Hitachi

JP1 Version 12 JP1/Navigation Platform Development Guide


2.3.4 Lifecycle of I/O Plugin instances

The following describes the lifecycle of plugin instances.

Organization of this subsection

(1) Creating and retaining I/O Plugin instances

The instances of I/O Plugins are managed on the basis of instance IDs. In the case of User Plugins, the instance ID can be defined as "instance ID = plugin ID".

Note

In the case of System Plugins, the instance ID can be defined as follows:

  • JavaScript Plugins

    Instance ID = Plugin ID + Plugin name

  • Plugins other than the above

    Instance ID = Plugin ID

For I/O Plugins having the same instance ID, one instance is retained in one window. The instances are retained in HTTP sessions based on window IDs as keys. The following figure shows instances of I/O Plugins.

Figure 2‒2: I/O Plugin instances

[Figure]

When you execute I/O Plugins, instances of the I/O Plugins to be executed are acquired from HTTP sessions by using window IDs and instance IDs as keys. If an instance cannot be acquired from HTTP sessions, new instances are created and then added to the HTTP sessions. At this time, only the instances to be executed are created. The figure below shows an example of Operational Content containing branch nodes. If transition occurs from node 1 to node 2, and to node 4 during execution of this Operational Content, plugins A, B, and D are executed but plugin C is not. Therefore, if operation of Operational Content containing this transition is executed, an instance of plugin C is not created.

Figure 2‒3: Operational Content containing branches

[Figure]

(2) Discarding I/O Plugin instances

The table below indicates when I/O Plugin instances are discarded. This applies regardless of whether the operation is performed in the Operational Content Execution Window or Operational Content Execution Window (preview).

Table 2‒2: When I/O Plugin instance are discarded

No.

Discarded when:

Plugin instance to be discarded

1

Operational Content is displayed in the Operational Content Execution Window or Operational Content Execution Window (preview)#

Instances retained by the HTTP session (when the operation is performed) based on the window ID of the window in which the operation is performed

2

The Editing Window View menu is clicked

3

The Logout button is clicked

All instances retained by the HTTP session to be discarded

4

A session times out

#

Instances are discarded when you select Operational Content in the menu area. If you specify a parameter for the basic URL, and then open a specific Operational Content, instances are not discarded.