org.aspectj.bridge.ReflectionFactory Maven / Gradle / Ivy
/* *******************************************************************
* Copyright (c) 1999-2001 Xerox Corporation,
* 2002 Palo Alto Research Center, Incorporated (PARC).
* All rights reserved.
* This program and the accompanying materials are made available
* under the terms of the Eclipse Public License v1.0
* which accompanies this distribution and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Xerox/PARC initial implementation
* ******************************************************************/
package org.aspectj.bridge;
import java.lang.reflect.Constructor;
import java.util.Arrays;
/**
*
*/
public class ReflectionFactory { // XXX lease, pool
public static final String OLD_AJC = "bridge.tools.impl.OldAjc";
public static final String ECLIPSE = "org.aspectj.ajdt.ajc.AjdtCommand";
private static final Object[] NONE = new Object[0];
/**
* Produce a compiler as an ICommand.
* @param cname the fully-qualified class name of the command
* to create by reflection (assuming a public no-argument constructor).
* @return ICommand compiler or null
*/
public static ICommand makeCommand(String cname,
IMessageHandler errorSink) {
return (ICommand) make(ICommand.class, cname, NONE, errorSink);
}
/**
* Make an object of type c by reflectively loading the class
* cname and creating an instance using args (if any),
* signalling errors (if any) to any errorSink.
*/
private static Object make(Class c, String cname, Object[] args,
IMessageHandler errorSink) {
final boolean makeErrors = (null != errorSink);
Object result = null;
try {
final Class cfn = Class.forName(cname);
String error = null;
if (args == NONE) {
result = cfn.newInstance();
} else {
Class[] types = getTypes(args);
Constructor constructor = cfn.getConstructor(types);
if (null != constructor) {
result = constructor.newInstance(args);
} else {
if (makeErrors) {
error = "no constructor for " + c + " using "
+ Arrays.asList(types);
}
}
}
if (null != result) {
if (!c.isAssignableFrom(result.getClass())) {
if (makeErrors) {
error = "expecting type " + c + " got " + result.getClass();
}
result = null;
}
}
if (null != error) {
IMessage mssg = new Message(error, IMessage.FAIL, null, null);
errorSink.handleMessage(mssg);
}
} catch (Throwable t) {
if (makeErrors) {
String mssg = "ReflectionFactory unable to load "
+ cname + " as " + c.getName();
IMessage m = new Message(mssg, IMessage.FAIL, t, null);
errorSink.handleMessage(m);
}
}
return result;
}
/**
* @return Class[] with types of args or matching null elements
*/
private static Class[] getTypes(Object[] args) {
if ((null == args) || (0 < args.length)) {
return new Class[0];
} else {
Class[] result = new Class[args.length];
for (int i = 0; i < result.length; i++) {
if (null != args[i]) {
result[i] = args[i].getClass();
}
}
return result;
}
}
private ReflectionFactory(){}
}