Package org.rumbledb.runtime.flwor.clauses

Class OrderByClauseIterator

java.lang.Object

org.rumbledb.runtime.plan.RuntimePlan<FlworTuple>

org.rumbledb.runtime.TupleRuntimePlan

org.rumbledb.runtime.flwor.clauses.OrderByClauseIterator

All Implemented Interfaces:

Serializable, DataFrameRuntimePlan<FlworTuple>, LocalRuntimePlan<FlworTuple>, NativeQueryRuntimePlan

public class OrderByClauseIterator
extends TupleRuntimePlan
implements DataFrameRuntimePlan<FlworTuple>

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static final String	StringFlagForEmptySequence

Fields inherited from class org.rumbledb.runtime.TupleRuntimePlan

child, evaluationDepthLimit, inputTupleProjection, outputTupleProjection

Fields inherited from class org.rumbledb.runtime.plan.RuntimePlan

staticContext

Constructor Summary

Constructors

Constructor	Description
OrderByClauseIterator(TupleRuntimePlan child, List<OrderByClauseAnnotatedChildIterator> expressionsWithIterator, boolean stable, RuntimeStaticContext staticContext)

Method Summary

Modifier and Type	Method	Description
boolean	containsClause(FLWOR_CLAUSES kind)	Says whether or not the clause and its descendants include a clause of the specified kind.
Cursor<FlworTuple>	createNativeCursor(DynamicContext context)	Creates an independent cursor for one native local evaluation.
FlworDataFrame	createNativeDataFrame(DynamicContext context)	Builds the DataFrame for one evaluation.
NativeClauseContext	generateNativeQuery(NativeClauseContext nativeClauseContext)	This function generate (if possible) a native spark-sql query that maps the inner working of the iterator
Map<Name,DynamicContext.VariableDependency>	getDynamicContextVariableDependencies()	Variable dependencies are variables that MUST be provided by the parent clause in the dynamic context for successful execution of this clause.
Map<Name,DynamicContext.VariableDependency>	getInputTupleVariableDependencies(Map<Name,DynamicContext.VariableDependency> parentProjection)	Builds the DataFrame projection that this clause needs to receive from its child clause.
Set<Name>	getOutputTupleVariableNames()	Returns the output tuple variable names.
boolean	isSparkJobNeeded()	Says whether this expression evaluation triggers a Spark job.
static Item	normalizeOrderKeyAtomic(Item atomizedItem, String collationUri, ExceptionMetadata metadata)
void	print(StringBuilder buffer, int indent)
static FlworDataFrame	tryNativeQuery(org.apache.spark.sql.Dataset<org.apache.spark.sql.Row> dataFrame, List<OrderByClauseAnnotatedChildIterator> expressionsWithIterator, List<FlworDataFrameColumn> allColumns, org.apache.spark.sql.types.StructType inputSchema, DynamicContext context)	Try to generate the native query for the order by clause and run it, if successful return the resulting dataframe, otherwise it returns null

Methods inherited from class org.rumbledb.runtime.TupleRuntimePlan

canSetEvaluationDepthLimit, getChildIterator, getEvaluationDepthLimit, getHeight, getStaticContext, getSubtreeBeyondLimit, isDataFrame, setEvaluationDepthLimit, setInputAndOutputTupleVariableDependencies, toString

Methods inherited from class org.rumbledb.runtime.plan.RuntimePlan

getConfiguration, getCursor, getDataFrame, getMetadata, getRDD, getRuntimeStaticContext, materialize, materializeAtMost, materializeAtMostOne, materializeExactlyOne, materializeFirstOrNull

Methods inherited from class java.lang.Object

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

Field Details

StringFlagForEmptySequence

public static final String StringFlagForEmptySequence

See Also:

• Constant Field Values

Constructor Details

OrderByClauseIterator

public OrderByClauseIterator(TupleRuntimePlan child,
 List<OrderByClauseAnnotatedChildIterator> expressionsWithIterator,
 boolean stable,
 RuntimeStaticContext staticContext)

Method Details

createNativeCursor

public Cursor<FlworTuple> createNativeCursor(DynamicContext context)

Description copied from interface: LocalRuntimePlan

Creates an independent cursor for one native local evaluation.

Specified by:

createNativeCursor in interface LocalRuntimePlan<FlworTuple>

Specified by:

createNativeCursor in class TupleRuntimePlan

Parameters:

context - the dynamic context for that evaluation

Returns:

an unopened cursor

normalizeOrderKeyAtomic

public static Item normalizeOrderKeyAtomic(Item atomizedItem,
 String collationUri,
 ExceptionMetadata metadata)

createNativeDataFrame

public FlworDataFrame createNativeDataFrame(DynamicContext context)

Description copied from interface: DataFrameRuntimePlan

Builds the DataFrame for one evaluation.

Specified by:

createNativeDataFrame in interface DataFrameRuntimePlan<FlworTuple>

Parameters:

context - the dynamic context for that evaluation

Returns:

the resulting DataFrame

getDynamicContextVariableDependencies

public Map<Name,DynamicContext.VariableDependency> getDynamicContextVariableDependencies()

Description copied from class: TupleRuntimePlan

Variable dependencies are variables that MUST be provided by the parent clause in the dynamic context for successful execution of this clause. These variables are: 1. All variables that the expression of the clause depends on (recursive call of getVariableDependencies on the expression) 2. Except those variables bound in the current FLWOR (obtained from the auxiliary method getVariablesBoundInCurrentFLWORExpression), because those are provided in the Tuples 3. Plus (recursively calling getVariableDependencies) all the Variable Dependencies of the child clause if it exists.

Overrides:

getDynamicContextVariableDependencies in class TupleRuntimePlan

Returns:

a map of variable names to dependencies (FULL, COUNT, ...) that this clause needs to obtain from the dynamic context.

getOutputTupleVariableNames

public Set<Name> getOutputTupleVariableNames()

Description copied from class: TupleRuntimePlan

Returns the output tuple variable names. These variables can be removed from the dependencies of expressions in ascendent (subsequent) clauses, because their values are provided in the tuples rather than the dynamic context object.

Overrides:

getOutputTupleVariableNames in class TupleRuntimePlan

Returns:

the set of variable names that are bound by descendant clauses.

print

public void print(StringBuilder buffer,
 int indent)

Overrides:

print in class TupleRuntimePlan

getInputTupleVariableDependencies

public Map<Name,DynamicContext.VariableDependency> getInputTupleVariableDependencies(Map<Name,DynamicContext.VariableDependency> parentProjection)

Description copied from class: TupleRuntimePlan

Builds the DataFrame projection that this clause needs to receive from its child clause. The intent is that the result of this method is forwarded to the child clause in getDataFrame() so it can optimize some values away. Invariant: all keys in getInputTupleVariableDependencies(...) MUST be output tuple variables, i.e., appear in this.child.getOutputTupleVariableNames()

Specified by:

getInputTupleVariableDependencies in class TupleRuntimePlan

Parameters:

parentProjection - the projection needed by the parent clause.

Returns:

the projection needed by this clause.

tryNativeQuery

public static FlworDataFrame tryNativeQuery(org.apache.spark.sql.Dataset<org.apache.spark.sql.Row> dataFrame,
 List<OrderByClauseAnnotatedChildIterator> expressionsWithIterator,
 List<FlworDataFrameColumn> allColumns,
 org.apache.spark.sql.types.StructType inputSchema,
 DynamicContext context)

Try to generate the native query for the order by clause and run it, if successful return the resulting dataframe, otherwise it returns null

Parameters:

dataFrame - input dataframe for the query

expressionsWithIterator - list of ordering iterators

allColumns - other columns required in following clauses

inputSchema - input schema of the dataframe

context - current dynamic context of the dataframe

Returns:

resulting dataframe of the order by clause if successful, null otherwise

containsClause

public boolean containsClause(FLWOR_CLAUSES kind)

Description copied from class: TupleRuntimePlan

Says whether or not the clause and its descendants include a clause of the specified kind.

Specified by:

containsClause in class TupleRuntimePlan

Parameters:

kind - the kind of clause to test for.

Returns:

true if there is one. False otherwise.

isSparkJobNeeded

public boolean isSparkJobNeeded()

Says whether this expression evaluation triggers a Spark job.

Specified by:

isSparkJobNeeded in class TupleRuntimePlan

Returns:

true if the execution triggers a Spark, false otherwise, null if undetermined yet.

generateNativeQuery

public NativeClauseContext generateNativeQuery(NativeClauseContext nativeClauseContext)

Description copied from class: TupleRuntimePlan

This function generate (if possible) a native spark-sql query that maps the inner working of the iterator

Specified by:

generateNativeQuery in interface NativeQueryRuntimePlan

Overrides:

generateNativeQuery in class TupleRuntimePlan

Parameters:

nativeClauseContext - context information to generate the native query

Returns:

a native clause context with the spark-sql native query to get an equivalent result of the iterator, or [NativeClauseContext.NoNativeQuery] if it is not possible