Class c2.framework.Component

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Class c2.framework.Component

java.lang.Object
   |
   +----c2.framework.Brick
           |
           +----c2.framework.Component

public class Component
extends Brick

System functionality is encapsulated into components . Components communicate with one another by passing messages via connectors . Messages come in two flavors:

Requests denote requests for functionality. They are sent from components that are located below the component.
Notifications denote change of component state. They are sent from components that are located above the component.

To declare a new component, inherit from Component and override the the handle() methods. Use send() to send Requests or Notifications to other components. Inherit from ComponentThread if you want the component to run in its own thread of control.

	class MyComponent extends Component {
	    protected void handle(Request r) {
		  // process a request
	    }
	    protected void handle(Notification n) {
		  // process a notification
	    }
	}

To use a component, create an instance of it and call the start() method:

	MyComponent c = new MyComponent("Test", FIFOPort.classType());
	c.start();
	...

See the Request and Notification classes for details on messages.

See Also:: Request, Notification, ComponentThread, start

bottom
top

Component(): Creates an uninitialized instance of the component.
Component(String, Class): Creates and initializes an instance of the component.

bottomPort(): Returns the bottom port of the component
create(String, Class): Initializes the component.
handle(Notification): This method is invoked when the component receives a notification from a component below it.
handle(Request): This method is invoked when the component receives a request from a component below it.
newMessage(Port): This method is invoked when the component receives a new request or notification.
send(Notification): Call this method to send a notification to a component below your component.
send(Request): Call this method to send a request to a component above your component.
topPort(): Returns the top port of the component
toString(): Returns a String representation of the Component, including the component's type, name, top and bottom ports.

top

  protected Port top

bottom

  protected Port bottom

Component

  public Component()

Creates an uninitialized instance of the component. Use the create() method to initialize the component. This constructor exists so that components can be dynamically loaded using Class.newInstance()

See Also:: Class

Component

  public Component(String name,
                   Class portClass)

Creates and initializes an instance of the component.

Parameters:: name - the name of the component; portClass - the Class of the port to use. The port processes all incomming and outgoing messages into and out of the component.
See Also:: Port

create

  public void create(String name,
                     Class portClass)

Initializes the component. NOTE: Only call this method once, and only if you used the empty constructor.

Parameters:: name - the name of the component; portClass - the Class of the port to use. The port processes all incomming and outgoing messages into and out of the component.
See Also:: Port

topPort

  public Port topPort()

Returns the top port of the component

bottomPort

  public Port bottomPort()

Returns the bottom port of the component

handle

  protected synchronized abstract void handle(Request r)

This method is invoked when the component receives a request from a component below it. Override this method to process requests.

Overrides:: handle in class Brick

handle

  protected synchronized abstract void handle(Notification n)

This method is invoked when the component receives a notification from a component below it. Override this method to process notifications.

Overrides:: handle in class Brick

send

  protected void send(Request r)

Call this method to send a request to a component above your component.

Overrides:: send in class Brick
See Also:: Request

send

  protected void send(Notification n)

Call this method to send a notification to a component below your component.

Overrides:: send in class Brick
See Also:: Notification

newMessage

  protected void newMessage(Port p)

This method is invoked when the component receives a new request or notification. By default, it invokes the appropriate handle() method. Override this function only if you need to do special processing on incomming messages.

Overrides:: newMessage in class Brick
See Also:: handle

toString

  public String toString()

Returns a String representation of the Component, including the component's type, name, top and bottom ports.

Overrides:: toString in class Brick

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