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GH-826 - Flatten result lists as late as possible.
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This removes the flattening of the lists inside the various rest model adapters and delegates this task to the rest model mapper. That way, individually structured lists of non-mappable types stay intact.

This fixes #821.
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@michael-simons
michael-simons committed Aug 26, 2020
1 parent f09c3d8 commit f4e9ef7
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Showing 4 changed files with 109 additions and 57 deletions.
31 changes: 4 additions & 27 deletions api/src/main/java/org/neo4j/ogm/result/adapter/RestModelAdapter.java
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Original file line number Diff line number Diff line change
Expand Up @@ -18,12 +18,13 @@
*/
package org.neo4j.ogm.result.adapter;

import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.function.Function;
import java.util.stream.Collectors;
import java.util.stream.StreamSupport;

import org.neo4j.ogm.response.model.NodeModel;
import org.neo4j.ogm.response.model.RelationshipModel;
Expand All @@ -43,12 +44,7 @@ public Map<String, Object> adapt(Map<String, Object> result) {
for (Map.Entry<String, Object> entry : result.entrySet()) {
Object value = entry.getValue();
if (value instanceof Collection) {
Collection<Object> adaptedValues = new ArrayList<>();
Collection<Object> values = (List) value;
for (Object element : values) {
handleAdaptedValue(adaptedValues, processData(element));
}
adaptedResults.put(entry.getKey(), adaptedValues);
adaptedResults.put(entry.getKey(), ((Collection) value).stream().map(this::processData).collect(Collectors.toList()));
} else {
adaptedResults.put(entry.getKey(), processData(value));
}
Expand All @@ -57,20 +53,6 @@ public Map<String, Object> adapt(Map<String, Object> result) {
return adaptedResults;
}

/**
* Not public API, for internal use only.
* @param adaptedValues already prepared values
* @param newValue new value to prepare
*/
public static void handleAdaptedValue(Collection<Object> adaptedValues, Object newValue) {

if (newValue instanceof Collection) {
adaptedValues.addAll((Collection<?>) newValue);
} else {
adaptedValues.add(newValue);
}
}

/**
* Not public API, for internal use only.
* @param element Element that maybe is a collection
Expand All @@ -80,12 +62,7 @@ public static void handleAdaptedValue(Collection<Object> adaptedValues, Object n
public static Object handlePossibleCollections(Object element, Function<Object, Object> mappingFunction) {

if (element instanceof Iterable) {
List<Object> adaptedValues = new ArrayList<>();
Iterable collection = (Iterable) element;
for (Object nestedElement : collection) {
handleAdaptedValue(adaptedValues, mappingFunction.apply(nestedElement));
}
return adaptedValues;
return StreamSupport.stream(((Iterable) element).spliterator(), false).map(mappingFunction).collect(Collectors.toList());
}
return element;
}
Expand Down
45 changes: 29 additions & 16 deletions core/src/main/java/org/neo4j/ogm/context/RestModelMapper.java
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Original file line number Diff line number Diff line change
Expand Up @@ -179,13 +179,23 @@ void handle(String alias, Object resultObject) {
} else if (resultObject instanceof List) {
// Mark that result object as list, as it needs to be reconstructed later
this.aliasesOfListResults.add(alias);
((List) resultObject).forEach(item -> this.addToGraphModel(alias, item));
this.recursivelyAddToGraphModel(alias, (List<Object>) resultObject);
} else {
// Just add the model as is to the graph model
this.addToGraphModel(alias, resultObject);
}
}

private void recursivelyAddToGraphModel(String alias, List<Object> current) {
for (Object o : current) {
if (o instanceof List) {
recursivelyAddToGraphModel(alias, (List<Object>) o);
} else {
addToGraphModel(alias, o);
}
}
}

/**
* Adds an individual result object to the nodes and relationship of the graph model being build
*
Expand Down Expand Up @@ -265,13 +275,15 @@ private static boolean canBeMapped(Object resultObject) {
Predicate<Object> isNodeModel = NodeModel.class::isInstance;
Predicate<Object> isRelationshipModel = RelationshipModel.class::isInstance;
Predicate<Object> isNodeOrRelationshipModel = isNodeModel.or(isRelationshipModel);
Predicate<Object> isListAndEachMemberCanBeMapped = o -> o instanceof List && ((List) o).stream()
.allMatch(isNodeOrRelationshipModel);

if (isNodeOrRelationshipModel.test(resultObject)) {
return true;
} else if (resultObject instanceof List) {
List listOfResultObjects = (List) resultObject;
return listOfResultObjects.size() > 0 && listOfResultObjects.stream()
.allMatch(isNodeOrRelationshipModel);
.allMatch(isNodeOrRelationshipModel.or(isListAndEachMemberCanBeMapped));
} else {
return false;
}
Expand All @@ -282,35 +294,36 @@ private static boolean canBeMapped(Object resultObject) {
* otherwise returns an {@link Object} array if result object is a list containing a mixed set of things,
* otherwise an array of the one elements class.
*
* @param resultObject The object to convert
* @param in The object to convert
* @return The original object or an array.
*/
private static Object convertToTargetContainer(Object resultObject) {
private static Object convertToTargetContainer(Object in) {

if (!(resultObject instanceof List)) {
return resultObject;
if (!(in instanceof List)) {
return in;
}

List entityList = (List) resultObject;
Class arrayClass = Void.class;
List hlp = new ArrayList();
for (Object element : ((List) in)) {
Object convertedElement = convertToTargetContainer(element);
hlp.add(convertedElement);

Class arrayClass = null;
for (Object element : entityList) {
Class clazz = element.getClass();
if (arrayClass == null) {
Class clazz = convertedElement.getClass();
if (arrayClass == Void.class) {
arrayClass = clazz;
} else if (arrayClass != clazz) {
arrayClass = null;
break;
}
}

Object array;
if (arrayClass == null) {
array = entityList.toArray();
array = hlp.toArray();
} else {
array = Array.newInstance(arrayClass, entityList.size());
for (int j = 0; j < entityList.size(); j++) {
Array.set(array, j, Utils.coerceTypes(arrayClass, entityList.get(j)));
array = Array.newInstance(arrayClass, hlp.size());
for (int i = 0; i < hlp.size(); i++) {
Array.set(array, i, Utils.coerceTypes(arrayClass, hlp.get(i)));
}
}
return array;
Expand Down
10 changes: 3 additions & 7 deletions http-driver/src/main/java/org/neo4j/ogm/drivers/http/response/RestModelAdapter.java
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Original file line number Diff line number Diff line change
Expand Up @@ -20,11 +20,11 @@

import static org.neo4j.ogm.result.adapter.RestModelAdapter.*;

import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

import org.neo4j.ogm.response.model.NodeModel;
import org.neo4j.ogm.response.model.RelationshipModel;
Expand All @@ -47,12 +47,8 @@ public Map<String, Object> adapt(Object[] result) {
String column = columns[i];
Object value = result[i];
if (value instanceof Collection) {
List<Object> adaptedValues = new ArrayList<>();
List<Object> values = (List) value;
for (Object element : values) {
handleAdaptedValue(adaptedValues, processData(element));
}
adaptedResults.put(column, adaptedValues);
adaptedResults.put(column, ((Collection) value).stream().map(this::processData).collect(
Collectors.toList()));
} else {
adaptedResults.put(column, processData(value));
}
Expand Down
80 changes: 73 additions & 7 deletions ...ntegration-tests/src/test/java/org/neo4j/ogm/persistence/model/EntityGraphMapperTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -29,7 +29,6 @@

import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Ignore;
import org.junit.Test;
import org.neo4j.ogm.context.EntityGraphMapper;
import org.neo4j.ogm.context.EntityMapper;
Expand All @@ -49,6 +48,7 @@
import org.neo4j.ogm.domain.types.EntityWithUnmanagedFieldType;
import org.neo4j.ogm.exception.core.InvalidRelationshipTargetException;
import org.neo4j.ogm.metadata.MetaData;
import org.neo4j.ogm.model.Result;
import org.neo4j.ogm.request.Statements;
import org.neo4j.ogm.session.Session;
import org.neo4j.ogm.session.SessionFactory;
Expand Down Expand Up @@ -712,11 +712,11 @@ public void testAppendReferenceFromIncomingSide() {
// Statements cypher = new Statements(this.mapper.map(immigration, 2).getCompiler().getAllStatements());
session.clear();
assertThat(session.query("MATCH (j:Person:DomainObject { name :'jim' }), " +
"(h:Policy:DomainObject { name: 'health' }), " +
"(i:Policy:DomainObject { name: 'immigration' }) " +
"WHERE (j)-[:WRITES_POLICY]->(h) and" +
"(j)-[:WRITES_POLICY]->(i) return j, h, i", emptyMap()).queryResults())
.hasSize(1);
"(h:Policy:DomainObject { name: 'health' }), " +
"(i:Policy:DomainObject { name: 'immigration' }) " +
"WHERE (j)-[:WRITES_POLICY]->(h) and" +
"(j)-[:WRITES_POLICY]->(i) return j, h, i", emptyMap()).queryResults())
.hasSize(1);
}

@Test(expected = IllegalArgumentException.class)
Expand All @@ -735,7 +735,8 @@ public void shouldThrowInvalidRelationshipTargetExceptionOnNullElements() {

assertThatExceptionOfType(InvalidRelationshipTargetException.class)
.isThrownBy(() -> session.save(course))
.withMessage("The relationship 'STUDENTS' from 'org.neo4j.ogm.domain.education.Course' to 'org.neo4j.ogm.domain.education.Student' stored on '#students' contains 'null', which is an invalid target for this relationship.'");
.withMessage(
"The relationship 'STUDENTS' from 'org.neo4j.ogm.domain.education.Course' to 'org.neo4j.ogm.domain.education.Student' stored on '#students' contains 'null', which is an invalid target for this relationship.'");

}

Expand All @@ -751,4 +752,69 @@ public void shouldNotThrowNpeOnUnknownEntityFieldType() {
assertThat(loaded).isNotNull();
}

@Test
public void shouldNotMessUpNestedLists() {

Result result = session.query("RETURN [[0,1,2], [3], [4], [5,6]] as nested_list", Collections.emptyMap());
assertThat(result).hasSize(1).first().satisfies(row -> {
Object nestedLists = row.get("nested_list");
assertThat(nestedLists).isInstanceOf(Long[][].class);

Long[][] columns = (Long[][]) nestedLists;
assertThat(columns).hasSize(4);
assertThat(columns[0]).isInstanceOf(Long[].class)
.satisfies(c -> assertThat(((Long[]) c)).containsExactly(0L, 1L, 2L));
assertThat(columns[1]).isInstanceOf(Long[].class)
.satisfies(c -> assertThat(((Long[]) c)).containsExactly(3L));
});
}

@Test
public void shouldNotMessUpMixedNestedLists() {

Result result = session.query("RETURN [[0,1,2], [[23,42]], [4], [5,6]] as nested_list", Collections.emptyMap());
assertThat(result).hasSize(1).first().satisfies(row -> {
Object nestedLists = row.get("nested_list");
assertThat(nestedLists).isInstanceOf(Object[].class);

Object[] columns = (Object[]) nestedLists;
assertThat(columns).hasSize(4);
assertThat(columns[0]).isInstanceOf(Long[].class)
.satisfies(c -> assertThat(((Long[]) c)).containsExactly(0L, 1L, 2L));
assertThat(columns[1]).isInstanceOf(Long[][].class)
.satisfies(c -> assertThat(((Long[][]) c)[0]).containsExactly(23L, 42L));
});
}

@Test
public void shouldNotMessUpMixedTypedLists() {

Teacher jim = new Teacher("Jim");
sessionFactory.openSession().save(jim);

Result result = session
.query("MATCH (n:Teacher) RETURN n, [[0,1,2], [[\"a\",\"b\"]], [\"c\"], \"d\"] as nested_list",
Collections.emptyMap());
assertThat(result).hasSize(1).first().satisfies(row -> {
Object nestedLists = row.get("nested_list");
assertThat(nestedLists).isInstanceOf(Object[].class);

Object[] columns = (Object[]) nestedLists;
assertThat(columns).hasSize(4);
assertThat(columns[0]).isInstanceOf(Long[].class)
.satisfies(c -> assertThat(((Long[]) c)).containsExactly(0L, 1L, 2L));
assertThat(columns[1]).isInstanceOf(String[][].class)
.satisfies(c -> assertThat(((String[][]) c)[0]).containsExactly("a", "b"));

assertThat(columns[2]).isInstanceOf(String[].class)
.satisfies(c -> assertThat(((String[]) c)).containsExactly("c"));

assertThat(columns[3]).isInstanceOf(String.class)
.isEqualTo("d");

assertThat(row.get("n"))
.isInstanceOf(Teacher.class)
.extracting("name").first().isEqualTo("Jim");
});
}
}

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