Package org.apache.jmeter.visualizers.backend

Interface BackendListenerClient

  • All Implemented Interfaces:
    
public interface BackendListenerClient

    This interface defines the interactions between the BackendListener and external Java programs which can be executed by JMeter. Any Java class which wants to be executed using the BackendListener test element must implement this interface (either directly or through AbstractBackendListenerClient).

    JMeter will create one instance of a BackendListenerClient implementation for each user/thread in the test. Additional instances may be created for internal use by JMeter (for example, to find out what parameters are supported by the client).

    When the test is started, setupTest() will be called on each thread's BackendListenerClient instance to initialize the client. Then handleSampleResults will be called for each SampleResult notification. Finally, teardownTest will be called to allow the client to do any necessary clean-up.

    The JMeter BackendListener GUI allows a list of parameters to be defined for the test. These are passed to the various test methods through the BackendListenerContext. A list of default parameters can be defined through the getDefaultParameters method. These parameters and any default values associated with them will be shown in the GUI. Users can add other parameters as well.

    Listeners should extend AbstractBackendListenerClient rather than implementing BackendListenerClient directly to protect your code from future changes to the interface.

    While it may be necessary to make changes to the BackendListenerClient interface from time to time (therefore requiring changes to any implementations of this interface), we intend to make this abstract class provide reasonable default implementations of any new methods so that subclasses do not necessarily need to be updated for new versions. Implementing BackendListenerClient directly will continue to be supported for cases where extending this class is not possible (for example, when the client class is already a subclass of some other class).

    Since:

    2.13

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description

    • Field Summary

      Fields 
      Modifier and Type Field Description

    • Constructor Summary

      Constructors 
      Constructor Description

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description

    • Method Summary

      Modifier and Type Method Description
      abstract void setupTest(BackendListenerContext context) Do any initialization required by this client.
      abstract void handleSampleResults(List<SampleResult> sampleResults, BackendListenerContext context) Handle sampleResults, this can be done in many ways:
      • Write to a file
      • Write to a remote server
      • ...
      abstract void teardownTest(BackendListenerContext context) Do any clean-up required at the end of a test run.
      Arguments getDefaultParameters() Provide a list of parameters which this test supports.
      SampleResult createSampleResult(BackendListenerContext context, SampleResult result) Create a copy of SampleResult, this method is here to allow customizing what is kept in the copy, for example copy could remove some useless fields.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Constructor Detail

    • Method Detail

      • setupTest

         abstract void setupTest(BackendListenerContext context)

        Do any initialization required by this client. It is generally recommended to do any initialization such as getting parameter values here rather than handleSampleResults in order to add as little overhead as possible to the test.

        Parameters:
        context - provides access to initialization parameters.

      • handleSampleResults

         abstract void handleSampleResults(List<SampleResult> sampleResults, BackendListenerContext context)

        Handle sampleResults, this can be done in many ways:

        • Write to a file
        • Write to a remote server
        • ...
        Parameters:
        sampleResults - List of SampleResult
        context - provides access to initialization parameters.

      • teardownTest

         abstract void teardownTest(BackendListenerContext context)

        Do any clean-up required at the end of a test run.

        Parameters:
        context - provides access to initialization parameters.

      • getDefaultParameters

         Arguments getDefaultParameters()

        Provide a list of parameters which this test supports. Any parameter names and associated values returned by this method will appear in the GUI by default so the user doesn't have to remember the exact names. The user can add other parameters which are not listed here. If this method returns null then no parameters will be listed. If the value for some parameter is null then that parameter will be listed in the GUI with an empty value.

        Returns:

        a specification of the parameters used by this test which should be listed in the GUI, or null if no parameters should be listed.

      • createSampleResult

         SampleResult createSampleResult(BackendListenerContext context, SampleResult result)

        Create a copy of SampleResult, this method is here to allow customizing what is kept in the copy, for example copy could remove some useless fields. Note that if it returns null, the sample result is not put in the queue. Defaults to returning result.

        Parameters:
        context - BackendListenerContext
        result - SampleResult
        Returns:

        SampleResult