net.sf.jett.tag
Class AggTag

java.lang.Object
  net.sf.jett.tag.BaseTag
      net.sf.jett.tag.AggTag

All Implemented Interfaces:

Tag

public class AggTag
extends BaseTag

An AggTag represents possibly many aggregate values calculated from a List of values already exposed to the context. It uses jAgg functionality and exposes the results and Aggregators used for display later.

Attributes:

• Inherits all attributes from BaseTag.
• items (required): List
• aggs (required): String
• aggsVar (optional): String
• valuesVar (required): String
• groupBy (optional): String
• parallel (optional): int
• useMsd (optional): boolean
• rollup (optional): int[]
• rollups (optional): int[][]
• cube (optional): int[]
• groupingSets (optional): int[][]

Author:

Randy Gettman

Field Summary

static java.lang.String	ATTR_AGGS Attribute that specifies the List of Aggregators to use.
static java.lang.String	ATTR_AGGS_VAR Attribute that specifies the name of the List of exposed aggregators.
static java.lang.String	ATTR_CUBE Attribute that specifies a data cube that should occur on the results.
static java.lang.String	ATTR_GROUP_BY Attribute that specifies the List of group-by properties.
static java.lang.String	ATTR_GROUPING_SETS Attribute that specifies the exact grouping sets that should occur on the results.
static java.lang.String	ATTR_ITEMS Attribute that specifies the List of items to aggregate.
static java.lang.String	ATTR_PARALLEL Attribute that specifies the degree of parallelism to use.
static java.lang.String	ATTR_ROLLUP Attribute that specifies a rollup that should occur on the results.
static java.lang.String	ATTR_ROLLUPS Attribute that specifies multiple rollups that should occur on the results.
static java.lang.String	ATTR_USE_MSD Attribute that specifies whether to use Multiset Discrimination instead of sorting during aggregation processing.
static java.lang.String	ATTR_VALUES_VAR Attribute that specifies the List of exposed aggregation values.

Fields inherited from class net.sf.jett.tag.BaseTag

ATTR_ON_PROCESSED, SPEC_SEP

Constructor Summary

AggTag()

Method Summary

java.lang.String	getName() Returns this Tag's name.
protected java.util.List<java.lang.String>	getOptionalAttributes() Returns a List of optional attribute names.
protected java.util.List<java.lang.String>	getRequiredAttributes() Returns a List of required attribute names.
boolean	process() Run a "group by" operation on the specified Aggregators, get the results, and expose the aggregate values and the Aggregators used.
void	validateAttributes() Validates the attributes for this Tag.

Methods inherited from class net.sf.jett.tag.BaseTag

checkAttributes, clearBlock, deleteBlock, getAttributes, getContext, getWorkbookContext, isBodiless, processTag, removeBlock, setAttributes, setBodiless, setContext, setWorkbookContext

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ATTR_ITEMS

public static final java.lang.String ATTR_ITEMS

Attribute that specifies the List of items to aggregate.

See Also:

Constant Field Values

ATTR_AGGS

public static final java.lang.String ATTR_AGGS

Attribute that specifies the List of Aggregators to use.

See Also:

Constant Field Values

ATTR_AGGS_VAR

public static final java.lang.String ATTR_AGGS_VAR

Attribute that specifies the name of the List of exposed aggregators.

See Also:

Constant Field Values

ATTR_VALUES_VAR

public static final java.lang.String ATTR_VALUES_VAR

Attribute that specifies the List of exposed aggregation values.

See Also:

Constant Field Values

ATTR_GROUP_BY

public static final java.lang.String ATTR_GROUP_BY

Attribute that specifies the List of group-by properties.

See Also:

Constant Field Values

ATTR_PARALLEL

public static final java.lang.String ATTR_PARALLEL

Attribute that specifies the degree of parallelism to use.

See Also:

Constant Field Values

ATTR_USE_MSD

public static final java.lang.String ATTR_USE_MSD

Attribute that specifies whether to use Multiset Discrimination instead of sorting during aggregation processing. This means that the results will not be sorted by the "group by" properties. It defaults to false -- don't use Multiset Discrimination, use sorting.

Since:

0.4.0

See Also:

Constant Field Values

ATTR_ROLLUP

public static final java.lang.String ATTR_ROLLUP

Attribute that specifies a rollup that should occur on the results. Specify a List of 0-based integer indexes that reference the original list of properties. E.g. when grouping by two properties, prop1 and prop2, specifying a List of {0} specifies a rollup on prop1.

Since:

0.4.0

See Also:

ATTR_GROUP_BY, Constant Field Values

ATTR_ROLLUPS

public static final java.lang.String ATTR_ROLLUPS

Attribute that specifies multiple rollups that should occur on the results. Specify a List of Lists of 0-based integer indexes that reference the original list of properties. E.g. when grouping by three properties, prop1, prop2, and prop3, specifying a List of {{0}, {1, 2}} specifies a rollup on prop1, and a separate rollup on prop2 and prop3.

Since:

0.4.0

See Also:

ATTR_GROUP_BY, Constant Field Values

ATTR_CUBE

public static final java.lang.String ATTR_CUBE

Attribute that specifies a data cube that should occur on the results. Specify a List of 0-based integer indexes that reference the original list of properties. E.g. when grouping by three properties, prop1, prop2, and prop3, specifying a List of {0, 1} specifies a cube on prop1 and prop2.

Since:

0.4.0

See Also:

ATTR_GROUP_BY, Constant Field Values

ATTR_GROUPING_SETS

public static final java.lang.String ATTR_GROUPING_SETS

Attribute that specifies the exact grouping sets that should occur on the results. Specify a List of Lists of 0-based integer indexes that reference the original list of properties. E.g. when grouping by three properties, prop1, prop2, and prop3, specifying a List of {{0}, {1, 2}, {}} specifies a grouping set on prop1, a separate grouping set on prop2 and prop3, and a third grouping set on no properties (a grand total).

Since:

0.4.0

See Also:

ATTR_GROUP_BY, Constant Field Values

Constructor Detail

AggTag

public AggTag()

Method Detail

getName

public java.lang.String getName()

Returns this Tag's name.

Returns:

This Tag's name.

getRequiredAttributes

protected java.util.List<java.lang.String> getRequiredAttributes()

Returns a List of required attribute names.

Overrides:

getRequiredAttributes in class BaseTag

Returns:

A List of required attribute names.

getOptionalAttributes

protected java.util.List<java.lang.String> getOptionalAttributes()

Returns a List of optional attribute names.

Overrides:

getOptionalAttributes in class BaseTag

Returns:

A List of optional attribute names.

validateAttributes

public void validateAttributes()
                        throws TagParseException

Validates the attributes for this Tag. The "items" attribute must be a List. The "parallel" attribute must be a positive integer (defaults to 1). The "aggs" attribute must be a semicolon-separated list of valid Aggregator specification strings. The "valuesVar" attribute must be a string that indicates the name to which the aggregate values will be exposed in the Map of beans. The "aggsVar" attribute must be a string that indicates the name of the List that contains all created Aggregators and to which that will be exposed in the Map of beans. The "groupBy" attribute must be a semicolon- separated list of properties with which to "group" aggregated calculations (defaults to no "group by" properties). The "agg" tag must have a body.

Overrides:

validateAttributes in class BaseTag

Throws:

TagParseException - If the attribute values are illegal or unacceptable.

process

public boolean process()

Run a "group by" operation on the specified Aggregators, get the results, and expose the aggregate values and the Aggregators used.

Specified by:

process in class BaseTag

Returns:

Whether the first Cell in the Block associated with this Tag was processed.