Master Worker

From Indus Communities

The Master Worker style of coordination may represent a single or a chain of calls from client programs to server side programs in an asynchronous fashion. It is the asynchronous equivalent of the existing synchronous 'call and return' style of coordination.

A Master Worker call syntax is similar to the 'call and return' syntax.

Syntax :

        agent | component.method( )

where,

• agent or component refers to an instance of type Agent or Component

Any invocation of a method declared in an Agent or Component definition automatically qualifies for a Master Worker call by a client.

public Agent MasterAgent
{
	public void setValue(int x);
	public int getValue();
	public void incrValue();
}

Definition file : MasterAgent.indus

public class Master implements MasterAgent
{
	Context{
		 setServantType("USER");
	}

	public int m_value = 0;

	public int getValue()
	{
		return m_value;
	}

	public void setValue(int v)
	{
		m_value = v;
	}

	public void incrValue()
	{
		m_value++;
	}

	public static void main(String [] args)
	{
		try 
		{
			Master m = newType Master("mh1");
			int value = m.getValue();
                        // First Master Worker call
			System.out.println("value = " + value);

			m.setValue(100);
			value = m.getValue();
                        // Second Master Worker call
			System.out.println("value = " + value);

			m.incrValue();	
			value = m.getValue();
			System.out.println("value = " + value);

			m.incrValue();	
			value = m.getValue();
			System.out.println("value = " + value);
		}
		catch (Exception e) 
		{
			e.printStackTrace();
		}	
	}
}

Implementation file : Master.indus

Syntactic sugar is applied over the Master Worker style to derive other forms of coordination in Indus.

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