protectiondomain.java

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/* ProtectionDomain.java -- A security domain
   Copyright (C) 1998 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.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
module.  An independent module is a module which is not derived from
or based on this library.  If you modify this library, you may extend
this exception to your version of the library, but you are not
obligated to do so.  If you do not wish to do so, delete this
exception statement from your version. */

package java.security;

/**
 * This class represents a group of classes, along with the permissions
 * they are granted.  The classes are identified by a <code>CodeSource</code>.
 * Thus, any class loaded from the specified <code>CodeSource</code> is
 * treated as part of this domain.  The set of permissions is represented
 * by a <code>PermissionCollection</code>.
 * <p>
 * Every class in the system will belong to one and only one
 * <code>ProtectionDomain</code>.
 *
 * @version 0.0
 *
 * @author Aaron M. Renn ([e-mail])
 */
public class ProtectionDomain
{
  /**
   * This is the <code>CodeSource</code> for this protection domain
   */
  private CodeSource code_source;

  /**
   * This is the set of permissions granted to this domain
   */
  private PermissionCollection perms;

  /**
   * This method initializes a new instance of <code>ProtectionDomain</code>
   * representing the specified <code>CodeSource</code> and permission set.
   * No permissions may be added to the <code>PermissionCollection</code>
   * and this contructor will call the <code>setReadOnly</code> method on
   * the specified permission set.
   *
   * @param code_source The <code>CodeSource</code> for this domain
   * @param perms The permission set for this domain
   *
   * @see java.security.PermissionCollection#setReadOnly()
   */
  public ProtectionDomain(CodeSource code_source, PermissionCollection perms)
  {
    this.code_source = code_source;
    this.perms = perms;
    if (perms != null)
      perms.setReadOnly();
  }

  /**
     * This method returns the <code>CodeSource</code> for this domain.
     *
     * @return This domain's <code>CodeSource</code>.
   */
  public final CodeSource getCodeSource()
  {
    return code_source;
  }

  /**
   * This method returns the set of permissions granted to this domain.
   *
   * @return The permission set for this domain
   */
  public final PermissionCollection getPermissions()
  {
    return perms;
  }

  /**
   * This method tests whether or not the specified <code>Permission</code> is
   * implied by the set of permissions granted to this domain.
   *
   * @param perm The <code>Permission</code> to test.
   *
   * @return <code>true</code> if the specified <code>Permission</code> is implied for this domain, <code>false</code> otherwise.
   */
  public boolean implies(Permission perm)
  {
    PermissionCollection pc = getPermissions();
    if (pc == null)
      return (false);

    return (pc.implies(perm));
  }

  /**
   * This method returns a <code>String</code> representation of this
   * object.  It will print the <code>CodeSource</code> and 
   * permission set associated with this domain.
   *
   * @return A <code>String</code> representation of this object.
   */
  public String toString()
  {
    String linesep = System.getProperty("line.separator");
    StringBuffer sb = new StringBuffer("");
    sb.append("ProtectionDomain (" + linesep);
    if (code_source == null)
      sb.append("CodeSource:null" + linesep);
    else
      sb.append(code_source + linesep);
    sb.append(perms);
    sb.append(linesep + ")" + linesep);
    
    return sb.toString();
  }
}