The Cleo Harmony/VLTrader (aka VersaLex) Connector Shell API allows new connector technologies to be plugged in to be configured and used by the administrator.
This sample project provides a basic example of a connector. It provides a
kind of virtual file whose contents are a random, but predictable based on
a provided seed, sequence of bytes. When used in a GET operation (which
produces a readable InputStream), the random bytes are retrieved. When used in a
PUT operation (which produces a writable OutputStream), the byte sequence
is compared with the expected values based on an InputStream with the same
seed, throwing an Exception in case of a mismatch in content or length.
As a special case, a seed of 0 produces a predictable sequence of null bytes
'\0', not unlike /dev/zero.
The POM for this project creates a ZIP archive intended to be expanded from
the Harmony/VLTrader installation directory ($CLEOHOME below).
git clone git@github.com:cleo/connector-random.git
mvn clean package
cp target/random-5.6.0.0-distribution.zip $CLEOHOME
cd $CLEOHOME
unzip -o random-5.6.0.0-distribution.zip
./Harmonyd stop
./Harmonyd start
When Harmony/VLTrader restarts, you will see a new Template in the host tree
under Connections > Generic > Generic RANDOM. Select Clone and Activate
and a new RANDOM connection (host) will appear on the Active tab.
Change the default <receive> action to read GET test.bin (instead of GET *)
and run the action. You will find a 1k (1024 byte) file of nulls in inbox/test.bin.
A Connector Shell project comprises n essential artifacts:
The connector schema class defines the properties required to configure connection instances using the connector. It is also used to automatically render a configuration UI. See About the Connector Schema.
The connector client class implements the methods supported by the connector.
In the connector shell, these methods are abstracted as commands and represent
canonical file-based operations like GET, PUT, and DIR that can be
executed directly from Command actions. See About the Connector Client.
File attributes are handled using a special ATTR command and associated
class implementing the DosFileAttributes and DosFileAttributeView interfaces
from the Java standard com.nio.file.attribute package.
See About Connector Attributes.
A specific mechanism is used to read connection configuration values according to the schema. The sample project uses a simple read-only bean to wrap this mechanism. See About Connector Configuration.
The sample Random connector uses a Maven project to import the dependency on the Connector Shell API and to build and package the connector for deployment. See About Maven and the Connector Shell.