropriate ClassLoader to be used by the ServiceLoader.load(java.lang.Class<S>, java.lang.ClassLoader) call, which by default would use the proposed ClassLoader, which can be null.
static java.lang.String	formatAnnotation(java.lang.annotation.Annotation annotation) A Function that returns a concise string for a Annotation.
static java.lang.String	formatMethod(java.lang.reflect.Method input) Returns a string representation of the signature of a Method.
static java.lang.String	formatMethodWithClass(java.lang.reflect.Method input) Returns a string representation of the class + method signature for a Method.
static java.lang.Iterable<java.lang.reflect.Method>	getClosureOfMethodsOnInterface(java.lang.Class<?> iface) Returns all the methods visible from iface.
static java.lang.Iterable<java.lang.reflect.Method>	getClosureOfMethodsOnInterfaces(java.lang.Iterable<? extends java.lang.Class<?>> interfaces) Returns all the methods visible from the provided interfaces.
static <T> java.lang.Iterable<T>	loadServicesOrdered(java.lang.Class<T> iface) A version of loadServicesOrdered that uses a default class loader.
static <T> java.lang.Iterable<T>	loadServicesOrdered(java.lang.Class<T> iface, java.lang.ClassLoader classLoader) Returns instances of all implementations of the the specified iface.
static java.lang.String	simpleTypeDescription(java.lang.reflect.Type input) A Function that formats types.

Methods inherited from class java.lang.Object

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

Constructor Detail

ReflectHelpers

public ReflectHelpers()

Method Detail

formatMethod

public static java.lang.String formatMethod(java.lang.reflect.Method input)

Returns a string representation of the signature of a Method.

formatMethodWithClass

public static java.lang.String formatMethodWithClass(java.lang.reflect.Method input)

Returns a string representation of the class + method signature for a Method.

formatAnnotation

public static java.lang.String formatAnnotation(java.lang.annotation.Annotation annotation)

A Function that returns a concise string for a Annotation.

simpleTypeDescription

public static java.lang.String simpleTypeDescription(java.lang.reflect.Type input)

A Function that formats types.

getClosureOfMethodsOnInterfaces

public static java.lang.Iterable<java.lang.reflect.Method> getClosureOfMethodsOnInterfaces(java.lang.Iterable<? extends java.lang.Class<?>> interfaces)

Returns all the methods visible from the provided interfaces.

Parameters:

interfaces - The interfaces to use when searching for all their methods.

Returns:

An iterable of Methods which interfaces expose.

getClosureOfMethodsOnInterface

public static java.lang.Iterable<java.lang.reflect.Method> getClosureOfMethodsOnInterface(java.lang.Class<?> iface)

Returns all the methods visible from iface.

Parameters:

iface - The interface to use when searching for all its methods.

Returns:

An iterable of Methods which iface exposes.

loadServicesOrdered

public static <T> java.lang.Iterable<T> loadServicesOrdered(java.lang.Class<T> iface,
                                                            java.lang.ClassLoader classLoader)

Returns instances of all implementations of the the specified iface. Instances are sorted by their class' name to ensure deterministic execution.

Type Parameters:

T - The type of iface

Parameters:

iface - The interface to load implementations of

classLoader - The class loader to use

Returns:

An iterable of instances of T, ordered by their class' canonical name

loadServicesOrdered

public static <T> java.lang.Iterable<T> loadServicesOrdered(java.lang.Class<T> iface)

A version of loadServicesOrdered that uses a default class loader.

Type Parameters:

T - The type of iface

Parameters:

iface - The interface to load implementations of

Returns:

An iterable of instances of T, ordered by their class' canonical name

findClassLoader

public static java.lang.ClassLoader findClassLoader(java.lang.ClassLoader proposed)

Finds the appropriate ClassLoader to be used by the ServiceLoader.load(java.lang.Class<S>, java.lang.ClassLoader) call, which by default would use the proposed ClassLoader, which can be null. The fallback is as follows: context ClassLoader, class ClassLoader and finaly the system ClassLoader.

findClassLoader

public static java.lang.ClassLoader findClassLoader(java.lang.Class<?>... classes)

Find the common classloader of all these classes.

findClassLoader

public static java.lang.ClassLoader findClassLoader()

Finds the appropriate ClassLoader to be used by the ServiceLoader.load(java.lang.Class<S>, java.lang.ClassLoader) call, which by default would use the context ClassLoader, which can be null. The fallback is as follows: context ClassLoader, class ClassLoader and finally the system ClassLoader.

declaredMethodsWithAnnotation

public static java.util.Collection<java.lang.reflect.Method> declaredMethodsWithAnnotation(java.lang.Class<? extends java.lang.annotation.Annotation> anno,
                                                                                           java.lang.Class<?> startClass,
                                                                                           java.lang.Class<?> stopClass)

declaredFieldsWithAnnotation

public static java.util.Collection<java.lang.reflect.Field> declaredFieldsWithAnnotation(java.lang.Class<? extends java.lang.annotation.Annotation> anno,
                                                                                         java.lang.Class<?> startClass,
                                                                                         java.lang.Class<?> stopClass)