This project provides a very simple in-memory graph. It is intended to be just sample code. No tooling is provided to facilitate using it in your own projects.
git clone https://github.com/jasonnet/halfgraph.git
cd halfgraph
If you've not already installed the Java 1.8 (or higher)
development tools, do that now. -- There are many ways to
do that. If you are a root user on a Linux machine, yum or
apt get can be used to achieve this. A web search for
'install java` should reveal additional methods.
If you've not installed Maven, you'll need it if you want to do unit testing. (If you are an expert in JUnit, you might be able to devise an alternate approach, but for the rest of us, installing Maven is an easy way to set up JUnit testing.)
If you already have Maven set up, you can skip this step.
There are a variety of ways to set up Maven. For example,
the root user of a machine can often use yum or apt get
to install it.
As a non-root user of Linux machines, I find mvninstall helpful. This project includes an updated copy of mvninstall which you can invoke to install Maven:
build/install_maven.sh
You might have to run this twice. If you are told to do that,
rm apache-maven-3.6.0
build/install_maven.sh
Once you finish, there will be a generated setenv.maven.template.source in
your directory. You should invoke it now and whenever you need Maven in a
new shell session:
source setenv.maven.template.source
The easiest way to use this code base is to do use and modify the function testing provided. To start function testing invoke:
make function
This will compile the code and then run the FunctionTest.java class. That
class will create a simple graph and run a set of traversals on it. The
results of that is captured in target/test.stdout.latest.log. It then
compares that snapshot to the test.stdout.expected.log that is provided
with this project. If they are identical, nothing will be shown. But
if there is a mismatch, the diff output will be shown on the sceen.
If you'd like to see some examples of how to use the HalfGraph API, look at FunctionTest.java.
Feel free to modify FunctionTest.java to suit your needs. If you change
runTestSuiteOnce, the output in target/test.stdout.latest.log might change
in which case the test will fail and you'll see the diff output each time you
run the test. If this is your intent, you might want to copy the output
produced there once you believe it is correct:
cp target/test.stdout.latest.log test.stdout.expected.log
This should let the tests complete without further warning.
FunctionTest.java also includes a runAssignment method. The output of that method will be shown on the screen during a function test, but it is not compared with any expected output. If you just want to experiment with the HalfGraph API, modify the runAssignment method to suit your needs.
The easiest way to run the unit tests is
make junit
This uses Maven to run the unit tests so if you've not set up Maven, you will need to do that.
Graph Size - One should not create a graph with more than a few million vertices or edges. Todo: this should be formally enforced in the code. (post-deadline-comment)
Thread Safety - This implementation is not thread safe. (post-deadline-comment)