public class GROUP_CONCAT extends AggregateBase<IV> implements INeedsMaterialization
| Modifier and Type | Class and Description |
|---|---|
static interface |
GROUP_CONCAT.Annotations |
INeedsMaterialization.Requirement| Modifier and Type | Field and Description |
|---|---|
protected BigdataValueFactory |
vf |
EMPTY_LITERAL, ZERODEFAULT_INITIAL_CAPACITY| Constructor and Description |
|---|
GROUP_CONCAT(boolean distinct,
IValueExpression<IV> expr,
String namespace,
String sep) |
GROUP_CONCAT(BOp[] args,
Map<String,Object> annotations) |
GROUP_CONCAT(GROUP_CONCAT op) |
| Modifier and Type | Method and Description |
|---|---|
IV |
done()
Return the final value.
|
IV |
get(IBindingSet bindingSet)
Return the current value of the aggregate (this has a side-effect on the
internal state of the
IAggregate operator). |
INeedsMaterialization.Requirement |
getRequirement()
We always need to have the materialized values.
|
void |
reset()
Reset the aggregate's internal state.
|
isDistinct, isWildcard_clearProperty, _setProperty__replaceArg, _set, annotations, annotationsCopy, annotationsEqual, annotationsRef, argIterator, args, argsCopy, arity, clearAnnotations, clearProperty, deepCopy, deepCopy, get, getProperty, setArg, setProperty, setUnboundProperty, toArray, toArrayannotationsEqual, annotationsToString, annotationsToString, annotationValueToString, checkArgs, clone, equals, getEvaluationContext, getId, getProperty, getRequiredProperty, hashCode, indent, isController, mutation, shortenName, toShortString, toString, toStringfinalize, getClass, notify, notifyAll, wait, wait, waittoStringannotations, argIterator, args, arity, clone, get, getEvaluationContext, getId, getProperty, getRequiredProperty, isController, setProperty, toArray, toArray, toShortString, toStringgetPropertyprotected transient BigdataValueFactory vf
public GROUP_CONCAT(GROUP_CONCAT op)
public GROUP_CONCAT(boolean distinct,
IValueExpression<IV> expr,
String namespace,
String sep)
var - The variable whose values will be combined.sep - The separator string (note that a space (0x20) is the default
in the SPARQL recommendation).public void reset()
IAggregatereset in interface IAggregate<IV>public IV done()
IAggregatedone in interface IAggregate<IV>public IV get(IBindingSet bindingSet)
AggregateBaseIAggregate operator). Functions which can
not produce an intermediate result, such as AVERAGE, MAY return
null.
Note: If evaluation of the IAggregate throws an error, then that
error must be "sticky" and reported out by IAggregate.done() as well. This
contract is relied on to correctly propagate errors within a group when
using incremental (pipelined) evaluation of IAggregates. The
error state is cleared by IAggregate.reset().
Operation is not implemented by this class and must be overridden if the
AggregateBase is to be directly evaluated. However, note that the
computation of aggregate functions is often based on hard coded
recognition of the appropriate function code.
Note: DISTINCT is merely carried as a marker on COUNT (and the other
aggregate functions). The application of DISTINCT to the inner expression
to form a column projection is handled by the driving evaluation logic
rather than by AggregateBase.get(IBindingSet).
get in interface IAggregate<IV>get in interface IValueExpression<IV>get in class AggregateBase<IV>bindingSet - The binding set.public INeedsMaterialization.Requirement getRequirement()
getRequirement in interface INeedsMaterializationCopyright © 2006–2019 SYSTAP, LLC DBA Blazegraph. All rights reserved.