unavailableexception.java

GridSphere 门户 提供一个基于 portlet 的高级开放源代码门户。GridSphere 是在欧盟提供基金的 GridLab 项目下开发的

/**
 * Copyright 2003 IBM Corporation and Sun Microsystems, Inc.
 * All rights reserved.
 * Use is subject to license terms.
 */

package javax.portlet;

/**
 * The portlet should throw the <CODE>UnavailableException</CODE> when
 * the portlet is either temporarily or permanently unavailable to handle requests.
 */

public class UnavailableException extends PortletException {

    private boolean permanent;         // needs admin action?
    private int seconds;           // unavailability estimate


    /**
     * Constructs a new exception with a descriptive
     * message indicating that the portlet is permanently
     * unavailable.
     *
     * @param text a <code>String</code> specifying the
     *             descriptive message
     */

    public UnavailableException(String text) {
        super(text);

        permanent = true;
    }

    /**
     * Constructs a new exception with a descriptive message
     * indicating that the portlet is temporarily unavailable
     * and giving an estimate of how long it will be unavailable.
     * <p/>
     * <p>In some cases, the portlet cannot make an estimate. For
     * example, the portlet might know that a server it needs is
     * not running, but it might not be able to report how long it will take
     * to be restored to functionality. This can be indicated with
     * a negative or zero value for the <code>seconds</code> argument.
     *
     * @param text    a <code>String</code> specifying the
     *                descriptive message. This message can be written
     *                to a log file or displayed for the user.
     * @param seconds an integer specifying the number of seconds
     *                for which the portlet expects to be unavailable; if
     *                this is zero or negative, it indicates that the portlet
     *                cannot make an estimate.
     */

    public UnavailableException(String text, int seconds) {
        super(text);

        if (seconds <= 0)
            this.seconds = -1;
        else
            this.seconds = seconds;

        permanent = false;
    }

    /**
     * Returns a <code>boolean</code> indicating
     * whether the portlet is permanently unavailable.
     * If so, something is wrong with the portlet, and the
     * system administrator must take some corrective action.
     *
     * @return		<code>true</code> if the portlet is
     * permanently unavailable; <code>false</code>
     * if the portlet is temporarily
     * unavailable.
     */

    public boolean isPermanent() {
        return permanent;
    }


    /**
     * Returns the time in seconds for which the portlet can be expected to
     * be unavailable.
     * <p/>
     * If the portlet is called again while it is still unavailable, it
     * indicates the same time estimate. No effort is
     * made to correct for the time elapsed since the exception was
     * first reported.
     * <p/>
     * If this method returns zero or a negative number, the portlet
     * is permanently unavailable or cannot provide an estimate of
     * how long it will be unavailable.
     *
     * @return		an integer specifying the number of seconds
     * the portlet will be temporarily unavailable,
     * or zero or a negative number if the portlet is permanently
     * unavailable or cannot make an estimate.
     */

    public int getUnavailableSeconds() {
        return permanent ? -1 : seconds;
    }


}