borland Packages Class Hierarchy jbcl.dataset Package Index
java.lang.Object +----borland.jbcl.dataset.AggOperator +----borland.jbcl.dataset.SumAggOperator +----borland.jbcl.dataset.BoundsAggOperator +----borland.jbcl.dataset.CustomAggOperator +----borland.jbcl.dataset.CountAggOperator
Variables Properties Methods
Implements Serializable, Cloneable
The AggOperator class is an abstract class that defines basic aggregator behavior of a calculated value or a calculated Column. All aggregation operators must extend from this class, therefore, you should extend this class when creating custom AggOperator classes. The following aggregator operators are provided and can be specified as the aggOperator of the AggDescriptor object:
For examples of applications that use aggregators, see the following projects in the specified directories of your JBuilder installation:
protected transient Column aggColumnThe Column in the DataSet that is being aggregated on.
protected transient DataSet aggDataSetThe internal StorageDataSet that contains and maintains aggregated values.
protected transient Variant aggValueThis variable is used internally by other classes in the JBCL. You should never use this variable directly.
protected transient StorageDataSet dataSetThe StorageDataSet that contains the Column ("aggColumn") that is being aggregated on.
protected transient Column resultColumnThe Column in aggDataSet that contains the aggregated value.
protected transient Variant resultValueThis variable is used internally by other classes in the JBCL. You should never use this variable directly.
public abstract void add(borland.jbcl.dataset.ReadRow row, long internalRow, boolean first)A row has been added or updated.
public Object clone()
Overrides: java.lang.Object.clone()
public abstract void delete(borland.jbcl.dataset.ReadRow row, long internalRow)A row has been deleted or updated. The DataRow parameter contains the values and internalRow is a unique identifier for the row.
public void init(borland.jbcl.dataset.StorageDataSet dataSet, java.lang.String[] groupColumnNames, borland.jbcl.dataset.StorageDataSet aggDataSet, borland.jbcl.dataset.Column resultColumn, borland.jbcl.dataset.Column aggColumn)Called when the AggOperator is being initialized. If overridden by an extended class, super.init() should still be called to ensure proper initialization. Note that this method is called before the aggDataSet is opened. This allows an AggOperator extension to add a column to the aggDataSet. This can be useful for some types of maintained aggregations like average that would need to accumulate count and total.
public boolean locate(borland.jbcl.dataset.ReadRow row)
public boolean needsAggDataSet()
public void open(borland.jbcl.dataset.DataSet aggDataSet)Called when the aggDataSet is opened and prepared for usage.