public DataRowDataSource() 
{
                    
    this(null);
}

Default constructor.

The expression name is empty ("", not null), the value initially null.

 public DataRowDataSource(String column) 
{
    this.field = column;
}

Constructs a new data source.

Parameters:

column - the name of the field, function or expression in the data-row.

 public Object clone() throws CloneNotSupportedException 
{
    final DataRowDataSource drs = (DataRowDataSource) super.clone();
    if (valueExpression != null)
    {
      drs.valueExpression = (FormulaExpression) valueExpression.clone();
    }
    return drs;
}

Clones the data source. A previously registered report definition is not inherited to the clone.

 public String getDataSourceColumnName() 
{
    return field;
}

Returns the data source column name.

 public String getFormula() 
{
    if (valueExpression == null)
    {
      return null;
    }
    return valueExpression.getFormula();
}

Returns the formula used to compute the value of the data source.

 public Object getValue(ExpressionRuntime runtime,
    Element element) 
{
    if (runtime == null)
    {
      return null;
    }
    if (field != null)
    {
      return runtime.getDataRow().get(field);
    }
    if (valueExpression == null)
    {
      return null;
    }
    valueExpression.setRuntime(runtime);
    try
    {
      return valueExpression.getValue();
    }
    catch (Exception e)
    {
      // ignore ..
      return null;
    }
    finally
    {
      valueExpression.setRuntime(null);
    }
}

Returns the current value of the data source, obtained from a particular column in the data-row.

 public  void setDataSourceColumnName(String dataSourceColumnName) 
{
    if (dataSourceColumnName == null)
    {
      throw new NullPointerException();
    }
    this.field = dataSourceColumnName;
    if (valueExpression != null)
    {
      this.valueExpression.setFormula(null);
    }
}

Defines the name of the column in the datarow to be queried.

 public  void setFormula(String formula) 
{
    if (formula == null)
    {
      throw new NullPointerException();
    }
    this.field = null;
    if (valueExpression == null)
    {
      valueExpression = new FormulaExpression();
    }
    this.valueExpression.setFormula(formula);
    if ("field".equals(valueExpression.getFormulaNamespace()))
    {
      DataRowDataSource.logger.warn("Encountered formula with 'field' prefix. Direct access to field-data should not be done using a formula. Auto-Fixing.");
      this.field = valueExpression.getFormulaExpression();
      this.valueExpression.setFormula(null);
    }
}

Defines the formula used to compute the value of this data source.