UnresolvedPermission.java

/* UnresolvedPermission.java -- Placeholder for unresolved permissions.
   Copyright (C) 1998, 2001 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Classpath 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 for more details.

You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA.

As a special exception, if you link this library with other files to
produce an executable, this library does not by itself cause the
resulting executable to be covered by the GNU General Public License.
This exception does not however invalidate any other reasons why the
executable file might be covered by the GNU General Public License. */

package java.security;

import java.io.Serializable;
// All uses of Certificate in this file refer to this class.
import java.security.cert.Certificate;

/**
 * This class is used to hold instances of all permissions that cannot
 * be resolved to available permission classes when the security 
 * <code>Policy</code> object is instantiated.  This may happen when the
 * necessary security class has not yet been downloaded from the network.
 * <p>
 * Instances of this class are re-resolved when <code>AccessController</code>
 * check is done.  At that time, a scan is made of all existing
 * <code>UnresolvedPermission</code> objects and they are converted to
 * objects of the appropriate permission type if the class for that type
 * is then available.
 *
 * @version 0.0
 *
 * @author Aaron M. Renn (arenn@urbanophile.com)
 */
public final class UnresolvedPermission
  extends Permission
  implements Serializable
{

  /**
   * The list of actions associated with this permission object
   */
  private String actions;

  /**
   * The list of <code>Certificates</code> associated with this object
   */
  private Certificate[] certs;

  /**
   * The name of the class this object should be resolved to.
   */
  private String type;

  /**
   * This method initializes a new instance of <code>UnresolvedPermission</code>
   * with all the information necessary to resolve it to an instance of the
   * proper class at a future time.
   *
   * @param type The name of the desired class this permission should be resolved to
   * @param name The name of this permission
   * @param actions The action list for this permission
   * @param certs The list of certificates this permission's class was signed with
   */
  public UnresolvedPermission(String type, String name, String actions,
			      Certificate[] certs)
  {
    super(name);

    this.type = type;
    this.actions = actions;
    this.certs = certs;
  }

  /**
   * This method returns the list of actions associated with this
   * permission.
   *
   * @return The action list
   */
  public String getActions()
  {
    return (actions);
  }

  /**
   * This method returns <code>false</code> always to indicate that this
   * permission does not imply the specified permission.  An 
   * <code>UnresolvedPermission</code> never grants any permissions.
   *
   * @param perm The <code>Permission</code> object to test against - ignored by this class
   *
   * @return <code>false</code> to indicate this permission does not imply the specified permission.
   */
  public boolean implies(Permission perm)
  {
    return (false);
  }

  /**
   * This method tests this permission for equality against the specified
   * <code>Object</code>.  This will be true if and only if the following
   * conditions are met:
   * <p>
   * <ul>
   * <li>The specified <code>Object</code> is an instance of 
   * <code>UnresolvedPermission</code>, or a subclass.
   * <li>The specified permission has the same type (i.e., desired class name)
   * as this permission.
   * <li>The specified permission has the same name as this one.
   * <li>The specified permissoin has the same action list as this one.
   * <li>The specified permission has the same certificate list as this one.
   * </ul>
   *
   * @param obj The <code>Object</code> to test for equality
   *
   * @return <code>true</code> if the specified object is equal to this one, <code>false</code> otherwise.
   */
  public boolean equals(Object obj)
  {
    if (!(obj instanceof UnresolvedPermission))
      return (false);

    UnresolvedPermission up = (UnresolvedPermission) obj;

    if (!getName().equals(up.getName()))
      return (false);

    if (!getActions().equals(up.getActions()))
      return (false);

    if (!type.equals(up.type))
      return (false);

    if (!certs.equals(up.certs))
      return (false);

    return (true);
  }

  /**
   * Returns a hash code value for this object.
   *
   * @return A hash value
   */
  public int hashCode()
  {
    return (System.identityHashCode(this));
  }

  /**
   * This method returns a <code>String</code> representation of this
   * class.  The format is: '(unresolved "ClassName "name" "actions")'
   *
   * @return A <code>String</code> representation of this object
   */
  public String toString()
  {
    return "(unresolved " + type + " " + getName() + " " + getActions() + ")";
  }

  /**
   * This class returns a <code>PermissionCollection</code> object that can
   * be used to store instances of <code>UnresolvedPermission</code>.  If
   * <code>null</code> is returned, the caller is free to use any desired
   * <code>PermissionCollection</code>.
   *
   * @return A new <code>PermissionCollection</code>.
   */
  public PermissionCollection newPermissionCollection()
  {
    return (null);
  }
}