/*
 * JBoss, Home of Professional Open Source
 * Copyright 2009, Red Hat Middleware LLC, and individual contributors
 * by the @authors tag. See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * Licensed 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.jboss.shrinkwrap.resolver.api;

import java.security.AccessController;
import java.security.PrivilegedAction;

/**
 * A set of privileged actions that are not to leak out of this package
 *
 * @author <a href="mailto:andrew.rubinger@jboss.org">ALR</a>
 * @author <a href="mailto:kpiwko@redhat.com">Karel Piwko</a>
 */
final class SecurityActions {

    // -------------------------------------------------------------------------------||
    // Constructor -------------------------------------------------------------------||
    // -------------------------------------------------------------------------------||

    /**
     * No instantiation
     */
    private SecurityActions() {
        throw new UnsupportedOperationException("No instantiation");
    }

    // -------------------------------------------------------------------------------||
    // Utility Methods ---------------------------------------------------------------||
    // -------------------------------------------------------------------------------||

    /**
     * Obtains the Thread Context ClassLoader
     */
    static ClassLoader getThreadContextClassLoader() {
        return AccessController.doPrivileged(GetTcclAction.INSTANCE);
    }

    // -------------------------------------------------------------------------------||
    // Inner Classes
    // ----------------------------------------------------------------||
    // -------------------------------------------------------------------------------||

    /**
     * Single instance to get the TCCL
     */
    private enum GetTcclAction implements PrivilegedAction<ClassLoader> {
        INSTANCE;

        public ClassLoader run() {
            return Thread.currentThread().getContextClassLoader();
        }

    }

}
