org.apache.flink.util

Class InstantiationUtil

java.lang.Object

org.apache.flink.util.InstantiationUtil

public final class InstantiationUtil
extends Object

Utility class to create instances from class objects and checking failure reasons.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	InstantiationUtil.ClassLoaderObjectInputStream A custom ObjectInputStream that can also load user-code using a user-code ClassLoader.

Method Summary

Methods

Modifier and Type	Method and Description
static void	checkForInstantiation(Class<?> clazz) Performs a standard check whether the class can be instantiated by Class#newInstance().
static String	checkForInstantiationError(Class<?> clazz)
static <T> T	deserializeFromByteArray(TypeSerializer<T> serializer, byte[] buf)
static <T> T	deserializeObject(byte[] bytes, ClassLoader cl)
static boolean	hasPublicNullaryConstructor(Class<?> clazz) Checks, whether the given class has a public nullary constructor.
static <T> T	instantiate(Class<T> clazz) Creates a new instance of the given class.
static <T> T	instantiate(Class<T> clazz, Class<? super T> castTo) Creates a new instance of the given class.
static boolean	isNonStaticInnerClass(Class<?> clazz) Checks, whether the class is an inner class that is not statically accessible.
static boolean	isProperClass(Class<?> clazz) Checks, whether the class is a proper class, i.e.
static boolean	isPublic(Class<?> clazz) Checks, whether the given class is public.
static <T> T	readObjectFromConfig(Configuration config, String key, ClassLoader cl)
static byte[]	serializeObject(Object o)
static <T> byte[]	serializeToByteArray(TypeSerializer<T> serializer, T record)
static void	writeObjectToConfig(Object o, Configuration config, String key)

Methods inherited from class java.lang.Object

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

Method Detail

instantiate

public static <T> T instantiate(Class<T> clazz,
                Class<? super T> castTo)

Creates a new instance of the given class.

Type Parameters:

T - The generic type of the class.

Parameters:

clazz - The class to instantiate.

castTo - Optional parameter, specifying the class that the given class must be a subclass off. This argument is added to prevent class cast exceptions occurring later.

Returns:

An instance of the given class.

Throws:

RuntimeException - Thrown, if the class could not be instantiated. The exception contains a detailed message about the reason why the instantiation failed.

instantiate

public static <T> T instantiate(Class<T> clazz)

Creates a new instance of the given class.

Type Parameters:

T - The generic type of the class.

Parameters:

clazz - The class to instantiate.

Returns:

An instance of the given class.

Throws:

RuntimeException - Thrown, if the class could not be instantiated. The exception contains a detailed message about the reason why the instantiation failed.

hasPublicNullaryConstructor

public static boolean hasPublicNullaryConstructor(Class<?> clazz)

Checks, whether the given class has a public nullary constructor.

Parameters:

clazz - The class to check.

Returns:

True, if the class has a public nullary constructor, false if not.

isPublic

public static boolean isPublic(Class<?> clazz)

Checks, whether the given class is public.

Parameters:

clazz - The class to check.

Returns:

True, if the class is public, false if not.

isProperClass

public static boolean isProperClass(Class<?> clazz)

Checks, whether the class is a proper class, i.e. not abstract or an interface, and not a primitive type.

Parameters:

clazz - The class to check.

Returns:

True, if the class is a proper class, false otherwise.

isNonStaticInnerClass

public static boolean isNonStaticInnerClass(Class<?> clazz)

Checks, whether the class is an inner class that is not statically accessible. That is especially true for anonymous inner classes.

Parameters:

clazz - The class to check.

Returns:

True, if the class is a non-statically accessible inner class.

checkForInstantiation

public static void checkForInstantiation(Class<?> clazz)

Performs a standard check whether the class can be instantiated by Class#newInstance().

Parameters:

clazz - The class to check.

Throws:

RuntimeException - Thrown, if the class cannot be instantiated by Class#newInstance().

checkForInstantiationError

public static String checkForInstantiationError(Class<?> clazz)

readObjectFromConfig

public static <T> T readObjectFromConfig(Configuration config,
                         String key,
                         ClassLoader cl)
                              throws IOException,
                                     ClassNotFoundException

Throws:

IOException

ClassNotFoundException

writeObjectToConfig

public static void writeObjectToConfig(Object o,
                       Configuration config,
                       String key)
                                throws IOException

Throws:

IOException

serializeToByteArray

public static <T> byte[] serializeToByteArray(TypeSerializer<T> serializer,
                              T record)
                                   throws IOException

Throws:

IOException

deserializeFromByteArray

public static <T> T deserializeFromByteArray(TypeSerializer<T> serializer,
                             byte[] buf)
                                  throws IOException

Throws:

IOException

deserializeObject

public static <T> T deserializeObject(byte[] bytes,
                      ClassLoader cl)
                           throws IOException,
                                  ClassNotFoundException

Throws:

IOException

ClassNotFoundException

serializeObject

public static byte[] serializeObject(Object o)
                              throws IOException

Throws:

IOException