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Statistical sampling library for use in virtualdataset libraries, based on apache commons math 4
/**
* Logback: the reliable, generic, fast and flexible logging framework.
* Copyright (C) 1999-2015, QOS.ch. All rights reserved.
*
* This program and the accompanying materials are dual-licensed under
* either the terms of the Eclipse Public License v1.0 as published by
* the Eclipse Foundation
*
* or (per the licensee's choosing)
*
* under the terms of the GNU Lesser General Public License version 2.1
* as published by the Free Software Foundation.
*/
package ch.qos.logback.core.util;
import java.io.IOException;
import java.net.URL;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Enumeration;
import java.util.Set;
import java.util.HashSet;
import ch.qos.logback.core.Context;
/**
* Load resources (or images) from various sources.
*
* @author Ceki Gülcü
*/
public class Loader {
static final String TSTR = "Caught Exception while in Loader.getResource. This may be innocuous.";
private static boolean ignoreTCL = false;
public static final String IGNORE_TCL_PROPERTY_NAME = "logback.ignoreTCL";
private static boolean HAS_GET_CLASS_LOADER_PERMISSION = false;
static {
String ignoreTCLProp = OptionHelper.getSystemProperty(IGNORE_TCL_PROPERTY_NAME, null);
if (ignoreTCLProp != null) {
ignoreTCL = OptionHelper.toBoolean(ignoreTCLProp, true);
}
HAS_GET_CLASS_LOADER_PERMISSION = AccessController.doPrivileged(new PrivilegedAction() {
public Boolean run() {
try {
AccessController.checkPermission(new RuntimePermission("getClassLoader"));
return true;
} catch (SecurityException e) {
// Using SecurityException instead of AccessControlException.
// See bug LOGBACK-760.
return false;
}
}
});
}
/**
* Compute the number of occurrences a resource can be found by a class
* loader.
*
* @param resource
* @param classLoader
* @return
* @throws IOException
*/
public static Set getResources(String resource, ClassLoader classLoader) throws IOException {
// See LBCLASSIC-159
Set urlSet = new HashSet();
Enumeration urlEnum = classLoader.getResources(resource);
while (urlEnum.hasMoreElements()) {
URL url = urlEnum.nextElement();
urlSet.add(url);
}
return urlSet;
}
/**
* Search for a resource using the classloader passed as parameter.
*
* @param resource the resource name to look for
* @param classLoader the classloader used for the search
*/
public static URL getResource(String resource, ClassLoader classLoader) {
try {
return classLoader.getResource(resource);
} catch (Throwable t) {
return null;
}
}
/**
* Attempt to find a resource by using the classloader that loaded this class,
* namely Loader.class.
*
* @param resource
* @return
*/
public static URL getResourceBySelfClassLoader(String resource) {
return getResource(resource, getClassLoaderOfClass(Loader.class));
}
// private static URL getResourceByTCL(String resource) {
// return getResource(resource, getTCL());
// }
/**
* Get the Thread Context Loader which is a JDK 1.2 feature. If we are running
* under JDK 1.1 or anything else goes wrong the method returns
* null.
*/
public static ClassLoader getTCL() {
return Thread.currentThread().getContextClassLoader();
}
public static Class loadClass(String clazz, Context context) throws ClassNotFoundException {
ClassLoader cl = getClassLoaderOfObject(context);
return cl.loadClass(clazz);
}
/**
* Get the class loader of the object passed as argument. Return the system
* class loader if appropriate.
*
* @param o
* @return
*/
public static ClassLoader getClassLoaderOfObject(Object o) {
if (o == null) {
throw new NullPointerException("Argument cannot be null");
}
return getClassLoaderOfClass(o.getClass());
}
/**
* Returns the class loader of clazz in an access privileged section.
*
* @param clazz
* @return
*/
public static ClassLoader getClassLoaderAsPrivileged(final Class clazz) {
if (!HAS_GET_CLASS_LOADER_PERMISSION)
return null;
else
return AccessController.doPrivileged(new PrivilegedAction() {
public ClassLoader run() {
return clazz.getClassLoader();
}
});
}
/**
* Return the class loader which loaded the class passed as argument. Return
* the system class loader if appropriate.
*
* @param clazz
* @return
*/
public static ClassLoader getClassLoaderOfClass(final Class clazz) {
ClassLoader cl = clazz.getClassLoader();
if (cl == null) {
return ClassLoader.getSystemClassLoader();
} else {
return cl;
}
}
/**
* If running under JDK 1.2 load the specified class using the
* Thread contextClassLoader if that fails try
* Class.forname. Under JDK 1.1 only Class.forName is used.
*/
public static Class loadClass(String clazz) throws ClassNotFoundException {
// Just call Class.forName(clazz) if we are running under JDK 1.1
// or if we are instructed to ignore the TCL.
if (ignoreTCL) {
return Class.forName(clazz);
} else {
try {
return getTCL().loadClass(clazz);
} catch (Throwable e) {
// we reached here because tcl was null or because of a
// security exception, or because clazz could not be loaded...
// In any case we now try one more time
return Class.forName(clazz);
}
}
}
}