Transactions Database

An implementation of an in-memory data store with support for transactions.

Start the Database

Running with Docker

Assuming Docker is available locally, the project can be built with:

% sh build.sh

Then, run:

% sh run.sh

with sample output, e.g.:

% sh run.sh
>> GET a
NULL
>> SET a 1
>> COUNT 1
1
>> END
jbg@MacBook-Pro-3 transactions % sh run.sh
>> GET a
NULL
>> SET a foo
>> GET a
foo
>> SET b foo
>> COUNT foo
2
>> END
%

Running with Gradle

Assuming dependencies are met, this application can be run with Gradle:

./gradlew bootRun --console=plain

A sample run might look like:

% ./gradlew bootRun --console=plain 
> Task :compileJava
> Task :processResources UP-TO-DATE
> Task :classes
> Task :bootRunMainClassName

> Task :bootRun

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v2.5.6)

>> GET a
NULL
>> SET a foo
>> GET a
foo
>> SET b foo
>> COUNT foo
2
>> END

BUILD SUCCESSFUL in 38s
4 actionable tasks: 3 executed, 1 up-to-date

Commands

SETs the name in the database to the given value.

SET [name] [value]

GETs and prints the value for the given name. If the value is not in the database, prints NULL.

GET [name]

DELETEs the value from the database.

DELETE [name]

Returns the number of names that have the given value assigned to them. If that value is not assigned anywhere, prints 0.

COUNT [value]

Exits the database.

END

Begins a new transaction.

BEGIN

Rolls back the most recent transaction. If there is no transaction to rollback, prints TRANSACTION NOT FOUND.

ROLLBACK

Commits all of the open transactions.

COMMIT

Dependencies

This is a Java 8 application that uses Gradle to manage tasks and dependencies.

Testing

Automated tests can be run with:

./gradlew test