/*

 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

package java.net.spi;

import java.net.URLStreamHandlerFactory;

/**

 * URL stream handler service-provider class.

 *

 *<p> A URL stream handler provider is a concrete subclass of this class that

 * has a zero-argument constructor. URL stream handler providers may be

 * installed in an instance of the Java platform by adding them to the

 * application class path.

 *

 * <p> A URL stream handler provider identifies itself with a

 * provider-configuration file named java.net.spi.URLStreamHandlerProvider in

 * the resource directory META-INF/services. The file should contain a list of

 * fully-qualified concrete URL stream handler provider class names, one per

 * line.

 *

 * <p> URL stream handler providers are located at runtime, as specified in the

 * {@linkplain java.net.URL#URL(String,String,int,String) URL constructor}.

 *

 * @since 9

 */

public abstract class URLStreamHandlerProvider

    implements URLStreamHandlerFactory

{

    private static Void checkPermission() {

        SecurityManager sm = System.getSecurityManager();

        if (sm != null)

            sm.checkPermission(new RuntimePermission("setFactory"));

        return null;

    }

    private URLStreamHandlerProvider(Void ignore) { }

    /**

     * Initializes a new URL stream handler provider.

     *

     * @throws  SecurityException

     *          If a security manager has been installed and it denies

     *          {@link RuntimePermission}{@code ("setFactory")}.

     */

    protected URLStreamHandlerProvider() {

        this(checkPermission());

    }

}