/*

 * Copyright (c) 2003, 2013, 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;

import java.util.Map;

import java.util.List;

import java.io.IOException;

import sun.security.util.SecurityConstants;

/**

 * A CookieHandler object provides a callback mechanism to hook up a

 * HTTP state management policy implementation into the HTTP protocol

 * handler. The HTTP state management mechanism specifies a way to

 * create a stateful session with HTTP requests and responses.

 *

 * <p> A system-wide CookieHandler to be used by the {@linkplain

 * HttpURLConnection HTTP URL stream protocol handler} can be registered by

 * doing a CookieHandler.setDefault(CookieHandler). The currently registered

 * CookieHandler can be retrieved by calling

 * CookieHandler.getDefault().

 *

 * For more information on HTTP state management, see <a

 * href="http://www.ietf.org/rfc/rfc2965.txt"><i>RFC&nbsp;2965: HTTP

 * State Management Mechanism</i></a>

 *

 * @author Yingxian Wang

 * @since 1.5

 */

public abstract class CookieHandler {

    /**

     * The system-wide cookie handler that will apply cookies to the

     * request headers and manage cookies from the response headers.

     *

     * @see setDefault(CookieHandler)

     * @see getDefault()

     */

    private static CookieHandler cookieHandler;

    /**

     * Gets the system-wide cookie handler.

     *

     * @return the system-wide cookie handler; A null return means

     *        there is no system-wide cookie handler currently set.

     * @throws SecurityException

     *       If a security manager has been installed and it denies

     * {@link NetPermission}{@code ("getCookieHandler")}

     * @see #setDefault(CookieHandler)

     */

    public static synchronized CookieHandler getDefault() {

        SecurityManager sm = System.getSecurityManager();

        if (sm != null) {

            sm.checkPermission(SecurityConstants.GET_COOKIEHANDLER_PERMISSION);

        }

        return cookieHandler;

    }

    /**

     * Sets (or unsets) the system-wide cookie handler.

     *

     * Note: non-standard http protocol handlers may ignore this setting.

     *

     * @param cHandler The HTTP cookie handler, or

     *       {@code null} to unset.

     * @throws SecurityException

     *       If a security manager has been installed and it denies

     * {@link NetPermission}{@code ("setCookieHandler")}

     * @see #getDefault()

     */

    public static synchronized void setDefault(CookieHandler cHandler) {

        SecurityManager sm = System.getSecurityManager();

        if (sm != null) {

            sm.checkPermission(SecurityConstants.SET_COOKIEHANDLER_PERMISSION);

        }

        cookieHandler = cHandler;

    }

    /**

     * Gets all the applicable cookies from a cookie cache for the

     * specified uri in the request header.

     *

     * <P>The {@code URI} passed as an argument specifies the intended use for

     * the cookies. In particular the scheme should reflect whether the cookies

     * will be sent over http, https or used in another context like javascript.

     * The host part should reflect either the destination of the cookies or

     * their origin in the case of javascript.</P>

     * <P>It is up to the implementation to take into account the {@code URI} and

     * the cookies attributes and security settings to determine which ones

     * should be returned.</P>

     *

     * <P>HTTP protocol implementers should make sure that this method is

     * called after all request headers related to choosing cookies

     * are added, and before the request is sent.</P>

     *

     * @param uri a {@code URI} representing the intended use for the

     *            cookies

     * @param requestHeaders - a Map from request header

     *            field names to lists of field values representing

     *            the current request headers

     * @return an immutable map from state management headers, with

     *            field names "Cookie" or "Cookie2" to a list of

     *            cookies containing state information

     *

     * @throws IOException if an I/O error occurs

     * @throws IllegalArgumentException if either argument is null

     * @see #put(URI, Map)

     */

    public abstract Map<String, List<String>>

        get(URI uri, Map<String, List<String>> requestHeaders)

        throws IOException;

    /**

     * Sets all the applicable cookies, examples are response header

     * fields that are named Set-Cookie2, present in the response

     * headers into a cookie cache.

     *

     * @param uri a {@code URI} where the cookies come from

     * @param responseHeaders an immutable map from field names to

     *            lists of field values representing the response

     *            header fields returned

     * @throws  IOException if an I/O error occurs

     * @throws  IllegalArgumentException if either argument is null

     * @see #get(URI, Map)

     */

    public abstract void

        put(URI uri, Map<String, List<String>> responseHeaders)

        throws IOException;

}