content: /*
   * Copyright (c) 1996, 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.security;
  
  import javax.security.auth.Subject;
  
  /**
   * This interface represents the abstract notion of a principal, which
   * can be used to represent any entity, such as an individual, a
   * corporation, and a login id.
   *
   * @see java.security.cert.X509Certificate
   *
   * @author Li Gong
   */
  public interface Principal {
  
      /**
       * Compares this principal to the specified object.  Returns true
       * if the object passed in matches the principal represented by
       * the implementation of this interface.
       *
       * @param another principal to compare with.
       *
       * @return true if the principal passed in is the same as that
       * encapsulated by this principal, and false otherwise.
       */
      public boolean equals(Object another);
  
      /**
       * Returns a string representation of this principal.
       *
       * @return a string representation of this principal.
       */
      public String toString();
  
      /**
       * Returns a hashcode for this principal.
       *
       * @return a hashcode for this principal.
       */
      public int hashCode();
  
      /**
       * Returns the name of this principal.
       *
       * @return the name of this principal.
       */
      public String getName();
  
      /**
       * Returns true if the specified subject is implied by this principal.
       *
       * <p>The default implementation of this method returns true if
       * {@code subject} is non-null and contains at least one principal that
       * is equal to this principal.
       *
       * <p>Subclasses may override this with a different implementation, if
       * necessary.
       *
       * @param subject the {@code Subject}
       * @return true if {@code subject} is non-null and is
       *              implied by this principal, or false otherwise.
       * @since 1.8
       */
      public default boolean implies(Subject subject) {
          if (subject == null)
              return false;
          return subject.getPrincipals().contains(this);
      }
  }
  