com.foreach.across.modules.entity.query.EntityQueryUtils Maven / Gradle / Ivy
/*
* Copyright 2014 the original author or authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.foreach.across.modules.entity.query;
import com.foreach.across.modules.entity.registry.EntityAssociation;
import com.foreach.across.modules.entity.registry.properties.EntityPropertyDescriptor;
import lombok.NonNull;
import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.StringUtils;
import org.springframework.core.convert.TypeDescriptor;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.Function;
import java.util.stream.Stream;
/**
* @author Steven Gentens
* @since 2.2.0
*/
public abstract class EntityQueryUtils
{
private EntityQueryUtils() {
}
/**
* Appends an optional predicate to an existing query using an AND operand.
* If the predicate is not an {@link EntityQueryExpression} then it will be parsed as an EQL statement.
*
* @param existing query to append to
* @param predicate to append
* @return new query instance
*/
public static EntityQuery and( EntityQuery existing, Object predicate ) {
return appendToQuery( existing, EntityQueryOps.AND, predicate );
}
/**
* Appends an optional predicate to an existing query using an OR operand.
* If the predicate is not an {@link EntityQueryExpression} then it will be parsed as an EQL statement.
*
* @param existing query to append to
* @param predicate to append
* @return new query instance
*/
public static EntityQuery or( EntityQuery existing, Object predicate ) {
return appendToQuery( existing, EntityQueryOps.OR, predicate );
}
/**
* Appends an optional predicate to an existing query using the specified operand.
* If the predicate is not an {@link EntityQueryExpression} then it will be parsed as an EQL statement.
*
* @param existing query to append to
* @param operand operand to use
* @param predicate to append
* @return new query instance
*/
public static EntityQuery appendToQuery( EntityQuery existing, EntityQueryOps operand, Object predicate ) {
if ( predicate != null ) {
if ( predicate instanceof String ) {
return EntityQuery.create( operand, existing, EntityQuery.parse( (String) predicate ) );
}
if ( predicate instanceof EntityQueryExpression ) {
return EntityQuery.create( operand, existing, (EntityQueryExpression) predicate );
}
return EntityQuery.create( operand, existing, EntityQuery.parse( predicate.toString() ) );
}
return existing;
}
/**
* Perform simple condition translation on an {@link EntityQuery}, for example to remove conditions.
* For more complex translation scenarios, see the {@link EntityQueryTranslator} implementations.
*
* If no properties are specified all conditions will be translated. Else only conditions for the specified
* properties will be passed to the translator.
*
* @param query to translate
* @param translator function, may return {@code null} to remove a condition entirely
* @param properties optional a set of properties whose conditions should be translated, if empty all properties will be passed
* @return new query instance - never {@code null}
*/
public static EntityQuery translateConditions( @NonNull EntityQuery query,
@NonNull Function translator,
String... properties ) {
EntityQuery translated = new EntityQuery( query.getOperand() );
translated.setSort( query.getSort() );
query.getExpressions()
.stream()
.map(
expression -> {
if ( expression instanceof EntityQueryCondition ) {
EntityQueryCondition condition = (EntityQueryCondition) expression;
if ( properties.length == 0 || ArrayUtils.contains( properties, condition.getProperty() ) ) {
return translator.apply( condition );
}
return condition;
}
return translateConditions( (EntityQuery) expression, translator, properties );
}
)
.filter( Objects::nonNull )
.forEach( translated::add );
return translated;
}
/**
* Simplifies a query by removing useless levels (grouping of predicates).
*
* @param query to simplify
* @return simplified
*/
public static EntityQuery simplify( @NonNull EntityQuery query ) {
EntityQuery simplified = new EntityQuery();
simplified.setSort( query.getSort() );
AtomicReference finalOperand = new AtomicReference<>();
simplify( finalOperand, query ).forEach( simplified::add );
simplified.setOperand( finalOperand.get() != null ? finalOperand.get() : query.getOperand() );
return simplified;
}
private static Stream simplify( AtomicReference parentOperand, EntityQueryExpression expression ) {
if ( expression instanceof EntityQueryCondition ) {
return Stream.of( expression );
}
return simplify( parentOperand, (EntityQuery) expression );
}
private static Stream simplify( AtomicReference parentOperand, EntityQuery query ) {
List expressions = query.getExpressions();
if ( expressions.isEmpty() ) {
return Stream.empty();
}
if ( expressions.size() == 1 ) {
return simplify( parentOperand, expressions.get( 0 ) );
}
if ( parentOperand.get() == null ) {
parentOperand.set( query.getOperand() );
}
if ( query.getOperand() == parentOperand.get() ) {
return expressions.stream()
.flatMap( e -> simplify( parentOperand, e ) );
}
return Stream.of( query );
}
/**
* Create the predicate for fetching entities associated to a specific parent entity, mapped by an {@link EntityAssociation}.
*
* @param association entities to fetch
* @param parent entity they belong to
* @return query predicate
*/
public static EntityQueryCondition createAssociationPredicate( @NonNull EntityAssociation association, @NonNull Object parent ) {
EntityPropertyDescriptor sourceProperty = association.getSourceProperty();
EntityPropertyDescriptor targetProperty = association.getTargetProperty();
Object sourceValue = sourceProperty != null ? sourceProperty.getPropertyValue( parent ) : parent;
TypeDescriptor targetTypeDescriptor = targetProperty.getPropertyTypeDescriptor();
EntityQueryOps operand = targetTypeDescriptor.isCollection() || targetTypeDescriptor.isArray() ? EntityQueryOps.CONTAINS : EntityQueryOps.EQ;
return new EntityQueryCondition( targetProperty.getName(), operand, sourceValue );
}
/**
* Finds all {@link EntityQueryCondition} conditions inside an {@link EntityQuery}
*
* @param propertyName the name of the property in the expression
* @return all {@link EntityQueryCondition} that match the propertyName
*/
public static List findConditionsForProperty( @NonNull EntityQuery entityQuery, @NonNull String propertyName ) {
return findConditionsForProperty( entityQuery, propertyName, new ArrayList<>() );
}
private static List findConditionsForProperty( @NonNull EntityQuery entityQuery,
@NonNull String propertyName,
@NonNull List matches ) {
for ( EntityQueryExpression expression : entityQuery.getExpressions() ) {
if ( expression instanceof EntityQuery ) {
findConditionsForProperty( (EntityQuery) expression, propertyName, matches );
}
else {
EntityQueryCondition entityQueryCondition = (EntityQueryCondition) expression;
if ( StringUtils.equals( propertyName, entityQueryCondition.getProperty() ) ) {
matches.add( entityQueryCondition );
}
}
}
return matches;
}
}
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