[Java] Proper use cases for Android UserManager.isUserAGoat()?


Answers

I don't know if this was "the" official use case, but the following produces a warning in Java (that can further produce compile errors if mixed with return statements, leading to unreachable code):

while (1 == 2) { // Note that "if" is treated differently
    System.out.println("Unreachable code");
}

However this is legal:

while (isUserAGoat()) {
    System.out.println("Unreachable but determined at runtime, not at compile time");
}

So I often find myself writing a silly utility method for the quickest way to dummy out a code block, then in completing debugging find all calls to it, so provided the implementation doesn't change this can be used for that.

JLS points out if (false) does not trigger "unreachable code" for the specific reason that this would break support for debug flags, i.e., basically this use case (h/t @auselen). (static final boolean DEBUG = false; for instance).

I replaced while for if, producing a more obscure use case. I believe you can trip up your IDE, like Eclipse, with this behavior, but this edit is 4 years into the future, and I don't have an Eclipse environment to play with.

Question

I was looking at the new APIs introduced in Android 4.2. While looking at the UserManager class I came across the following method:

 public boolean isUserAGoat()

Used to determine whether the user making this call is subject to teleportations.

Returns whether the user making this call is a goat.

How and when should this be used?




In the most remote mountains of the planet, lies an advanced species of goat that appear to be currently able to use phones, just like us humans!

Leaked footage: youtu.be/YJwZMUn7GdQ

Google must have spotted this and decided to provide support for them, in an attempt to stay in the frontline of technology advancement.




As of API 21 (the first Android 5.0/Lollipop SDK), this detects whether the Goat Simulator app is installed:

/**
 * Used to determine whether the user making this call is subject to
 * teleportations.
 *
 * <p>As of {@link android.os.Build.VERSION_CODES#LOLLIPOP}, this method can
 * now automatically identify goats using advanced goat recognition technology.</p>
 *
 * @return Returns true if the user making this call is a goat.
 */
public boolean isUserAGoat() {
    return mContext.getPackageManager()
            .isPackageAvailable("com.coffeestainstudios.goatsimulator");
}

This should make it clear that djechlin's suggestion of using it as a warning-free if (false) is a potentially disastrous strategy. What previously returned false for every device now returns a seemingly random value: if this was buried deep enough in your code it could take a long time to figure out where your new bugs are coming from.

Bottom line: if you don't control the implementation of a method and decide to use it for purposes other than stated in the API documentation, you're heading for trouble.




Complementing the @djechlin answer (good answer by the way!), this function call could be also used as dummy code to hold a breakpoint in an IDE when you want to stop in some specific iteration or a particular recursive call, for example:

isUserAGoat() could be used instead of a dummy variable declaration that will be shown in the IDE as a warning and, in Eclipse particular case, will clog the breakpoint mark, making it difficult to enable/disable it. If the method is used as a convention, all the invocations could be later filtered by some script (during commit phase maybe?).

Google guys are heavy Eclipse users (they provide several of their projects as Eclipse plugins: Android SDK, GAE, etc), so the @djechlin answer and this complementary answer make a lot of sense (at least for me).




Google has a serious liking for goats and goat based Easter eggs. There has even been previous Stack Overflow posts about it.

As has been mentioned in previous posts, it also exists within the Chrome task manager (it first appeared in the wild in 2009):

<message name="IDS_TASK_MANAGER_GOATS_TELEPORTED_COLUMN" desc="The goats teleported column">
    Goats Teleported
</message>

And then in Windows, Linux and Mac versions of Chrome early 2010). The number of "Goats Teleported" is in fact random:

 int TaskManagerModel::GetGoatsTeleported(int index) const {
     int seed = goat_salt_ * (index + 1);
     return (seed >> 16) & 255;
 }

Other Google references to goats include:

The earliest correlation of goats and Google belongs in the original "Mowing with goats" blog post, as far as I can tell.

We can safely assume that it's merely an Easter egg and has no real-world use, except for returning false.