currentTimeMillis()中4小时

有个问题，如下函数，有一个名为cachetime的参数，如何设置为4小时？设置4 * 3600000？

public static File getCache(String name, Context c, int cacheTime) 
{
    if (cacheTime <= 0)
        return null;
    File cache = new File(c.getCacheDir(), name);
    long now = System.currentTimeMillis();
    if (cache.exists() && (now - cache.lastModified() < cacheTime))
        return cache;
    return null;
}

// 4 hours * 60 (min/hour) * 60 (sec/min) * 1000 (msec/sec)
getCache(name, c, 4 * 3600 * 1000);