I am looking into using Spring Data mongodb and so far I like what I see. However, when I try to store more complicated objects, for example one created using APache XMLBeans, I get a StackOverFlowError. I think this is due to the cyclic nature of object refrences in the XMlBean. Does anyone have any suggestions as to a general way to store an XmlBean in mongodb as a BSON object that will allow for searching?
The solution does not need to use Spring.
Related
I am working on a new project using spring data jdbc because it is very easy to handle and indeed splendid.
In my scenario i have three (maybe more in the future) types of projects. So my domain model could be easily modelled with plain old java objects using type inheritance.
First question:
As i am using spring data jdbc, is this way (inheritance) even supported like it is in JPA?
Second question - as addition to the first one:
I could not found anything regarding this within the official docs. So i am assuming there are good reasons why it is not supported. Speaking of that, may i be on the wrong track modelling entities with inheritance in general?
Currently Spring Data JDBC does not support inheritance.
The reason for this is that inheritance make things rather complicated and it was not at all clear what the correct approach is.
I have a couple of vague ideas how one might create something usable. Different repositories per type is one option, using a single type for persisting, but having some post processing to obtain the correct type upon reading is another one.
I am trying out reactive support in spring-data with MongoDB. I am using spring-boot 2.0.0.
Generally I would write a domain object like this in my project:
#Document
public class PriceData {
......
}
With this spring-data it would create a collection with name priceData in MongoDB. If I want to customize it, then I would do it using the collection attribute:
#Document(collection = "MyPriceData")
Since I want to try reactive support of MongoDB, I want to create a capped collection so that I can use #Tailable cursor queries.
I can create a capped collection in my MongoDB database as specified here:
CollectionOptions options = new CollectionOptions(null, 50, true);
mongoOperations.createCollection("myCollection", options);
or
db.runCommand({ convertToCapped: 'MyPriceData', size: 9128 })
This is not a big problem if I use some external MongoDB database where I can just run this command once. But if I use an embedded MongoDB, then I would have put this in a class which would be executed every time during start up.
Either way I would be creating a collection even before the first request. So I was wondering if there is a way, I could specify to spring-data-mongodb that I need a capped collection instead of regular collection.
Unfortunately #Document doesn't help in this case.
So below is from Oliver
Might be a good idea to have those options exposed to the #Document annotation to automatically take care of them when building the mapping context but we generally got the feedback of people wanting to manually handle those collection setup and indexing operations without too much automagic behavior. Feel free to open a JIRA in case you'd like to see that supported nevertheless.
This is back in 2011. And it seems its still true to date. If you really need the change to handle it using annotation, you should open a JIRA ticket
I was given a task to introduce solr to our product so I thought about spring-data-solr. I have seen this blog:
http://www.petrikainulainen.net/spring-data-jpa-tutorial/
and I was able to run embedded solr in integration test. Since I have a simple POC I wanted to make it more advanced to see whether it fits our needs. So I started to search for mapping nested objects. I found this:
https://stackoverflow.com/questions/30561245/is-is-possible-to-use-embeddables-in-spring-data-solr
Someone answered that version 1.4.0 did not support nested objects. Anyone knows whether it changed? These links look promising:
https://dzone.com/articles/using-solr-49-new
Solr: Indexing nested Documents via DIH
https://issues.apache.org/jira/browse/SOLR-1945
So, wrapping up, here is a list of my questions:
Is it possible to map parent-child relation? (on one level at least?)
If you answered 'no' to first question - then how can I flatten child's fields to be part of solr's document? Should I register some kind of converter somehow? Is there anything else I should do?
I found also this: http://docs.spring.io/spring-data/solr/docs/current/api/org/springframework/data/solr/core/mapping/Indexed.html What is the purpose of this annotation? So far I have seen example with #Id and #Field annotations only. Is it used to generate schema based on model maybe? If so then how can I do that?
Last, but not least - when I create a SolrRepository should I use my JPA entity (annotated with #Fields annotations) as a generic type? Or rather should I create a totally different POJO which should be a view/dto of my jpa entity? This question is again about conversion I guess. If I create a dedicated POJO than I can convert/map fields manually in constructor, but this feels rather bad idea.
is there any tool for Ruby which can transform XML (SOAP) to objects and vice versa? And if possible, generate all the objects (models) from XML schema (XSD). I worked several times with JAXB tool (in Java) and I need something simmilar:
generate models from XML schema
easily create component for serializing and deserializing them
easily create component for storing the objects to database
if possible, generate database tables according to that schema
Do you know any tool for this? What approach would you recommend to complete such task?
Thanks for your answers.
Savon should cover SOAP part of it.
I haven't used it but there is a library called HappyMapper: http://happymapper.rubyforge.org/
I am currently designing a solution to a problem I have. I need to dynamically generate an XML file on the fly using Java objects, in the same way JAXB generates Java classes from XML files, however the opposite direction. Is there something out there already like this?
Alternatively, a way in which one could 'save' a state of java classes.
The goal I am working towards is a dynamically changing GUI, where a user can redesign their GUI in the same way you can with iGoogle.
You already have the answer. It's JAXB! You can annotate your classes and then have JAXB marshal them to XML (and back) without the need to create an XML schema first.
Look at https://jaxb.dev.java.net/tutorial/section_6_1-JAXB-Annotations.html#JAXB%20Annotations to get started.
I don't know, if this is exactly what you're looking for, but there's the java.beans.XMLEncoder:
XMLEncoder enc = new XMLEncoder(new FileOutputStream(file));
enc.writeObject(obj);
enc.close();
The result can then be loaded by XMLDecoder:
XMLDecoder dec = new XMLDecoder(new FileInputStream(file));
Object obj = dec.readObject();
dec.close();
"generate xml from java objects:"
try xtream.
Here's what is said on the tin:
No mappings required. Most objects can be serialized without need for specifying mappings.
Requires no modifications to objects.
Full object graph support
For saving java object state:
Serialization is the way to do this in Java