Introduction

This project contains schemas used for TA3 serialization. Those schemas can be written in the versbose Avro schema language (JSON format), or they can be written using [Avro's IDL specification] (http://avro.apache.org/docs/1.8.0/idl.html) (avdl format). The IDL is much easier to understand since it is not as verbose as the json. The Common Data Model (CDM) is specified using the IDL which is used to automatically generate avsc files.

The json avsc files can be used directly by different serialization APIs. In addition, classes can be compiled for the Java serialization API from the schema files.

Layout

The layout for the project is as follows:

Schema files both avdl and generated avsc: avro/
Java classes generated from schemas: src/main/java/com/bbn/tc/schema/avro
Utility code: src/main/java/com/bbn/tc/schema/utils
Unit tests: src/test/java/com/bbn/tc/schema/

Updating the CDM version

Make edits to the CDM directly in the avdl file CDMxx.avdl, where xx is the version number
If the CDM version changes, then we create a new file CDMyy.avdl, where yy is the new version number
Update the pom.xml property CDM-IDL-FILE to point to the new yy version. For example,

<CDM-IDL-FILE>CDM06.avdl</CDM-IDL-FILE>

Installation

Schema file and Java bindings

To install using maven, first we create the avsc schema files from the avdl file using the exec:java. Then we install which auto runs the unit tests.

mvn clean exec:java
mvn install

Note that exec:java will run the idl2schemata from avro-tools which is not well designed. The tool has a System.exit() which halts the JVM (and the maven process) but that's ok.

C++ bindings

To generate the C++ bindings, run the following:

sudo mvn compile -Pcpp

The sudo is required because we install the generated sources to /usr/local/include. Note that we expect that the schema file has already been generated by the above steps.