Interface QOM.Rollup

All Superinterfaces:

GroupField, QueryPart, Serializable

Enclosing class:

QOM

public static interface QOM.Rollup
extends GroupField

Author:

Lukas Eder

Method Summary

Modifier and Type	Method	Description
QOM.UnmodifiableList<? extends FieldOrRow>	$arg1()
default QOM.Rollup	$arg1(QOM.UnmodifiableList<? extends FieldOrRow> newArg1)
default @NotNull List<?>	$args()
@NotNull Function1<? super QOM.UnmodifiableList<? extends FieldOrRow>, ? extends QOM.Rollup>	$constructor()
default QueryPart	$replace(Replacer replacer)	Traverse a QueryPart hierarchy and recursively replace its elements by alternatives.
default <T> T	$traverse(Traverser<?,T> traverser)	Traverser this QueryPart expression tree using a composable Traverser, producing a result.

Methods inherited from interface QueryPart

$replace, $traverse, equals, hashCode, toString

Method Details

$arg1

QOM.UnmodifiableList<? extends FieldOrRow> $arg1()

$arg1

@CheckReturnValue
@NotNull
default QOM.Rollup $arg1(QOM.UnmodifiableList<? extends FieldOrRow> newArg1)

$constructor

@NotNull
@NotNull Function1<? super QOM.UnmodifiableList<? extends FieldOrRow>, ? extends QOM.Rollup> $constructor()

$args

@NotNull
default @NotNull List<?> $args()

$traverse

default <T> T $traverse(Traverser<?,T> traverser)

Description copied from interface: QueryPart

Traverser this QueryPart expression tree using a composable Traverser, producing a result.

This offers a generic way to traverse expression trees to translate the tree to arbitrary other data structures. The simplest traversal would just count all the tree elements:

int count = CUSTOMER.NAME.eq(1).$traverse(0, (i, p) -> i + 1);

The same can be achieved by translating the JDK Collector API to the Traverser API using Traversers.collecting(Collector).

CUSTOMER.NAME.eq(1).$traverse(Traversers.collecting(Collectors.counting()));

Unlike a Collector, a Traverser is optimised for tree traversal, not stream traversal:

• Is not designed for parallelism
• It can Traverser.abort() traversal early when the result can be produced early (e.g. when running Traversers.containing(QueryPart), and a result has been found).
• It can decide whether to Traverser.recurse() into a QueryPart subtree, or whether that is not necessary or even undesirable, e.g. to prevent entering new subquery scopes.
• Unlike a Collector, which can use its Collector.accumulator() to accumulate each element only once, in tree traversal, it's desirable to be able to distinguish between accumulating an item Traverser.before() or Traverser.after() recursing into it. This is useful e.g. to wrap each tree node in XML opening and closing tags.

This is a commercial jOOQ edition only feature.

Specified by:

$traverse in interface QueryPart

$replace

@NotNull
default QueryPart $replace(Replacer replacer)

Description copied from interface: QueryPart

Traverse a QueryPart hierarchy and recursively replace its elements by alternatives.

While replacing contents, this QueryPart isn't modified. Instead, a new object is returned.

This is a commercial jOOQ edition only feature.

Specified by:

$replace in interface QueryPart