public TotalCalculationFunction() 
{
    results = new HashMap();
}

Constructs a new function.

Initially the function has no name...be sure to assign one before using the function.

 public String getField() 
{
    return field;
}

Returns the field used by the function. The field name corresponds to a column name in the report's data-row.

 public String getGroup() 
{
    return group;
}

Returns the name of the group to be totalled.

 public Expression getInstance() 
{
    final TotalCalculationFunction fn =
        (TotalCalculationFunction) super.getInstance();
    fn.results = new HashMap();
    return fn;
}

 public Object getValue() 
{
    return result;
}

Return the current expression value.

The value depends (obviously) on the expression implementation.

 public  void groupFinished(ReportEvent event) 
{
    if (FunctionUtilities.isDefinedGroup(getGroup(), event) == false)
    {
      // wrong group ...
      return;
    }
    if (FunctionUtilities.isDefinedPrepareRunLevel(this, event))
    {
      result = getDataRow().get(getField());
      results.put(globalStateKey, result);
      if (groupStateKey != null)
      {
        results.put(groupStateKey, result);
      }
    }
}

Receives notification that a group has finished.

 public  void groupStarted(ReportEvent event) 
{
    if (FunctionUtilities.isDefinedGroup(getGroup(), event) == false)
    {
      // wrong group ...
      return;
    }
    groupStateKey = event.getState().getProcessKey();
    if (FunctionUtilities.isDefinedPrepareRunLevel(this, event))
    {
      result = getDataRow().get(getField());
      results.put(globalStateKey, result);
      results.put(groupStateKey, result);
    }
    else
    {
      // Activate the current group, which was filled in the prepare run.
      result = results.get(groupStateKey);
    }
}

Receives notification that a group has started.

 public  void reportFinished(ReportEvent event) 
{
    if (FunctionUtilities.isDefinedPrepareRunLevel(this, event))
    {
      result = getDataRow().get(getField());
      results.put(globalStateKey, result);
      if (groupStateKey != null)
      {
        results.put(groupStateKey, result);
      }
    }
}

Receives notification that the report has finished.

 public  void reportInitialized(ReportEvent event) 
{
    globalStateKey = event.getState().getProcessKey();
    if (FunctionUtilities.isDefinedPrepareRunLevel(this, event))
    {
      results.clear();
      result = getDataRow().get(getField());
      results.put(globalStateKey, result);
    }
    else
    {
      result = results.get(globalStateKey);
    }
}

Receives notification that the report has started.

 public  void setField(String field) 
{
    this.field = field;
}

Sets the field name for the function. The field name corresponds to a column name in the report's data-row.

 public  void setGroup(String group) 
{
    this.group = group;
}

Defines the name of the group to be totalled. If the name is null, all groups are totalled.