javassist.runtime.Desc Maven / Gradle / Ivy
/*
* Javassist, a Java-bytecode translator toolkit.
* Copyright (C) 1999- Shigeru Chiba. All Rights Reserved.
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. Alternatively, the contents of this file may be used under
* the terms of the GNU Lesser General Public License Version 2.1 or later,
* or the Apache License Version 2.0.
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*/
package javassist.runtime;
/**
* A support class for implementing $sig and
* $type.
* This support class is required at runtime
* only if $sig or $type is used.
*/
public class Desc {
/**
* Specifies how a java.lang.Class object is loaded.
*
* If true, it is loaded by:
*
Thread.currentThread().getContextClassLoader().loadClass()
* If false, it is loaded by Class.forName().
* The default value is false.
*/
public static boolean useContextClassLoader = false;
private static final ThreadLocal USE_CONTEXT_CLASS_LOADER_LOCALLY = new ThreadLocal() {
@Override
protected Boolean initialValue() {
return false;
}
};
/**
* Changes so that the current thread will use the context class loader
* when a class is loaded.
* This method changes the behavior per thread unlike {@link useContextClassLoader}.
*
* @since 3.25
*/
public static void setUseContextClassLoaderLocally() {
USE_CONTEXT_CLASS_LOADER_LOCALLY.set(true);
}
/**
* Changes so that the current thread will not use the context class loader
* when a class is loaded.
* Call this method before releasing the current thread for reuse.
* It invokes ThreadLocal.remvoe().
*
* @since 3.25
*/
public static void resetUseContextClassLoaderLocally() {
USE_CONTEXT_CLASS_LOADER_LOCALLY.remove();
}
private static Class getClassObject(String name)
throws ClassNotFoundException
{
if (useContextClassLoader || USE_CONTEXT_CLASS_LOADER_LOCALLY.get())
return Class.forName(name, true, Thread.currentThread().getContextClassLoader());
return Class.forName(name);
}
/**
* Interprets the given class name.
* It is used for implementing $class.
*/
public static Class getClazz(String name) {
try {
return getClassObject(name);
}
catch (ClassNotFoundException e) {
throw new RuntimeException(
"$class: internal error, could not find class '" + name
+ "' (Desc.useContextClassLoader: "
+ Boolean.toString(useContextClassLoader) + ")", e);
}
}
/**
* Interprets the given type descriptor representing a method
* signature. It is used for implementing $sig.
*/
public static Class[] getParams(String desc) {
if (desc.charAt(0) != '(')
throw new RuntimeException("$sig: internal error");
return getType(desc, desc.length(), 1, 0);
}
/**
* Interprets the given type descriptor.
* It is used for implementing $type.
*/
public static Class getType(String desc) {
Class[] result = getType(desc, desc.length(), 0, 0);
if (result == null || result.length != 1)
throw new RuntimeException("$type: internal error");
return result[0];
}
private static Class[] getType(String desc, int descLen,
int start, int num) {
Class clazz;
if (start >= descLen)
return new Class[num];
char c = desc.charAt(start);
switch (c) {
case 'Z' :
clazz = Boolean.TYPE;
break;
case 'C' :
clazz = Character.TYPE;
break;
case 'B' :
clazz = Byte.TYPE;
break;
case 'S' :
clazz = Short.TYPE;
break;
case 'I' :
clazz = Integer.TYPE;
break;
case 'J' :
clazz = Long.TYPE;
break;
case 'F' :
clazz = Float.TYPE;
break;
case 'D' :
clazz = Double.TYPE;
break;
case 'V' :
clazz = Void.TYPE;
break;
case 'L' :
case '[' :
return getClassType(desc, descLen, start, num);
default :
return new Class[num];
}
Class[] result = getType(desc, descLen, start + 1, num + 1);
result[num] = clazz;
return result;
}
private static Class[] getClassType(String desc, int descLen,
int start, int num) {
int end = start;
while (desc.charAt(end) == '[')
++end;
if (desc.charAt(end) == 'L') {
end = desc.indexOf(';', end);
if (end < 0)
throw new IndexOutOfBoundsException("bad descriptor");
}
String cname;
if (desc.charAt(start) == 'L')
cname = desc.substring(start + 1, end);
else
cname = desc.substring(start, end + 1);
Class[] result = getType(desc, descLen, end + 1, num + 1);
try {
result[num] = getClassObject(cname.replace('/', '.'));
}
catch (ClassNotFoundException e) {
// "new RuntimeException(e)" is not available in JDK 1.3.
throw new RuntimeException(e.getMessage());
}
return result;
}
}