MessageGenerator (PerfCake API Documentation (version 7.5))

All Known Implementing Classes:

AbstractMessageGenerator, ConstantSpeedMessageGenerator, CustomProfileGenerator, DefaultMessageGenerator, RampUpDownGenerator
```
public interface MessageGenerator
```
A definition of contract for all message generators.

A message generator controls how many threads are being used to generate the messages, is responsible for creating and submitting SenderTasks and controls the other components involved in the performance test execution.

A message generator is the most crucial and complicated component of PerfCake and it is highly recommended to reuse one of existing implementations as they already offer mostly wanted features.

The main task of a message generator is to take care of the sending threads, create SenderTasks as needed and monitor test progress. It is important to properly shutdown the message generation for both time and iteration based test length control. In the case of an iteration based control, a generator must wait for all the messages to be processed. In the case of a time based control, the test stops immediately after the time has elapsed.

Each SenderTask takes a MessageGenerator instance to be able to notify the parent generator of any errors that might have occurred.

When there is a separate message channel used to receive messages, a Correlator is set to match requests and responses. The Correlator is also passed to the SenderTask so it can register sent messages with it.

Author:

Martin Večeřa

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`void`	`close()` Closes and finalizes the generator.
`void`	`generate()` Generates the messages.
`int`	`getActiveThreadsCount()` Gets the number of active threads used currently by the generator.
`long`	`getTasksInQueue()` Gets the number of sender tasks in the queue awaiting to be processed.
`int`	`getThreads()` Gets the number of threads that should be used to generate the messages.
`void`	`init(MessageSenderManager messageSenderManager, List<MessageTemplate> messageStore)` Initializes the generator.
`void`	`interrupt(Exception exception)` Interrupts the execution with a message from failed sender.
`boolean`	`isFailFast()` Tells whether we should interrupt the generator immediately after a first error occurred.
`void`	`setCorrelator(Correlator correlator)` Sets a `Correlator` to match requests and responses when a separate message channel is used for receiving responses.
`void`	`setReportManager(ReportManager reportManager)` Sets the `ReportManager` to be used for the current performance test execution.
`void`	`setRunInfo(RunInfo runInfo)` Sets the current `RunInfo` to control generating of the messages.
`void`	`setSequenceManager(SequenceManager sequenceManager)` Sets a manager of sequences that can be used to replace placeholders in a message template and sender's target.
`MessageGenerator`	`setThreads(int threads)` Sets the number of threads used to generate the messages.
`void`	`setValidationManager(ValidationManager validationManager)` Configures the `ValidationManager` to be used for the performance test execution.

- Method Detail
  - init
```
void init(MessageSenderManager messageSenderManager,
          List<MessageTemplate> messageStore)
   throws PerfCakeException
```
    Initializes the generator. During the initialization the MessageSenderManager should be initialized as well.
    
    Parameters:
    
    messageSenderManager - Message sender manager.
    
    messageStore - Message store where the messages are taken from.
    
    Throws:
    
    PerfCakeException - When it was not possible to initialize the generator.
  - generate
```
void generate()
       throws Exception
```
    Generates the messages. This actually executes the whole performance test.
    
    Throws:
    
    Exception - When it was not possible to generate the messages.
  - interrupt
```
void interrupt(Exception exception)
```
    Interrupts the execution with a message from failed sender.
    
    Parameters:
    
    exception - The cause of the interruption.
  - close
```
void close()
    throws PerfCakeException
```
    Closes and finalizes the generator. The MessageSenderManager must be closed as well.
    
    Throws:
    
    PerfCakeException - When it was not possible to smoothly finalize the generator.
  - setRunInfo
```
void setRunInfo(RunInfo runInfo)
```
    Sets the current RunInfo to control generating of the messages.
    
    Parameters:
    
    runInfo - RunInfo to be used.
  - setReportManager
```
void setReportManager(ReportManager reportManager)
```
    Sets the ReportManager to be used for the current performance test execution.
    
    Parameters:
    
    reportManager - ReportManager to be used.
  - setValidationManager
```
void setValidationManager(ValidationManager validationManager)
```
    Configures the ValidationManager to be used for the performance test execution.
    
    Parameters:
    
    validationManager - ValidationManager to be used
  - setSequenceManager
```
void setSequenceManager(SequenceManager sequenceManager)
```
    Sets a manager of sequences that can be used to replace placeholders in a message template and sender's target.
    
    Parameters:
    
    sequenceManager - The SequenceManager to be used to replace placeholders in a message template and sender's target.
  - getThreads
```
int getThreads()
```
    Gets the number of threads that should be used to generate the messages. The return value can change over time during the test execution.
    
    Returns:
    
    Number of currently running threads.
  - setThreads
```
MessageGenerator setThreads(int threads)
```
    Sets the number of threads used to generate the messages. This can be changed during a running test.
    
    Parameters:
    
    threads - The number of threads to be used.
    
    Returns:
    
    Instance of this to support fluent API.
  - getActiveThreadsCount
```
int getActiveThreadsCount()
```
    Gets the number of active threads used currently by the generator. This can help determine if there were some threads blocked waiting for reply.
    
    Returns:
    
    Number of active threads in use.
  - getTasksInQueue
```
long getTasksInQueue()
```
    Gets the number of sender tasks in the queue awaiting to be processed.
    
    Returns:
    
    The number of sender tasks in the queue awaiting to be processed.
  - setCorrelator
```
void setCorrelator(Correlator correlator)
```
    Sets a Correlator to match requests and responses when a separate message channel is used for receiving responses. Null means that no correlator and no receiver is used.
    
    Parameters:
    
    correlator - The correlator to be used to match requests and responses.
  - isFailFast
```
boolean isFailFast()
```
    Tells whether we should interrupt the generator immediately after a first error occurred.
    
    Returns:
    
    True if and only if we are supposed to fail fast. Can be set by perfcake.fail.fast system property.

Interface MessageGenerator

Method Summary

Method Detail

init

generate

interrupt

close

setRunInfo

setReportManager

setValidationManager

setSequenceManager

getThreads

setThreads

getActiveThreadsCount

getTasksInQueue

setCorrelator

isFailFast