org.jpc.query

Class Query

java.lang.Object

org.jpc.query.Cursor<Solution>

org.jpc.query.Query

All Implemented Interfaces:

AutoCloseable, Iterator<Solution>

Direct Known Subclasses:

PrologQuery, QueryAdapter

public abstract class Query
extends Cursor<Solution>

Disclaimer: The following comment was adapted from the JPL library: This class represents a cursor of query solutions. A query solution is an implementation of java.util.Map, which represents a set of bindings from the names of query variables to terms within the solution.

For example, if a Query has an occurrence of a Variable, say, named "X", one can obtain the Term bound to "X" in the solution by looking up "X" in the Map.

 Variable x = new Variable("X");
 Query q = // obtain Query reference (with x in the Term array)
 while (q.hasNext()) {
     Solution solution = q.next();
     // make t the Term bound to "X" in the solution
     Term t = solution.get("X");
     // ...
 }

Author:

sergioc

Constructor Summary

Constructors

Constructor and Description
Query()

Method Summary

Modifier and Type	Method and Description
com.google.common.collect.ListMultimap<String,Term>	allSolutionsMultimap()
protected Term	asTerm(String termString)
protected List<Solution>	basicAllSolutions() The default implementation for obtaining all the solutions consists on just making use of the existing next() method However, children could override this in case many calls to next() are more expensive that obtaining all the results of the query at once (e.g., a findall/3 query in Prolog)
Solution	cachedNext()
protected void	errorCheck(Solution solution)
protected Term	getAllSolutionsBindingsTerm() Answers a list term with the form [f(Name,Term), ...] Where f is an arbitrary functor id, Name is the id of a variable present in the original goal and Term the value bound to such variable.
protected abstract Term	getDefaultSelectedTerm() The default selected term when select* methods are called without specifying a select term By default, a PrologEngineQuery uses its goal.
abstract Term	getGoal()
abstract Jpc	getJpcContext()
abstract PrologEngine	getPrologEngine()
abstract boolean	isErrorHandledQuery()
Cursor<Term>	select()
Cursor<Term>	select(String selector)
Cursor<Term>	select(Term selector) Selects a cursor of terms.
<O> Cursor<O>	selectObject()
<O> Cursor<O>	selectObject(String selector)
<O> Cursor<O>	selectObject(String selector, Type targetType)
<O> Cursor<O>	selectObject(Term selector)
<O> Cursor<O>	selectObject(Term selector, Type targetType)
<O> Cursor<O>	selectObject(Type targetType)
protected boolean	shouldVerifySolution()

Methods inherited from class org.jpc.query.Cursor

abort, adapt, allSolutions, basicAbort, basicClose, basicNext, basicOneSolutionOrThrow, basicSolutionsRange, close, filter, finalize, getState, hasNext, hasSolution, isAbortable, isExhausted, isOpen, isReady, iterativeAllSolutions, next, nonSynchronizedClose, nSolutions, numberOfSolutions, oneSolution, oneSolutionOrThrow, remove, setState, solutionsRange

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Iterator

forEachRemaining

Constructor Detail

Query

public Query()

Method Detail

getPrologEngine

public abstract PrologEngine getPrologEngine()

getGoal

public abstract Term getGoal()

getJpcContext

public abstract Jpc getJpcContext()

isErrorHandledQuery

public abstract boolean isErrorHandledQuery()

shouldVerifySolution

protected boolean shouldVerifySolution()

errorCheck

protected void errorCheck(Solution solution)

cachedNext

public Solution cachedNext()

Overrides:

cachedNext in class Cursor<Solution>

basicAllSolutions

protected List<Solution> basicAllSolutions()

Description copied from class: Cursor

The default implementation for obtaining all the solutions consists on just making use of the existing next() method However, children could override this in case many calls to next() are more expensive that obtaining all the results of the query at once (e.g., a findall/3 query in Prolog)

Overrides:

basicAllSolutions in class Cursor<Solution>

Returns:

a list with all solutions.

getAllSolutionsBindingsTerm

protected Term getAllSolutionsBindingsTerm()

Answers a list term with the form [f(Name,Term), ...] Where f is an arbitrary functor id, Name is the id of a variable present in the original goal and Term the value bound to such variable.

Returns:

a list term where each entry in the list binds a variable id to a term

allSolutionsMultimap

public com.google.common.collect.ListMultimap<String,Term> allSolutionsMultimap()

getDefaultSelectedTerm

protected abstract Term getDefaultSelectedTerm()

The default selected term when select* methods are called without specifying a select term By default, a PrologEngineQuery uses its goal. QueryAdapter queries use their adapted default selected term. Other QueryAdapter classes may find useful to override this method. For example, ExceptionHandledQuery overrides this method so it is the first argument in the catch block of the original goal. Logtalk queries overrides this so the default selected term is the Logtalk method and parameters (excluding the id of the Logtalk object and the :: operator)

Returns:

asTerm

protected Term asTerm(String termString)

select

public Cursor<Term> select(String selector)

select

public Cursor<Term> select()

select

public Cursor<Term> select(Term selector)

Selects a cursor of terms. Each row in the cursor corresponds to a different binding of the term free variables according to a given solution

Parameters:

selector - a term with free variables

Returns:

selectObject

public <O> Cursor<O> selectObject()

selectObject

public <O> Cursor<O> selectObject(Type targetType)

selectObject

public <O> Cursor<O> selectObject(String selector)

selectObject

public <O> Cursor<O> selectObject(String selector,
                                  Type targetType)

selectObject

public <O> Cursor<O> selectObject(Term selector)

selectObject

public <O> Cursor<O> selectObject(Term selector,
                                  Type targetType)