/*
 * 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

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;
}