Package org.apache.druid.query.groupby.orderby

Class DefaultLimitSpec

java.lang.Object

org.apache.druid.query.groupby.orderby.DefaultLimitSpec

All Implemented Interfaces:

Cacheable, LimitSpec

public class DefaultLimitSpec
extends Object
implements LimitSpec

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	DefaultLimitSpec.Builder
static class	DefaultLimitSpec.LimitJsonIncludeFilter	JsonInclude filter for getLimit().

Constructor Summary

Constructors

Constructor	Description
DefaultLimitSpec(List<OrderByColumnSpec> columns, Integer limit)	Constructor that does not accept "offset".
DefaultLimitSpec(List<OrderByColumnSpec> columns, Integer offset, Integer limit)

Method Summary

Modifier and Type	Method	Description
com.google.common.base.Function<Sequence<ResultRow>,Sequence<ResultRow>>	build(GroupByQuery query)	Returns a function that applies a limit to an input sequence that is assumed to be sorted on dimensions.
static DefaultLimitSpec.Builder	builder()
boolean	equals(Object o)
LimitSpec	filterColumns(Set<String> names)	Discard sorting columns not contained in given set.
byte[]	getCacheKey()	Get a byte array used as a cache key.
List<OrderByColumnSpec>	getColumns()
static StringComparator	getComparatorForDimName(DefaultLimitSpec limitSpec, String dimName)
int	getLimit()	Limit for this query; behaves like SQL "LIMIT".
int	getOffset()	Offset for this query; behaves like SQL "OFFSET".
int	hashCode()
boolean	isLimited()
boolean	isOffset()
static boolean	sortingOrderHasNonGroupingFields(DefaultLimitSpec limitSpec, List<DimensionSpec> dimensions)	Check if a limitSpec has columns in the sorting order that are not part of the grouping fields represented by `dimensions`.
String	toString()
DefaultLimitSpec	withOffsetToLimit()	Returns a new DefaultLimitSpec identical to this one except for one difference: an offset parameter, if any, will be removed and added to the limit.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Details

DefaultLimitSpec

public DefaultLimitSpec(List<OrderByColumnSpec> columns,
 Integer offset,
 Integer limit)

DefaultLimitSpec

public DefaultLimitSpec(List<OrderByColumnSpec> columns,
 Integer limit)

Constructor that does not accept "offset". Useful for tests that only want to provide "columns" and "limit".

Method Details

builder

public static DefaultLimitSpec.Builder builder()

sortingOrderHasNonGroupingFields

public static boolean sortingOrderHasNonGroupingFields(DefaultLimitSpec limitSpec,
 List<DimensionSpec> dimensions)

Check if a limitSpec has columns in the sorting order that are not part of the grouping fields represented by `dimensions`.

Parameters:

limitSpec - LimitSpec, assumed to be non-null

dimensions - Grouping fields for a groupBy query

Returns:

True if limitSpec has sorting columns not contained in dimensions

getComparatorForDimName

public static StringComparator getComparatorForDimName(DefaultLimitSpec limitSpec,
 String dimName)

getColumns

public List<OrderByColumnSpec> getColumns()

getOffset

public int getOffset()

Offset for this query; behaves like SQL "OFFSET". Zero means no offset. Negative values are invalid.

getLimit

public int getLimit()

Limit for this query; behaves like SQL "LIMIT". Will always be positive. Integer.MAX_VALUE is used in situations where the user wants an effectively unlimited result set.

isOffset

public boolean isOffset()

isLimited

public boolean isLimited()

build

public com.google.common.base.Function<Sequence<ResultRow>,Sequence<ResultRow>> build(GroupByQuery query)

Description copied from interface: LimitSpec

Returns a function that applies a limit to an input sequence that is assumed to be sorted on dimensions.

Specified by:

build in interface LimitSpec

Parameters:

query - the query that this limit spec belongs to

Returns:

limit function

filterColumns

public LimitSpec filterColumns(Set<String> names)

Description copied from interface: LimitSpec

Discard sorting columns not contained in given set. This is used when generating new queries, e.g. to process subtotal spec in GroupBy query.

Specified by:

filterColumns in interface LimitSpec

Parameters:

names - columns names to keep

Returns:

new LimitSpec that works with fitlered set of columns

withOffsetToLimit

public DefaultLimitSpec withOffsetToLimit()

Returns a new DefaultLimitSpec identical to this one except for one difference: an offset parameter, if any, will be removed and added to the limit. This is designed for passing down queries to lower levels of the stack. Only the highest level should apply the offset parameter, and any pushed-down limits must be increased to accommodate the offset.

toString

public String toString()

Overrides:

toString in class Object

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

getCacheKey

public byte[] getCacheKey()

Description copied from interface: Cacheable

Get a byte array used as a cache key.

Specified by:

getCacheKey in interface Cacheable

Returns:

bytes to be used as cache key - or null if this object should not be cached.