imit_model / AnyLogic / UsersManual(AnyLogic)

AnyLogic V User’s Manual

7.1.1.2 Port properties

A port has a set of customizable properties. To set the port properties, first select the port on the structure diagram by clicking, and next set the property values in the Properties window.

The following properties can be set on the General page of the Properties window (Figure 66):

Figure 66. General page of the port’s Properties window

General properties

Name – the name of the port.

Message type – [optional] every message received by the port is cast to this type. If the message cannot be cast, it is discarded. Using combo box you can choose from all known message classes of this project. Message class definition is described in section 7.2, “Messages”.

AnyLogic V User’s Manual

You can change the default port behavior by writing code on the Code page of the port’s Properties window. AnyLogic provides you an ability to specify port reactions to different occurrences by writing your own Java code.

Code properties

Constructor parameters – [optional] parameters to be passed to the port’s constructor, e.g.: /*count*/ 20, /*load*/ load.

On receive action – [optional] a sequence of Java statements to be executed on every message reception.

On send action – [optional] a sequence of Java statements to be executed on every message sending.

Additional class code – [optional] Java code to be inserted into the port class definition. Arbitrary constants, variables, and methods can be defined here.

An active object – owner of the port can be accessed by the getOwner() method of the port. The detailed description of AnyLogic port classes methods is given in section 7.3.1, “Predefined port classes”.

When writing your code for an active object – e.g., in its Additional class code – you can access a port myPort of an active object as its member variable myPort.

7.1.2Port queue

You can specify that a port has a queue to store incoming messages. Stored messages can be extracted afterwards. A port queue is commonly used to store port incoming messages while the active object is busy with processing another message – e.g., while a server processes client request in the client-server system. A port queue can also model a data storage.

The presence of a port queue and its capacity is specified on the General page of the Properties window.

You may have noticed that ports with queues and ports without them appear somewhat differently on the structure diagram. A port with a queue is displayed on the structure diagram with a dot inside it, see Figure 68.

AnyLogic V User’s Manual

You can also connect a port to a statechart, see section 7.1.4, “Connecting ports to statecharts”.

This section describes the technique of establishing connections between ports.

7.1.3.1 Connecting ports of encapsulated objects

To establish message passing between two encapsulated objects, you should connect ports of encapsulated objects.

►To connect ports of encapsulated objects

1.Drag the port of one encapsulated object onto the port of another encapsulated object, or

Click the Connector toolbar button, click one port, and then click another port, or Choose Draw|Structure|Connector from the main menu, click one port, and then click another port.

The connector linking two ports appears.

Figure 69. Ports of encapsulated objects connected

7.1.3.2 Connecting a public port with a port of an encapsulated object

To establish communication between the encapsulated object and the container object neighborhood, you should connect a port of an encapsulated object with a public port of the container active object.

AnyLogic V User’s Manual

7.1.3.4 Connecting a public port with a private port

To establish a communication between a private port and other active objects you should connect the private port with a public port. However, if you need only to send messages via the private port to other active objects, it can be made public.

►To connect a public port with a private port

1.Click the Connector toolbar button, click one port, and then click another port, or Choose Draw|Structure|Connector from the main menu, click one port, and then click another port.

The connector linking two ports appears.

Figure 72. Public and private ports connected

7.1.4Connecting ports to statecharts

Ports can also be connected to statecharts. In that case messages received in a port are forwarded to a connected statechart, where they are processed as signal events. Using such a connection, you can react to the message arrival in the statechart. For detailed information on statecharts see Chapter 9, “Statecharts”.

You can connect a statechart to:

•A public port,

•A private port.

You cannot connect active object’s statechart to a port of its encapsulated object.

This section describes the technique of establishing connections between ports and statecharts.

AnyLogic V User’s Manual

Figure 74. A private port connected to a statechart

7.1.5Message routing rules

Message processing at a port depends on the direction the message is going and on the type of a port.

Public ports act as relay ports, forwarding messages depending on the direction the message is going. If the message arrives at a public port from inside the active object, it is forwarded along all external connections of the port. Otherwise, if it is received from outside, it is forwarded along all port connections inside the active object.

A message received at a private port is forwarded only to connected statecharts.

Message routing rules are illustrated in Figure 75.