extscript-core-root/extscript-core/src/main/java/org/apache/myfaces/extensions/scripting/core/common/util/ClassUtils.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses 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 org.apache.myfaces.extensions.scripting.core.common.util;

//TODO this needs to be moved into the JSF 2.0 and 1.2 packages
//reason due to the changes caused by the shade plugin it the ClassLoader
//Extensions is in shared_impl in 1.2 and in shared in 2.x

import javax.faces.FacesException;
import java.io.File;
import java.security.AccessController;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;

/**
 * A generic utils class dealing with different aspects
 * (naming and reflection) of java classes
 *
 * @author werpu
 *         <p>&nbsp;</p>
 */
public class ClassUtils
{

    public static Class forName(String name)
    {
        try
        {
            return Class.forName(name);
        }
        catch (ClassNotFoundException e)
        {
            throw new RuntimeException(e);
        }
    }

    public static boolean isPresent(String clazz)
    {
        try
        {
            getContextClassLoader().loadClass(clazz);
        }
        catch (ClassNotFoundException e)
        {
            return false;
        }
        return true;
    }

    public static File classNameToFile(String classPath, String className)
    {
        String classFileName = classNameToRelativeFileName(className);
        return new File(classPath + File.separator + classFileName);
    }

    private static String classNameToRelativeFileName(String className)
    {
        String separator = FileUtils.getFileSeparatorForRegex();

        return className.replaceAll("\\.", separator) + ".class";
    }

    public static String relativeFileToClassName(String relativeFileName)
    {
        String className = relativeFileName.replaceAll("\\\\", ".").replaceAll("\\/", ".");
        className = className.substring(0, className.lastIndexOf("."));
        if(className.startsWith(".")) {
            className = className.substring(1);
        }
        return className;
    }

    public static void addClassLoadingExtension(Object extension, boolean top)
    {
        try
        {
            ReflectUtil.executeStaticMethod(forName("org.apache.myfaces.shared_impl.util.ClassUtils"),
                    "addClassLoadingExtension");
        }
        catch (Exception e)
        {
            ReflectUtil.executeStaticMethod(forName("org.apache.myfaces.shared.util.ClassUtils"),
                    "addClassLoadingExtension", extension, top);
        }

        //ClassUtils.addClassLoadingExtension(extension, top);
    }

    public static ClassLoader getContextClassLoader()
    {
        if (System.getSecurityManager() != null)
            {
                try
                {
                    ClassLoader cl = AccessController.doPrivileged(new PrivilegedExceptionAction<ClassLoader>()
                    {
                        public ClassLoader run() throws PrivilegedActionException
                        {
                            return Thread.currentThread().getContextClassLoader();
                        }
                    });
                    return cl;
                }
                catch (PrivilegedActionException pae)
                {
                    throw new RuntimeException(pae);
                }
            }
            else
            {
                return Thread.currentThread().getContextClassLoader();
            }
    }

}