Say I have the following Collections
public #Data class Customer {
#Id
private String id;
private String firstName;
private String lastName;
#DBRef
private List<Address> addressList= new ArrayList<Address>();
}
and
public #Data class Address {
#Id
private String id;
private String address;
private String type;
private String customerID;
}
And each Customer has multiple addresses, and I have implemented MongoRepository. Saving customer for the First time is working pretty well customerRepo.save(customerObject) and before calling the save I am persisting multiple Address Objects and then setting those to the addressList.
Next time when I am updating the same document and want to add a New set of Address to the existing list it is overwriting the whole addressList array. So basically what I have to do now to set new address like thisexistingCustomerObject.getAddressList().addAll(my new List of address) if there are thousand(or more than thousand) of elements or I am slicing the addressList array the following procedure won't be a good idea. My question is what is the best way to achieve this scenario? say if I don't want to use MongoTemplate. Is it possible Just using the MongoRepository
I don't think you can do it in that way. Previously i had the same situation, and I tried the following
1.org.springframework.core.convert.converter.Converter even I have managed to manipulate the DBObject but functions like $push or $set(wrapping them under key) does not work over there.
2.AbstractMongoEventListener by overriding onBeforeSave but Object manipulation was not taking place during save.
However you can try altering the mentioned
you can try override MongoRepository save method, It would better if someone point to the right direction.
Otherwise for my scenario I had to create Custom repository(To update and delete document) which is working parallel with MongoRepository (for Insert and retrieve data/document), but I believe thats an ugly workaround. There has to be a cleaner way to do it.
Related
We have model class saved in Redis as mentioned below:-
#Data
#NoArgsConstructor
#AllArgsConstructor
#RedisHash("book")
public class Book implements Serializable {
private static final long serialVersionUID = 2208852329346517265L;
#Id
private Integer bookID;
#Indexed
private String title;
#Indexed
private String authors;
private String averageRating;
private String isbn;
private String languageCode;
private String ratingsCount;
private BigDecimal price;
}
We have title and authors as our indexed property.
Now we wanted to search all the records from Redis by passing title and a list of authors using the spring crud repository as mentioned below.
public interface BookSpringRepository extends CrudRepository<Book, String> {
List<Book> findAllByTitleAndAuthors(String title, List<String> authors);
}
Service layer:-
#Override
public Optional<List<Book>> searchBooksByTitleAndAuthorNames(String title, List<String>
autherNames) {
return Optional.ofNullable(bookSpringRepository.findAllByTitleAndAuthors(title,
autherNames));
}
Here we are getting below exception
Unable to fetch data from Spring data Redis cache using List of Integer or
String.
Getting error while fetching - "Resolved
[org.springframework.core.convert.ConversionFailedException: Failed to convert from type
[java.lang.String] to type [byte] for value 'Ronak';
nested exception is java.lang.NumberFormatException: For input string: "Ronak"]."
We would not want to convert the list of string/integer to byte as it is a time-consuming process and as we tried took so much amount of time. Also when the results are retrieved we will again have to convert back to normal integer or string values.
The other option is to loop through the list and pass a single value at a time to the Redis crud repository and this time Redis crud repository is happy but that will be a loop call to Redis and network latency.
We cannot add ID attributes on authors' property as these can be duplicate records.
Does the spring crud repository support the LIKE query in search that way we can create a unique id having these authors' names and make put ID annotation on that new derived property to search the records using spring crud repository using LIKE or contains kind of query.
Any suggestions here are highly appreciated!!
Try to add serialization to your redis key and value. This might help :
https://medium.com/#betul5634/redis-serialization-with-spring-redis-data-lettuce-codec-1a1d2bc73d26
Using spring-data-jpa and working on getting data out of table where there are about a dozen columns which are used in queries to find particular rows, and then a payload column of clob type which contains the actual data that is marshalled into java objects to be returned.
Entity object very roughly would be something like
#Entity
#Table(name = "Person")
public class Person {
#Column(name="PERSON_ID", length=45) #Id private String personId;
#Column(name="NAME", length=45) private String name;
#Column(name="ADDRESS", length=45) private String address;
#Column(name="PAYLOAD") #Lob private String payload;
//Bunch of other stuff
}
(Whether this approach is sensible or not is a topic for a different discussion)
The clob column causes performance to suffer on large queries ...
In an attempt to improve things a bit, I've created a separate entity object ... sans payload ...
#Entity
#Table(name = "Person")
public class NotQuiteAWholePerson {
#Column(name="PERSON_ID", length=45) #Id private String personId;
#Column(name="NAME", length=45) private String name;
#Column(name="ADDRESS", length=45) private String address;
//Bunch of other stuff
}
This gets me a page of NotQuiteAPerson ... I then query for the page of full person objects via the personIds.
The hope is that in not using the payload in the original query, which could filtering data over a good bit of the backing table, I only concern myself with the payload when I'm retrieving the current page of objects to be viewed ... a much smaller chunk.
So I'm at the point where I want to map the contents of the original returned Page of NotQuiteAWholePerson to my List of Person, while keeping all the Paging info intact, the map method however only takes a Converter which will iterate over the NotQuiteAWholePerson objects ... which doesn't quite fit what I'm trying to do.
Is there a sensible way to achieve this ?
Additional clarification for #itsallas as to why existing map() will not suffice..
PageImpl::map has
#Override
public <S> Page<S> map(Converter<? super T, ? extends S> converter) {
return new PageImpl<S>(getConvertedContent(converter), pageable, total);
}
Chunk::getConvertedContent has
protected <S> List<S> getConvertedContent(Converter<? super T, ? extends S> converter) {
Assert.notNull(converter, "Converter must not be null!");
List<S> result = new ArrayList<S>(content.size());
for (T element : this) {
result.add(converter.convert(element));
}
return result;
}
So the original List of contents is iterated through ... and a supplied convert method applied, to build a new list of contents to be inserted into the existing Pageable.
However I cannot convert a NotQuiteAWholePerson to a Person individually, as I cannot simply construct the payload... well I could, if I called out to the DB for each Person by Id in the convert... but calling out individually is not ideal from a performance perspective ...
After getting my Page of NotQuiteAWholePerson I am querying for the entire List of Person ... by Id ... in one call ... and now I am looking for a way to substitute the entire content list ... not interively, as the existing map() does, but in a simple replacement.
This particular use case would also assist where the payload, which is json, is more appropriately persisted in a NoSql datastore like Mongo ... as opposed to the sql datastore clob ...
Hope that clarifies it a bit better.
You can avoid the problem entirely with Spring Data JPA features.
The most sensible way would be to use Spring Data JPA projections, which have good extensive documentation.
For example, you would first need to ensure lazy fetching for your attribute, which you can achieve with an annotation on the attribute itself.
i.e. :
#Basic(fetch = FetchType.LAZY) #Column(name="PAYLOAD") #Lob private String payload;
or through Fetch/Load Graphs, which are neatly supported at repository-level.
You need to define this one way or another, because, as taken verbatim from the docs :
The query execution engine creates proxy instances of that interface at runtime for each element returned and forwards calls to the exposed methods to the target object.
You can then define a projection like so :
interface NotQuiteAWholePerson {
String getPersonId();
String getName();
String getAddress();
//Bunch of other stuff
}
And add a query method to your repository :
interface PersonRepository extends Repository<Person, String> {
Page<NotQuiteAWholePerson> findAll(Pageable pageable);
// or its dynamic equivalent
<T> Page<T> findAll(Pageable pageable, Class<T>);
}
Given the same pageable, a page of projections would refer back to the same entities in the same session.
If you cannot use projections for whatever reason (namely if you're using JPA < 2.1 or a version of Spring Data JPA before projections), you could define an explicit JPQL query with the columns and relationships you want, or keep the 2-entity setup. You could then map Persons and NotQuiteAWholePersons to a PersonDTO class, either manually or (preferably) using your object mapping framework of choice.
NB. : There are a variety of ways to use and setup lazy/eager relations. This covers more in detail.
First let me say I'm a complete novice with Spring AOP, and I apologize if this is a duplicate question.
Here's my scenario:
Let's say I have the following domain class:
#Entity(name="MyTable")
#Table(name="MY_TABLE")
public class MyTable {
private static final long serialVersionUID = 1234567890123456L;
#Id
#Column(name = "USER_ID")
private Long userID;
#Transient
private String key;
#Column(name = "KEY")
private String secureKey;
/* Other columns */
/* Getters and Setters */
}
and I have the following JPARepository class to manage it:
#Repository
public interface MyTableRepository extends JpaRepository<MyTable, Long> {
/* findBy methods */
}
As you can see, I have a secureKey field and a transient key field. In this case secureKey is an encrypted version of key.
What I need is for the secureKey value to be populated before a domain object is saved, and for the key value to be populated after a domain object is fetched. (This is a trivial example but in the real case I have multiple transient and encrypted values.) The idea is for the secure values to be persisted to the DB, but users of the domain class will only need to work with the "insecure" values.
Currently I'm handling this in my service layer. After I call a fetch method I'm populating the transient values, and before calling a save method I'm populating the "secure" values. This is working as expected but ideally I'd like this to be managed transparently, because now the burden is on each developer to remember to update those values after fetching or before saving.
I'm assuming the best way to handle this would be through some AOP class, but I confess I have little to no idea where to begin there. Is this a common scenario, and if so, would someone be willing to point me in the right direction? Also, if you have a suggestion for a better way to implement this decrypted/encrypted field pair scenario, please let me know.
Ideally I'd like to be able to add an annotation to both the secure and insecure fields, maybe pointing to each other, maybe something like:
#Insecure(secureValue = "secureKey")
#Transient
private String key;
#Secure(insecureValue = "key")
#Column(name = "KEY")
private String secureKey;
Any assistance you could provide is most appreciated.
Thanks,
B.J.
I think Spring AOP isn't the correct technology in your use case, i would recommend to use EntityListeners.
Hibernate: https://docs.jboss.org/hibernate/entitymanager/3.5/reference/en/html/listeners.html
Eclipselink: https://wiki.eclipse.org/EclipseLink/Release/2.5/JPA21#CDI_Entity_Listeners
Here is a part of Files.java
#Entity(name="files")
public class Files {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String title;
#ElementCollection
private List<String> filenames= new ArrayList<String>();
//<< getter and setter >>
}
it is correctly created the table 'Files' and 'Files_filenames' on mySql
and I can put data there on Controller with it
Files files = new Files();
files.setTitle(ufile.getTitle());
files.setFilenames(Arrays.asList(ufile.getFilename().split(",")));
so far, everything looks ok
However, when I try to get the data from the database, the filename always returns something like 'persistentbag' not ArrayList.
I would like to know how to get ArrayList from the database
I'm using Spring data JPA using Hibernate as a Jpa vendor.
Thanks in advance
PersistentBag is a List (i.e., it implements List), therefore you can use it as a regular List. There is no need to care about actual implementation of that List in this case.
Using spring-data-neo4j, I want to create two classes using #RelationshipEntity(type="OWNS") to link a Person class to both a Pet and Car.
#RelationshipEntity(type="OWNS")
public class OwnsCar {
#Indexed
private String name;
#StartNode
private Person person;
#EndNode
private Car car;
}
#RelationshipEntity(type="OWNS")
public class OwnsPet {
#Indexed
private String name;
#EndNode
private Person person;
#StartNode
private Pet pet;
}
This saves to the Graph Database properly with no problems, as I can query the actual Node and Relationship and see they type, etc.
But when I attempt to use #RelatedTo(type="OWNS", elementClass=Pet.class) I either get a class cast exception, or when using lazy-initialization I get incorrect results.
#NodeEntity
public class Person {
#Indexed
private String name;
#RelatedTo(type="OWNS", direction=Direction.OUTGOING, elementClass=Pet.class)
private Set<Pet> pets;
#RelatedTo(type="OWNS", direction=Direction.OUTGOING, elementClass=Car.class)
private Set<Car> cars;
}
The result I get when I attempt to print our my person(my toString() has been omitted, but it simply calls the toString() for each field) is this:
Person [nodeId=1, name=Nick, pets=[Car [nodeId=3, name=Thunderbird]], cars=[Car [nodeId=3, name=Thunderbird]]]
Does anyone know if this can be done, should be done, is just a bug or a feature that is missing?
It seems like the problem is, that the annotation causes springDataNeo4j to priorize the relationship name. I tried the same on another sample I created. If both annotations contain
type="OWNS" it mixes both 'objects'. When I omit this information, and only use direction and type, it works for me.
Unfortunately this will lead to a problem if you are using another #RelatedTo annotation with more Pets or Cars related with another annotation. As it would not differ between "OWNS" and any other relation to a Pet-Type, the set returns all related pets (example: peter ->(HATES-Relationsip)->dogs).
If it's a bug or not, I can't tell... But for the database: There are only nodes and relations. Both are not typed, so neo4j does not know anything about your 'Pet'- or 'Car'-Class. Spring data neo4j handles this, either by indexing all nodes per type and setting a type-attribute, or using a specific graph-layout (with subreferences). Even if you would want to fetch all pets of a person with a traversal description, you would have so much more code to write, since the outgoing relations with name 'OWNS' contains two types of objects.
I would recommend using two different names. It's easier to write your custom traversals/queries later on, and its probably even faster as well, because no class-type comparison will be needed. Is there any reason, why you would need these specific names?
PS: It is possible, that not everything is 100% accurate. I don't know springdataneo4j in detail, but that's what I figured out so far.