/*

* Copyright (c) 2008 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:

*

*/

package javax.microedition.io;

import java.security.Permission;

import java.security.PermissionCollection;

/**

 * This class represents access rights to connections via the "socket"

 * protocol. A SocketProtocolPermission consists of a URI string but no

 * actions list.

 * <p>

 * The URI string specifies a socket stream connection. It takes the following

 * general form:

 * <p>

 * socket://{host}:{portspec} | socket://[:{portspec}]

 * <p>

 * The exact syntax for the SocketProtocolPermission URI is provided by this

 * BNF. The value of the {host} field must be a symbolic hostname, a literal

 * IPv4 address or a literal IPv6 address, as specified by RFC 3986. The

 * {host} field is omitted to indicate a "server mode" connection. Server-mode

 * URIs may also omit the {portspec} field to indicate a system-assigned port

 * number. In such a case, the SocketProtocolPermission is normalized to the

 * equivalent URI "socket://:1024-65535".

 * <p>

 * If the {host} string is a DNS name, an asterisk may appear in the leftmost

 * position to indicate a match of 1 or more entire domain labels. Partial

 * domain label matches are not permitted, therefore "*.sun.com" is valid,

 * but "*sun.com" is not. An asterisk by itself matches all hosts in

 * "client-mode" connections;

 * <p>

 * The {portspec} string takes the following form:

 * <p>

 * portnumber | -portnumber | portnumber-[portnumber] | "*"

 * <p>

 * A {portspec} specification of the form "N-" (where N is a port number)

 * signifies all ports numbered N and above, while a specification of the

 * form "-N" indicates all ports numbered N and below. A single asterisk may

 * be used in place of the {portspec} field to indicate all ports. Therefore,

 * the URI "socket://:*" matches server-mode socket connections to all ports,

 * and the URI "socket://*:*" matches client-mode socket connections to all

 * hosts on all ports.

 *

 * @see Connector.open(java.lang.String)

 * @see "javax.microedition.io.SocketConnection" in MIDP 3.0 Specification

 *

 * @author Nokia Corporation

 * @version 1.0

 */

public final class SocketProtocolPermission

        extends GCFPermission

{

    /**

     * Creates a new SocketProtocolPermission with the specified URI as its

     * name. The URI string must conform to the specification given above,

     * and is normalized  to facilitate subsequent comparisons.

     *

     * @param uri the URI string.

     * @throws IllegalArgumentException if uri is malformed.

     * @throws NullPointerException if uri is null.

     */

    public SocketProtocolPermission(String uri)

    {

        super(uri);

    }

    /**

     * Checks if this SocketProtocolPermission object "implies" the

     * specified permission.

     * <p>

     * Because the {host} field of the permission URI may indicate an

     * individual host by means of either a symbolic hostname or an IP

     * address, a thorough evaluation of the implies relation between

     * two SocketProtocolPermission objects requires the underlying

     * platform to be able to transform symbolic hostnames into IP

     * addresses (via address lookup) and vice-versa (via name lookup).

     * Either service may be unavailable on a given platform. As a result,

     * the comparison of URI strings from two permissions can only be

     * best-effort. For each SocketProtocolPermission constructed with a

     * URI that contains a {host} field, the implementation will attempt

     * to determine both the fully-qualified domain name (the "canonical

     * name") and the IP address(es) of the host. However, either value

     * may be unknown.

     * <p>

     * To determine whether this object implies another permission, p,

     * this method first ensures that all of the following are true

     * (and returns false if any of them are not):

     * <ul>

     * <li>p is an instanceof SocketProtocolPermission, and</li>

     * <li>p's port range is included in this port range</li>

     * </ul>

     * Then implies checks each of the following, in order, and for each

     * returns true if the stated condition is true:

     * <ul>

     * <li>If both this object and p lack the {host}  field.</li>

     * <li>If this object has a single IP address and one of p's IP addresses

     * is equal to this object's IP address.</li>

     * <li>If this object has a wildcard domain (such as *.sun.com), and p's

     * absolute name (the name with any preceding * removed) ends with this

     * object's absolute name. For example, *.sun.com implies *.eng.sun.com.

     * </li>

     * <li>If this object has multiple IP addresses, and one of this object's

     * IP addresses equals one of p's IP addresses.</li>

     * <li>If this object's canonical name equals p's canonical name.</li>

     * </ul>

     * If none of the above are true, implies returns false.

     *

     * @param p the permission to check against.

     * @return true if the specified permission is implied by this object,

     *        false if not.

     */

    public boolean implies(Permission p)

    {

        if (p instanceof SocketProtocolPermission)

        {

            return true;

        }

        return false;

    }

    /**

     * Checks two SocketProtocolPermission objects for equality.

     *

     * @param obj the object we are testing for equality with this object.

     * @return true if obj is a SocketProtocolPermission and has the same

     *         URI string as this SocketProtocolPermission object.

     */

    public boolean equals(Object obj)

    {

        return true;

    }

    /**

     * Returns the hash code value for this object.

     *

     * @return a hash code value for this object.

     */

    public int hashCode()

    {

        return 0;

    }

    /**

     * Returns the canonical string representation of the actions, which

     * currently is the empty string "", since there are no actions defined

     * for SocketProtocolPermission.

     *

     * @return the empty string "".

     */

    public String getActions()

    {

        return "";

    }

    /**

     * Returns a new PermissionCollection for storing

     * SocketProtocolPermission objects.

     * <p>

     * SocketProtocolPermission objects must be stored in a manner that allows

     * them to be inserted into the collection in any order, but that also

     * enables the PermissionCollection implies method to be implemented in an

     * efficient (and consistent) manner.

     *

     * @return a new PermissionCollection suitable for storing

     *         SocketProtocolPermission objects.

     */

    public PermissionCollection newPermissionCollection()

    {

        return null;

    }

}