Package com.clickhouse.data

Class UnloadableClassLoader

java.lang.Object

java.lang.ClassLoader

com.clickhouse.data.UnloadableClassLoader

public final class UnloadableClassLoader
extends ClassLoader

Custom class loader for generated classes. It uses a thread-safe WeakHashMap to maintain relationship between class name(String) and class content(byte[]). The class will be only unloaded once there's no place referring to the class name and GC is triggered.

Field Summary

Fields

Modifier and Type	Field	Description
static final boolean	HAS_ASM

Constructor Summary

Constructors

Constructor	Description
UnloadableClassLoader()	Default constructor using Thread.getContextClassLoader() as parent.
UnloadableClassLoader(ClassLoader parent)	Constructs an unloadable class loader with specified parent class loader.

Method Summary

Modifier and Type	Method	Description
void	addClass(String name, byte[] bytes)	Adds a generated class.
protected Class<?>	findClass(String name)
Class<?>	loadClass(String name)
void	unloadClass(String name)	Explicitly unloads a generated class.

Methods inherited from class java.lang.ClassLoader

clearAssertionStatus, defineClass, defineClass, defineClass, defineClass, definePackage, findClass, findLibrary, findLoadedClass, findResource, findResource, findResources, findSystemClass, getClassLoadingLock, getDefinedPackage, getDefinedPackages, getName, getPackage, getPackages, getParent, getPlatformClassLoader, getResource, getResourceAsStream, getResources, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, getUnnamedModule, isRegisteredAsParallelCapable, loadClass, registerAsParallelCapable, resolveClass, resources, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, setSigners

Methods inherited from class java.lang.Object

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

Field Details

HAS_ASM

public static final boolean HAS_ASM

Constructor Details

UnloadableClassLoader

public UnloadableClassLoader()

Default constructor using Thread.getContextClassLoader() as parent.

UnloadableClassLoader

public UnloadableClassLoader(ClassLoader parent)

Constructs an unloadable class loader with specified parent class loader.

Parameters:

parent - optional class loader

Method Details

addClass

public void addClass(String name,
 byte[] bytes)

Adds a generated class.

Parameters:

name - non-empty class name

bytes - non-empty byte array representing the class

unloadClass

public void unloadClass(String name)

Explicitly unloads a generated class.

Parameters:

name - non-empty class name

findClass

protected Class<?> findClass(String name)
                      throws ClassNotFoundException

Overrides:

findClass in class ClassLoader

Throws:

ClassNotFoundException

loadClass

public Class<?> loadClass(String name)
                   throws ClassNotFoundException

Overrides:

loadClass in class ClassLoader

Throws:

ClassNotFoundException