Java example source code file (Authenticator.java)

This example Java source code file (Authenticator.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

authenticator, inetaddress, netpermission, passwordauthentication, proxy, requestortype, securitymanager, server, string, url

The Authenticator.java Java example source code

/*
 * Copyright (c) 1997, 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;

/**
 * The class Authenticator represents an object that knows how to obtain
 * authentication for a network connection.  Usually, it will do this
 * by prompting the user for information.
 * <p>
 * Applications use this class by overriding {@link
 * #getPasswordAuthentication()} in a sub-class. This method will
 * typically use the various getXXX() accessor methods to get information
 * about the entity requesting authentication. It must then acquire a
 * username and password either by interacting with the user or through
 * some other non-interactive means. The credentials are then returned
 * as a {@link PasswordAuthentication} return value.
 * <p>
 * An instance of this concrete sub-class is then registered
 * with the system by calling {@link #setDefault(Authenticator)}.
 * When authentication is required, the system will invoke one of the
 * requestPasswordAuthentication() methods which in turn will call the
 * getPasswordAuthentication() method of the registered object.
 * <p>
 * All methods that request authentication have a default implementation
 * that fails.
 *
 * @see java.net.Authenticator#setDefault(java.net.Authenticator)
 * @see java.net.Authenticator#getPasswordAuthentication()
 *
 * @author  Bill Foote
 * @since   1.2
 */

// There are no abstract methods, but to be useful the user must
// subclass.
public abstract
class Authenticator {

    // The system-wide authenticator object.  See setDefault().
    private static Authenticator theAuthenticator;

    private String requestingHost;
    private InetAddress requestingSite;
    private int requestingPort;
    private String requestingProtocol;
    private String requestingPrompt;
    private String requestingScheme;
    private URL requestingURL;
    private RequestorType requestingAuthType;

    /**
     * The type of the entity requesting authentication.
     *
     * @since 1.5
     */
    public enum RequestorType {
        /**
         * Entity requesting authentication is a HTTP proxy server.
         */
        PROXY,
        /**
         * Entity requesting authentication is a HTTP origin server.
         */
        SERVER
    }

    private void reset() {
        requestingHost = null;
        requestingSite = null;
        requestingPort = -1;
        requestingProtocol = null;
        requestingPrompt = null;
        requestingScheme = null;
        requestingURL = null;
        requestingAuthType = RequestorType.SERVER;
    }


    /**
     * Sets the authenticator that will be used by the networking code
     * when a proxy or an HTTP server asks for authentication.
     * <p>
     * First, if there is a security manager, its {@code checkPermission}
     * method is called with a
     * {@code NetPermission("setDefaultAuthenticator")} permission.
     * This may result in a java.lang.SecurityException.
     *
     * @param   a       The authenticator to be set. If a is {@code null} then
     *                  any previously set authenticator is removed.
     *
     * @throws SecurityException
     *        if a security manager exists and its
     *        {@code checkPermission} method doesn't allow
     *        setting the default authenticator.
     *
     * @see SecurityManager#checkPermission
     * @see java.net.NetPermission
     */
    public synchronized static void setDefault(Authenticator a) {
        SecurityManager sm = System.getSecurityManager();
        if (sm != null) {
            NetPermission setDefaultPermission
                = new NetPermission("setDefaultAuthenticator");
            sm.checkPermission(setDefaultPermission);
        }

        theAuthenticator = a;
    }

    /**
     * Ask the authenticator that has been registered with the system
     * for a password.
     * <p>
     * First, if there is a security manager, its {@code checkPermission}
     * method is called with a
     * {@code NetPermission("requestPasswordAuthentication")} permission.
     * This may result in a java.lang.SecurityException.
     *
     * @param addr The InetAddress of the site requesting authorization,
     *             or null if not known.
     * @param port the port for the requested connection
     * @param protocol The protocol that's requesting the connection
     *          ({@link java.net.Authenticator#getRequestingProtocol()})
     * @param prompt A prompt string for the user
     * @param scheme The authentication scheme
     *
     * @return The username/password, or null if one can't be gotten.
     *
     * @throws SecurityException
     *        if a security manager exists and its
     *        {@code checkPermission} method doesn't allow
     *        the password authentication request.
     *
     * @see SecurityManager#checkPermission
     * @see java.net.NetPermission
     */
    public static PasswordAuthentication requestPasswordAuthentication(
                                            InetAddress addr,
                                            int port,
                                            String protocol,
                                            String prompt,
                                            String scheme) {

        SecurityManager sm = System.getSecurityManager();
        if (sm != null) {
            NetPermission requestPermission
                = new NetPermission("requestPasswordAuthentication");
            sm.checkPermission(requestPermission);
        }

        Authenticator a = theAuthenticator;
        if (a == null) {
            return null;
        } else {
            synchronized(a) {
                a.reset();
                a.requestingSite = addr;
                a.requestingPort = port;
                a.requestingProtocol = protocol;
                a.requestingPrompt = prompt;
                a.requestingScheme = scheme;
                return a.getPasswordAuthentication();
            }
        }
    }

    /**
     * Ask the authenticator that has been registered with the system
     * for a password. This is the preferred method for requesting a password
     * because the hostname can be provided in cases where the InetAddress
     * is not available.
     * <p>
     * First, if there is a security manager, its {@code checkPermission}
     * method is called with a
     * {@code NetPermission("requestPasswordAuthentication")} permission.
     * This may result in a java.lang.SecurityException.
     *
     * @param host The hostname of the site requesting authentication.
     * @param addr The InetAddress of the site requesting authentication,
     *             or null if not known.
     * @param port the port for the requested connection.
     * @param protocol The protocol that's requesting the connection
     *          ({@link java.net.Authenticator#getRequestingProtocol()})
     * @param prompt A prompt string for the user which identifies the authentication realm.
     * @param scheme The authentication scheme
     *
     * @return The username/password, or null if one can't be gotten.
     *
     * @throws SecurityException
     *        if a security manager exists and its
     *        {@code checkPermission} method doesn't allow
     *        the password authentication request.
     *
     * @see SecurityManager#checkPermission
     * @see java.net.NetPermission
     * @since 1.4
     */
    public static PasswordAuthentication requestPasswordAuthentication(
                                            String host,
                                            InetAddress addr,
                                            int port,
                                            String protocol,
                                            String prompt,
                                            String scheme) {

        SecurityManager sm = System.getSecurityManager();
        if (sm != null) {
            NetPermission requestPermission
                = new NetPermission("requestPasswordAuthentication");
            sm.checkPermission(requestPermission);
        }

        Authenticator a = theAuthenticator;
        if (a == null) {
            return null;
        } else {
            synchronized(a) {
                a.reset();
                a.requestingHost = host;
                a.requestingSite = addr;
                a.requestingPort = port;
                a.requestingProtocol = protocol;
                a.requestingPrompt = prompt;
                a.requestingScheme = scheme;
                return a.getPasswordAuthentication();
            }
        }
    }

    /**
     * Ask the authenticator that has been registered with the system
     * for a password.
     * <p>
     * First, if there is a security manager, its {@code checkPermission}
     * method is called with a
     * {@code NetPermission("requestPasswordAuthentication")} permission.
     * This may result in a java.lang.SecurityException.
     *
     * @param host The hostname of the site requesting authentication.
     * @param addr The InetAddress of the site requesting authorization,
     *             or null if not known.
     * @param port the port for the requested connection
     * @param protocol The protocol that's requesting the connection
     *          ({@link java.net.Authenticator#getRequestingProtocol()})
     * @param prompt A prompt string for the user
     * @param scheme The authentication scheme
     * @param url The requesting URL that caused the authentication
     * @param reqType The type (server or proxy) of the entity requesting
     *              authentication.
     *
     * @return The username/password, or null if one can't be gotten.
     *
     * @throws SecurityException
     *        if a security manager exists and its
     *        {@code checkPermission} method doesn't allow
     *        the password authentication request.
     *
     * @see SecurityManager#checkPermission
     * @see java.net.NetPermission
     *
     * @since 1.5
     */
    public static PasswordAuthentication requestPasswordAuthentication(
                                    String host,
                                    InetAddress addr,
                                    int port,
                                    String protocol,
                                    String prompt,
                                    String scheme,
                                    URL url,
                                    RequestorType reqType) {

        SecurityManager sm = System.getSecurityManager();
        if (sm != null) {
            NetPermission requestPermission
                = new NetPermission("requestPasswordAuthentication");
            sm.checkPermission(requestPermission);
        }

        Authenticator a = theAuthenticator;
        if (a == null) {
            return null;
        } else {
            synchronized(a) {
                a.reset();
                a.requestingHost = host;
                a.requestingSite = addr;
                a.requestingPort = port;
                a.requestingProtocol = protocol;
                a.requestingPrompt = prompt;
                a.requestingScheme = scheme;
                a.requestingURL = url;
                a.requestingAuthType = reqType;
                return a.getPasswordAuthentication();
            }
        }
    }

    /**
     * Gets the {@code hostname} of the
     * site or proxy requesting authentication, or {@code null}
     * if not available.
     *
     * @return the hostname of the connection requiring authentication, or null
     *          if it's not available.
     * @since 1.4
     */
    protected final String getRequestingHost() {
        return requestingHost;
    }

    /**
     * Gets the {@code InetAddress} of the
     * site requesting authorization, or {@code null}
     * if not available.
     *
     * @return the InetAddress of the site requesting authorization, or null
     *          if it's not available.
     */
    protected final InetAddress getRequestingSite() {
        return requestingSite;
    }

    /**
     * Gets the port number for the requested connection.
     * @return an {@code int} indicating the
     * port for the requested connection.
     */
    protected final int getRequestingPort() {
        return requestingPort;
    }

    /**
     * Give the protocol that's requesting the connection.  Often this
     * will be based on a URL, but in a future JDK it could be, for
     * example, "SOCKS" for a password-protected SOCKS5 firewall.
     *
     * @return the protocol, optionally followed by "/version", where
     *          version is a version number.
     *
     * @see java.net.URL#getProtocol()
     */
    protected final String getRequestingProtocol() {
        return requestingProtocol;
    }

    /**
     * Gets the prompt string given by the requestor.
     *
     * @return the prompt string given by the requestor (realm for
     *          http requests)
     */
    protected final String getRequestingPrompt() {
        return requestingPrompt;
    }

    /**
     * Gets the scheme of the requestor (the HTTP scheme
     * for an HTTP firewall, for example).
     *
     * @return the scheme of the requestor
     *
     */
    protected final String getRequestingScheme() {
        return requestingScheme;
    }

    /**
     * Called when password authorization is needed.  Subclasses should
     * override the default implementation, which returns null.
     * @return The PasswordAuthentication collected from the
     *          user, or null if none is provided.
     */
    protected PasswordAuthentication getPasswordAuthentication() {
        return null;
    }

    /**
     * Returns the URL that resulted in this
     * request for authentication.
     *
     * @since 1.5
     *
     * @return the requesting URL
     *
     */
    protected URL getRequestingURL () {
        return requestingURL;
    }

    /**
     * Returns whether the requestor is a Proxy or a Server.
     *
     * @since 1.5
     *
     * @return the authentication type of the requestor
     *
     */
    protected RequestorType getRequestorType () {
        return requestingAuthType;
    }
}