Scala, Java, Unix, MacOS tutorials (page 1)

Dr. Foreman: The kid was just taking his calculus exam when all of a sudden he got nauseous and disoriented.

Dr. House: That’s the way calculus presents.

Our sunset on the evening of Thursday, March 26, 2020, had a pastel feel.

Pastel sunset

I think a lot of people in the United States will remember the New York Times front page for March 27, 2020, for a long time.

The New York Times front page, March 27, 2020

As a brief note, here’s a Scala function to get the Unix epoch time for X days ago:

/**
 * Returns a 10-digit Long (like 1585275929) representing the date/time.
 * Use it to get the time for 1 day ago, 2 days ago, etc. `0` will give
 * you the current time.
 */
def unixEpochTimeForNumberOfDaysAgo(numDaysAgo: Int): Long = {
    import java.time._
    val numDaysAgoDateTime: LocalDateTime = LocalDateTime.now().minusDays(numDaysAgo)
    val zdt: ZonedDateTime = numDaysAgoDateTime.atZone(ZoneId.of("America/Denver"))
    val numDaysAgoDateTimeInMillis = zdt.toInstant.toEpochMilli
    val unixEpochTime = numDaysAgoDateTimeInMillis / 1000L
    unixEpochTime
}

As shown in the comments, if you give it a 0 it will return the current epoch time.

Of course you can make the code shorter and better; I just wanted to show the steps in the approach using the Time classes in Java 8.

“As of last weekend, the nation had 17,000 confirmed cases, but the actual number was probably somewhere between 60,000 and 245,000. Numbers are now starting to rise exponentially: As of Wednesday morning, the official case count was 54,000, and the actual case count is unknown.”

I had a lot of chest pain last night, but if anything, these days that tends to keep me focused in the present moment, and make me grateful for each moment. And fortunately the universe has been giving us some amazing sunsets here lately in Colorado.

Another amazing Colorado sunset

In terms of being a nice person, Steve Jobs may have been the worst Buddhist in the history of the world, but he captures the Zen/Buddhist essence in this quote:

“Remembering that I’ll be dead soon is the most important tool I’ve ever encountered to help me make the big choices in life. Because almost everything — all external expectations, all pride, all fear of embarrassment or failure — these things just fall away in the face of death, leaving only what is truly important. Remembering that you are going to die is the best way I know to avoid the trap of thinking you have something to lose. You are already naked. There is no reason not to follow your heart.”

Photo from forbes.com, words from Steve Jobs.

Steve Jobs - remembering that i will be dead soon

I’ll write more about this when I have some free time, but for the moment I’ll just say that if you ever need to emit raw HTML when using the Play Framework and Twirl template library, code like this will do the trick:

@play.twirl.api.HtmlFormat.raw(currentBookNode.bodyValue)

In this case the bodyValue field already contains HTML as a Scala String, and I don’t want Twirl to mess with that, so I use its HtmlFormat.raw method as shown.

As a brief “note to self,” this is the Bourne shell script I use to copy images from my Drupal 8 sites directory to the same directory on my new “Static Drupal” website:

tarFile=newImagesFromDrupalSitesDir.tar
drupalHtmlDir=/drupal8/html
staticHtmlDir=/staticDrupal/html

cd $drupalHtmlDir
rm $tarFile 2> /dev/null

# create a tar file containing all new images
find sites -type f \( -name "*.jpg" -o -name "*.jpeg"  -o -name "*.png" -o -name "*.gif"  \) -mtime -2 -print0 | xargs -0 tar rvf $tarFile

# TODO make sure the tar file exists
if [ -e $tarFile ]
then
    echo "tar file exists, moving it to $staticHtmlDir"
    mv $tarFile $staticHtmlDir
    cd $staticHtmlDir
    tar xvf $tarFile
    rm $tarFile
else
    echo "POSSIBLE ERROR: the tar file DOES NOT exist"
fi

I changed the three initial variable names, but the rest of the script shows one possible way to copy all of the images in the original sites directory into the new Static Drupal directory. If you wanted to see things such as how to use multiple filenames with the Linux find command, or how to use the find command to create a tar file, I hope this example is helpful.

All those places on Amazon Prime Video where there should be an image, but there isn’t, reminds me of WeakHashMap.

Amazon Prime Video reminds me of WeakHashMap

After switching from Drupal 8 to my Static Drupal app — which generates static HTML pages from a Drupal 8 database — the CPU use on this website has dropped from an average of 22% CPU use down to 9.2%. The max CPU use has also dropped from a whopping 59% down to 22.5%.

My Static Drupal app: CPU usage drops by more than 50%

The CliffsNotes of my favorite meditation instruction for beginners is:

Sit as usual, then ~ every 4 seconds say “hear” or “calm,” depending on whether you hear thoughts in your mind, or not.

That comes from Core 1, Lesson 8 of the Brightmind app, which is now free for a year.

As one note and example of how to avoid using var fields in Scala, I initially wrote this code:

var numDaysToProcess = 0

if (args.length != 0) {
    numDaysToProcess = args(0).toInt
}

After I looked at that code for a moment I realized that I could write it without a var like this instead:

val numDaysToProcess =
    if (args.length == 0) {
        0
    } else {
        args(0).toInt
    }

That’s a simple example of one situation where you can easily avoid using a var field in Scala. I’ll share more examples as they come up.

Just like my Jenny Lane Cottage painting, this is another small version of a “faux painting” I recently created from a photo. This one is of a sidewalk in Santa Fe, New Mexico.

The complexity of this image was in removing several modern aspects from the original photo, including signs that were on those green columns, and cars that were in the street. Everything after that is what has become fairly standard work with Gimp for me, including making it look like an oil painting, and signficantly modifying and enhancing the colors.

Sidewalk in Santa Fe, New Mexico

“The world is won by those who let it go.”

Lao Tzu: The world is won by those who let it go

After ten years of this site running on Drupal, it is now delivering static web pages to you. More news after I get some sleep. :)

While looking for something else I just ran across this image that shows an example of outlined text created in Gimp. I had forgotten all about it, but I created it when I wrote my How to create outlined text using Gimp tutorial.

Outlined text in Gimp

This image makes me think of the angst of many American voters in this election. They’re angry at “politics as usual,” so they think, “I’m angry, let’s just blow it up.” But it also makes me think of the young people, and the future.

The angst of American voters

We don’t usually get a lot of snow in the Boulder/Louisville/Broomfield area, but up in the mountains near Vail and Aspen, Colorado, they usually get plenty. This was taken at a rest area near Vail.

~ March 21, 2013, on the drive back from Las Vegas

Snow in the mountains near Vail, Colorado

The postal code in Stewart, British Columbia, is “VOT 1WO,” which the locals tell me stands for Very Old Town, One Way Out.

Very Old Town, One Way Out