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title: Task layout: documentation documentation: true

Task is similar to a job in Hadoop. Task is an execution entity. A topology must be defined inside a task. SAMOA can only execute classes that implement Task interface.

###1. Implementation

package org.apache.samoa.tasks;

import org.apache.samoa.topology.ComponentFactory;
import org.apache.samoa.topology.Topology;

/**
 * Task interface, the mother of all SAMOA tasks!
 */
public interface Task {

	/**
	 * Initialize this SAMOA task, 
	 * i.e. create and connect Processors and Streams
	 * and initialize the topology
	 */
	public void init();	
	
	/**
	 * Return the final topology object to be executed in the cluster
	 * @return topology object to be submitted to be executed in the cluster
	 */
	public Topology getTopology();
	
	/**
	 * Sets the factory.
	 * TODO: propose to hide factory from task, 
	 * i.e. Task will only see TopologyBuilder, 
	 * and factory creation will be handled by TopologyBuilder
	 *
	 * @param factory the new factory
	 */
	public void setFactory(ComponentFactory factory) ;
}

###2. Methods #####2.1 void init() This method should build the desired topology by creating Processors and Streams and connecting them to each other.

#####2.2 Topology getTopology() This method should return the topology built by init to the engine for execution.

#####2.3 void setFactory(ComponentFactory factory) Utility method to accept a ComponentFactory to use in building the topology.