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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**
+
+```java
+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:
+```xml
+<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
+ 
+ 
+