Plugins.md

Task Plugins

The Task entities defined in a Processor definition can be implemented as dedicated native java plugins or as scripts written in Perl, Python or Shell.

Java plugins

Dedicated native java plugins can be developed by implementing the GenericTaskInterface process method defined in the DES library

GenericTaskInterface Interface

public interface GenericTaskInterface {

	/**
	 * 
	 * @param basepath Basepath as configured in DistributionServer.ini
	 * @param aoi_name AOI name contained in the $processor.processor_config.xml
	 * @param processor_name Processor name related to the $processor.processor_config.xml
	 * @param entity_name Name of executing entity (Task, Consumer, etc.)
	 * @param parameters Parameters as defined by <Parameter>
	 * @param args List of arguments of the Task (String or Hashtables, to be checked by the plugin)
	 * @param files List of files of the Task iff <FileType>regexp</FileType> is defined, else null
	 * @return ExitCodes
	 */
	public int process(String basepath, String aoi_name,
			String processor_name, String entity_name, Hashtable parameters, Object[] args, String[] files);
	
}

The implemented plugin should be packaged as a jar file and placed in the DES ./plugins directory where it is automatically loaded at Runtime.

The plugin can be executed in a given Processor Task with the following definition:

Example:

<Task name="renameFiles" type="class" active="yes" priority="NORM">
	<Command>class</Command>
	<FileType>SAMPLE.*.AA.txt</FileType>
	<Parameter>edu.eurac.distributionserver.tasks.generic.FileRename</Parameter>
	<FilePrefix>RENAME</FilePrefix>
</Task>

The parameters can be passed to the Task plugin with one of the following options: - By using a custom keyword tag eg. FilePrefix in the Task definition and then accessing the parameter with the Hashtable parameters in the Interface

```java
String file_prefix = (String)parameters.get("FilePrefix");
```

- By using the <Parameter> keyword tag in the *Task* definition and than referencing the parameter with the Object[] args type in the Interface

```java
String classname = (String)args[1];
```
Note: Note: args[0] is the class name