ARQ (Apache Jena ARQ)

java.lang.Object
- com.hp.hpl.jena.query.ARQ

```
public class ARQ
extends Object
```
ARQ - miscellaneous settings

Field Summary

Fields
Modifier and Type	Field and Description
`static boolean`	`allowDuplicateSelectColumns` Indicate whether duplicate select and groupby variables are allowed.
`static String`	`arqIRI` IRI for ARQ
`static String`	`arqParamNS` Root of ARQ-defined parameter names
`static String`	`arqSymbolPrefix` Prefix for ARQ-defined parameter names
`static String`	`BUILD_DATE` The date and time at which this release was built
`static Symbol`	`constantBNodeLabels` Controls bNode labels as <_:...> or not - that is a pseudo URIs.
`static Symbol`	`enableExecutionTimeLogging` Enable logging of execution timing.
`static Symbol`	`enablePropertyFunctions` Enable built-in property functions - also called "magic properties".
`static Symbol`	`enableRomanNumerals` Context symbol controlling Roman Numerals in Filters.
`static Symbol`	`extensionValueTypes` Expression evaluation without extension types (e.g.
`static Symbol`	`generateToList` Generate the ToList operation in the algebra (as ARQ is stream based, ToList is a non-op).
`static Symbol`	`hideNonDistiguishedVariables` Context key to control hiding non-distinuished variables
`static Symbol`	`inputGraphBNodeLabels` If true, XML result sets will use the bNode label in the result set itself.
`static Symbol`	`javaRegex` Symbol to name java.util.regex regular expression engine
`static String`	`logExecName` Name of the execution logger
`static String`	`logHttpRequestName` Name of the logger for remote HTTP requests
`static String`	`logInfoName` Name of the information logger
`static String`	`NAME` The product name
`static Symbol`	`optDistinctToReduced` Context key controlling whether a DISTINCT-ORDER BY query is done by replacing the distinct with a reduced.
`static Symbol`	`optFilterConjunction` Context key controlling whether the standard optimizer applies optimizations to conjunctions (&&) in filters.
`static Symbol`	`optFilterDisjunction` Context key controlling whether the standard optimizer applies optimizations to disjunctions (\|\|) in filters.
`static Symbol`	`optFilterEquality` Context key controlling whether the standard optimizer applies optimizations to equalities in FILTERs.
`static Symbol`	`optFilterExpandOneOf` Context key controlling whether the standard optimizer applies optimizations to IN and NOT IN.
`static Symbol`	`optFilterPlacement` Context key controlling whether the main query engine moves filters to the "best" place.
`static Symbol`	`optimization` Context key controlling whether the main query engine applies the default optimization transformations.
`static Symbol`	`optOrderByDistinctApplication` Context key controlling whether a DISTINCT-ORDER BY query is done by applying the ORDER BY after the DISTINCT when default SPARQL semantics usually mean ORDER BY applies before DISTINCT.
`static Symbol`	`optTermStrings` Context key for a declaration that xsd:strings and simple literals are different in the storage.
`static Symbol`	`optTopNSorting` Context key controlling whether an ORDER BY-LIMIT query is done avoiding total sort using an heap.
`static Symbol`	`outputGraphBNodeLabels` If true, XML result sets written will contain the graph bNode label See also inputGraphBNodeLabels
`static String`	`PATH` The root package name for ARQ
`static Symbol`	`propertyFunctions` Context key controlling whether the main query engine
`static Symbol`	`queryTimeout` Set timeout.
`static Symbol`	`regexImpl` Determine which regular expression system to use.
`static Symbol`	`serviceParams` Use this Symbol to allow passing additional query parameters to a SERVICE call.
`static Symbol`	`spillToDiskThreshold` A Long value that specifies the number of bindings (or triples for CONSTRUCT queries) to be stored in memory by sort operations or hash tables before switching to temporary disk files.
`static Symbol`	`stageGenerator` Context key for StageBuilder used in BGP compilation
`static Symbol`	`strictGraph` Use a simple (and non-scalable) graph implementation that does no value testing.
`static Symbol`	`strictSPARQL` Stick exactly to the spec.
`static Symbol`	`symLogExec` Symbol to enable logging of execution.
`static Symbol`	`useSAX` Use the SAX parser for XML result sets.
`static String`	`VERSION` The full name of the current ARQ version
`static Symbol`	`xercesRegex` Symbol to name the Xerces-J regular expression engine

Constructor Summary

Constructors
Constructor and Description

ARQ()

Constructors
Constructor and Description
`ARQ()`

Method Summary

Methods
Modifier and Type	Method and Description
`static void`	`enableBlankNodeResultLabels()` Turn on processing of blank node labels in queries
`static void`	`enableBlankNodeResultLabels(boolean val)` Turn on/off processing of blank node labels in queries
`static void`	`enableOptimizer(boolean state)` Globally switch the default optimizer on and off : Note that storage subsystems may also be applying separately controlled optimizations.
`static void`	`enableOptimizer(Context context, boolean state)` Switch the default optimizer on and off for a specific Context.
`static Context`	`getContext()`
`static org.slf4j.Logger`	`getExecLogger()` The execution logger
`static Explain.InfoLevel`	`getExecutionLogging()` Get the currentl global execution logging setting
`static org.slf4j.Logger`	`getHttpRequestLogger()` The HTTP Request logger
`static org.slf4j.Logger`	`getInfoLogger()` The information logger
`static void`	`init()` Ensure things have started - applications do not need call this.
`static boolean`	`isFalse(Symbol symbol)`
`static boolean`	`isFalseOrUndef(Symbol symbol)`
`static boolean`	`isStrictMode()`
`static boolean`	`isTrue(Symbol symbol)`
`static boolean`	`isTrueOrUndef(Symbol symbol)`
`static void`	`set(Symbol symbol, boolean value)`
`static void`	`setExecutionLogging(Explain.InfoLevel infoLevel)` Set execution logging - logging is to logger "com.hp.hpl.jena.arq.exec" at level INFO.
`static void`	`setFalse(Symbol symbol)`
`static void`	`setNormalMode()`
`static void`	`setNormalMode(Context context)`
`static void`	`setStrictMode()` Set global strict mode
`static void`	`setStrictMode(Context context)` Set strict mode for a given Context
`static void`	`setTrue(Symbol symbol)`
`static void`	`unset(Symbol symbol)`

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - logExecName
```
public static final String logExecName
```
    Name of the execution logger
    
    See Also:
    Constant Field Values
  - logInfoName
```
public static final String logInfoName
```
    Name of the information logger
    
    See Also:
    Constant Field Values
  - logHttpRequestName
```
public static final String logHttpRequestName
```
    Name of the logger for remote HTTP requests
    
    See Also:
    Constant Field Values
  - symLogExec
```
public static final Symbol symLogExec
```
    Symbol to enable logging of execution. Must also set log4j, or other logging system, for logger "com.hp.hpl.jena.sparql.exec" e.g. log4j.properties -- log4j.logger.com.hp.hpl.jena.sparql.exec=INFO See the ARQ Logging Documentation.
  - arqIRI
```
public static final String arqIRI
```
    IRI for ARQ
    
    See Also:
    Constant Field Values
  - arqParamNS
```
public static final String arqParamNS
```
    Root of ARQ-defined parameter names
    
    See Also:
    Constant Field Values
  - arqSymbolPrefix
```
public static final String arqSymbolPrefix
```
    Prefix for ARQ-defined parameter names
    
    See Also:
    Constant Field Values
  - strictSPARQL
```
public static final Symbol strictSPARQL
```
    Stick exactly to the spec.
  - constantBNodeLabels
```
public static final Symbol constantBNodeLabels
```
    Controls bNode labels as <_:...> or not - that is a pseudo URIs. This does not affect [] or _:a bNodes as variables in queries.
  - enablePropertyFunctions
```
public static final Symbol enablePropertyFunctions
```
    Enable built-in property functions - also called "magic properties". These are properties in triple patterns that need calculation, not matching. See ARQ documentation for more details. rdfs:member and http://jena.hpl.hp.com/ARQ/list#member are provided.
  - enableExecutionTimeLogging
```
public static final Symbol enableExecutionTimeLogging
```
    Enable logging of execution timing.
  - outputGraphBNodeLabels
```
public static final Symbol outputGraphBNodeLabels
```
    If true, XML result sets written will contain the graph bNode label See also inputGraphBNodeLabels
  - inputGraphBNodeLabels
```
public static final Symbol inputGraphBNodeLabels
```
    If true, XML result sets will use the bNode label in the result set itself. See also outputGraphBNodeLabels
  - queryTimeout
```
public static final Symbol queryTimeout
```
    Set timeout. The value of this symbol gives thevalue of the timeout in milliseconds
    - A Number; the long value is used
    - A string, e.g. "1000", parsed as a number
    - A string, as two numbers separated by a comma, e.g. "500,10000" parsed as two numbers
    See Also:
    QueryExecution.setTimeout(long), QueryExecution.setTimeout(long,long)
  - enableRomanNumerals
```
public static final Symbol enableRomanNumerals
```
    Context symbol controlling Roman Numerals in Filters.
  - stageGenerator
```
public static final Symbol stageGenerator
```
    Context key for StageBuilder used in BGP compilation
  - hideNonDistiguishedVariables
```
public static final Symbol hideNonDistiguishedVariables
```
    Context key to control hiding non-distinuished variables
  - useSAX
```
public static final Symbol useSAX
```
    Use the SAX parser for XML result sets. The default is to use StAX for full streaming of XML results. The SAX parser takes a copy of the result set before giving the ResultSet to the calling application.
  - allowDuplicateSelectColumns
```
public static final boolean allowDuplicateSelectColumns
```
    Indicate whether duplicate select and groupby variables are allowed. If false, duplicates are silently supressed; it's not an error.
    
    See Also:
    Constant Field Values
  - regexImpl
```
public static final Symbol regexImpl
```
    Determine which regular expression system to use. The value of this context entry should be a string or symbol of one of the following: javaRegex : use java.util.regex (support features outside the strict SPARQL regex language) xercesRegex : use the internal XPath regex engine (more compliant)
  - javaRegex
```
public static final Symbol javaRegex
```
    Symbol to name java.util.regex regular expression engine
  - xercesRegex
```
public static final Symbol xercesRegex
```
    Symbol to name the Xerces-J regular expression engine
  - serviceParams
```
public static final Symbol serviceParams
```
    Use this Symbol to allow passing additional query parameters to a SERVICE call. Parameters need to be grouped by SERVICE , a Map>> is assumed. The key of the first map is the SERVICE IRI, the value is a Map which maps the name of a query string parameters to its values.
    
    See Also:
    Service
  - spillToDiskThreshold
```
public static final Symbol spillToDiskThreshold
```
    A Long value that specifies the number of bindings (or triples for CONSTRUCT queries) to be stored in memory by sort operations or hash tables before switching to temporary disk files. The value defaults to -1, which will always keep the bindings in memory and never write to temporary files. The amount of memory used will vary based on the size of the bindings. If you are retrieving large literal strings, then you may need to lower the value.
    Note that for a complex query, several sort or hash operations might be running in parallel; each one will be allowed to retain as many bindings in memory as this value specifies before it starts putting data in temporary files. Also, several running sessions could be doing such operations concurrently. Therefore, the total number of bindings held in memory could be many times this value; it is necessary to keep this fact in mind when choosing the value.
    Operations currently affected by this symbol:
    ORDER BY, SPARQL Update, CONSTRUCT (optionally)
    TODO: Give a reasonable suggested value here. 10,000?
    
    See Also:
    JENA-119
  - optimization
```
public static final Symbol optimization
```
    Context key controlling whether the main query engine applies the default optimization transformations.
  - optFilterPlacement
```
public static final Symbol optFilterPlacement
```
    Context key controlling whether the main query engine moves filters to the "best" place. Default is "true" - filter placement is done.
  - optTopNSorting
```
public static final Symbol optTopNSorting
```
    Context key controlling whether an ORDER BY-LIMIT query is done avoiding total sort using an heap. Default is "true" - total sort if avoided by default when ORDER BY is used with LIMIT.
  - optDistinctToReduced
```
public static final Symbol optDistinctToReduced
```
    Context key controlling whether a DISTINCT-ORDER BY query is done by replacing the distinct with a reduced. Default is "true" - the reduced operator does not need to keep a data structure with all previously seen bindings.
  - optOrderByDistinctApplication
```
public static final Symbol optOrderByDistinctApplication
```
    Context key controlling whether a DISTINCT-ORDER BY query is done by applying the ORDER BY after the DISTINCT when default SPARQL semantics usually mean ORDER BY applies before DISTINCT. This optimization applies only in a subset of cases unlike the more general optDistinctToReduced optimization.
    See TransformOrderByDistinctAppplication for more discussion on exactly when this may apply
  - optFilterEquality
```
public static final Symbol optFilterEquality
```
    Context key controlling whether the standard optimizer applies optimizations to equalities in FILTERs. This optimization is conservative - it does not take place if there is a potential risk of changing query semantics.
  - optTermStrings
```
public static final Symbol optTermStrings
```
    Context key for a declaration that xsd:strings and simple literals are different in the storage. They are the same value in a memory store. When in doubt, xsd:strings are assumed to be the same value as simple literals
  - optFilterConjunction
```
public static final Symbol optFilterConjunction
```
    Context key controlling whether the standard optimizer applies optimizations to conjunctions (&&) in filters.
  - optFilterExpandOneOf
```
public static final Symbol optFilterExpandOneOf
```
    Context key controlling whether the standard optimizer applies optimizations to IN and NOT IN.
  - optFilterDisjunction
```
public static final Symbol optFilterDisjunction
```
    Context key controlling whether the standard optimizer applies optimizations to disjunctions (||) in filters.
  - propertyFunctions
```
public static final Symbol propertyFunctions
```
    Context key controlling whether the main query engine
  - strictGraph
```
public static final Symbol strictGraph
```
    Use a simple (and non-scalable) graph implementation that does no value testing. Needed for DAWG tests where matching is exact and results compared by graph-equivalence.
  - extensionValueTypes
```
public static final Symbol extensionValueTypes
```
    Expression evaluation without extension types (e.g. xsd:date, language tags)
  - generateToList
```
public static final Symbol generateToList
```
    Generate the ToList operation in the algebra (as ARQ is stream based, ToList is a non-op). Default is not to do so. Strict mode will also enable this.
  - PATH
```
public static final String PATH
```
    The root package name for ARQ
    
    See Also:
    Constant Field Values
  - NAME
```
public static final String NAME
```
    The product name
    
    See Also:
    Constant Field Values
  - VERSION
```
public static final String VERSION
```
    The full name of the current ARQ version
  - BUILD_DATE
```
public static final String BUILD_DATE
```
    The date and time at which this release was built
- Constructor Detail
  - ARQ
```
public ARQ()
```
- Method Detail
  - getExecLogger
```
public static org.slf4j.Logger getExecLogger()
```
    The execution logger
  - getInfoLogger
```
public static org.slf4j.Logger getInfoLogger()
```
    The information logger
  - getHttpRequestLogger
```
public static org.slf4j.Logger getHttpRequestLogger()
```
    The HTTP Request logger
  - getExecutionLogging
```
public static Explain.InfoLevel getExecutionLogging()
```
    Get the currentl global execution logging setting
  - setExecutionLogging
```
public static void setExecutionLogging(Explain.InfoLevel infoLevel)
```
    Set execution logging - logging is to logger "com.hp.hpl.jena.arq.exec" at level INFO. An appropriate logging configuration is also required.
  - enableBlankNodeResultLabels
```
public static void enableBlankNodeResultLabels()
```
    Turn on processing of blank node labels in queries
  - enableBlankNodeResultLabels
```
public static void enableBlankNodeResultLabels(boolean val)
```
    Turn on/off processing of blank node labels in queries
  - enableOptimizer
```
public static void enableOptimizer(boolean state)
```
    Globally switch the default optimizer on and off : Note that storage subsystems may also be applying separately controlled optimizations.
  - enableOptimizer
```
public static void enableOptimizer(Context context,
                   boolean state)
```
    Switch the default optimizer on and off for a specific Context. Note that storage subsystems may also be applying separately controlled optimizations.
  - setStrictMode
```
public static void setStrictMode()
```
    Set global strict mode
  - setStrictMode
```
public static void setStrictMode(Context context)
```
    Set strict mode for a given Context
  - isStrictMode
```
public static boolean isStrictMode()
```
  - setNormalMode
```
public static void setNormalMode()
```
  - setNormalMode
```
public static void setNormalMode(Context context)
```
  - init
```
public static void init()
```
    Ensure things have started - applications do not need call this. The method is public so any part of ARQ can call it. Note the final static initializer call
  - getContext
```
public static Context getContext()
```
  - set
```
public static void set(Symbol symbol,
       boolean value)
```
  - setTrue
```
public static void setTrue(Symbol symbol)
```
  - setFalse
```
public static void setFalse(Symbol symbol)
```
  - unset
```
public static void unset(Symbol symbol)
```
  - isTrue
```
public static boolean isTrue(Symbol symbol)
```
  - isFalse
```
public static boolean isFalse(Symbol symbol)
```
  - isTrueOrUndef
```
public static boolean isTrueOrUndef(Symbol symbol)
```
  - isFalseOrUndef
```
public static boolean isFalseOrUndef(Symbol symbol)
```

Class ARQ

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

logExecName

logInfoName

logHttpRequestName

symLogExec

arqIRI

arqParamNS

arqSymbolPrefix

strictSPARQL

constantBNodeLabels

enablePropertyFunctions

enableExecutionTimeLogging

outputGraphBNodeLabels

inputGraphBNodeLabels

queryTimeout

enableRomanNumerals

stageGenerator

hideNonDistiguishedVariables

useSAX

allowDuplicateSelectColumns

regexImpl

javaRegex

xercesRegex

serviceParams

spillToDiskThreshold

optimization

optFilterPlacement

optTopNSorting

optDistinctToReduced

optOrderByDistinctApplication

optFilterEquality

optTermStrings

optFilterConjunction

optFilterExpandOneOf

optFilterDisjunction

propertyFunctions

strictGraph

extensionValueTypes

generateToList

PATH

NAME

VERSION

BUILD_DATE

Constructor Detail

ARQ

Method Detail

getExecLogger

getInfoLogger

getHttpRequestLogger

getExecutionLogging

setExecutionLogging

enableBlankNodeResultLabels

enableBlankNodeResultLabels

enableOptimizer

enableOptimizer

setStrictMode

setStrictMode

isStrictMode

setNormalMode

setNormalMode

init

getContext

set

setTrue

setFalse

unset

isTrue

isFalse

isTrueOrUndef

isFalseOrUndef