com.uqbar.apo.APOClassLoader.scala Maven / Gradle / Ivy
package com.uqbar.apo
import java.io.InputStream
import javassist.ClassPool
import javassist.CtClass
import javassist.NotFoundException
import scala.collection.mutable.Buffer
import scala.collection.mutable.ListBuffer
import scala.collection.JavaConversions._
import scala.collection.JavaConverters._
/**
* Nuestro classloader, que al cargar una clase, le hace weaving para meterle la magia de aspectos.
*
* Parametro para correr tests con este ClassLoader.
*
* -Djava.system.class.loader=com.uqbar.apo.APOClassLoader
*
* @author nny
* @author jfernandes
* @author npasserini
*/
class APOClassLoader(parent: ClassLoader, cp: ClassPool) extends ClassLoader(parent) {
val EXCLUDE_PACKAGE_KEY = "apo.exclude.package"
lazy val defaultNotDefinedPackages = List("java", "javax", "sun", "com.sun", "org.w3c", "org.xml", "org.apache", "net.sf", "scala")
lazy val notDefinedPackages = APOConfig.getProperty(EXCLUDE_PACKAGE_KEY).values
var classPool: ClassPool = _
var adviceWeaver: AdviceWeaver = _
/**
* Creates a new class loader using the specified parent class loader for delegation.
* @param parent the parent class loader.
* @param cp the source of class files.
* @param adviceWeaverClass2
*/
def this(parent: ClassLoader) {
this(parent, ClassPool.getDefault())
this.init(cp)
}
def init(cp: ClassPool) {
this.classPool = cp
}
// ***************************
// ** Metodos
// ***************************
/**
* Requests the class loader to load a class.
*/
override def loadClass(name: String, resolve: Boolean): Class[_] = {
var c = this.findLoadedClass(name)
if (c == null) {
c = this.loadClassByDelegation(name)
}
if (c == null) {
c = this.findClass(name)
}
if (c == null) {
c = this.delegateToParent(name)
}
if (resolve) {
this.resolveClass(c)
}
return c
}
override def loadClass(name: String) = super.loadClass(name)
/**
* Finds the specified class using ClassPath. If the source throws an exception, this returns
* null.
*
*
* This method can be overridden by a subclass of Loader. Note that the overridden method
* must not throw an exception when it just fails to find a class file.
*
* @return null if the specified class could not be found.
* @throws ClassNotFoundException if an exception is thrown while obtaining a class file.
*/
override def findClass(name: String): Class[_] = {
var classfile: Array[Byte] = this.applyAPO(name)
var i = name.lastIndexOf('.')
if (i != -1) {
var pname = name.substring(0, i)
if (this.getPackage(pname) == null) {
this.definePackage(pname, null, null, null, null, null, null, null)
}
}
if (classfile != null) {
this.defineClass(name, classfile, 0, classfile.length)
} else {
null
}
}
protected def applyAPO(name: String): Array[Byte] = {
var classfile: Array[Byte] = null
if (this.classPool != null) {
try {
var ctClass = this.classPool.get(name)
this.weaver.applyAdvice(ctClass)
classfile = ctClass.toBytecode
} catch {
case e: NotFoundException => return null
}
}
classfile
}
/**
* The swing components must be loaded by a system class loader. javax.swing.UIManager loads a (concrete)
* subclass of LookAndFeel by a system class loader and cast an instance of the class to LookAndFeel for
* (maybe) a security reason. To avoid failure of type conversion, LookAndFeel must not be loaded by this
* class loader.
*
* java., javax. (and probably sun. and com.sun) can't be loaded with a custom classloader
* because the security manager throws a java.lang.SecurityException.
*/
def loadClassByDelegation(name: String) = if (mustDelegate(name)) this.delegateToParent(name) else null
def mustDelegate(name: String) = filterDelegate(name, defaultNotDefinedPackages) || filterDelegate(name, notDefinedPackages)
def filterDelegate(name: String, packages: Seq[String]) = packages.exists(p => name.startsWith(p))
def delegateToParent(classname: String): Class[_] = {
var cl = this.getParent()
return if (cl != null) cl.loadClass(classname) else this.findSystemClass(classname)
}
def weaver: AdviceWeaver = {
this.synchronized {
if (this.adviceWeaver == null) {
this.adviceWeaver = new AdviceWeaver(this.classPool)
this.adviceWeaver.init()
}
}
this.adviceWeaver
}
}