Java Implementation of Flow-Based Programming (FBP)
In computer programming, flow-based programming (FBP) is a programming paradigm that defines applications as networks of "black box" processes, which exchange data across predefined connections by message passing, where the connections are specified externally to the processes. These black box processes can be reconnected endlessly to form different applications without having to be changed internally. FBP is thus naturally component-oriented.
FBP is a particular form of dataflow programming based on bounded buffers, information packets with defined lifetimes, named ports, and separate definition of connections.
Web sites for FBP:
JavaFBP Syntax and Component API:
The project requires Gradle for building (tested with version 2.0). You can download the corresponding package from the following URL: http://www.gradle.org
Windows and Linux users should follow the installation instructions on the Maven website (URL provided above).
OSX users (using Brew, http://brew.sh) can install Maven by executing the following command:
brew install gradle
Eclipse IDE Integration
You can generate Eclipse project using the following mvn command:
If you already created an Eclipse project you can run:
gradle cleanEclipse Eclipse
You need to install a Gradle plugin for Eclipse as explain here:
Then import a generated project in Eclipse, right (ctrl for OSX) click on the project in Eclipse -> Configure -> Convert to Gradle Project. After the conversion you can Right (ctrl for OSX) click on the project -> Gradle -> Task Quick Launcher and type
You may have to go to the project Properties and select Java Build Path/Source; remove whatever is there and select
JavaFBP/src/main/java; then close Eclipse, and reopen it.
Building from command line
For building the project simply run the following command:
As a result a
javafbp-3.0.1.jar file will be created in the
build/libs directory. It will include the JavaFBP core (runtime) and all the examples from the source code (sub-package
For running any of the examples use the following command:
java -cp build/libs/javafbp-3.0.1.jar com.jpmorrsn.fbp.examples.networks.<Class name of the network>
java -cp build/libs/javafbp-3.0.1.jar com.jpmorrsn.fbp.examples.networks.TestIPCounting
Running a test
Here is a simple test that can be run to test that everything is working.
In the project directory, enter
java -cp build/libs/javafbp-3.0.1.jar com.jpmorrsn.fbp.examples.networks.MergeandSort
Here is a picture of MergeandSort, drawn using DrawFBP:
This network contains 4 processes:
- 2 occurrences of GenerateTestData,
- a Sort process - a very simple-minded Sort, which can only handle up to 9,999 information packets
- a text display component, which invokes Java Swing to display the sorted data in a scroll pane.
The outputs of the two GenerateTestData processes are merged on a "first come, first served" basis. During the run you should see a scroll pane with the sorted data scrolling down.
At the end of the run, you should see:
Run complete. Time: x.xxx seconds Counts: C: 150, D: 153, S: 300, R (non-null): 304, DO: 0
where the counts are respectively: creates, normal drops, sends, non-null receives, and drops done by "drop oldest".
Tracing and other options
To trace JavaFBP services and/or lock usage, set the appropriate parameter(s) in
JavaFBPProperties.xml in the user directory to
These traces will appear in the project directory under the name
xxxx is the name of the network being run. Subnets have their own trace output files.
Two other options are also supported in the properties file:
deadlocktest(defaults to true, so you might set it to
forceconsole(used if immediate console output is required during debugging - normally, console output is sent to a file)