The demo application is a Java GUI application which has multiple independent small sections.

The demo application could be used for the following:

• Learn SNMP basics. Modify various scalars and tables in the application and watch how these modifications are reflected in the SNMP browser. Modify read-write scalars and tables in a MIB browser and watch how these modifications are reflected in the application. Create notifications.
• Learn FriendlySNMP and SNMP4J functionality. Demo application source code is an open source and you are welcome to use it.
• Test SNMP connection with different protocols and credentials.

The demo application depends on the following Java libraries:

• FriendlySNMP
• SNMP4J (snmp4j and snmp4j-agent libraries)
• SLF4j (core and Log4J adapter libraries)
• Log4J

The demo application could be downloaded in two forms:

• Binary form as zip or tar. Archive contains a single JAR file, cmd-file to start the demo application and all supported MIB files. All required dependent JAR files packed into a single distribution JAR.
• Eclipse project as zip or tar. Archive file contains Eclipse project with source code, all required libraries, all supported MIB files, build and run scripts.

The demo application has the following panes:

• About and Info
• Scalar read-only
• Scalar read-write
• Static table (URL)
• Dynamic table (flights)
• Two-index table (warehouse)
• Two-index table (marriage)
• Notifications
• Deadlock detection
• Uncaught exception detection
• Caught exception reporting
• Agent & Remote shutdown

Pane: About and Info
This pane has two tabs in the right pane: About and Info. The About tab contains generic information about the application.

The Info tab contains a list of properties which were loaded from the DemoApp.properties file. This tab could be helpful to debug SNMP connection.

Pane-1: Scalar read-only
Java code for this pane shows how to use read-only SNMP scalars. Load DEMO-SCALAR-RO-MIB into a MIB browser to access the demo scalars. The code uses org.friendlysnmp.event.FScalarGetListener listeners to respond to GET requests from a MIB browser. These listeners are implemented only for scalars which values are changing during the application lifetime.

• Scalar Default user directory is an example of a static value which does not change during application lifetime. Scalar managed object of this type should be initialized only once at application startup. It makes no sense to implement org.friendlysnmp.event.FScalarGetListener listener to respond to GET requests from a MIB browser for this scalar value because the value never changes. The code shows how to use class org.friendlysnmp.FHandler to initialize static objects.
• Scalar Ticks is an example of a value which is changing at runtime. The dedicated ticker thread is used to increment ticks counter each second. The code shows how to use class org.friendlysnmp.FHandler to start / stop ticker thread.
• Scalar User name is an example of a string value which could be modified during application lifetime. Update the value in the UI and monitor the update in a MIB browser.
• Scalar User level is an example of an enumeration value which could be modified during application lifetime. Update the value in the UI and monitor the update in a MIB browser.
• Scalar User age is an example of an integer value which could be modified during application lifetime. Update the value in the UI and monitor the update in a MIB browser.

The demo application has registered org.friendlysnmp.event.FExceptionListener with the agent. Test the listener with the following steps. Enter invalid value (for example 25a) for the User age and click button Validate Age. The validation is performed indirectly by using FriendlySNMP functionality. Attempt to set value of a wrong type to a scalar throws an exception while string-to-integer conversion. The input string value is received from a UI text box, the output value type is retrieved from a scalar syntax type. The conversion exception is propagated to all registered org.friendlysnmp.event.FExceptionListener event listeners. The demo application receives the exception and presents it in a message box:

Pane-2: Scalar read-write
Java code for this pane shows how to use read-write SNMP scalars. Load DEMO-SCALAR-RW-MIB into a MIB browser to access the demo scalars. The code shows how to use the following listeners:

• org.friendlysnmp.event.FScalarGetListener Scalar values on this pane could be retrieved by a MIB browser using GET request. The demo application receives a GET request, processes it in a listener and returns the requested value to be displayed in a MIB browser. Usually read-write managed objects are not modified in the application. The demo application gives this option to test GET requests. The modified in the UI value will be reverted to the default value after application restart.
• org.friendlysnmp.event.FScalarSetListener Scalar values on this pane could be updated from a MIB browser. The demo application receives a SET request, processes it in a listener and updates the UI. The received value is stored in a persistent storage and is loaded as an initial value after the demo application restart. A user of the MIB browser has an option to view and modify persistent storage content.
• org.friendlysnmp.event.FScalarValidationListener Scalar with validation listener has an option to reject the value SET from a MIB browser.
• org.friendlysnmp.event.FRestoreDefaultListener Removing an entry from a persistent storage triggers the org.friendlysnmp.event.FRestoreDefaultEvent which is processed in the demo application and restores original default value.

• Scalar Image file name is an example of a string value.
• Scalar Image format is an example of an enumeration value.
• Scalar Image size is an example of a value which has a validation rule. The valid format for the image size is NNNxMMM. Attempt to set invalid value is rejected by validator in org.friendlysnmp.event.FScalarValidationListener code. Try to set invalid image size from a MIB browser and check how it is rejected by the demo application with error code WRONG VALUE.

Pane-3: Static table (URL)
Java code for this pane shows how to use data stored in the SNMP agent without preserving a copy in Java member variables. This technique is useful for data which has a static nature. Examples of this data are application version, configuration parameters, dictionaries and so on. The application takes responsibility to update data of this type in the SNMP agent directly when data is available, e.g. when data is loaded from external sources. Usually this is happening only at application startup.

Load DEMO-TABLE-URL-MIB into a MIB browser to access the demo table. Try to modify data in the demo table. Modified data is stored directly in the SNMP agent and retrieved from it for display. MIB browser GET requests are served by SNMP agent with data already available.

Pane-4: Dynamic table (flights)
Java code for this pane shows how to use read-write SNMP tables. Load DEMO-TABLE-FLIGHT-MIB into a MIB browser to access the demo table. The code shows how to use the following listeners:

• org.friendlysnmp.event.FTableGetListener Table content could be retrieved by a MIB browser using GET request. The demo application receives a GET request, processes it in a listener and returns the requested values to a MIB browser. Usually read-write managed objects are not modified in the application. The demo application gives this option to test GET requests. The modified table cell values via UI are not marking the table modified. The table content in this case is not preserved in the persistent storage and is set to the default value after application restart.
• org.friendlysnmp.event.FTableSetListener Table content could be updated from a MIB browser. The demo application receives a SET request, processes it in a listener and updates the UI. Setting a new value of any single cell from a MIB browser makes the whole table flagged as modified and preserves the whole table in a persistent storage. The next time application is restarted the whole table is loaded from the persistent storage. A user of the MIB browser has an option to view and modify persistent storage content.
• org.friendlysnmp.event.FTableValidationListener Table with validation listener has an option to reject the value SET from a MIB browser.
• org.friendlysnmp.event.FRestoreDefaultListener Removing an entry from a persistent storage triggers the org.friendlysnmp.event.FRestoreDefaultEvent which is processed in the demo application and restores original default value.

• The columns Carrier and Destination are examples of string values.
• The column Flight No is an example of a numeric value.
• The column Depart Time is an example of a string value which has a validation rule. The valid departure time has the form HH:MM where HH=00..23, MM=00..59. Attempt to set invalid value is rejected by validator in org.friendlysnmp.event.FTableValidationListener code. Try to set invalid value from a MIB browser and check how it is rejected by the demo application with error code WRONG TYPE.
• The column Status is an example of an enumeration value.

Pane-5: Two-index table (warehouse)
This demo is very similar to the Dynamic table (flights) demo.

Java code for this pane shows how to use read-write SNMP tables with two numeric indices. Load DEMO-TABLE-WAREHOUSE-MIB into a MIB browser to access the demo table.

• The column Department is an index of enumeration value.
• The column ID is an index of an numeric value (most commonly used in SNMP tables).
• The columns Brand and Item are examples of string values.
• The column Price is an example of float value which is stored as SNMP numeric value and formatted for display with two decimal points.

Pane-6: Two-index table (marriage)
This demo is very similar to the Dynamic table (flights) demo.

Java code for this pane shows how to use read-write SNMP tables with two string indices. Load DEMO-TABLE-MARRIAGE-MIB into a MIB browser to access the demo table.

• The columns Husband and Wife are string indices.
• The column Year is a numeric value.
• The column City is a string value.

Pane-7: Notifications
Java code for this pane shows how to SNMP notifications. Load DEMO-NOTIFY-WEATHER-MIB into a MIB browser to declare notifications. Select radio button for one of notifications and click Send Notification button. Examine received notification in the MIB browser. Check parameters sent with notifications. The notification rain has additional parameters.

Pane-8: Deadlock detection
The FriendlySNMP agent has built-in deadlock detection functionality. The user of the demo application has an option to test this functionality by creating deadlocks with multiple threads in a chain. Each new deadlock chain is labeled with letters A, B, C and so on. The FriendlySNMP agent sends SNMP notification on deadlock detection. The extensive information about deadlocked threads is available in a MIB browser.

See details in Deadlock Detection section.

Pane-9: Uncaught exception detection
The FriendlySNMP agent has built-in uncaught runtime exceptions detection functionality. The user of the demo application has an option to test this functionality by creating runtime exceptions. The FriendlySNMP agent sends SNMP notification on uncaught runtime exception detection. The extensive information about each exception is available in a MIB browser.

See details in Exceptions section.

The FriendlySNMP agent generates uncaught exception event and distributes it to registered listeners. The demo application has a registered such a listener and receives these events which are displayed in a message box.

Pane-10: Caught exception reporting
The FriendlySNMP agent could report any caught exception to the MIB browser. The application discovers exception of this kind in try / catch blocks and notifies FriendlySNMP agent about this event. The user of the demo application has an option to test this functionality by creating checked exceptions. Exceptions created manually could have any message and might have any level of cause exceptions. The exception could be also supplied with an optional comment.

See details in Exceptions section.

Pane-11: Agent & Remote shutdown
The FriendlySNMP agent could be stopped and restarted. This functionality could be tested on this pane. Each time the agent is cold-started, stopped, re-started or shutdown it sends a SNMP notification.

The demo application could be shutdown remotely from a MIB browser by sending SET request. The demo application has an option to enable or disable this functionality.

See details in Events and Listeners section.