org.apache.ode.bpel.evar

## Interface ExternalVariableModule

- All Known Implementing Classes:
    JdbcExternalVariableModule

      public interface ExternalVariableModule

  Representation of an external source for variable data.

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Interface and Description
    --- | ---
    `static class` | `ExternalVariableModule.Locator` Structure used to identify an external variable to the external variable subsystem.
    `static class` | `ExternalVariableModule.Value` Data structure used to report the value of the variable to the BPEL engine from the external sub system.

  - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `configure(javax.xml.namespace.QName pid, java.lang.String extVarId, org.w3c.dom.Element config)` Configure an external variable.
    `javax.xml.namespace.QName` | `getName()` Get the QName of this external variable engine; this method must always return a valid non-null value.
    `boolean` | `isTransactional()` Report whether this engine is transactional, i.e.
    `ExternalVariableModule.Value` | `readValue(javax.xml.namespace.QName varType, ExternalVariableModule.Locator locator)` The the value of an external variable.
    `void` | `shutdown()` Shutdown the external variable subsystem.
    `void` | `start()` Start the external variable subsystem.
    `void` | `stop()` Stop the external variable subsystem.
    `ExternalVariableModule.Value` | `writeValue(javax.xml.namespace.QName varType, ExternalVariableModule.Value newval)` Update the value of the external variable.

- - ### Method Detail

    - #### getName

          javax.xml.namespace.QName getName()

      Get the QName of this external variable engine; this method must always return a valid non-null value. The name of the external variable engine is used to identify it in the external variable declaration.
      Returns:

    - #### start

          void start()

      Start the external variable subsystem. This method is called before the engine is started.

    - #### stop

          void stop()

      Stop the external variable subsystem. This method is called right after the engine is stopped.

    - #### shutdown

          void shutdown()

      Shutdown the external variable subsystem. This method is called right after the engine is shutdown.

    - #### isTransactional

          boolean isTransactional()

      Report whether this engine is transactional, i.e. do the update/fetch methods use the JTA TX?
      Returns:
        `true` if transactional, `false` otherwsie.

    - #### configure

          void configure(javax.xml.namespace.QName pid,
                         java.lang.String extVarId,
                         org.w3c.dom.Element config)
                  throws ExternalVariableModuleException

      Configure an external variable.
      Parameters:
        `pid` - process
        `extVarId` - external variable identifier
        `config` - configuration element
      Throws:
        `ExternalVariableModuleException`

    - #### readValue

          ExternalVariableModule.Value readValue(javax.xml.namespace.QName varType,
                                                 ExternalVariableModule.Locator locator)
                                          throws ExternalVariableModuleException

      The the value of an external variable.
      Parameters:
        `locator` - variable locator
        `initialize` - indicates if this is the first time the value is being read
      Returns:
        value of the variable
      Throws:
        `ExternalVariableModuleException`

    - #### writeValue

          ExternalVariableModule.Value writeValue(javax.xml.namespace.QName varType,
                                                  ExternalVariableModule.Value newval)
                                           throws ExternalVariableModuleException

      Update the value of the external variable.
      Parameters:
        `newval` - new variable value
        `initialize` - indicates if this is a variable initialization
      Throws:
        `ExternalVariableModuleException`