Package com.alibaba.graphscope.runtime

Class GraphScopeClassLoader

java.lang.Object

com.alibaba.graphscope.runtime.GraphScopeClassLoader

public class GraphScopeClassLoader
extends Object

GraphScope Class Loader contains several static functions which will be used by GraphScope grape_engine at runtime, to initiating java runtime environment. When java app(packed in jar) is submitted to grape engine, a jvm will be initiated via JNI interface pointer if jvm has not been created is this process. Rather than directly load java classes via JNI interface pointer, we utilize a URLClassLoader for each jar to do this. The benefit of this solution is the ioslated jvm environment provided by class loaders, which can avoid possible class conflicts.

Constructor Summary

Constructors

Constructor	Description
GraphScopeClassLoader()

Method Summary

Modifier and Type	Method	Description
static Object	CreateFFIPointer(URLClassLoader classLoader, String foreignName, long address)	This function wrap one C++ object into a java object, namely a FFIPointer.
static Object	loadAndCreate(URLClassLoader classLoader, String className, String serialPath)	Load the specified class with one URLClassLoader, return a new instance for this class.
static Class<?>	loadClass(URLClassLoader classLoader, String className)	We now accept two kind of className, a/b/c or a.b.c are both ok.
static Class<?>	loadCommunicatorClass(URLClassLoader classLoader)	A special case for loadClass, i.e.
static URLClassLoader	newGraphScopeClassLoader()	Return a default URLClassLoader with no classPath.
static URLClassLoader	newGraphScopeClassLoader(String classPath)	Create a new URLClassLoaders with given classPaths.

Methods inherited from class java.lang.Object

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

Constructor Detail

GraphScopeClassLoader

public GraphScopeClassLoader()

Method Detail

newGraphScopeClassLoader

public static URLClassLoader newGraphScopeClassLoader(String classPath)
                                               throws IllegalAccessException

Create a new URLClassLoaders with given classPaths. The classPath shall be in form /path/to/A:B.jar.

Parameters:

classPath - a string will be interpreted as java class path.

Returns:

new classloader with specified classPath.

Throws:

IllegalAccessException - if ClassScope cannot get loaded libraries.

newGraphScopeClassLoader

public static URLClassLoader newGraphScopeClassLoader()
                                               throws IllegalAccessException

Return a default URLClassLoader with no classPath.

Returns:

the default class loader.

Throws:

IllegalAccessException - if ClassScope cannot get loaded libraries.

loadAndCreate

public static Object loadAndCreate(URLClassLoader classLoader,
                                   String className,
                                   String serialPath)
                            throws ClassNotFoundException,
                                   InstantiationException,
                                   IllegalAccessException,
                                   InvocationTargetException,
                                   NoSuchMethodException

Load the specified class with one URLClassLoader, return a new instance for this class. The class name could be fully-specified or dash-separated.

Parameters:

classLoader -

className - a/b/c/ or a.b.c

Returns:

a instance for loaded class.

Throws:

ClassNotFoundException - if class cannot be found in current path.

InstantiationException - if error in creating new instance.

IllegalAccessException - if error in creating new instance.

InvocationTargetException

NoSuchMethodException

CreateFFIPointer

public static Object CreateFFIPointer(URLClassLoader classLoader,
                                      String foreignName,
                                      long address)
                               throws ClassNotFoundException,
                                      NoSuchMethodException,
                                      InvocationTargetException,
                                      IllegalAccessException,
                                      InstantiationException

This function wrap one C++ object into a java object, namely a FFIPointer.

Parameters:

classLoader - The class loader with used to load java classes.

foreignName - The foreign name for C++ object,shall be fully specified.

address - The address for C++ object.

Returns:

a FFIPointer wrapper.

Throws:

ClassNotFoundException - if class cannot be found in current path.

NoSuchMethodException - if method for ffi type factory cannot be found.

InvocationTargetException - if error in invoke the specific method.

IllegalAccessException - if error in invoke the specific method.

InstantiationException - if error in creating new instance.

loadClass

public static Class<?> loadClass(URLClassLoader classLoader,
                                 String className)
                          throws ClassNotFoundException

We now accept two kind of className, a/b/c or a.b.c are both ok.

Parameters:

classLoader - url class loader to utilized.

className - full name for java class.

Returns:

loaded class.

Throws:

ClassNotFoundException - if target class cannot be found in current path.

loadCommunicatorClass

public static Class<?> loadCommunicatorClass(URLClassLoader classLoader)
                                      throws ClassNotFoundException

A special case for loadClass, i.e. loading the communicator class.

Parameters:

classLoader - url class loader to utilized.

Returns:

loaded class.

Throws:

ClassNotFoundException - if target class cannot be found in current path.