JpaMetamodelRedGProvider.java 文件源码

private Map<String, String> getReferenceColumnNamesMapForReferenceAttribute(SingularAttribute<?, ?> attribute, ManagedType<?> targetEntity) {
    List<String> idAttributeNames = targetEntity.getSingularAttributes().stream()
               .filter(this::isIdAttribute)
               .map(this::getSingularAttributeColumnName)
               .collect(Collectors.toList());

    JoinColumns joinColumnsAnnotation =
               ((AnnotatedElement) attribute.getJavaMember()).getAnnotation(JoinColumns.class);
    JoinColumn joinColumnAnnotation =
               ((AnnotatedElement) attribute.getJavaMember()).getAnnotation(JoinColumn.class);
    JoinColumn[] joinColumns = joinColumnsAnnotation != null ? joinColumnsAnnotation.value() :
               joinColumnAnnotation != null ? new JoinColumn[]{joinColumnAnnotation} : null;
    Map<String, String> referenceColumnNamesMap;
    if (joinColumns != null) {
           referenceColumnNamesMap = Arrays.stream(joinColumns)
                   .collect(Collectors.toMap(JoinColumn::name, joinColumn ->
                           joinColumn.referencedColumnName().length() > 0 ? joinColumn.referencedColumnName() :
                                   idAttributeNames.get(0)));
       } else {
           referenceColumnNamesMap = idAttributeNames.stream()
                   .collect(Collectors.toMap(idAttributeName -> attribute.getName().toUpperCase() + "_"
                           + idAttributeName, idAttributeName -> idAttributeName));
       }
    return referenceColumnNamesMap;
}