/*
 * Copyright 2002 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package javax.security.auth.callback;

/**
 * <p> Underlying security services instantiate and pass a
 * <code>PasswordCallback</code> to the <code>invokeCallback</code>
 * method of a <code>CallbackHandler</code> to retrieve password information.
 *
 * @version 1.10, 01/11/00
 * @see javax.security.auth.callback.CallbackHandler
 */
public class PasswordCallback implements Callback {

    private String prompt;
    private boolean echoOn;
    private char[] inputPassword;

    /**
     * Construct a <code>PasswordCallback</code> with a prompt
     * and a boolean specifying whether the password should be displayed
     * as it is being typed.
     *
     * <p>
     *
     * @param prompt the prompt used to request the password. <p>
     *
     * @param echoOn true if the password should be displayed
     *			as it is being typed.
     *
     * @exception IllegalArgumentException if <code>prompt</code> is null or
     *			if <code>prompt</code> has a length of 0.
     */
    public PasswordCallback(String prompt, boolean echoOn) {
	if (prompt == null || prompt.length() == 0)
	    throw new IllegalArgumentException();

	this.prompt = prompt;
	this.echoOn = echoOn;
    }

    /**
     * Get the prompt.
     *
     * <p>
     *
     * @return the prompt.
     */
    public String getPrompt() {
	return prompt;
    }

    /**
     * Return whether the password
     * should be displayed as it is being typed.
     *
     * <p>
     *
     * @return the whether the password
     *		should be displayed as it is being typed.
     */
    public boolean isEchoOn() {
	return echoOn;
    }

    /**
     * Set the retrieved password.
     *
     * <p> This method makes a copy of the input <i>password</i>
     * before storing it.
     * 
     * <p>
     *
     * @param password the retrieved password, which may be null.
     */
    public void setPassword(char[] password) {
	this.inputPassword = (password == null ?
			null : (char[])password.clone());
    }

    /**
     * Get the retrieved password.
     *
     * <p> This method returns a copy of the retrieved password.
     *
     * <p>
     *
     * @return the retrieved password, which may be null.
     */
    public char[] getPassword() {
	return (inputPassword == null?
			null : (char[])inputPassword.clone());
    }

    /**
     * Clear the retrieved password.
     */
    public void clearPassword() {
	if (inputPassword != null) {
	    for (int i = 0; i < inputPassword.length; i++)
		inputPassword[i] = ' ';
	}
    }
}