Make listener properties in StartLiveData dynamic

Framework/LiveData/inc/MantidLiveData/StartLiveData.h

@@ -56,6 +56,11 @@ class DLLExport StartLiveData : public LiveDataAlgorithm {
 private:
   void init() override;
   void exec() override;
+  void afterPropertySet(const std::string &) override;
+
+  void copyListenerProperties(
+      const boost::shared_ptr<Mantid::API::ILiveListener> &listener);
+  void removeListenerProperties();
 };
 
 } // namespace LiveData

Framework/LiveData/src/StartLiveData.cpp

@@ -59,21 +59,6 @@ void StartLiveData::init() {
       "If you specify 0, MonitorLiveData will not launch and you will get only "
       "one chunk.");
 
-  // Properties used with ISISHistoDataListener
-  declareProperty(make_unique<ArrayProperty<specnum_t>>("SpectraList"),
-                  "An optional list of spectra to load. If blank, all "
-                  "available spectra will be loaded. Applied to ISIS histogram"
-                  " data only.");
-  getPointerToProperty("SpectraList")->setGroup(listenerPropertyGroup);
-
-  auto validator = boost::make_shared<ArrayBoundedValidator<int>>();
-  validator->setLower(1);
-  declareProperty(make_unique<ArrayProperty<int>>("PeriodList", validator),
-                  "An optional list of periods to load. If blank, all "
-                  "available periods will be loaded. Applied to ISIS histogram"
-                  " data only.");
-  getPointerToProperty("PeriodList")->setGroup(listenerPropertyGroup);
-
   // Initialize the properties common to LiveDataAlgorithm.
   initProps();
 
@@ -85,6 +70,52 @@ void StartLiveData::init() {
                   "completes.");
 }
 
+/**
+ * After Instrument property is set copy any properties that the instrument's
+ * listener may have to this algorithm.
+ */
+void StartLiveData::afterPropertySet(const std::string &propName) {
+  if (propName == "Instrument") {
+    // Properties of old listener, if any, need to be removed
+    removeListenerProperties();
+
+    // Get of instance of listener for this instrument
+    auto listener = LiveListenerFactory::Instance().create(
+        getPropertyValue(propName), false);
+
+    // Copy over properties of new listener to this algorithm
+    copyListenerProperties(listener);
+  }
+}
+
+/**
+ * Copies properties from an ILiveListener to this algorithm. This makes them
+ * appear in the "listener properties" group on the StartLiveData custom dialog.
+ *
+ * @param listener ILiveListener from which to copy properties
+ */
+void StartLiveData::copyListenerProperties(
+    const boost::shared_ptr<ILiveListener> &listener) {
+  // Add clones of listener's properties to this algorithm
+  for (auto listenerProp : listener->getProperties()) {
+    auto prop = std::unique_ptr<Property>(listenerProp->clone());
+    prop->setGroup(listenerPropertyGroup);
+    declareProperty(std::move(prop));
+  }
+}
+
+/**
+ * Removes previously copied ILiveListener properties.
+ */
+void StartLiveData::removeListenerProperties() {
+  // Remove all properties tagged with the listener property group
+  for (auto prop : getProperties()) {
+    if (prop->getGroup() == listenerPropertyGroup) {
+      removeProperty(prop->name());
+    }
+  }
+}
+
 //----------------------------------------------------------------------------------------------
 /** Execute the algorithm.
  */

Framework/PythonInterface/mantid/simpleapi.py

@@ -38,7 +38,7 @@
 
 #------------------------ Specialized function calls --------------------------
 # List of specialized algorithms
-__SPECIALIZED_FUNCTIONS__ = ["Load", "CutMD", "RenameWorkspace"]
+__SPECIALIZED_FUNCTIONS__ = ["Load", "StartLiveData", "CutMD", "RenameWorkspace"]
 # List of specialized algorithms
 __MDCOORD_FUNCTIONS__ = ["PeakIntensityVsRadius", "CentroidPeaksMD","IntegratePeaksMD"]
 # The "magic" keyword to enable/disable logging
@@ -215,6 +215,66 @@ def LoadDialog(*args, **kwargs):
     algm.execute()
     return algm
 
+#------------------------------------------------------------------------------
+
+def StartLiveData(*args, **kwargs):
+    """
+    StartLiveData dynamically adds the properties of the specific LiveListener
+    that is used to itself, to allow usage such as the following:
+
+        StartLiveData(Instrument='ISIS_Histogram', ...
+                      PeriodList=[1,3], SpectraList=[2,4,6])
+
+    Where PeriodList and SpectraList are properties of the ISISHistoDataListener
+    rather than of StartLiveData. For StartLiveData to know those are valid
+    properties, however, it first needs to know what the Instrument is.
+
+    This is a similar situation as in the Load algorithm, where the Filename
+    must be provided before other properties become available, and so it is
+    solved here in the same way.
+    """
+    instrument, = _get_mandatory_args('StartLiveData', ["Instrument"], *args, **kwargs)
+
+    # Create and execute
+    (_startProgress, _endProgress, kwargs) = extract_progress_kwargs(kwargs)
+    algm = _create_algorithm_object('StartLiveData',
+                                    startProgress=_startProgress,
+                                    endProgress=_endProgress)
+    _set_logging_option(algm, kwargs)
+    try:
+        algm.setProperty('Instrument', instrument) # Must be set first
+    except ValueError as ve:
+        raise ValueError('Problem when setting Instrument. This is the detailed error '
+                         'description: ' + str(ve))
+
+    # Remove from keywords so it is not set twice
+    try:
+        del kwargs['Instrument']
+    except KeyError:
+        pass
+
+    # LHS Handling currently unsupported for StartLiveData
+    lhs = _kernel.funcinspect.lhs_info()
+    if lhs[0] > 0:  # Number of terms on the lhs
+        raise RuntimeError("Assigning the output of StartLiveData is currently "
+                           "unsupported due to limitations of the simpleapi. "
+                           "Please call StartLiveData without assigning it to "
+                           "to anything.")
+
+    lhs_args = _get_args_from_lhs(lhs, algm)
+    final_keywords = _merge_keywords_with_lhs(kwargs, lhs_args)
+
+    # Check for any properties that aren't known and warn they will not be used
+    for key in list(final_keywords.keys()):
+        if key not in algm:
+            logger.warning("You've passed a property (%s) to StartLiveData() that doesn't apply to this Instrument." % key)
+            del final_keywords[key]
+
+    set_properties(algm, **final_keywords)
+    algm.execute()
+
+    return _gather_returns("StartLiveData", lhs, algm)
+
 #---------------------------- Fit ---------------------------------------------
 
 def fitting_algorithm(f):
@@ -702,7 +762,7 @@ def _merge_keywords_with_lhs(keywords, lhs_args):
     final_keywords.update(keywords)
     return final_keywords
 
-def _gather_returns(func_name, lhs, algm_obj, ignore_regex=[]):
+def _gather_returns(func_name, lhs, algm_obj, ignore_regex=None):
     """Gather the return values and ensure they are in the
        correct order as defined by the output properties and
        return them as a tuple. If their is a single return
@@ -713,6 +773,8 @@ def _gather_returns(func_name, lhs, algm_obj, ignore_regex=[]):
        :param algm_obj: An executed algorithm object.
        :param ignore_regex: A list of strings containing regex expressions to match against property names that will be ignored & not returned.
     """
+    if ignore_regex is None: ignore_regex = []
+
     import re
     def ignore_property(name, ignore_regex):
         for regex in ignore_regex:

docs/source/algorithms/StartLiveData-v1.rst

@@ -23,6 +23,29 @@ simply calls :ref:`algm-LoadLiveData` at a fixed interval.
 Instructions for setting up a "fake" data stream are found `here
 <http://www.mantidproject.org/MBC_Live_Data_Simple_Examples>`__.
 
+Listener Properties
+###################
+
+Specific LiveListeners may provide their own properties, in addition to
+properties provided by StartLiveData. For convenience and accessibility, these
+properties are made available through StartLiveData as well.
+
+In the StartLiveData algorithm dialog, a group box called "Listener Properties"
+will appear at the bottom of the sidebar on the left, if the currently selected
+listener provides additional properties.
+
+In the Python API, these listener properties may also be set as keyword
+arguments when calling StartLiveData. For example, in this code snippet:
+
+.. code-block:: python
+
+    StartLiveData(Instrument='ISIS_Histogram', OutputWorkspace='wsOut', UpdateEvery=1,
+                  AccumulationMethod='Replace', PeriodList=[1,3], SpectraList=[2,4,6])
+
+PeriodList and SpectraList are properties of the ISISHistoDataListener. They
+are available as arguments in this call because Instrument is set to
+'ISIS_Histogram', which uses that listener.
+
 Live Plots
 ##########
 

docs/source/release/v3.9.0/framework.rst

@@ -16,6 +16,7 @@ Improved
 ########
 
 - :ref:`CalculateFlatBackground <algm-CalculateFlatBackground>` has now a new mode 'Moving Average' which takes the minimum of a moving window average as the flat background.
+- :ref:`StartLiveData <algm-StartLiveData>` and its dialog now support dynamic listener properties, based on the specific LiveListener being used.
 
 Deprecated
 ##########
@@ -40,6 +41,7 @@ Python Algorithms
 
 - :ref:`MatchPeaks <algm-MatchPeaks>` performs circular shift operation (numpy roll) along the x-axis to align the peaks in the spectra.
 - :ref:`FindEPP <algm-FindEPP>` is improved to better determine the initial parameters and range for the fitting.
+- :ref:`StartLiveData <algm-StartLiveData>` can now accept LiveListener properties as parameters, based on the value of the "Instrument" parameter.
 
 Bug Fixes
 ---------