jlibs.core.lang.ClassUtil Maven / Gradle / Ivy
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/**
* Copyright 2015 Santhosh Kumar Tekuri
*
* The JLibs authors license this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package jlibs.core.lang;
import jlibs.core.io.FileUtil;
import jlibs.core.net.URLUtil;
import java.net.MalformedURLException;
import java.net.URL;
import java.security.CodeSource;
import java.util.HashMap;
/**
* @author Santhosh Kumar T
*/
public class ClassUtil{
/**
* Returns the classpath resource(directory or jar) from which
* specified class is loaded.
*
* @param clazz class
* @return resource from which the class is loaded
*/
public static String getClassPath(Class clazz){
CodeSource codeSource = clazz.getProtectionDomain().getCodeSource();
if(codeSource!=null)
return URLUtil.toSystemID(codeSource.getLocation());
else{
URL url = clazz.getResource(clazz.getSimpleName() + ".class");
if("jar".equals(url.getProtocol())){
String path = url.getPath();
try{
return URLUtil.toSystemID(new URL(path.substring(0, path.lastIndexOf('!'))));
}catch(MalformedURLException ex){
throw new ImpossibleException("as per JAR URL Syntax this should never happen", ex);
}
}
String resource = URLUtil.toSystemID(url);
String relativePath = "/"+clazz.getName().replace(".", FileUtil.SEPARATOR)+".class";
if(resource.endsWith(relativePath))
resource = resource.substring(0, resource.length()-relativePath.length());
return resource;
}
}
/**
* Returns the classloader for the speficied clazz. Unlike
* {@link Class#getClassLoader()} this will never return null.
*/
public static ClassLoader getClassLoader(Class clazz){
ClassLoader classLoader = clazz.getClassLoader();
return classLoader==null ? ClassLoader.getSystemClassLoader() : classLoader;
}
/*-------------------------------------------------[ PRIMITIVES ]---------------------------------------------------*/
private static final HashMap PRIMITIVES = new HashMap();
static{
PRIMITIVES.put(Void.class, void.class );
PRIMITIVES.put(Boolean.class, boolean.class );
PRIMITIVES.put(Character.class, char.class );
PRIMITIVES.put(Byte.class, byte.class );
PRIMITIVES.put(Short.class, short.class );
PRIMITIVES.put(Integer.class, int.class );
PRIMITIVES.put(Long.class, long.class );
PRIMITIVES.put(Float.class, float.class );
PRIMITIVES.put(Double.class, double.class );
}
public static Class unbox(Class clazz){
Class unboxedClass = PRIMITIVES.get(clazz);
return unboxedClass==null ? clazz : unboxedClass;
}
public static boolean isPrimitiveWrapper(Class clazz){
return PRIMITIVES.containsKey(clazz);
}
private static final HashMap PRIMITIVE_WRAPPERS = new HashMap();
static{
PRIMITIVE_WRAPPERS.put(void.class, void.class );
PRIMITIVE_WRAPPERS.put(boolean.class, Boolean.class );
PRIMITIVE_WRAPPERS.put(char.class, Character.class);
PRIMITIVE_WRAPPERS.put(byte.class, Byte.class );
PRIMITIVE_WRAPPERS.put(short.class, Short.class );
PRIMITIVE_WRAPPERS.put(int.class, Integer.class );
PRIMITIVE_WRAPPERS.put(long.class, Long.class );
PRIMITIVE_WRAPPERS.put(float.class, Float.class );
PRIMITIVE_WRAPPERS.put(double.class, Double.class );
}
public static Class box(Class clazz){
Class boxedClass = PRIMITIVE_WRAPPERS.get(clazz);
return boxedClass==null ? clazz : boxedClass;
}
public static Class getPrimitiveType(String className){
if(className.equals("void"))
return void.class;
else if(className.equals("boolean"))
return boolean.class;
else if(className.equals("char"))
return char.class;
else if(className.equals("byte"))
return byte.class;
else if(className.equals("short"))
return short.class;
else if(className.equals("int"))
return int.class;
else if(className.equals("long"))
return long.class;
else if(className.equals("float"))
return float.class;
else if(className.equals("double"))
return double.class;
else
return null;
}
/*-------------------------------------------------[ ClassContext ]---------------------------------------------------*/
/**
* A helper class to get the call context. It subclasses SecurityManager
* to make getClassContext() accessible.
*/
private static class ClassContext extends SecurityManager{
public static final ClassContext INSTANCE = new ClassContext();
@Override
protected Class[] getClassContext(){
return super.getClassContext();
}
}
/**
* returns the calling class.
*
* offset 0 returns class who is calling this method
* offset 1 returns class who called your method
* and so on
*/
public static Class getClassingClass(int offset){
Class[] context = ClassContext.INSTANCE.getClassContext();
offset += 2;
return context.length>offset ? context[offset] : null;
}
public static Class getClassingClass(){
return getClassingClass(1);
}
public static ClassLoader getClassingClassLoader(){
Class caller = getClassingClass(1);
return caller==null ? ClassLoader.getSystemClassLoader() : getClassLoader(caller);
}
}