/*
 * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

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
 * @since 1.1
 */
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.
 *
 * @implSpec
 * 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);
 }
}