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A light but powerful object mapper and SQL generator for Java/Android
/*
* Copyright 2016 requery.io
*
* 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 io.requery.processor;
import javax.lang.model.element.Element;
import javax.lang.model.element.TypeElement;
import javax.lang.model.type.TypeKind;
import javax.lang.model.type.TypeMirror;
import javax.lang.model.util.Types;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import java.util.stream.Collectors;
import java.util.stream.Stream;
/**
* Holds entity types and navigates relationships between entity objects that will be generated.
*
* @author Nikhil Purushe
*/
class EntityGraph {
private final Map entities;
private final Map embeddedTypes;
private final Types types;
EntityGraph(Types types, Map embeddedTypes) {
this.types = types;
this.embeddedTypes = embeddedTypes;
this.entities = new HashMap<>();
}
/**
* @return the collection of {@link EntityDescriptor} descriptors in this graph.
*/
Collection entities() {
return Collections.unmodifiableCollection(entities.values());
}
/**
* Add an {@link EntityDescriptor} to this graph.
*
* @param entity to add
*/
public void add(EntityDescriptor entity) {
entities.putIfAbsent(entity.element(), entity);
}
Optional embeddedDescriptorOf(AttributeDescriptor attribute) {
TypeMirror mirror = attribute.typeMirror();
Element element = types.asElement(mirror);
if (element instanceof TypeElement) {
return Optional.ofNullable(embeddedTypes.get(element));
}
return Optional.empty();
}
private Optional entityByName(QualifiedName name) {
boolean ignorePackage = Names.isEmpty(name.packageName());
for (EntityDescriptor entity : entities.values()) {
QualifiedName entityName = entity.typeName();
if ((ignorePackage && entityName.className().equals(name.className())) ||
entityName.equals(name) || match(entity, name.className())) {
return Optional.of(entity);
}
}
return Optional.empty();
}
/**
* Given a association attribute in an Entity find the Entity the attribute is referencing.
*
* @param attribute association attribute
* @return Optional Entity type being referenced.
*/
Optional referencingEntity(AttributeDescriptor attribute) {
if (!Names.isEmpty(attribute.referencedTable())) {
// match by table name
return entities.values().stream()
.filter(entity -> entity.tableName().equalsIgnoreCase(attribute.referencedTable()))
.findFirst();
} else if (!Names.isEmpty(attribute.referencedType())) {
// match by type name
Optional primitiveType = Stream.of(TypeKind.values())
.filter(TypeKind::isPrimitive)
.filter(kind -> kind.toString().toLowerCase().equals(attribute.referencedType()))
.findFirst();
if (!primitiveType.isPresent()) {
QualifiedName referencedType = new QualifiedName(attribute.referencedType());
return entityByName(referencedType);
} // else attribute is basic foreign key and not referring to an entity
} else {
TypeMirror referencedType = attribute.typeMirror();
if (attribute.isIterable()) {
referencedType = collectionElementType(referencedType);
}
TypeElement referencedElement = (TypeElement) types.asElement(referencedType);
if (referencedElement != null) {
String referencedName = referencedElement.getSimpleName().toString();
return entities.values().stream()
.filter(entity -> match(entity, referencedName))
.findFirst();
}
}
return Optional.empty();
}
private static boolean match(EntityDescriptor entity, String referenceName) {
return (entity.typeName().className().equals(referenceName) ||
entity.element().getSimpleName().contentEquals(referenceName));
}
/**
* Given an attribute in a given type finds the corresponding attribute that it is referencing
* in that referencing type.
*
* @param attribute attribute
* @param referenced type being referenced
* @return optional element it references
*/
Optional referencingAttribute(AttributeDescriptor attribute,
EntityDescriptor referenced) {
String referencedColumn = attribute.referencedColumn();
if (Names.isEmpty(referencedColumn)) {
// using the id
List keys = referenced.attributes().values().stream()
.filter(AttributeDescriptor::isKey).collect(Collectors.toList());
if (keys.size() == 1) {
return Optional.of(keys.get(0));
} else {
return keys.stream()
.filter(other -> other.typeMirror().equals(attribute.typeMirror()))
.findFirst();
}
} else {
return referenced.attributes().values().stream()
.filter(other -> other.name().equals(referencedColumn))
.findFirst();
}
}
/**
* Given an association in an entity find the attributes it maps onto in the referenced entity.
*
* @param entity entity owning the attribute
* @param attribute association attribute
* @param referenced type being referenced
* @return set of mapped attributes
*/
Set mappedAttributes(EntityDescriptor entity,
AttributeDescriptor attribute,
EntityDescriptor referenced) {
String mappedBy = attribute.mappedBy();
if (Names.isEmpty(mappedBy)) {
return referenced.attributes().values().stream()
.filter(other -> other.cardinality() != null)
.filter(other -> referencingEntity(other).isPresent())
.filter(other -> referencingEntity(other)
.orElseThrow(IllegalStateException::new) == entity)
.collect(Collectors.toSet());
} else {
return referenced.attributes().values().stream()
.filter(other -> other.name().equals(mappedBy))
.collect(Collectors.toSet());
}
}
private static TypeMirror collectionElementType(TypeMirror typeMirror) {
List arguments = Mirrors.listGenericTypeArguments(typeMirror);
return arguments.isEmpty() ? typeMirror : arguments.get(0);
}
}