JarClassLoader.java
/*
** Module : JarClassLoader.java
** Abstract : Provides a custom class loader which handles classes loaded from
** a jar file.
**
** Copyright (c) 2011-2024, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------Description----------------------------------
** 001 CA 20111130 Initial version.
** 002 EVL 20151027 Adding method to perform resource search depending on case sensitivity mode.
** 003 EVL 20160223 Javadoc fixes to make compatible with Oracle Java 8 for Solaris 10.
** 004 ECF 20180102 Use String.replace instead of more expensive String.replaceAll in methods
** called frequently
** 005 SBI 20210414 Moved jclCache from FieSystemOps, added createJarClassLoader and getOrCreateCachedJarClassLoader
** for two scenarios of usages.
** 006 GBB 20230512 Logging methods replaced by CentralLogger/ConversionStatus.
** 007 GBB 20240425 containsResource() and getResourceName() to work for Windows file separator too.
** 008 ICP 20240705 Fixed method of obtaining the class loader.
*/
/*
** This program is free software: you can redistribute it and/or modify
** it under the terms of the GNU Affero General Public License as
** published by the Free Software Foundation, either version 3 of the
** License, or (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU Affero General Public License for more details.
**
** You may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
**
** Additional terms under GNU Affero GPL version 3 section 7:
**
** Under Section 7 of the GNU Affero GPL version 3, the following additional
** terms apply to the works covered under the License. These additional terms
** are non-permissive additional terms allowed under Section 7 of the GNU
** Affero GPL version 3 and may not be removed by you.
**
** 0. Attribution Requirement.
**
** You must preserve all legal notices or author attributions in the covered
** work or Appropriate Legal Notices displayed by works containing the covered
** work. You may not remove from the covered work any author or developer
** credit already included within the covered work.
**
** 1. No License To Use Trademarks.
**
** This license does not grant any license or rights to use the trademarks
** Golden Code, FWD, any Golden Code or FWD logo, or any other trademarks
** of Golden Code Development Corporation. You are not authorized to use the
** name Golden Code, FWD, or the names of any author or contributor, for
** publicity purposes without written authorization.
**
** 2. No Misrepresentation of Affiliation.
**
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**
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** Golden Code Development Corporation, FWD, or any author or contributor to
** the covered work, without written authorization.
**
** 3. No Misrepresentation of Source or Origin.
**
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** versions of the covered work must be marked in a reasonable way to make it
** clear that the modified work is not originating from Golden Code Development
** Corporation or FWD. All modified versions must contain the notices of
** attribution required in this license.
*/
package com.goldencode.p2j.classloader;
import com.goldencode.p2j.util.logging.*;
import org.apache.bcel.classfile.*;
import java.io.*;
import java.net.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.jar.*;
import java.util.logging.*;
/**
* Provides a class loader for files in a specified jar.
*/
public class JarClassLoader
extends ClassLoader
{
/** Logger */
private static final CentralLogger LOG = CentralLogger.get(JarClassLoader.class.getName(), false, false);
/** Jar classloader cache. */
private static Map<String, JarClassLoader> jclCache = new ConcurrentHashMap<>();
/** The resources contained in this jar. */
private final Set<String> resources = new HashSet<String>();
/** The resources contained in this jar. Case insensitive version. */
private final Map<String, String> resourcesNoCase = new HashMap<String, String>();
/** The classes loaded from this jar. */
private final Map<String, Class<?>> classes = new HashMap<String, Class<?>>();
/** The classes loaded from this jar using BCEL. */
private Map<String, JavaClass> bcelClasses = null;
/** The jar name, including path. */
private final String jarName;
/** The jar file. */
private JarFile jar = null;
/**
* Gets jar file class loader to obtain resources. If not in current cache - the new
* loader is created and stored in cache.
*
* @param jarFullName
* The fully qualified jar file name to load. It must be correct refined name.
* @param parentCl
* The class loader to be used as parent class loaded when new class loader should
* be created.
*
* @return The instance of the JarClassLoader to use in resource loading.
*/
public static JarClassLoader getOrCreateCachedJarClassLoader(String jarFullName, ClassLoader parentCl)
{
// TODO: This code is NOT thread safe and needs to be rewritten.
// first try to reuse the cache
JarClassLoader jclRes = jclCache.get(jarFullName);
// not in cache, create and store for further usage
if (jclRes == null)
{
jclRes = createJarClassLoader(jarFullName, parentCl);
if (jclRes != null)
{
JarClassLoader currLoader = jclCache.putIfAbsent(jarFullName, jclRes); // cache this loader
if (currLoader != null && currLoader != jclRes)
{
jclRes.closeLoader();
jclRes = null;
jclRes = currLoader;
}
}
}
return jclRes;
}
/**
* Creates jar file class loader to obtain resources.
*
* @param jarFullName
* The fully qualified jar file name to load. It must be correct refined name.
* @param parentCl
* The class loader to be used as parent class loaded when new class loader should
* be created.
*
* @return The instance of the JarClassLoader to use in resource loading.
*/
public static JarClassLoader createJarClassLoader(String jarFullName, ClassLoader parentCl)
{
JarClassLoader jclRes = new JarClassLoader(jarFullName, parentCl);
// loader created, initialize
if (!jclRes.init())
{
jclRes = null;
}
return jclRes;
}
/**
* Initiate a new jar classloader instance, setting its parent classloader
* to the given instance.
*
* @param jarName
* The jar name, including path.
* @param parent
* The parent classloader.
*/
private JarClassLoader(String jarName, ClassLoader parent)
{
super(parent);
this.jarName = jarName;
}
/**
* Initiatilize this classloader, by opening the jar file and saving all
* its resources into the {@link #resources} set.
*
* @return <code>true</code> if the jar was initialized, else
* <code>false</code>.
*/
private synchronized boolean init()
{
if (jar != null && !closeLoader())
{
return false;
}
try
{
jar = new JarFile(jarName);
Enumeration<JarEntry> entries = jar.entries();
while (entries.hasMoreElements())
{
JarEntry entry = entries.nextElement();
// actual resource name inside jar
String name = entry.getName();
resources.add(name);
// also make mapping from case insensitive version to actual name
// directories and classes are not something we are interesting in this time
if (!name.endsWith("/") && !name.endsWith(".class"))
{
resourcesNoCase.put(name.toLowerCase(), name);
}
}
}
catch (IOException e)
{
if (LOG.isLoggable(Level.SEVERE))
{
LOG.log(Level.SEVERE,
"Could not initiatilize this classloader " + jarName + "!", e);
}
return false;
}
return true;
}
/**
* Get the {@link #jarName jar name}.
*
* @return See above.
*/
public String getJarName()
{
return jarName;
}
/**
* Check if the given class is handled by this jar class loader (i.e. the
* class is defined in the jar).
*
* @param className
* The fully qualified class name.
*
* @return <code>true</code> if the class belongs to this class loader.
*/
public boolean containsClass(String className)
{
String resName = classNameToResource(className);
return containsResource(resName);
}
/**
* Check if the given resource belongs to this jar.
*
* @param name
* The fully qualified resource name.
*
* @return <code>true</code> if the resource belongs to this jar.
*/
public synchronized boolean containsResource(String name)
{
if (name != null && name.startsWith("/"))
name = name.substring(1);
return resources.contains(name);
}
/**
* Check if the given resource belongs to this jar.
*
* @param name
* The fully qualified resource name.
* @param caseSens
* The flag to control case sensitivity while searching.
*
* @return The name of the resource in given jar that match to the given name and case
* sensitivy flag or <code>null</code> if not found.
*/
public synchronized String getResourceName(String name, boolean caseSens)
{
// prepare string to check
if (name != null && name.startsWith("/"))
{
name = name.substring(1);
}
return caseSens ? resources.contains(name) ? name : null
: resourcesNoCase.get(name.toLowerCase());
}
/**
* Finds the resource with the given name.
*
* @param resName
* The resource name
*
* @return A <tt>URL</tt> object for reading the resource, or
* <tt>null</tt> if the resource could not be found
*/
public URL findResource(String resName)
{
try
{
File f = new File(jarName);
String jarPath = f.getAbsolutePath();
return new URL("jar:file:" + jarPath + "!/" + resName);
}
catch (MalformedURLException e)
{
LOG.warning("Couldn't fine the resource " + resName, e);
return null;
}
}
/**
* Loads the class with the specified <a href="#name">binary name</a>.
* This method searches for classes in the same manner as the {@link
* #loadClass(String, boolean)} method. It is invoked by the Java virtual
* machine to resolve class references. Invoking this method is equivalent
* to invoking {@link #loadClass(String, boolean) <tt>loadClass(name,
* false)</tt>}.
*
* @param name
* The <a href="#name">binary name</a> of the class
*
* @return The resulting <tt>Class</tt> object
*
* @throws ClassNotFoundException
* If the class was not found
*/
public synchronized Class<?> loadClass(String name)
throws ClassNotFoundException
{
if (name == null)
throw new NullPointerException("The class name can not be null !");
if (!containsClass(name))
{
// class is not handled by this jar loader, delegate the loading to
// the system class loader.
return MultiClassLoader.getClassLoader().loadClass(name);
}
if (classes.containsKey(name))
{
// class already loaded, get it from cache
return classes.get(name);
}
// load the bytecode of the class
byte[] data = null;
try
{
String resName = classNameToResource(name);
JarEntry entry = (JarEntry) jar.getEntry(resName);
data = new byte[(int) entry.getSize()];
DataInputStream dis = new DataInputStream(jar.getInputStream(entry));
int off = 0;
while (dis.available() > 0)
{
off = off + dis.read(data, off, Math.min(data.length - off, 2048));
}
dis.close();
}
catch (IOException e)
{
throw new ClassNotFoundException("Error reading bytecode for class "
+ name, e);
}
try
{
Class<?> clazz = defineClass(name, data, 0, data.length);
classes.put(name, clazz);
return clazz;
}
catch (LinkageError e)
{
throw new ClassNotFoundException("Linkage error for class "
+ name, e);
}
}
/**
* Loads the class information for the class with the specified
* <a href="#name">binary name</a>. This method uses information provided
* by system class loader if the class is already loaded. Otherwise it uses
* BCEL to get class information. in this case, if any of the superclasses
* of the target class were not found, that is not treated as error, the
* class information that was already loaded is returned. I.e. at least the
* target class definitions are returned, and, if it is possible,
* definitions of the superclasses are included too.
*
* @param name
* The <a href="#name">binary name</a> of the class
*
* @return The resulting <tt>ClassInfo</tt> object
*
* @throws ClassNotFoundException
* If the class itself (not a superclass of it) was not found or
* an error occurred while reading bytecode.
*/
public ClassInfo loadClassInfo(String name)
throws ClassNotFoundException
{
return loadClassInfo(name, null);
}
/**
* Closes this class loader, by closing the jar handle.
*
* @return <code>true</code> if the class loader was closed.
*/
public synchronized boolean closeLoader()
{
try
{
JarClassLoader loader = jclCache.get(jarName);
if (loader == this)
{
jclCache.remove(jarName);
}
jar.close();
jar = null;
resources.clear();
classes.clear();
bcelClasses = null;
}
catch (IOException e)
{
if (LOG.isLoggable(Level.SEVERE))
{
LOG.log(Level.SEVERE,
"Could not find close jar file " + jarName + "!", e);
}
return false;
}
return true;
}
/**
* Loads class information for all classes handled by this jar, without
* initiating them (i.e. their static c'tor is not called).
*
* @return The classes handled by this classloader.
*/
public synchronized ClassInfo[] listClasses()
{
List<ClassInfo> classes = new ArrayList<ClassInfo>();
for (String resource : resources)
{
if (!resource.endsWith(".class") ||
resource.endsWith("package-info.class"))
continue;
try
{
String className = resourceToClassName(resource);
ClassInfo cls = loadClassInfo(className);
classes.add(cls);
}
catch (ClassNotFoundException e)
{
if (LOG.isLoggable(Level.SEVERE))
{
LOG.log(Level.SEVERE,
"Could not load class " + resource +
" in jar " + jarName + " while listing jar classes.", e);
}
}
catch (LinkageError e)
{
if (LOG.isLoggable(Level.SEVERE))
{
LOG.log(Level.SEVERE,
"Could not load class " + resource +
" in jar " + jarName + " while listing jar classes.", e);
}
}
catch (Error e)
{
if (LOG.isLoggable(Level.SEVERE))
{
LOG.log(Level.SEVERE,
"Unexpected class loading error " + resource +
" in jar " + jarName + "!", e);
}
throw e;
}
}
return classes.toArray(new ClassInfo[classes.size()]);
}
/**
* Convert the fully-qualified class name to resource name. This is done
* by replacing all dots with the <code>/</code> char and adding the
* ".class" suffix.
*
* @param name
* The fully-qualified class name.
*
* @return The name of the resource which contains the bytecode of this
* class.
*/
private String classNameToResource(String name)
{
return name.replace('.', '/') + ".class";
}
/**
* Convert the resource name to fully-qualified class name. This is done
* by replacing all <code>/</code> chars with dots with and removing
* trailing ".class" suffix.
*
* @param resource
* Resource name.
*
* @return Fully-qualified class name which corresponds the given
* resource.
*/
private String resourceToClassName(String resource)
{
String name = resource.replace('/', '.');
if (name.endsWith(".class"))
name = name.substring(0, name.lastIndexOf(".class"));
return name;
}
/**
* Loads the class information for the class with the specified
* <a href="#name">binary name</a>. This method uses information provided
* by system class loader if the class is already loaded. Otherwise it uses
* BCEL to get class information. in this case, if any of the superclasses
* of the target class were not found, that is not treated as error, the
* class information that was already loaded is returned. I.e. at least the
* target class definitions are returned, and, if it is possible,
* definitions of the superclasses are included too.<br>
* Also, the information about the interfaces implemented by target class
* is loaded. If the class to be loaded represents an interface it added to
* the specified <tt>ClassInfo</tt> object using add*Interface functions.
*
* @param name
* The <a href="#name">binary name</a> of the class to be loaded.
* @param classInfo
* <tt>ClassInfo</tt> object that stores definitions of already
* loaded child classes. <code>null</code> if it is the first
* class in hierarchy we are trying to load.
*
* @return The resulting <tt>ClassInfo</tt> object
*
* @throws ClassNotFoundException
* If the first class in hierarchy we are trying to load was not
* found or an error occurred while reading bytecode.
*/
private synchronized ClassInfo loadClassInfo(String name,
ClassInfo classInfo)
throws ClassNotFoundException
{
if (name == null)
throw new NullPointerException("The class name can not be null !");
boolean firstClass = classInfo == null;
if (!containsClass(name))
{
// class is not handled by this jar loader, delegate the loading to
// the system class loader.
try
{
Class cls = MultiClassLoader.getClassLoader().loadClass(name);
if (cls.isInterface() && !firstClass)
{
classInfo.addInterface(cls);
}
else
{
if (firstClass)
classInfo = new ClassInfo(cls);
else
classInfo.setRootSuperclass(cls);
}
}
catch (ClassNotFoundException e)
{
// if it is not the first class in hierarchy then we return as
// much class info as we have loaded
if (firstClass)
throw e;
}
return classInfo;
}
if (classes.containsKey(name))
{
// class already loaded, get it from cache
Class cls = classes.get(name);
if (cls.isInterface() && !firstClass)
{
classInfo.addInterface(cls);
}
else
{
if (firstClass)
classInfo = new ClassInfo(cls);
else
classInfo.setRootSuperclass(cls);
}
return classInfo;
}
JavaClass cls = null;
if (bcelClasses != null && bcelClasses.containsKey(name))
{
// class already loaded using BCEL, get it from cache
cls = bcelClasses.get(name);
}
// load the bytecode of the class
if (cls == null)
{
try
{
String resName = classNameToResource(name);
JarEntry entry = (JarEntry) jar.getEntry(resName);
ClassParser parser = new ClassParser(jar.getInputStream(entry),
resName);
cls = parser.parse();
if (bcelClasses == null)
bcelClasses = new HashMap<String, JavaClass>();
bcelClasses.put(name, cls);
}
catch (IOException e)
{
throw new ClassNotFoundException("Error reading bytecode for class "
+ name, e);
}
catch (ClassFormatException e)
{
throw new ClassNotFoundException("Class format error for class "
+ name, e);
}
}
if (cls.isInterface() && !firstClass)
{
classInfo.addBcelInterface(cls.getClassName());
// load super interfaces
String[] superIfaces = cls.getInterfaceNames();
if (superIfaces != null)
{
for (String iface : superIfaces)
{
classInfo = loadClassInfo(iface, classInfo);
}
}
}
else
{
if (firstClass)
classInfo = new ClassInfo(cls);
else
classInfo.addSuperclass(cls);
// load super class
String superclassName = cls.getSuperclassName();
if (!superclassName.equals(Object.class.getName()))
{
classInfo = loadClassInfo(superclassName, classInfo);
}
}
if (firstClass)
{
// at this point we have loaded the first class in hierarchy using
// BCEL and all its superclasses, so we should manually load
// information about interfaces (and their parent interfaces) for
// the classes which were loaded using BCEL
String[] ifaces = classInfo.getFirstLevelBcelInterfaces();
for (String iface : ifaces)
{
loadClassInfo(iface, classInfo);
}
}
return classInfo;
}
}