Plugin Development Guide

DeepaMehta is made to be extensible by 3rd-party developers. Developers extend DeepaMehta by developing plugins (resp. "modules" resp. "applications" which is all synonymous).

Setup the development environment

The best way to start with DeepaMehta plugin development is to build DeepaMehta from source. This way you get a hot-deploy environment, that is DeepaMehta redeploys your plugin automatically once you compile it. This is very handy while development.

Requirements:

• Java 6 (newer versions might work as well, older versions do not work)
• Maven 3 (older versions do not work)
• Git

Build DeepaMehta from source:

git clone git://github.com/jri/deepamehta.git
cd deepamehta
mvn install -P all

This builds all components of the DeepaMehta Standard Distribution and installs them in your local Maven repository.

After a minute or so you'll see:

...
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 53.515s
...

A very simple plugin: Tagging

Let's start with a very simple plugin. This plugin will just create a new topic type called Tag. Once the plugin is installed the topic type will appear in the DeepaMehta webclient's Create menu, so you can create instances. And you will be able to fulltext search for tags.

Developing such a simple plugin involves no Java coding at all. All is declarative, mainly in JSON format.

Of course the topic type could be created interactively as well, by using DeepaMehta's type editor. However, being packaged as a plugin you can publish it. When other DeepaMehta users install your plugin they can use your type definitions.

Create the plugin

You create the plugin just by creating directories and text files. A DeepaMehta plugin project adheres to a certain directory structure and file name conventions.

Setup a directory structure as follows:

dm4-tagging/
    pom.xml
    src/
        main/
            resources/
                migrations/
                    migration1.json
                plugin.properties

The plugin directory can have an arbitrary name and exist at an arbitrary location. By convention the plugin directory begins with dm4- as it is aimed to the DeepaMehta 4 platform.

Create the file pom.xml with this content:

<project>
    <modelVersion>4.0.0</modelVersion>

    <name>DeepaMehta 4 Tagging</name>
    <groupId>org.mydomain.dm4</groupId>
    <artifactId>tagging</artifactId>
    <version>0.1-SNAPSHOT</version>
    <packaging>bundle</packaging>

    <parent>
        <groupId>de.deepamehta</groupId>
        <artifactId>deepamehta-plugin-parent</artifactId>
        <version>4.1.1-SNAPSHOT</version>
    </parent>
</project>

Create the file migration1.json:

{
    topic_types: [
        {
            value: "Tag",
            uri: "domain.tagging.tag",
            data_type_uri: "dm4.core.text",
            index_mode_uris: ["dm4.core.fulltext"],
            view_config_topics: [
                {
                    type_uri: "dm4.webclient.view_config",
                    composite: {
                        dm4.webclient.show_in_create_menu: true
                    }
                }
            ]
        }
    ]
}

Create the file plugin.properties:

requiredPluginMigrationNr=1
importModels=de.deepamehta.webclient

Setup for Hot-Deployment

In order to let DeepaMehta hot-deploy the plugin you must include it in DeepaMehta's hot-deployment list.

In DeepaMehta's pom.xml: add the plugin's target directory (here: /home/myhome/deepamehta-dev/dm4-tagging/target) to the felix.fileinstall.dir property's CDATA section. Important: don't forget to append a comma to the previous line:

<project>
    ...
    <felix.fileinstall.dir>
        <![CDATA[
            ${project.basedir}/modules/dm4-core/target,
            ${project.basedir}/modules/dm4-webservice/target,
            ${project.basedir}/modules/dm4-webclient/target,
            ...
            ${project.basedir}/modules/dm4-storage-neo4j/target,
            /home/myhome/deepamehta-dev/dm4-tagging/target
        ]]>
    </felix.fileinstall.dir>
    ...
</project>

Now start DeepaMehta. In the directory deepamehta (where you've build):

mvn pax:run

This starts DeepaMehta in development mode, that is with hot-deployment activated. You'll see a lot of information logged, commulating with:

...
Apr 6, 2013 11:21:20 PM de.deepamehta.core.impl.PluginManager checkAllPluginsActivated
INFO: ### Bundles total: 32, DeepaMehta plugins: 16, Activated: 16
Apr 6, 2013 11:21:20 PM de.deepamehta.core.impl.PluginManager activatePlugin
INFO: ########## All Plugins Activated ##########
Apr 6, 2013 11:21:20 PM de.deepamehta.plugins.webclient.WebclientPlugin allPluginsActive
INFO: ### Launching webclient (url="http://localhost:8080/de.deepamehta.webclient/")
...

Then a browser windows opens automatically and displays the typical DeepaMehta webclient.

The terminal is now occupied by the Gogo shell. Press the return key some times and you'll see its g! prompt.

Type the lb command to get the list of activated bundles:

g! lb

The output looks like this:

START LEVEL 6
   ID|State      |Level|Name
    0|Active     |    0|System Bundle (3.2.1)
   ...
   14|Active     |    5|DeepaMehta 4 Help (4.1.1.SNAPSHOT)
   15|Active     |    5|DeepaMehta 4 Topicmaps (4.1.1.SNAPSHOT)
   16|Active     |    5|DeepaMehta 4 Webservice (4.1.1.SNAPSHOT)
   17|Active     |    5|DeepaMehta 4 Files (4.1.1.SNAPSHOT)
   18|Active     |    5|DeepaMehta 4 Geomaps (4.1.1.SNAPSHOT)
   19|Active     |    5|DeepaMehta 4 Storage - Neo4j (4.1.1.SNAPSHOT)
   20|Active     |    5|DeepaMehta 4 Core (4.1.1.SNAPSHOT)
   21|Active     |    5|DeepaMehta 4 Access Control (4.1.1.SNAPSHOT)
   22|Active     |    5|DeepaMehta 4 Webclient (4.1.1.SNAPSHOT)
   23|Active     |    5|DeepaMehta 4 Webbrowser (4.1.1.SNAPSHOT)
   24|Active     |    5|DeepaMehta 4 Type Search (4.1.1.SNAPSHOT)
   25|Active     |    5|DeepaMehta 4 Workspaces (4.1.1.SNAPSHOT)
   26|Active     |    5|DeepaMehta 4 Notes (4.1.1.SNAPSHOT)
   27|Active     |    5|DeepaMehta 4 Type Editor (4.1.1.SNAPSHOT)
   28|Active     |    5|DeepaMehta 4 Contacts (4.1.1.SNAPSHOT)
   29|Active     |    5|DeepaMehta 4 Facets (4.1.1.SNAPSHOT)
   30|Active     |    5|DeepaMehta 4 File Manager (4.1.1.SNAPSHOT)
   31|Active     |    5|DeepaMehta 4 Icon Picker (4.1.1.SNAPSHOT)

The DeepaMehta 4 Tagging plugin does not yet appear in that list as it is not yet build.

Build the plugin

In another terminal:

cd dm4-tagging
mvn clean package

This builds the plugin. After some seconds you'll see:

...
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 3.988s
...

Once build, DeepaMehta hot-deploys the plugin automatically. In the terminal where you've started DeepaMehta the logging informs you about plugin activation:

Apr 6, 2013 11:38:40 PM de.deepamehta.core.impl.PluginImpl readConfigFile
INFO: Reading config file "/plugin.properties" for plugin "DeepaMehta 4 Tagging"
Apr 6, 2013 11:38:40 PM de.deepamehta.core.osgi.PluginActivator start
INFO: ========== Starting plugin "DeepaMehta 4 Tagging" ==========
Apr 6, 2013 11:38:40 PM de.deepamehta.core.impl.PluginImpl createPluginServiceTrackers
INFO: Tracking plugin services for plugin "DeepaMehta 4 Tagging" ABORTED -- no consumed services declared
Apr 6, 2013 11:38:40 PM de.deepamehta.core.impl.PluginImpl addService
INFO: Adding DeepaMehta 4 core service to plugin "DeepaMehta 4 Tagging"
Apr 6, 2013 11:38:40 PM de.deepamehta.core.impl.PluginImpl addService
INFO: Adding Web Publishing service to plugin "DeepaMehta 4 Tagging"
Apr 6, 2013 11:38:40 PM de.deepamehta.core.impl.PluginImpl registerWebResources
INFO: Registering Web resources of plugin "DeepaMehta 4 Tagging" ABORTED -- no Web resources provided
Apr 6, 2013 11:38:40 PM de.deepamehta.core.impl.PluginImpl registerRestResources
INFO: Registering REST resources of plugin "DeepaMehta 4 Tagging" ABORTED -- no REST resources provided
Apr 6, 2013 11:38:40 PM de.deepamehta.core.impl.PluginImpl registerRestResources
INFO: Registering provider classes of plugin "DeepaMehta 4 Tagging" ABORTED -- no provider classes provided
Apr 6, 2013 11:38:40 PM de.deepamehta.core.impl.PluginImpl addService
INFO: Adding Event Admin service to plugin "DeepaMehta 4 Tagging"
Apr 6, 2013 11:38:40 PM de.deepamehta.core.impl.PluginManager activatePlugin
INFO: ----- Activating plugin "DeepaMehta 4 Tagging" -----
Apr 6, 2013 11:38:40 PM de.deepamehta.core.impl.PluginImpl createPluginTopicIfNotExists
INFO: Installing plugin "DeepaMehta 4 Tagging" in the database
Apr 6, 2013 11:38:40 PM de.deepamehta.core.impl.MigrationManager runPluginMigrations
INFO: Running 1 migrations for plugin "DeepaMehta 4 Tagging" (migrationNr=0, requiredMigrationNr=1)
Apr 6, 2013 11:38:40 PM de.deepamehta.core.impl.MigrationManager$MigrationInfo readMigrationConfigFile
INFO: Reading migration config file "/migrations/migration1.properties" ABORTED -- file does not exist
Apr 6, 2013 11:38:40 PM de.deepamehta.core.impl.MigrationManager runMigration
INFO: Running migration 1 of plugin "DeepaMehta 4 Tagging" (runMode=ALWAYS, isCleanInstall=true)
Apr 6, 2013 11:38:40 PM de.deepamehta.core.util.DeepaMehtaUtils readMigrationFile
INFO: Reading migration file "/migrations/migration1.json"
Apr 6, 2013 11:38:40 PM de.deepamehta.core.impl.MigrationManager runMigration
INFO: Completing migration 1 of plugin "DeepaMehta 4 Tagging"
Apr 6, 2013 11:38:40 PM de.deepamehta.core.impl.MigrationManager runMigration
INFO: Updating migration number (1)
Apr 6, 2013 11:38:40 PM de.deepamehta.core.impl.AttachedTopic update
INFO: Updating topic 2690 (new topic (id=-1, uri="", typeUri="dm4.core.plugin_migration_nr", value="1", composite={}))
Apr 6, 2013 11:38:40 PM de.deepamehta.core.impl.AttachedDeepaMehtaObject updateSimpleValue
INFO: ### Changing simple value of topic 2690 from "0" -> "1"
Apr 6, 2013 11:38:40 PM de.deepamehta.core.impl.PluginImpl registerListeners
INFO: Registering listeners of plugin "DeepaMehta 4 Tagging" at DeepaMehta 4 core service ABORTED -- no listeners implemented
Apr 6, 2013 11:38:40 PM de.deepamehta.core.impl.PluginImpl registerPluginService
INFO: Registering OSGi service of plugin "DeepaMehta 4 Tagging" ABORTED -- no OSGi service provided
Apr 6, 2013 11:38:40 PM de.deepamehta.core.impl.PluginManager activatePlugin
INFO: ----- Activation of plugin "DeepaMehta 4 Tagging" complete -----
Apr 6, 2013 11:38:40 PM de.deepamehta.core.impl.PluginManager checkAllPluginsActivated
INFO: ### Bundles total: 33, DeepaMehta plugins: 17, Activated: 17
Apr 6, 2013 11:38:40 PM de.deepamehta.core.impl.PluginManager activatePlugin
INFO: ########## All Plugins Activated ##########
Apr 6, 2013 11:38:40 PM de.deepamehta.plugins.webclient.WebclientPlugin allPluginsActive
INFO: ### Launching webclient (url="http://localhost:8080/de.deepamehta.webclient/") ABORTED -- already launched
...

When you type again lb in the DeepaMehta terminal you'll see the plugin in the list of activated bundles:

START LEVEL 6
   ID|State      |Level|Name
    0|Active     |    0|System Bundle (3.2.1)
   ...
   30|Active     |    5|DeepaMehta 4 File Manager (4.1.1.SNAPSHOT)
   31|Active     |    5|DeepaMehta 4 Icon Picker (4.1.1.SNAPSHOT)
   32|Active     |    5|DeepaMehta 4 Tagging (0.1.0.SNAPSHOT)