com.tangosol.dev.component.ComponentClassLoader Maven / Gradle / Ivy
/*
* Copyright (c) 2000, 2020, Oracle and/or its affiliates.
*
* Licensed under the Universal Permissive License v 1.0 as shown at
* http://oss.oracle.com/licenses/upl.
*/
package com.tangosol.dev.component;
import com.tangosol.dev.assembler.ClassFile;
import com.tangosol.util.Base;
import com.tangosol.util.ClassHelper;
import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.io.IOException;
import java.util.Hashtable;
/**
* A class-loader that uses the Loader to load customized classes
* and resources. Since the loadClassData and loadResourceData are
* used repetitevely by the Packager, and the CacheStorage doesn't
* cache the classes and resources, we cache the results here.
*
* @version 1.0, 2000.01.12
* @version 1.1, 2001.06.20
* @author cp
* @author gg
*/
public class ComponentClassLoader
extends ClassLoader
{
// ----- constructors ---------------------------------------------------
/**
* Instantiate the ClassLoader using a default parent
* and the specified Loader
*/
public ComponentClassLoader(Loader loader)
{
this(null, loader);
}
/**
* Instantiate the ClassLoader using a specified parent ClassLoader
* and Loader
*/
public ComponentClassLoader(ClassLoader parent, Loader loader)
{
super(ensureParent(parent));
if (loader == null)
{
throw new IllegalArgumentException("The loader must be specified");
}
m_loader = loader;
}
// ----- Accessors ------------------------------------------------------
/**
* Return the Loader used by this ComponentClassLoader
*/
public Loader getLoader()
{
return m_loader;
}
// ----- ClassLoader ----------------------------------------------------
/**
* Load a class by name.
*
* @param sName the name of the class
* @param fResolve if true then resolve the class
*
* @return the Class class
*
* @exception ClassNotFoundException
*/
protected Class loadClass(String sName, boolean fResolve)
throws ClassNotFoundException
{
// a) the Loader can load any class
// b) relocatable class can only be loaded by the Loader
byte[] ab = null;
if (!isSystemClass(sName))
{
try
{
if (DEBUG && sName.startsWith(CLASS_PREFIX))
{
Base.out("Loading relocatable class: " + sName);
}
ab = loadClassData(sName);
}
catch (ComponentException e)
{
if (DEBUG)
{
Base.err("An error (" + e + ") occurred loading the class " + sName + ":");
Base.err(e);
}
throw new ClassNotFoundException(sName, e);
}
}
if (ab == null)
{
if (sName.startsWith(CLASS_PREFIX))
{
throw new ClassNotFoundException(sName);
}
return super.loadClass(sName, fResolve);
}
try
{
Class clz = defineClass(sName, ab, 0, ab.length);
if (fResolve)
{
resolveClass(clz);
}
return clz;
}
catch (Throwable e)
{
if (DEBUG)
{
Base.out("Failed to define class " + sName + ": " + e);
}
return super.loadClass(sName, fResolve);
}
}
/**
* Returns an input stream for reading the specified resource.
*
* @param sName the resource name
* @return an input stream for reading the resource, or null
* if the resource could not be found
*/
public InputStream getResourceAsStream(String sName)
{
if (DEBUG && sName.startsWith(RESOURCE_PREFIX))
{
Base.out("Loading relocatable resource: " + sName);
}
byte[] ab;
try
{
ab = loadResourceData(sName);
}
catch (IOException e)
{
if (DEBUG)
{
Base.err("An error (" + e + ") occurred loading the resource " + sName + ":");
Base.err(e);
}
return null;
}
if (ab == null)
{
if (sName.startsWith(RESOURCE_PREFIX))
{
return null;
}
else
{
return super.getResourceAsStream(sName);
}
}
else
{
return new ByteArrayInputStream(ab);
}
}
// ----- helpers --------------------------------------------------------
/**
* Load the byte codes for the specified class name
*/
public byte[] loadClassData(String sName)
throws ComponentException
{
byte[] ab = (byte[]) m_tblClasses.get(sName);
if (ab == null)
{
ClassFile clsf = m_loader.loadClass(sName);
if (clsf != null)
{
ab = clsf.getBytes();
m_tblClasses.put(sName, ab);
}
}
return ab;
}
/**
* Load the binary data for the specified resource
*/
public byte[] loadResourceData(String sName)
throws IOException
{
byte[] ab = (byte[]) m_tblResources.get(sName);
if (ab == null)
{
ab = m_loader.loadResource(sName);
if (ab != null)
{
m_tblResources.put(sName, ab);
}
}
return ab;
}
/**
* If no parent class loader is specified, use this class's loader.
*
* @param parent the parent class loader to use or null
*
* @return a parent class loader
*/
static ClassLoader ensureParent(ClassLoader parent)
{
if (parent == null)
{
parent = ComponentClassLoader.class.getClassLoader();
if (parent == null)
{
parent = getSystemClassLoader();
}
}
return parent;
}
// ----- TAPS support ---------------------------------------------------
/**
* @return true if the class should not be attemted to be loaded via TAPS
*/
protected boolean isSystemClass(String sName)
{
return sName.startsWith("java")
|| sName.startsWith("sun")
|| sName.startsWith("com.sun")
|| sName.startsWith("com.tangosol")
|| sName.startsWith("com.xtangosol");
}
/**
* The entry point for the any application that wants to load
* classes from a TAPS storage usong TAPSLoader as a class loader.
*
* Currently the storage intialization requires the following environment
* variables be set:
* tangosol.taps.repos - the repository URI (i.e. "j:\tangosol\prj")
* tangosol.taps.prj = the project name (i.e. "examples:1.0")
*/
public static void main(String[] asArg)
throws Exception
{
int cArgs = asArg.length;
Base.azzert(cArgs > 0, "Class name must be specified");
Class clzTapsLoader = Class.forName(TAPS_LOADER);
Loader loader = (Loader) clzTapsLoader.newInstance();
ClassHelper.invoke(loader, "configureStorage", ClassHelper.VOID);
ClassLoader cl = new ComponentClassLoader(loader);
Class clzMain = cl.loadClass(asArg[0]);
if (--cArgs > 0)
{
String[] as = new String[cArgs];
System.arraycopy(asArg, 1, as, 0, cArgs);
asArg = as;
}
else
{
asArg = new String[0];
}
Thread.currentThread().setContextClassLoader(cl);
ClassHelper.invokeStatic(clzMain, "main", new Object[] {asArg});
}
// ----- TAPS loader ----------------------------------------------------
/**
* The TAPSLoader component
*/
private final static String TAPS_LOADER = "com.tangosol.tde.component.dev.service.TAPSLoader";
// ----- data members ---------------------------------------------------
/**
* Used to determine whether additional debug output is permitted.
*/
private static final boolean DEBUG = false;
/**
* Package handled by this ClassLoader.
*/
private static final String CLASS_PREFIX = ClassFile.Relocator.PACKAGE.replace('/', '.');
/**
* Resources handled by this ClassLoader.
*/
private static final String RESOURCE_PREFIX = ClassFile.Relocator.PACKAGE;
/**
* The Loader to use.
*/
private Loader m_loader;
/**
* The cache for classes and resources
*/
private Hashtable m_tblClasses = new Hashtable();
private Hashtable m_tblResources = new Hashtable();
}
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