Class QueryStatement

java.lang.Object

org.projog.api.QueryStatement

public final class QueryStatement
extends Object

Represents a query.

single use, not multi-threaded

See Also:

• Projog.createStatement(String)
• Projog.createPlan(String)

Method Summary

Modifier and Type	Method	Description
void	executeOnce()	Evaluate once the query represented by this statement.
QueryResult	executeQuery()	Returns a new QueryResult for the query represented by this object.
List<String>	findAllAsAtomName()	Find all solutions generated by the query and return String representations of the atoms the single query variable was unified with.
List<Double>	findAllAsDouble()	Find all solutions generated by the query and return the double values the single query variable was unified with.
List<Long>	findAllAsLong()	Find all solutions generated by the query and return the long values the single query variable was unified with.
List<Term>	findAllAsTerm()	Find all solutions generated by the query and return the Term values the single query variable was unified with.
String	findFirstAsAtomName()	Execute the query once and return a String representation of the atom the single query variable was unified with.
double	findFirstAsDouble()	Execute the query once and return a double representation of the term the single query variable was unified with.
long	findFirstAsLong()	Execute the query once and return a long representation of the term the single query variable was unified with.
Optional<String>	findFirstAsOptionalAtomName()	Attempt to execute the query once and return a String representation of the atom the single query variable was unified with.
Optional<Double>	findFirstAsOptionalDouble()	Attempt to execute the query once and return a Double representation of the term the single query variable was unified with.
Optional<Long>	findFirstAsOptionalLong()	Attempt to execute the query once and return a Long representation of the term the single query variable was unified with.
Optional<Term>	findFirstAsOptionalTerm()	Attempt to execute the query once and return a Term representation of the term the single query variable was unified with.
Term	findFirstAsTerm()	Execute the query once and return the Term the single query variable was unified with.
void	setAtomName(String variableId, String atomName)	Attempts to unify the specified String value as an Atom to the variable with the specified id.
void	setDouble(String variableId, double value)	Attempts to unify the specified double as a DecimalFraction to the variable with the specified id.
void	setListOfAtomNames(String variableId, String... atomNames)	Attempts to unify the specified String values as a Prolog list of atoms to the variable with the specified id.
void	setListOfAtomNames(String variableId, List<String> atomNames)	Attempts to unify the specified String values as a Prolog list of atoms to the variable with the specified id.
void	setListOfDoubles(String variableId, double... doubles)	Attempts to unify the specified double values as a Prolog list to the variable with the specified id.
void	setListOfDoubles(String variableId, List<Double> doubles)	Attempts to unify the specified Double values as a Prolog list to the variable with the specified id.
void	setListOfLongs(String variableId, long... longs)	Attempts to unify the specified long values as a Prolog list to the variable with the specified id.
void	setListOfLongs(String variableId, List<Long> longs)	Attempts to unify the specified Long values as a Prolog list to the variable with the specified id.
void	setListOfTerms(String variableId, List<? extends Term> terms)	Attempts to unify the specified Term values as a Prolog list to the variable with the specified id.
void	setListOfTerms(String variableId, Term... terms)	Attempts to unify the specified Term values as a Prolog list to the variable with the specified id.
void	setLong(String variableId, long value)	Attempts to unify the specified long as a IntegerNumber to the variable with the specified id.
void	setTerm(String variableId, Term term)	Attempts to unify the specified term to the variable with the specified id.

Methods inherited from class Object

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

Method Details

setTerm

public void setTerm(String variableId,
 Term term)

Attempts to unify the specified term to the variable with the specified id.

Parameters:

variableId - the id of the variable

term - the term to unify to the variable

Throws:

ProjogException - if no variable with the specified id exists in the query this object represents, or the given term cannot be unified with the variable

See Also:

• setAtomName(String, String)
• setDouble(String, double)
• setLong(String, long)
• setListOfAtomNames(String, List)
• setListOfAtomNames(String, String...)
• setListOfDoubles(String, List)
• setListOfDoubles(String, double...)
• setListOfLongs(String, List)
• setListOfLongs(String, long...)
• setListOfTerms(String, List)
• setListOfTerms(String, Term...)

setAtomName

public void setAtomName(String variableId,
 String atomName)

Attempts to unify the specified String value as an Atom to the variable with the specified id.

Parameters:

variableId - the id of the variable

atomName - the value to use as the name of the Atom that the variable will be unified with

Throws:

ProjogException - if no variable with the specified id exists in the query this object represents, or the given term cannot be unified with the variable

See Also:

• setTerm(String, Term)

setDouble

public void setDouble(String variableId,
 double value)

Attempts to unify the specified double as a DecimalFraction to the variable with the specified id.

Parameters:

variableId - the id of the variable

value - the value to use as the name of the DecimalFraction that the variable will be unified with

Throws:

ProjogException - if no variable with the specified id exists in the query this object represents, or the given term cannot be unified with the variable

See Also:

• setTerm(String, Term)

setLong

public void setLong(String variableId,
 long value)

Attempts to unify the specified long as a IntegerNumber to the variable with the specified id.

Parameters:

variableId - the id of the variable

value - the value to use as the name of the IntegerNumber that the variable will be unified with

Throws:

ProjogException - if no variable with the specified id exists in the query this object represents, or the given term cannot be unified with the variable

See Also:

• setTerm(String, Term)

setListOfAtomNames

public void setListOfAtomNames(String variableId,
 String... atomNames)

Attempts to unify the specified String values as a Prolog list of atoms to the variable with the specified id.

Parameters:

variableId - the id of the variable

atomNames - the values to use as atom elements in the list that the variable will be unified with

Throws:

ProjogException - if no variable with the specified id exists in the query this object represents, or the given term cannot be unified with the variable

See Also:

• setTerm(String, Term)

setListOfAtomNames

public void setListOfAtomNames(String variableId,
 List<String> atomNames)

Attempts to unify the specified String values as a Prolog list of atoms to the variable with the specified id.

Parameters:

variableId - the id of the variable

atomNames - the values to use as atom elements in the list that the variable will be unified with

Throws:

ProjogException - if no variable with the specified id exists in the query this object represents, or the given term cannot be unified with the variable

See Also:

• setTerm(String, Term)

setListOfDoubles

public void setListOfDoubles(String variableId,
 double... doubles)

Attempts to unify the specified double values as a Prolog list to the variable with the specified id.

Parameters:

variableId - the id of the variable

doubles - the values to use as elements in the list that the variable will be unified with

Throws:

ProjogException - if no variable with the specified id exists in the query this object represents, or the given term cannot be unified with the variable

See Also:

• setTerm(String, Term)

setListOfDoubles

public void setListOfDoubles(String variableId,
 List<Double> doubles)

Attempts to unify the specified Double values as a Prolog list to the variable with the specified id.

Parameters:

variableId - the id of the variable

doubles - the values to use as elements in the list that the variable will be unified with

Throws:

ProjogException - if no variable with the specified id exists in the query this object represents, or the given term cannot be unified with the variable

See Also:

• setTerm(String, Term)

setListOfLongs

public void setListOfLongs(String variableId,
 long... longs)

Attempts to unify the specified long values as a Prolog list to the variable with the specified id.

Parameters:

variableId - the id of the variable

longs - the values to use as elements in the list that the variable will be unified with

Throws:

ProjogException - if no variable with the specified id exists in the query this object represents, or the given term cannot be unified with the variable

See Also:

• setTerm(String, Term)

setListOfLongs

public void setListOfLongs(String variableId,
 List<Long> longs)

Attempts to unify the specified Long values as a Prolog list to the variable with the specified id.

Parameters:

variableId - the id of the variable

longs - the values to use as elements in the list that the variable will be unified with

Throws:

ProjogException - if no variable with the specified id exists in the query this object represents, or the given term cannot be unified with the variable

See Also:

• setTerm(String, Term)

setListOfTerms

public void setListOfTerms(String variableId,
 Term... terms)

Attempts to unify the specified Term values as a Prolog list to the variable with the specified id.

Parameters:

variableId - the id of the variable

terms - the values to use as elements in the list that the variable will be unified with

Throws:

ProjogException - if no variable with the specified id exists in the query this object represents, or the given term cannot be unified with the variable

See Also:

• setTerm(String, Term)

setListOfTerms

public void setListOfTerms(String variableId,
 List<? extends Term> terms)

Attempts to unify the specified Term values as a Prolog list to the variable with the specified id.

Parameters:

variableId - the id of the variable

terms - the values to use as elements in the list that the variable will be unified with

Throws:

ProjogException - if no variable with the specified id exists in the query this object represents, or the given term cannot be unified with the variable

See Also:

• setTerm(String, Term)

executeQuery

public QueryResult executeQuery()

Returns a new QueryResult for the query represented by this object.

Note that the query is not evaluated as part of a call to executeQuery(). It is on the first call of QueryResult.next() that the first attempt to evaluate the query will be made.

Returns:

a new QueryResult for the query represented by this object.

executeOnce

public void executeOnce()

Evaluate once the query represented by this statement.

The query will only be evaluated once, even if further solutions could of been found on backtracking.

Throws:

ProjogException - if no solution can be found

See Also:

• executeQuery()

findFirstAsAtomName

public String findFirstAsAtomName()

Execute the query once and return a String representation of the atom the single query variable was unified with.

Returns:

the name of the atom the query variable has been unified with as a result of executing the query

Throws:

ProjogException - if the query could not be evaluated successfully

ProjogException - of there is not exactly one named variable in the query this statement represents

findFirstAsDouble

public double findFirstAsDouble()

Execute the query once and return a double representation of the term the single query variable was unified with.

Returns:

the value the query variable has been unified with as a result of executing the query

Throws:

ProjogException - if the query could not be evaluated successfully

ProjogException - of there is not exactly one named variable in the query this statement represents

findFirstAsLong

public long findFirstAsLong()

Execute the query once and return a long representation of the term the single query variable was unified with.

Returns:

the value query variable has been unified with as a result of executing the query

Throws:

ProjogException - if the query could not be evaluated successfully

ProjogException - of there is not exactly one named variable in the query this statement represents

findFirstAsTerm

public Term findFirstAsTerm()

Execute the query once and return the Term the single query variable was unified with.

Returns:

the value query variable has been unified with as a result of executing the query

Throws:

ProjogException - if the query could not be evaluated successfully

ProjogException - of there is not exactly one named variable in the query this statement represents

findFirstAsOptionalAtomName

public Optional<String> findFirstAsOptionalAtomName()

Attempt to execute the query once and return a String representation of the atom the single query variable was unified with.

Returns:

the name of the atom the query variable has been unified with, or an empty optional if the query was not successfully evaluated

Throws:

ProjogException - if the query could not be evaluated successfully

ProjogException - of there is not exactly one named variable in the query this statement represents

findFirstAsOptionalDouble

public Optional<Double> findFirstAsOptionalDouble()

Attempt to execute the query once and return a Double representation of the term the single query variable was unified with.

Returns:

the value the query variable has been unified with, or an empty optional if the query was not successfully evaluated

Throws:

ProjogException - if the query could not be evaluated successfully

ProjogException - of there is not exactly one named variable in the query this statement represents

findFirstAsOptionalLong

public Optional<Long> findFirstAsOptionalLong()

Attempt to execute the query once and return a Long representation of the term the single query variable was unified with.

Returns:

the value the query variable has been unified with, or an empty optional if the query was not successfully evaluated

Throws:

ProjogException - if the query could not be evaluated successfully

ProjogException - of there is not exactly one named variable in the query this statement represents

findFirstAsOptionalTerm

public Optional<Term> findFirstAsOptionalTerm()

Attempt to execute the query once and return a Term representation of the term the single query variable was unified with.

Returns:

the value the query variable has been unified with, or an empty optional if the query was not successfully evaluated

Throws:

ProjogException - if the query could not be evaluated successfully

ProjogException - of there is not exactly one named variable in the query this statement represents

findAllAsAtomName

public List<String> findAllAsAtomName()

Find all solutions generated by the query and return String representations of the atoms the single query variable was unified with.

Returns:

list of atom names the query variable was been unified with as a result of executing the query until no more solutions were found

Throws:

ProjogException - if the query could not be evaluated successfully

ProjogException - of there is not exactly one named variable in the query this statement represents

findAllAsDouble

public List<Double> findAllAsDouble()

Find all solutions generated by the query and return the double values the single query variable was unified with.

Returns:

list of values the query variable was been unified with as a result of executing the query until no more solutions were found

Throws:

ProjogException - if the query could not be evaluated successfully

ProjogException - of there is not exactly one named variable in the query this statement represents

findAllAsLong

public List<Long> findAllAsLong()

Find all solutions generated by the query and return the long values the single query variable was unified with.

Returns:

list of values the query variable was been unified with as a result of executing the query until no more solutions were found

Throws:

ProjogException - if the query could not be evaluated successfully

ProjogException - of there is not exactly one named variable in the query this statement represents

findAllAsTerm

public List<Term> findAllAsTerm()

Find all solutions generated by the query and return the Term values the single query variable was unified with.

Returns:

list of values the query variable was been unified with as a result of executing the query until no more solutions were found

Throws:

ProjogException - if the query could not be evaluated successfully

ProjogException - of there is not exactly one named variable in the query this statement represents