Package org.pentaho.reporting.engine.classic.core.function

Class ItemAvgFunction

  • All Implemented Interfaces:
    Serializable, Cloneable, EventListener, ReportListener, AggregationFunction, Expression, FieldAggregationFunction, Function
    public class ItemAvgFunction
extends AbstractFunction
implements FieldAggregationFunction
    A report function that calculates the average of one field (column) from the TableModel. This function produces a running total, no global total. The function can be used in two ways:
    • to calculate an average value for the entire report;
    • to calculate an average value within a particular group;
    This function expects its input values to be either java.lang.Number instances or Strings that can be parsed to java.lang.Number instances using a java.text.DecimalFormat.

    The function understands two parameters, the field parameter is required and denotes the name of an ItemBand-field which gets summed up.

    The parameter group denotes the name of a group. When this group is started, the counter gets reset to null.

    Author:
    Thomas Morgner
    See Also:
    Serialized Form

    • Constructor Detail

      • ItemAvgFunction

        public ItemAvgFunction()
        Constructs an unnamed function. Make sure to set a Name or function initialisation will fail.

      • ItemAvgFunction

        public ItemAvgFunction​(String name)
        Constructs a named function.

        The field must be defined before using the function.

        Parameters:
        name - The function name.

    • Method Detail

      • groupStarted

        public void groupStarted​(ReportEvent event)
        Receives notification that a new group is about to start. If this is the group defined for the function, then the running total is reset to zero.
        Specified by:
        groupStarted in interface ReportListener
        Overrides:
        groupStarted in class AbstractFunction
        Parameters:
        event - Information about the event.

      • setGroup

        public void setGroup​(String name)
        Sets the group name.

        If a group is defined, the functions value is reset to zero at the start of every instance of this group.

        Specified by:
        setGroup in interface AggregationFunction
        Parameters:
        name - The group name (null permitted).

      • getField

        public String getField()
        Returns the field used by the function. The field name corresponds to a column name in the report's data-row.
        Specified by:
        getField in interface FieldAggregationFunction
        Returns:
        The field name.

      • setField

        public void setField​(String field)
        Sets the field name for the function. The field name corresponds to a column name in the report's data-row.
        Specified by:
        setField in interface FieldAggregationFunction
        Parameters:
        field - the field name.

      • getRoundingMode

        public int getRoundingMode()
        Returns the defined rounding mode. This influences the precision of the divide-operation.
        Returns:
        the rounding mode.
        See Also:
        BigDecimal.divide(java.math.BigDecimal, int)

      • setRoundingMode

        public void setRoundingMode​(int roundingMode)
        Defines the rounding mode. This influences the precision of the divide-operation.
        Parameters:
        roundingMode - the rounding mode.
        See Also:
        BigDecimal.divide(java.math.BigDecimal, int)

      • getScale

        public int getScale()
        Returns the scale for the divide-operation. The scale influences the precision of the division.
        Returns:
        the scale.

      • setScale

        public void setScale​(int scale)
        Defines the scale for the divide-operation. The scale influences the precision of the division.
        Parameters:
        scale - the scale.

      • getValue

        public Object getValue()
        Returns the function value, in this case the average of all values of a specific column in the report's TableModel.
        Specified by:
        getValue in interface Expression
        Returns:
        The function value.

      • getInstance

        public Expression getInstance()
        Return a completly separated copy of this function. The copy does no longer share any changeable objects with the original function.
        Specified by:
        getInstance in interface Expression
        Overrides:
        getInstance in class AbstractExpression
        Returns:
        a copy of this function.

      • clone

        public Object clone()
        Description copied from class: AbstractExpression
        Clones the expression. The expression should be reinitialized after the cloning.

        Expressions maintain no state, cloning is done at the beginning of the report processing to disconnect the expression from any other object space.

        Specified by:
        clone in interface Expression
        Overrides:
        clone in class AbstractExpression
        Returns:
        a clone of this expression.