com.day.cq.search.eval

Class AbstractPredicateEvaluator

java.lang.Object

com.day.cq.search.eval.AbstractPredicateEvaluator

All Implemented Interfaces:

PredicateEvaluator

Direct Known Subclasses:

AssetRenditionFilterPredicateEvaluator, CollectionPredicateEvaluator, FulltextPredicateEvaluator, JcrPropertyPredicateEvaluator, NodenamePredicateEvaluator, PathPredicateEvaluator, PermissionPredicateEvaluator, PredicateGroupEvaluator, RangePropertyPredicateEvaluator, SimilarityPredicateEvaluator, SubAssetFilterPredicateEvaluator, TypePredicateEvaluator

public abstract class AbstractPredicateEvaluator
extends java.lang.Object
implements PredicateEvaluator

AbstractPredicateEvaluator is a base implementation for predicate evaluators. Predicate evaluator implementations are encouraged to extend from this abstract base class to minimize migration efforts when new changes are added to the PredicateEvaluator API.

This implementation basically does "nothing":

• returns no xpath expression
• does not filter
• (implementations have to implement at least one of the two above)
• provides no order by properties or order comparator
• provides no facet extractor
• automatically covers newer interface methods by implementing them using the old methods

Since:

5.2

Constructor Summary

Constructors

Constructor and Description
AbstractPredicateEvaluator()

Method Summary

Modifier and Type	Method and Description
boolean	canFilter(Predicate predicate, EvaluationContext context) Returns the same as the deprecated isFiltering(Predicate, EvaluationContext) method (ie.
boolean	canXpath(Predicate predicate, EvaluationContext context) Returns the inverted boolean value of the deprecated isFiltering(Predicate, EvaluationContext) method (ie.
FacetExtractor	getFacetExtractor(Predicate predicate, EvaluationContext context) Default implementation that always returns null, ie.
java.util.Comparator<Row>	getOrderByComparator(Predicate predicate, EvaluationContext context) Default implementation that always returns null.
java.lang.String[]	getOrderByProperties(Predicate predicate, EvaluationContext context) Default implementation that always returns null.
java.lang.String	getXPathExpression(Predicate predicate, EvaluationContext context) Default implementation that always returns null, ie.
boolean	includes(Predicate predicate, Row row, EvaluationContext context) Default implementation that always returns true, ie.
boolean	isFiltering(Predicate predicate, EvaluationContext context) Deprecated.

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractPredicateEvaluator

public AbstractPredicateEvaluator()

Method Detail

getXPathExpression

public java.lang.String getXPathExpression(Predicate predicate,
                                           EvaluationContext context)

Default implementation that always returns null, ie. adds nothing to the XPath query. Subclasses can choose whether they want to implement this method or use the includes(Predicate, Row, EvaluationContext) method for advanced filtering (or both).

Specified by:

getXPathExpression in interface PredicateEvaluator

Parameters:

predicate - predicate (for this evaluator type) which is evaluated

context - helper class which provides access to various elements of the query evaluation

Returns:

string containing an XPath predicateEvaluator expression

getOrderByProperties

public java.lang.String[] getOrderByProperties(Predicate predicate,
                                               EvaluationContext context)

Default implementation that always returns null.

Specified by:

getOrderByProperties in interface PredicateEvaluator

Parameters:

predicate - predicate (for this evaluator type) which is evaluated

context - helper class which provides access to various elements of the query evaluation

Returns:

one or multiple relative paths to JCR properties or null

canXpath

public boolean canXpath(Predicate predicate,
                        EvaluationContext context)

Returns the inverted boolean value of the deprecated isFiltering(Predicate, EvaluationContext) method (ie. if not overridden, true).

Specified by:

canXpath in interface PredicateEvaluator

Parameters:

predicate - predicate (for this evaluator type) which is evaluated

context - helper class which provides access to various elements of the query evaluation

Returns:

true if this evaluator can express itself via xpath, ie. PredicateEvaluator.getXPathExpression(Predicate, EvaluationContext)

canFilter

public boolean canFilter(Predicate predicate,
                         EvaluationContext context)

Returns the same as the deprecated isFiltering(Predicate, EvaluationContext) method (ie. if not overridden, false).

Specified by:

canFilter in interface PredicateEvaluator

Parameters:

predicate - predicate (for this evaluator type) which is evaluated

context - helper class which provides access to various elements of the query evaluation

Returns:

true if this evaluator can be express itself via filtering, ie. PredicateEvaluator.includes(Predicate, Row, EvaluationContext)

isFiltering

@Deprecated
public boolean isFiltering(Predicate predicate,
                                       EvaluationContext context)

Deprecated.

Default implementation that always returns false, because the includes(Predicate, Row, EvaluationContext) also always returns true in this implementation and hence does no filtering at all.

Specified by:

isFiltering in interface PredicateEvaluator

Parameters:

predicate - predicate (for this evaluator type) which is evaluated

context - helper class which provides access to various elements of the query evaluation

Returns:

true if this evaluator is filtering the result set for the given predicate

includes

public boolean includes(Predicate predicate,
                        Row row,
                        EvaluationContext context)

Default implementation that always returns true, ie. it does not "touch" the result set at all.

Specified by:

includes in interface PredicateEvaluator

Parameters:

predicate - predicate (for this evaluator type) which is evaluated

row - current row of the result set returned through the xpath query

context - helper class which provides access to various elements of the query evaluation

Returns:

true if this row should be part of the final result set, false if it should be dropped

getOrderByComparator

public java.util.Comparator<Row> getOrderByComparator(Predicate predicate,
                                                      EvaluationContext context)

Default implementation that always returns null.

Specified by:

getOrderByComparator in interface PredicateEvaluator

Parameters:

predicate - predicate (for this evaluator type) which is evaluated

context - helper class which provides access to various elements of the query evaluation

Returns:

a custom comparator for the given predicate or null

getFacetExtractor

public FacetExtractor getFacetExtractor(Predicate predicate,
                                        EvaluationContext context)

Default implementation that always returns null, ie. no facets will be extracted for the predicate.

Specified by:

getFacetExtractor in interface PredicateEvaluator

Parameters:

predicate - predicate (for this evaluator type) which is evaluated

context - helper class which provides access to various elements of the query evaluation

Returns:

a FacetExtractor that is used to create a Facet or null if no extractor shall be provided