com.hazelcast.nio

Class ClassLoaderUtil

java.lang.Object

com.hazelcast.nio.ClassLoaderUtil

@PrivateApi
public final class ClassLoaderUtil
extends Object

Utility class to deal with class loaders.

Field Summary

Fields

Modifier and Type	Field and Description
static String	HAZELCAST_ARRAY
static String	HAZELCAST_BASE_PACKAGE

Method Summary

Modifier and Type	Method and Description
static Class<?>[]	getAllInterfaces(Class<?> clazz)
static <T> T	getOrCreate(T instance, ClassLoader classLoader, String className) Returns the instance, if not null, or constructs a new instance of the class using newInstance(ClassLoader, String).
static boolean	implementsInterfaceWithSameName(Class<?> clazz, Class<?> iface) Check whether given class implements an interface with the same name.
static boolean	isClassAvailable(ClassLoader classLoader, String className)
static boolean	isClassDefined(String className) Indicates whether or not the given class exists
static boolean	isInternalType(Class type)
static Class<?>	loadClass(ClassLoader classLoaderHint, String className)
static <T> T	newInstance(ClassLoader classLoaderHint, String className) Creates a new instance of class with className, using the no-arg constructor.
static Class<?>	tryLoadClass(String className) Tries to load the given class.

Methods inherited from class java.lang.Object

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

Field Detail

HAZELCAST_BASE_PACKAGE

public static final String HAZELCAST_BASE_PACKAGE

See Also:

Constant Field Values

HAZELCAST_ARRAY

public static final String HAZELCAST_ARRAY

See Also:

Constant Field Values

Method Detail

getOrCreate

public static <T> T getOrCreate(T instance,
                                ClassLoader classLoader,
                                String className)

Returns the instance, if not null, or constructs a new instance of the class using newInstance(ClassLoader, String).

Parameters:

instance - the instance of the class, can be null

classLoader - the classloader used for class instantiation

className - the name of the class being constructed. If null, null is returned.

Returns:

the provided instance or a newly constructed instance of className or null, if className was null

newInstance

public static <T> T newInstance(ClassLoader classLoaderHint,
                                String className)
                         throws Exception

Creates a new instance of class with className, using the no-arg constructor. Preferably uses the class loader specified in classLoaderHint. A constructor cache is used to reduce reflection calls.

The implementation first chooses candidate class loaders. Then checks the constructor cache if a constructor is found for either of them. If not, it queries them and caches the used Constructor under the classloader key that was used to retrieve it (might not the actual classloader that loaded the returned instance, but a parent one). To choose the candidate class loaders, a peculiar, hard-to-explain-more-simply-than-reading-the-code logic is used, beware.

Parameters:

classLoaderHint - Suggested class loader to use, can be null

className - Class name (can be also primitive name or array ("[Lpkg.Class]"), required

Returns:

New instance

Throws:

Exception - ClassNotFoundException, IllegalAccessException, InstantiationException, or InvocationTargetException

loadClass

public static Class<?> loadClass(ClassLoader classLoaderHint,
                                 String className)
                          throws ClassNotFoundException

Throws:

ClassNotFoundException

isClassAvailable

public static boolean isClassAvailable(ClassLoader classLoader,
                                       String className)

isInternalType

public static boolean isInternalType(Class type)

tryLoadClass

public static Class<?> tryLoadClass(String className)
                             throws ClassNotFoundException

Tries to load the given class.

Parameters:

className - Name of the class to load

Returns:

Loaded class

Throws:

ClassNotFoundException - when the class is not found

isClassDefined

public static boolean isClassDefined(String className)

Indicates whether or not the given class exists

Parameters:

className - Name of the class

Returns:

true if the class exists, false otherwise

implementsInterfaceWithSameName

public static boolean implementsInterfaceWithSameName(Class<?> clazz,
                                                      Class<?> iface)

Check whether given class implements an interface with the same name. It returns true even when the implemented interface is loaded by a different classloader and hence the class is not assignable into it. An interface is considered as implemented when either:

• The class directly implements the interface
• The class implements an interface which extends the original interface
• One of superclasses directly implements the interface
• One of superclasses implements an interface which extends the original interface

This is useful for logging purposes.

Parameters:

clazz - class to check whether implements the interface

iface - interface to be implemented

Returns:

true when the class implements the inteface with the same name

getAllInterfaces

public static Class<?>[] getAllInterfaces(Class<?> clazz)