Lightweight Java Plugin Framework
1. Features
- Simple api
- Sandboxing with custom java classloader
- Build plugins with maven
2. Usage
2.1 Create plugin
Create Plugin class that implements ljpf.Plugin interface.
public class CustomPlugin implements Plugin {
@Override
public void load() {
...
}
@Override
public void unload() {
...
}
}Create descriptor file for corresponding plugin and place it in project resources. Descriptor file must have .plugin extension.
src/main/resources/custom.plugin
id=CustomPluginId
version=0.0.1
pluginClass=ljpf.examples.plugin.CustomPlugin
description=My Custom plugin2.2 Create app
Load plugins in your main application using PluginManager interface. Use plugin id from descriptor file to load extensions. Plugin repository determines way of loading plugins. Base case is to load jars from classpath plugins/ directory.
public class App {
public static void main(String[] args) {
PluginRepository pluginRepository = new DirPluginRepository("plugins");
PluginManager pluginManager = new DefaultPluginManager(pluginRepository);
pluginManager.load("CustomPluginId");
}
}2.3 Build with Maven
Build plugin with Maven
Use light-jpf-maven-plugin to create maven artifact (*-plugin.jar). Maven will create fat jar with plugin code and all its dependencies.
<build>
<plugins>
<plugin>
<groupId>com.github.souzen</groupId>
<artifactId>light-jpf-maven-plugin</artifactId>
<version>0.0.2</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>make-plugin</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
....
</build>Add plugins to app
light-jpf-maven-plugin can also prepare plugins/ directory in your application.
<build>
<plugins>
<plugin>
<groupId>com.github.souzen</groupId>
<artifactId>light-jpf-maven-plugin</artifactId>
<version>0.0.2</version>
<executions>
<execution>
<phase>process-sources</phase>
<goals>
<goal>make-plugin-repository</goal>
</goals>
<configuration>
<outputDirectory>${project.build.directory}/plugins</outputDirectory>
<artifactItems>
<artifactItem>
<groupId>ljpf.examples.plugin</groupId>
<artifactId>custom-plugin</artifactId>
<version>0.0.1</version>
</artifactItem>
</artifactItems>
</configuration>
</execution>
</executions>
</plugin>
...
</plugins>
....
</build>3. Plugin Repositories
DirPluginRepository
TODO Loads plugins from given directory
ClasspathPluginRepository
TODO Loads plugins from java classpath
MultiPluginRepository
TODO Enables mixing multiple plugin reposiotories
4. Debugging
In app create plugins dir and run or place plugins as dependencies
<dependencies>
<dependency>
<groupId>ljpf.examples.plugin</groupId>
<artifactId>custom-plugin</artifactId>
<version>0.0.1</version>
</dependency>
...
</dependencies>5. Examples
See example project here
Build and run example
mvn clean package
unzip examples/app/target/app-0.0.3-SNAPSHOT-bin.zip
./app-0.0.3-SNAPSHOT/start.bat
6. Licence
Copyright 2017 Luke Sosnicki
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.