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
(2) Discarding I/O Plugin instances

(1) Creating and retaining I/O Plugin instances

For I/O Plugins having the same plugin 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

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 plugin 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

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(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)^#1	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 Close button is clicked^#2
4	The Done button is clicked^#3
5	The Logout button is clicked	All instances retained by the HTTP session to be discarded
6	A session times out	All instances retained by the HTTP session to be discarded

#1: 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.
#2: If logout_close is specified for the ucnp.base.server.close.button.setting property in the user property file (ucnp_user.properties), clicking the Close button discards the same instance as those when the Logout button is clicked in No. 5. For details about the property, see the description about the ucnp.base.server.close.button.setting property (whether to display the Close button in the header area) in the Hitachi Navigation Platform Setup and Operations Guide.
#3: Instances are discarded only when true is specified for the ucnp.base.client.complete.button.window.close property in the user property file (ucnp_user.properties). For details about the property, see the description of the ucnp.base.client.complete.button.window.close property (Web browser operation when the Done button is clicked in the Operational Content Execution Window) in the Hitachi Navigation Platform Setup and Operations Guide.

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