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Fluent query implementation for JPA repositories
package co.streamx.fluent.JPA;
import java.lang.annotation.Annotation;
import java.lang.reflect.AccessibleObject;
import java.lang.reflect.AnnotatedElement;
import java.lang.reflect.Field;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.Supplier;
import java.util.stream.Collectors;
import javax.persistence.AccessType;
import javax.persistence.AttributeOverride;
import javax.persistence.AttributeOverrides;
import javax.persistence.Column;
import javax.persistence.Embeddable;
import javax.persistence.Embedded;
import javax.persistence.EmbeddedId;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinColumns;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.ManyToOne;
import javax.persistence.MapsId;
import javax.persistence.OneToMany;
import javax.persistence.OneToOne;
import javax.persistence.Table;
import co.streamx.fluent.extree.expression.Expression;
import co.streamx.fluent.extree.expression.InvocationExpression;
import co.streamx.fluent.extree.expression.MemberExpression;
import co.streamx.fluent.notation.Tuple;
import lombok.AccessLevel;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.RequiredArgsConstructor;
import lombok.ToString;
@NoArgsConstructor(access = AccessLevel.PRIVATE)
final class JPAHelpers {
private static final char DOT = IdentifierPath.DOT;
private static final char UNDERSCORE = '_';
private static final Map membersToFields = new ConcurrentHashMap<>();
// https://stackoverflow.com/questions/3473756/java-convert-primitive-class/17836370
private static final Class[] wrappers = { Integer.class, Double.class, Byte.class, Boolean.class,
Character.class, Void.class, Short.class, Float.class, Long.class };
@SuppressWarnings("unchecked")
public static Class wrap(final Class clazz) {
if (!clazz.isPrimitive())
return clazz;
final String name = clazz.getName();
final int c0 = name.charAt(0);
final int c2 = name.charAt(2);
final int mapper = (c0 + c0 + c0 + 5) & (118 - c2);
return (Class) wrappers[mapper];
}
@FunctionalInterface
private interface SneakyBiFunction {
R apply(T t,
U u) throws Exception;
};
@Getter
@RequiredArgsConstructor
@ToString
private static class ID {
private final CharSequence path;
private final CharSequence column;
}
@Getter
@ToString
private static final class ClassMeta {
public ClassMeta(AccessType accessType) {
this.accessType = accessType;
}
private final AccessType accessType;
private final List ids = new ArrayList<>();
}
@Getter
@ToString
public static final class Association {
private final List left;
private final List right;
public Association(List that, List other, boolean left) {
if (that.size() != other.size())
throw new IllegalArgumentException("keys of different sizes: " + that.size() + "-" + other.size());
if (left) {
this.left = that;
this.right = other;
} else {
this.left = other;
this.right = that;
}
}
public int getCardinality() {
return left.size();
}
}
private static final Map, ClassMeta> ids = new ConcurrentHashMap<>();
public static Association getAssociation(Expression left,
Expression right) {
if (left instanceof InvocationExpression) {
return getAssociation((InvocationExpression) left, true);
}
if (right instanceof InvocationExpression) {
return getAssociation((InvocationExpression) right, false);
}
if (left.getResultType() == right.getResultType()) {// self
List typeIds = getClassMeta(left.getResultType()).getIds();
List columns = Streams.map(typeIds, ID::getColumn);
return new Association(columns, columns, false);
}
throw new IllegalStateException(
String.format("Cannot bind association for [(%s)%s = (%s)%s]. Ensure both sides are entities.",
left.getResultType().getSimpleName(), left, right.getResultType().getSimpleName(), right));
}
private static Association getAssociation(InvocationExpression e,
boolean left) {
Member member = ((MemberExpression) e.getTarget()).getMember();
member = (member instanceof Method) ? getAnnotatedField((Method) member) : member;
return getAssociation(member, left);
}
private static Class getType(Member m) {
if (m instanceof Field)
return ((Field) m).getType();
return ((Method) m).getReturnType();
}
private static void calcEmbeddedId(Class embeddable,
List ids,
StringBuilder path,
Map overrides) {
int length = path.append(DOT).length();
for (Field f : embeddable.getDeclaredFields()) {
path.append(f.getName());
if (f.getAnnotation(Embeddable.class) != null)
calcEmbeddedId(f.getType(), ids, path, overrides);
else {
String cur = path.toString();
String override = overrides.get(cur);
ids.add(new ID(cur, override != null ? override : getColumnName(f)));
}
path.setLength(length);
}
}
// TODO: overrides for MappedClass objects
private static Map calcOverrides(AccessibleObject member) {
AttributeOverride override = member.getAnnotation(AttributeOverride.class);
if (override != null)
return Collections.singletonMap(override.name(), override.column().name());
AttributeOverrides overrides = member.getAnnotation(AttributeOverrides.class);
if (overrides != null)
return Arrays.stream(overrides.value())
.collect(Collectors.toMap(AttributeOverride::name, o -> o.column().name()));
return Collections.emptyMap();
}
private static ClassMeta findId(Class type) {
ClassMeta meta = null;
while (type != Object.class && type != null) {
if (!type.isInterface()) {
for (Field f : type.getDeclaredFields()) {
if (f.isAnnotationPresent(Id.class)) {
if (meta == null)
meta = new ClassMeta(AccessType.FIELD);
meta.getIds().add(new ID(f.getName(), getColumnName(f)));
} else if (f.isAnnotationPresent(EmbeddedId.class)) {
if (meta == null)
meta = new ClassMeta(AccessType.FIELD);
calcEmbeddedId(f.getType(), meta.getIds(), new StringBuilder(f.getName()), calcOverrides(f));
}
}
if (meta != null)
return meta;
}
for (Method m : type.getDeclaredMethods()) {
if (m.isAnnotationPresent(Id.class)) {
if (meta == null)
meta = new ClassMeta(AccessType.PROPERTY);
meta.getIds().add(new ID(m.getName(), getColumnName(m)));
} else if (m.isAnnotationPresent(EmbeddedId.class)) {
if (meta == null)
meta = new ClassMeta(AccessType.PROPERTY);
calcEmbeddedId(m.getReturnType(), meta.getIds(), new StringBuilder(m.getName()), calcOverrides(m));
}
}
if (meta != null)
return meta;
type = type.getSuperclass();
}
return new ClassMeta(AccessType.FIELD);
}
private static AccessType getAccessType(Class type) {
if (type.isInterface())
return AccessType.PROPERTY;
return getClassMeta(type).getAccessType();
}
private static Association getAssociation(Member field,
boolean left) {
AnnotatedElement leftField = (AnnotatedElement) field;
OneToOne oneToOne = leftField.getAnnotation(OneToOne.class);
if (oneToOne != null) {
Class targetEntity = oneToOne.targetEntity();
String mappedBy = oneToOne.mappedBy();
return getAssociation(field, targetEntity, mappedBy, left);
}
ManyToOne manyToOne = leftField.getAnnotation(ManyToOne.class);
if (manyToOne != null) {
return getAssociation(field, manyToOne.targetEntity(), null, left);
}
OneToMany oneToMany = leftField.getAnnotation(OneToMany.class);
if (oneToMany != null) {
Class targetEntity = oneToMany.targetEntity();
String mappedBy = oneToMany.mappedBy();
return getAssociation(field, targetEntity, mappedBy, left);
}
throw new IllegalStateException("association was not resolved for " + field + ".");
}
public static Association getAssociationMTM(Member field,
boolean inverse) {
field = getAnnotatedField(field);
AnnotatedElement leftField = (AnnotatedElement) field;
ManyToMany manyToMany = leftField.getAnnotation(ManyToMany.class);
if (manyToMany != null) {
String mappedBy = manyToMany.mappedBy();
Class declaringClass = field.getDeclaringClass();
if (mappedBy.length() > 0) {
field = resolveMappedBy(getTargetForMTM(field), mappedBy);
leftField = (AnnotatedElement) field;
inverse = !inverse;
}
else if (inverse) {
declaringClass = manyToMany.targetEntity();
if (declaringClass == void.class)
declaringClass = getTargetByParameterizedType((Field) field);
}
List entity = null;
List join = null;
JoinTable joinTable = leftField.getAnnotation(JoinTable.class);
String declaringTableName = getTableName(declaringClass);
if (joinTable != null) {
JoinColumn[] columns = inverse ? joinTable.inverseJoinColumns() : joinTable.joinColumns();
if (columns != null) {
join = new ArrayList<>();
for (int i = 0; i < columns.length; i++) {
JoinColumn column = columns[i];
String columnName = column.name();
String referencedColumnName = column.referencedColumnName();
if (Strings.isNullOrEmpty(referencedColumnName)) {
if (entity == null)
entity = Streams.map(getClassMeta(declaringClass).getIds(), ID::getColumn);
if (entity.get(i) == null) {
throw new IllegalStateException(
"referencedColumnName not specified on field: " + field);
}
} else {
if (entity == null)
entity = new ArrayList<>();
entity.set(i, referencedColumnName);
}
join.add(Strings.isNullOrEmpty(columnName)
? concatWithUnderscore(declaringTableName, entity.get(i))
: columnName);
}
}
}
if (entity == null) {
entity = Streams.map(getClassMeta(declaringClass).getIds(), ID::getColumn);
join = entity.stream()
.map(col -> concatWithUnderscore(declaringTableName, col))
.collect(Collectors.toList());
}
return new Association(join, entity, true);
}
throw new IllegalStateException("association was not resolved for " + field + ".");
}
private static Association getAssociation(Member field,
Class targetEntity,
String mappedBy,
boolean left) {
AnnotatedElement leftField = (AnnotatedElement) field;
Class type = targetEntity == void.class ? getType(field) : targetEntity;
if (Strings.isNullOrEmpty(mappedBy)) {
// should have JoinColumn or defaults
JoinColumn[] joins;
JoinColumn joinColumn = leftField.getAnnotation(JoinColumn.class);
if (joinColumn != null)
joins = new JoinColumn[] { joinColumn };
else {
JoinColumns joinColumns = leftField.getAnnotation(JoinColumns.class);
joins = joinColumns != null ? joinColumns.value() : null;
}
List that;
List other;
if (joins != null) {
other = new ArrayList<>();
that = new ArrayList<>();
for (int i = 0; i < joins.length; i++) {
JoinColumn join = joins[i];
if (!Strings.isNullOrEmpty(join.referencedColumnName()))
other.add(join.referencedColumnName());
else {
// extension to Standard: HN seems to go positional here
List typeIds = getClassMeta(type).getIds();
other.add(typeIds.get(i).getColumn());
}
if (!Strings.isNullOrEmpty(join.name()))
that.add(join.name());
else {
that.add(concatWithUnderscore(getColumnName(field), other.get(other.size() - 1)));
}
}
} else {
MapsId mapsId = leftField.getAnnotation(MapsId.class);
if (mapsId != null) {
List leftId = getClassMeta(field.getDeclaringClass()).getIds();
String idPath = mapsId.value();
if (!Strings.isNullOrEmpty(idPath)) {
leftId = Collections
.singletonList(
leftId.stream().filter(id -> isIDMapped(id, idPath)).findFirst().get());
}
List id = getClassMeta(type).getIds();
return new Association(Streams.map(leftId, ID::getColumn), Streams.map(id, ID::getColumn), left);
}
other = Streams.map(getClassMeta(type).getIds(), ID::getColumn);
that = Collections.singletonList(concatWithUnderscore(getColumnName(field), other.get(0)));
}
return new Association(that, other, left);
} else {
return getAssociation(resolveMappedBy(type, mappedBy), !left);
}
}
private static boolean isIDMapped(ID id,
String mappedIdPath) {
CharSequence path = id.getPath();
int firstDot = Strings.indexOf(path, DOT);
int secondDot = path.length();
if (firstDot >= 0) {
firstDot++;
secondDot = Strings.indexOf(path, DOT, firstDot);
if (secondDot < 0)
secondDot = path.length();
} else {
firstDot = 0;
}
int len = secondDot - firstDot;
if (len != mappedIdPath.length())
return false;
return Strings.compare(mappedIdPath, 0, path, firstDot, len) == 0;
}
private static String buildFullTableName(String catalog,
String schema,
String name) {
if (schema.length() > 0 || catalog.length() > 0) {
StringBuilder b = new StringBuilder();
if (catalog.length() > 0)
b.append(catalog).append(DOT);
if (schema.length() > 0)
b.append(schema).append(DOT);
name = b.append(name).toString();
}
return name;
}
public static String getTableName(Class entity) {
if (!isEntityLike(entity))
return null;
Table tableA = entity.getAnnotation(Table.class);
String name;
if (tableA != null) {
name = tableA.name();
if (!Strings.isNullOrEmpty(name))
return buildFullTableName(tableA.catalog(), tableA.schema(), name);
}
Entity ent = entity.getAnnotation(Entity.class);
if (ent != null)
name = ent.name();
else {
Tuple tuple = entity.getAnnotation(Tuple.class);
if (tuple != null) {
String tupleName = tuple.value();
return tupleName.length() > 0 ? tupleName : null;
}
name = null;
}
if (!Strings.isNullOrEmpty(name))
return name;
return entity.getSimpleName();
}
public static boolean isCollection(Class entity) {
return Collection.class.isAssignableFrom(entity);
}
public static boolean isScalar(Class entity) {
// assuming all scalars must be Comparable
return entity.isPrimitive() || Comparable.class.isAssignableFrom(entity) || Number.class.isAssignableFrom(entity);
}
public static boolean isEntity(Class entity) {
return entity.isAnnotationPresent(Entity.class);
}
public static boolean isEntityLike(Class entity) {
return isEntity(entity) || entity.isAnnotationPresent(Tuple.class);
}
public static boolean isEmbeddable(Class entity) {
return entity.isAnnotationPresent(Embedded.class);
}
public static boolean isEmbedded(Member field) {
return getAnnotationFromProperty(field, Embeddable.class) != null;
}
private static IdentifierPath getColumnName(Member field) {
Column column = ((AnnotatedElement) field).getAnnotation(Column.class);
if (column != null) {
String cname = column.name();
if (!Strings.isNullOrEmpty(cname))
return new IdentifierPath.Resolved(cname);
}
JoinColumn join = ((AnnotatedElement) field).getAnnotation(JoinColumn.class);
if (join != null) {
String cname = join.name();
if (!Strings.isNullOrEmpty(cname))
return new IdentifierPath.Resolved(cname);
}
JoinColumns joins = ((AnnotatedElement) field).getAnnotation(JoinColumns.class);
if (joins != null)
return new IdentifierPath.MultiColumnIdentifierPath(field.getName(), getAssociation(field, true));
MapsId mapsId = ((AnnotatedElement) field).getAnnotation(MapsId.class);
if (mapsId != null) {
Class declaringClass = field.getDeclaringClass();
List entityIds = getClassMeta(declaringClass).getIds();
String idPath = mapsId.value();
if (Strings.isNullOrEmpty(idPath)) {
// should be the sole PK column
return entityIds.size() == 1 ? new IdentifierPath.Resolved(entityIds.get(0).getColumn())
: // if this case is possible, we are covered
new IdentifierPath.MultiColumnIdentifierPath(field.getName(), getAssociation(field, true));
}
return new IdentifierPath.Resolved(
entityIds.stream().filter(id -> isIDMapped(id, idPath)).findFirst().get().getColumn());
}
return new IdentifierPath.Resolved(toDBNotation(getFieldName(field)));
}
private static ClassMeta getClassMeta(Class declaringClass) {
return ids.computeIfAbsent(declaringClass, JPAHelpers::findId);
}
public static Field getField(Member m1) {
if (membersToFields.size() > 10000)
membersToFields.clear();
return membersToFields.computeIfAbsent(m1, m -> {
String original = m.getName();
String name = getFieldName(m);
String decapitalized = decapitalize(name);
Class clazz = m.getDeclaringClass();
for (;;) {
try {
return clazz.getDeclaredField(decapitalized);
} catch (NoSuchFieldException e) {
try {
return clazz.getDeclaredField(name);
} catch (NoSuchFieldException e1) {
try {
return clazz.getDeclaredField(original);
} catch (NoSuchFieldException e2) {
clazz = clazz.getSuperclass();
if (clazz == Object.class || clazz == null)
throw TranslationError.UNMAPPED_FIELD.getError(e2, original);
}
}
}
}
});
}
private static String getFieldName(Member m) {
String name = m.getName();
if (m instanceof Method) {
if (name.startsWith("is"))
name = name.substring(2);
else if (name.startsWith("get") || name.startsWith("set"))
name = name.substring(3);
}
return name;
}
public static IdentifierPath getColumnNameFromProperty(Member member) {
return getColumnName(getAnnotatedField(member));
}
public static T getAnnotationFromProperty(Member member,
Class annotationClass) {
AnnotatedElement annotated = (AnnotatedElement) getAnnotatedField(member);
return annotated.getAnnotation(annotationClass);
}
public static String getJoinTableName(Member member) {
Member field = getAnnotatedField(member);
AnnotatedElement annotated = (AnnotatedElement) field;
ManyToMany mtm = annotated.getAnnotation(ManyToMany.class);
String mappedBy = mtm.mappedBy();
if (mappedBy.length() > 0) {
field = resolveMappedBy(getTargetForMTM(field), mappedBy);
annotated = (AnnotatedElement) field;
}
String name = "", catalog = "", schema = "";
JoinTable joinTable = annotated.getAnnotation(JoinTable.class);
if (joinTable != null) {
name = joinTable.name();
catalog = joinTable.catalog();
schema = joinTable.schema();
}
Member f = field;
Supplier> targetSupplier = () -> getTargetForMTM(f);
return getJoinTableName(field, name, catalog, schema, targetSupplier);
}
private static Class getTargetForMTM(Member field) {
AnnotatedElement annotated = (AnnotatedElement) field;
ManyToMany mtm = annotated.getAnnotation(ManyToMany.class);
Class target = mtm.targetEntity();
if (target == void.class)
target = getTargetByParameterizedType((Field) field);
return target;
}
private static String getJoinTableName(Member field,
String name,
String catalog,
String schema,
Supplier> target) {
if (Strings.isNullOrEmpty(name)) {
String first = getTableName(field.getDeclaringClass());
name = concatWithUnderscore(first, getTableName(target.get()));
}
return buildFullTableName(catalog, schema, name);
}
private static Class getTargetByParameterizedType(Field field) {
ParameterizedType genericType = (ParameterizedType) field.getGenericType();
Type[] types = genericType.getActualTypeArguments();
return (Class) types[0];
}
private static String concatWithUnderscore(CharSequence first,
CharSequence second) {
return first + "_" + second;
}
public static Member getAnnotatedField(Member member) {
return getAccessType(member.getDeclaringClass()) == AccessType.PROPERTY ? member : getField(member);
}
private static Member resolveMappedBy(Class type,
String mappedBy) {
SneakyBiFunction, String, ? extends Member> memberAccessor = getAccessType(type) == AccessType.PROPERTY
? (clazz,
name) -> clazz.getDeclaredMethod(name, (Class[]) null)
: Class::getDeclaredField;
for (;;) {
try {
return memberAccessor.apply(type, mappedBy);
} catch (Exception e) {
type = type.getSuperclass();
if (type == Object.class || type == null)
throw new RuntimeException(e);
}
}
}
/**
* Utility method to take a string and convert it to normal Java variable name capitalization. This normally means
* converting the first character from upper case to lower case, but in the (unusual) special case when there is
* more than one character and both the first and second characters are upper case, we leave it alone.
*
* Thus "FooBah" becomes "fooBah" and "X" becomes "x", but "URL" stays as "URL".
*
* @param name The string to be decapitalized.
* @return The decapitalized version of the string.
*/
private static String decapitalize(String name) {
if (Strings.isNullOrEmpty(name)) {
return name;
}
if (name.length() > 1 && Character.isUpperCase(name.charAt(1)) && Character.isUpperCase(name.charAt(0))) {
return name;
}
char chars[] = name.toCharArray();
chars[0] = Character.toLowerCase(chars[0]);
return new String(chars);
}
private static CharSequence toDBNotation(String name) {
if (Strings.isNullOrEmpty(name)) {
return name;
}
StringBuilder out = null;
boolean foundUppercase = true;
for (int i = 0; i < name.length(); i++) {
char charAtI = name.charAt(i);
if (Character.isUpperCase(charAtI)) {
if (out == null) {
out = new StringBuilder(name.length() + 6).append(name, 0, i);
}
if (!foundUppercase) {
out.append(UNDERSCORE);
foundUppercase = true;
}
out.append(Character.toLowerCase(charAtI));
} else {
foundUppercase = false;
if (out != null)
out.append(charAtI);
}
}
return out != null ? out : name;
}
}