15 Testing Applications With the Load Generator and csvgen Adapter

15.1 Overview of Testing Applications With the Load Generator and csvgen Adapter

The load generator is a simple utility provided by Oracle CEP to simulate a data feed. The utility is useful for testing the Oracle CQL or EPL rules in your application without needing to connect to a real-world data feed.

The load generator reads an ASCII file that contains the sample data feed information and sends each data item to the configured port. The load generator reads items from the sample data file in order and inserts them into the channel, looping around to the beginning of the data file when it reaches the end; this ensures that a continuous stream of data is available, regardless of the number of data items in the file. You can configure the rate of sent data, from the rate at which it starts, the final rate, and how long it takes the load generator to ramp up to the final rate.

In your application, you must use the Oracle CEP-provided csvgen adapter, rather than your own adapter, to read the incoming data; this is because the csvgen adapter is specifically coded to decipher the data packets generated by the load generator.

If you redeploy your application, you must also restart the load generator.

15.2 Configuring and Running the Load Generator Utility

This procedure describes how to configure and run the load generator utility.

To configure and run the load generator utility:

1. Optionally create a property file that contains configuration properties for particular run of the load generator; these properties specify the location of the file that contains simulated data, the port to which the generator feeds the data, and so on.

   Oracle CEP provides a default property file you can use if the default property values are adequate.

   See Section 15.3, "Creating a Load Generator Property File."

2. Create a file that contains the actual data feed values.

   See Section 15.4, "Creating a Data Feed File."

3. Configure the csvgen adapter so that it correctly reads the data feed generated by the load generator. You configure the adapter in the EPN assembly file that describes your Oracle CEP application.

   See Section 15.5, "Configuring the csvgen Adapter in Your Application."

4. Be sure that you configure a builder factory for creating your event types. Although specifying event type builder factories is typically an optional task, it is required when using the load generator.

   See Section 1.5, "Creating Oracle CEP Event Types" for details.

5. Open a command window and set your environment as described in "Setting Your Development Environment" in the Oracle CEP Getting Started.

6. Change to the ORACLE_CEP_HOME\ocep_11.1\utils\load-generator directory, where ORACLE_CEP_HOME refers to the main Oracle CEP installation directory, such as d:\oracle_cep.

7. Run the load generator specifying the properties file you created in step 1 to begin the simulated data feed. For example, if the name of your properties file is c:\loadgen\myDataFeed.prop, execute the following command:

   prompt> runloadgen.cmd c:\loadgen\myDataFeed.prop
   

15.3 Creating a Load Generator Property File

The load generator uses an ASCII properties file for its configuration purposes. Properties include the location of the file that contains the sample data feed values, the port to which the utility should send the data feed, and so on.

Oracle CEP provides a default properties file called csvgen.prop, located in the ORACLE_CEP_HOME\ocep_11.1\utils\load-generator directory, where ORACLE_CEP_HOME refers to the main Oracle CEP installation directory, such as d:\oracle_cep.

The format of the file is simple: each property-value pair is on its own line. The following example shows the default csvgen.prop file; Oracle recommends you use this file as a template for your own property file:

test.csvDataFile=test.csv
  test.port=9001
  test.packetType=CSV
  test.mode=client
  test.senders=1
  test.latencyStats=false
  test.statInterval=2000

In the preceding sample properties file, the file that contains the sample data is called test.csv and is located in the same directory as the properties file. The load generator will send the data feed to port 9001.

The following table lists the additional properties you can set in your properties file.

15.4 Creating a Data Feed File

The file that contains the sample data feed values correspond to the event type registered for your Oracle CEP application. The file follows a simple format:

• Each item of a particular data feed is on its own line.

• Separate the fields of a data feed item with commas.

• Do not include extraneous spaces before or after the commas, unless the space is literally part of the field value.

• Include only string and numerical data in a data feed file such as integer, long, double, and float.

  For more information, see "Event Types for use With the csvgen Adapter".

The following example shows a sample data feed file where each item corresponds to a person with name, age, and birthplace fields:

Lucy,23,Madagascar
 Nick,44,Canada
 Amanda,12,Malaysia
 Juliet,43,Spain
 Horatio,80,Argentina

15.5 Configuring the csvgen Adapter in Your Application

When using the load generator utility, you must use the csvgen adapter in your application because this Oracle CEP-provided adapter is specifically coded to read the data packets generated by the load generator.

You register the csvgen adapter using the wlevs:adapter element in the EPN assembly file of your application, as with all adapters. Set the provide attribute to csvgen to specify that the provider is the csvgen adapter, rather than your own adapter. Additionally, you must specify the following child tags:

• wlevs:instance-property element with name attribute port and value attribute configured_port, where configured_port corresponds to the value of the test.port property in the load generator property file. See Section 15.3, "Creating a Load Generator Property File."

• wlevs:instance-property element with name attribute eventTypeName and value attribute event_type_name, where event_type_name corresponds to the name of the event type that represents an item from the load-generated feed.

• wlevs:instance-property element with name attribute eventPropertyNames and value attribute ordered_list_of_properties, where ordered_list_of_properties lists the names of the properties in the order that the load generator sends them, and consequently the csvgen adapter receives them.

Before showing an example of how to configure the adapter, first assume that your application registers an event type called PersonType in the EPN assembly file using the wlevs:metada element shown below:

<wlevs:event-type-repository>
        <wlevs:event-type type-name="PersonType">
            <wlevs:property>
               <entry key="name" value="java.lang.String"/>
               <entry key="age" value="java.lang.Integer"/>
               <entry key="birthplace" value="java.lang.String"/>
            </wlevs:property>
        </wlevs:event-type>
</wlevs:event-type-repository>

This event type corresponds to the data feed file shown in Section 15.4, "Creating a Data Feed File."

To configure the csvgen adapter that receives this data, use the following wlevs:adapter element:

<wlevs:adapter id="csvgenAdapter" provider="csvgen">
   <wlevs:instance-property name="port" value="9001"/>
   <wlevs:instance-property name="eventTypeName" value="PersonType"/>
   <wlevs:instance-property name="eventPropertyNames" value="name,age,birthplace"/>
</wlevs:adapter>

Note how the bolded values in the adapter configuration example correspond to the PersonType event type registration.

If you use the wlevs:class element to specify your own JavaBean when registering the event type, then the eventPropertyNames value corresponds to the JavaBean properties. For example, if your JavaBean has a getName() method, then one of the properties of your JavaBean is name.

For more information on event types, see Section 1.5, "Creating Oracle CEP Event Types".