Raspberry Pi Gaming 4 KidsStephen Chin (@steveonjava)

What Runs Java?

What Runs Java?

Java and 3G in a Tiny Package

> Cinterion EHS5

Really Tiny…

27.6mm

18.8

mm

http://upload.wikimedia.org/wikipedia/commons/3/3d/Cloud_forest_Ecuador.jpg

=

Have Java With Your DessertRaspberry Pi

Pis are Affordable

$35

Pis are Affordable

$35 1 Box of Diapers

Bicycle(but just 1 wheel)

A Cake

Chalkboard Electronics Touchscreen

10" or 7" Form Factor

Connects via HDMI/USB

Tested with JavaFX 8

10% Exclusive Discount:

G1F0U796Z083

How to Setup Your Pi

> Step 1: Install Linux

> Step 2: Download/Copy Java 8 for ARM EA

> Step 3: Deploy and Run JVM Language Apps

http://steveonjava.com/javafx-on-raspberry-pi-3-easy-steps/

What Comes in Your Lab Kit

1. Touch Screen2. SD Card3. Keyboard4. Yellow Box:

Power Adapter LVDS Cable/Board Raspberry Pi Model B Mini-USB Cable (power) Micro-USB Cable (keyboard)

Please Save All the Packaging for Later

Electronic Safety!

> Unplug from wall before wiring

> Get rid of static by touching a metal surface

> Don't touch exposed wires/metal

> Never remove/insert SD Card while power is on

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Hooking Up the Pi (Part A)

1. Insert the SD Card in to the Pi Will appear upside down when looking at the top

of your Pi

2. Insert the HDMI board into the Pi's HDMI jack

3. Connect the Pi power to the HDMI board Use the Micro USB Cable (short one)

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Important: Connect everything before plugging into the wall

Hooking Up the Pi (Part B)

4. Slide the LCD cable into the back of the display Side with gold connectors goes up Be careful, the connector is fragile!

5. Connect the USB end to one of the Pi's USB host ports

This provides touch input6. Hook up the USB keyboard

1. Use the Mini USB cable (long one)

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Verify connections and plug into power now

Is it Working?

> Should get a bunch of flashing LEDs to indicate booting Boot takes approx 30 seconds

> The LCD screen should light up Might be dim if the light sensor is obstructed

> And you will should see a Linux boot screen with lots of text

Hacking Time!

Logging In

At the login prompt type your username:> piAnd enter the password:> raspberry

Running Your First Application

Change directory to the project folder> cd MaryHadALittleLambdaRun the build script> ant

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Hacking the Code

Run the nano text editor:> nano src/sample/MapObject.javaSave your changes:> Control-O EnterExit Nano:> Control-XCompile/Run:> ant

Mary Had a Little Lambda

Mary had a little lambdaWhose fleece was white as snowAnd everywhere that Mary wentLambda was sure to go!

https://github.com/steveonjava/MaryHadALittleLambda

Generating Streams

From a collection:> anyCollection.stream();Known set of objects:> Stream.of("bananas", "oranges", "apples");Numeric range:> IntStream.range(0, 50)Iteratively:> Stream.iterate(Color.RED, > c -> Color.hsb(c.getHue() + .1, c.getSaturation(), > c.getBrightness())); 22

Let's Create Some Barn Animals!

SpriteView tail = s.getAnimals().isEmpty() ? s : s.getAnimals().get(s.getAnimals().size() - 1);

Stream.iterate(tail, SpriteView.Lamb::new) .substream(1, 8) .forEach(s.getAnimals()::add);

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Filtering Streams

Predicate Expression> public interface Predicate<T> {> public boolean test(T t);> }

Filter out minors> adults = attendees.filter(a -> a.getAge() >= 1.8)

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Rainbow-colored Lambs!

s.getAnimals().stream() .filter(a -> a.getNumber() % 4 == 2) .forEach(a -> a.setColor(Color.YELLOW));s.getAnimals().stream() .filter(a -> a.getNumber() % 4 == 3) .forEach(a -> a.setColor(Color.CYAN));s.getAnimals().stream() .filter(a -> a.getNumber() % 4 == 0) .forEach(a -> a.setColor(Color.GREEN));

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Filtering Collections

Collection.removeIf> Removes all elements that match the predicateList.replaceAll> In-place filtering and replacement using an unary operator

ObservableCollection.filtered> Returns a list filtered by a predicate this is also Observable

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Picky Eaters…

Predicate<SpriteView> pure = a -> a.getColor() == null;

mealsServed.set(mealsServed.get() + s.getAnimals().filtered(pure).size());

s.getAnimals().removeIf(pure);

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Mapping Streams

Applies a Map Function to each element:> Function<? super T, ? extends R>

Result: List is the same size, but may be a different type.

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Single Map

s.getAnimals().setAll(s.getAnimals() .stream() .map(sv -> new Eggs(sv.getFollowing()) .collect(Collectors.toList()));

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Or a Double Map!

s.getAnimals().setAll(s.getAnimals() .stream() .map(SpriteView::getFollowing) .map(Eggs::new) .collect(Collectors.toList()));

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Flat Map

Applies a One-to-Many Map Function to each element:> Function<? super T, ? extends Stream<? extends R>>And then flattens the result into a single stream.

Result: The list may get longer and the type may be different.

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Hatching Eggs

s.getAnimals().setAll(s.getAnimals() .stream() .flatMap(SpriteView.Eggs::hatch) .collect(Collectors.toList()));

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Reduce

Reduces a list to a single element given:> Identity: T> Accumulator: BinaryOperator<T>

Result: List of the same type, but only 1 element left.

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And the (formerly little) Fox ate them all!

Double mealSize = shepherd.getAnimals() .stream() .map(SpriteView::getScaleX) .reduce(0.0, Double::sum);

setScaleX(getScaleX() + mealSize * .2);setScaleY(getScaleY() + mealSize * .2);shepherd.getAnimals().clear();

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Mary Had a Little Lambda Project

> Open-source project to demonstrate lambda features> Visual representation of streams, filters, and maps

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https://github.com/steveonjava/MaryHadALittleLambda

Stephen Chin (@steveonjava)http://steveonjava.com/

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