com.google.api.explorer.client.history.PrettyDate.java Source code

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Here is the source code for com.google.api.explorer.client.history.PrettyDate.java

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/*
 * Copyright (C) 2010 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

package com.google.api.explorer.client.history;

import com.google.gwt.dom.client.Element;
import com.google.gwt.user.client.Timer;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;

/**
 * Handles the human-readability of dates in the form of "X
 * minutes/hours/days/weeks ago".
 *
 * @author jasonhall@google.com (Jason Hall)
 */
public abstract class PrettyDate {

    private PrettyDate() {
    }

    private static String getPrettyText(Date date) {
        long diff = (new Date().getTime() - date.getTime()) / 1000;
        double dayDiff = Math.floor(diff / 86400);

        if (diff < 0) {
            return "in the future?";
        } else if (diff < 60) {
            return "moments ago";
        } else if (diff < 120) {
            return "one minute ago";
        } else if (diff < 3600) {
            return diff / 60 + " minutes ago";
        } else if (diff < 7200) {
            return "one hour ago";
        } else if (diff < 86400) {
            return diff / 3600 + " hours ago";
        } else if (dayDiff == 1) {
            return "yesterday";
        } else if (dayDiff < 7) {
            return dayDiff + " days ago";
        } else {
            return Math.ceil(dayDiff / 7) + " weeks ago";
        }
    }

    /**
     * Sets the text to the pretty-date, once, and never again.
     */
    public static void makePretty(Date date, String prefix, Element element) {
        element.setInnerText(prefix + getPrettyText(date));
    }

    private static final Map<Element, Timer> TIMERS = new HashMap<Element, Timer>();

    /**
     * Schedules a repeating timer to continually update the text with the
     * pretty-date, every minute until the text is more than an hour old, at which
     * point it stops. The assumption is that nobody will wait for 60+ minutes for
     * "one hour ago" to turn into "2 hours ago"
     */
    public static void keepMakingPretty(final Date date, final String prefix, final Element element) {
        makePretty(date, prefix, element);
        if (!TIMERS.containsKey(element)) {
            Timer timer = new Timer() {
                @Override
                public void run() {
                    makePretty(date, prefix, element);
                    if (element.getInnerText().contains("hour")) {
                        stopMakingPretty(element);
                    }
                }
            };
            timer.scheduleRepeating(60000);
            TIMERS.put(element, timer);
        }
    }

    public static void stopMakingPretty(Element element) {
        if (TIMERS.containsKey(element)) {
            TIMERS.get(element).cancel();
            TIMERS.remove(element);
        }
    }
}