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 * 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.
 *
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package javax.security.auth.callback;

/**
 * <p> Underlying security services instantiate and pass a
 * {@code PasswordCallback} to the {@code handle}
 * method of a {@code CallbackHandler} to retrieve password information.
 *
 * @since 1.4
 * @see javax.security.auth.callback.CallbackHandler
 */
public class PasswordCallback implements Callback, java.io.Serializable {

    private static final long serialVersionUID = 2267422647454909926L;

    /**
     * @serial
     * @since 1.4
     */
    private String prompt;
    /**
     * @serial
     * @since 1.4
     */
    private boolean echoOn;
    /**
     * @serial
     * @since 1.4
     */
    private char[] inputPassword;

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

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

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

    /**
     * Return whether the password
     * should be displayed as it is being typed.
     *
     * @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 {@code password}
     * before storing it.
     *
     * @param password the retrieved password, which may be null.
     *
     * @see #getPassword
     */
    public void setPassword(char[] password) {
        this.inputPassword = (password == null ? null : password.clone());
    }

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

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