I commonly use a prefix pattern when storing documents in couchbase. For example a user document might have a key like "user::myusername" and an order document might have a key of "order::1".
I'm new to spring-data and don't see a way to easily make it work with these prefixes. I can specify a field in my object like:
public class UserLogin {
public static final String dbPrefix = "user_login::";
#Id
private String id;
private String username;
.
.
.
public void setUsername(String username) {
this.username = username;
this.id = dbPrefix + this.username;
}
}
and have a Crud repository
public interface UserLoginRepo extends CrudRepository<UserLogin, String> {
}
This is an ok work around because I can:
...
userLoginRepo.save(login)
UserLogin login = userLoginRepo.findOne(UserLogin.dbPrefix + "someuser");
...
It would be really nice if there were some way to have the repository automatically use the prefix behind the scenes.
not sure if you are asking a question here. Spring-data doesn't have any built-in mechanism to do what you want. If you are using Spring-cache with couchbase this is possible since you can annotate your cached methods with naming patterns like this, for example, in spring cache you can do something like this on the persistence method:
#Cacheable(value = "myCache", key = "'user_login::'+#id")
public UserLogin getUserLogin()
Obviously though, this is Spring cache and not spring data, however both are supported in the same library.
Related
I'm using a IStringLoclizer approach with a resx file containing key-value pairs to localize my app as decribed in the documentation.
I've just discovered that:
On the one hand the .resx file is case insensitive (storing the key Firstname and FirstName will throw an error of key already existing).
On the second hand, when I want to RETRIEVE the keys, it IS case sensitive (if the key Firstname exists and I want to get the value of FirstName, the value is not retrieved by IStringLoclizer - which makes sense from the key-value pair point of view!).
Is there a way to override the IStringLocalizer getters, in order to implement some logic (e.g. change all keys to lowercase, and search any key by lowercase)? The key of a valid solution is to avoid changing all keys in the .resx file AND wherever I call the IStringLocalizer.
Edit
I found out about ResourceManager.IgnoreCase here, but it is not clear to me how to access the resource manager - probably this has to be done in Startup.cs somehow?
This can be achieved by overwriting the ResourceManagerStringLocalizerFactory.
public class CaseInsensitiveResourceManagerStringLocalizerFactory : ResourceManagerStringLocalizerFactory
{
public CaseInsensitiveResourceManagerStringLocalizerFactory(IOptions<LocalizationOptions> localizationOptions, ILoggerFactory loggerFactory) : base(localizationOptions, loggerFactory)
{
}
//unfortunately we need to use reflection to the the ResourceManager as the field is private
private readonly FieldInfo _field = typeof(ResourceManagerStringLocalizer).GetField("_resourceManager", BindingFlags.NonPublic | BindingFlags.Instance);
//override this method to access the resource manager at the time it is created
protected override ResourceManagerStringLocalizer CreateResourceManagerStringLocalizer(Assembly assembly, string baseName)
{
//call the base method to get the localizer, I would like to override this implementation but the fields used in the construction are private
var localizer = base.CreateResourceManagerStringLocalizer(assembly, baseName);
if (_field == null) return localizer;
//set the resource manager to ignore case
if (_field.GetValue(localizer) is ResourceManager resourceManager) resourceManager.IgnoreCase = true;
return localizer;
}
}
The you need to register the factory before you add the localization.
public void ConfigureServices(IServiceCollection services)
{
services.AddSingleton<IStringLocalizerFactory, CaseInsensitiveResourceManagerStringLocalizerFactory>();
services.AddLocalization(options => { options.ResourcesPath = "Resources"; });
//other service configurations....
}
I hope in the future these class are made more extensible. Private fields in both in ResourceManagerStringLocalizerFactory and ResourceManagerStringLocalizer necessitates reflection.
I'm using OrmLite with both SqlServer, Oracle and PostgreSQL dialects.
I want to use GUIDs as primary keys and have a simple object, using the AutoId attribute:
public class MyObject
{
[AutoId]
public Guid Id { get; set; }
[Required]
public string Name { get; set; }
...
All goes well with SqlServer and PostgreSQL dialetcs, but with Oracle I get an initial GUID with all zeros in the db, and a subsequent INSERT violates the unique key constraint of my primary key. How can this be accomplished db agnostic so it also works with Oracle?
Based on the source code I'm looking at, it doesn't appear to properly generate GUIDs for anything that's not SQL Server or PostgreSQL, regardless of what the documentation actually says on the README. Relevant code links below:
SQL Server
PostgreSQL
Base Dialect Provider
The best alternative I can provide here is to override the OracleOrmLiteDialectProvider. Specifically, I would override the GetAutoIdDefaultValue method to return "SYS_GUID()" if the field type is a GUID. Sample code below...
public OracleNewGuidOrmLiteDialectProvider : OracleOrmLiteDialectProvider
{
public static OracleNewGuidOrmLiteDialectProvider Instance = new OracleNewGuidOrmLiteDialectProvider();
public string AutoIdGuidFunction { get; set; } = "SYS_GUID()";
public override string GetAutoIdDefaultValue(FieldDefinition fieldDef)
{
return fieldDef.FieldType == typeof(Guid)
? AutoIdGuidFunction
: null;
}
}
To match the rest of the provider implementations, I would recommend creating a OracleNewGuidDialect class, like below...
public static class OracleNewGuidDialect
{
public static IOrmLiteDialectProvider Provider => OracleNewGuidOrmLiteDialectProvider.Instance;
}
Then you would set the provider when you instantiate your OrmLiteConnectionFactory to OracleNewGuidOrmLiteDialectProvider.Instance, similar to below...
var dbFactory = new OrmLiteConnectionFactory(oracleConnectionString, OracleNewGuidDialect.Provider);
This isn't the best solution, but the pluggable nature of ServiceStack ORMLite allows you to control everything to the extent that you need. Hope this helps. Also, quick caveat--I didn't fully bake this solution, so you may need to tweak it, but based on the other implementations of the providers, it seems straightforward.
I have a graph of objects that I'd like to return different views of. I don't want to use Jackson's #JsonViews to implement this. Right now, I use Jackson MixIn classes to configure which fields are shown. However, all my rest methods return a String rather than a type like BusinessCategory or Collection< BusinessCategory >. I can't figure out a way to dynamically configure the Jackson serializer based on what view I'd like of the data. Is there any feature built into Spring to configure which Jackson serializer to use on a per-function basis? I've found posts mentioning storing which fields you want in serialized in thread-local and having a filter send them and another post filtering based on Spring #Role, but nothing addressing choosing a serializer (or MixIn) on a per-function basis. Any ideas?
The key to me thinking a proposed solution is good is if the return type is an object, not String.
Here are the objects in my graph.
public class BusinessCategory implements Comparable<BusinessCategory> {
private String name;
private Set<BusinessCategory> parentCategories = new TreeSet<>();
private Set<BusinessCategory> childCategories = new TreeSet<>();
// getters, setters, compareTo, et cetera
}
I am sending these across the wire from a Spring MVC controller as JSON like so:
#RestController
#RequestMapping("/business")
public class BusinessMVC {
private Jackson2ObjectMapperBuilder mapperBuilder;
private ObjectMapper parentOnlyMapper;
#Autowired
public BusinessMVCfinal(Jackson2ObjectMapperBuilder mapperBuilder) {
this.mapperBuilder = mapperBuilder;
this.parentOnlyMapper = mapperBuilder.build();
parentOnlyMapper.registerModule(new BusinessCategoryParentsOnlyMapperModule());
}
#RequestMapping(value="/business_category/parents/{categoryName}")
#ResponseBody
public String getParentCategories(#PathVariable String categoryName) throws JsonProcessingException {
return parentOnlyMapper.writeValueAsString(
BusinessCategory.businessCategoryForName(categoryName));
}
}
I have configure the serialization in a MixIn which is in turn added to the ObjectMapper using a module.
public interface BusinessCategoryParentsOnlyMixIn {
#JsonProperty("name") String getName();
#JsonProperty("parentCategories") Set<BusinessCategory> getParentCategories();
#JsonIgnore Set<BusinessCategory> getChildCategories();
}
public class BusinessCategoryParentsOnlyMapperModule extends SimpleModule {
public BusinessCategoryParentsOnlyMapperModule() {
super("BusinessCategoryParentsOnlyMapperModule",
new Version(1, 0, 0, "SNAPSHOT", "", ""));
}
public void setupModule(SetupContext context) {
context.setMixInAnnotations(
BusinessCategory.class,
BusinessCategoryParentsOnlyMixIn.class);
}
}
My current solution works, it just doesn't feel very clean.
"categories" : [ {
"name" : "Personal Driver",
"parentCategories" : [ {
"name" : "Transportation",
"parentCategories" : [ ]
} ]
}
Oh yes, I'm using:
spring-boot 1.2.7
spring-framework: 4.1.8
jackson 2.6.3
Others listed here: http://docs.spring.io/spring-boot/docs/1.2.7.RELEASE/reference/html/appendix-dependency-versions.html
In the end, the only process that met my needs was to create a set of view objects which exposed only the fields I wanted to expose. In the grand scheme of things, it only added a small amount of seemingly unnecessary code to the project and made the flow of data easier to understand.
I want to use Realm to replace SqLite in Android to store a list of classes, my code is very simple as below.
public class MyRealmObject extends RealmObject {
public String getField() {
return field;
}
public void setField(String field) {
this.field = field;
}
private String field;
...
}
List<MyObject> myObjects = new ArrayList();
Realm realm = Realm.getInstance(this);
for(MyRealmObject realm : realm.allobjects(MyRealmObject.class)) {
myObjects.add(new MyObject(realm));
}
realm.close();
return myObjects;
However, its performance is actually slower than a simple SqlLite table on my tested device, am I using it the wrong way? Is there any optimization tricks?
Why do you want to wrap all your RealmObjects in the MyObject class?. Especially copying the entire result set means you will loose the benefit of using Realm, namely that it doesn't copy data unless needed to.
RealmResults implements the List interface so you should be able to use the two interchangeably.
List<MyRealmObject> myObjects;
Realm realm = Realm.getInstance(this);
myObjects = realm.allObjects(MyRealmObject.class();
return myObjects;
Suppose I use the [RemoteClass] tag to endow a custom Flex class with serialization intelligence.
What happens when I need to change my object (add a new field, remove a field, rename a field, etc)?
Is there a design pattern for handling this in an elegant way?
Your best bet is to do code generation against your backend classes to generation ActionScript counterparts for them. If you generate a base class with all of your object properties and then create a subclass for it which is never modified, you can still add custom code while regenerating only the parts of your class that change. Example:
java:
public class User {
public Long id;
public String firstName;
public String lastName;
}
as3:
public class UserBase {
public var id : Number;
public var firstName : String;
public var lastName : String;
}
[Bindable] [RemoteClass(...)]
public class User extends UserBase {
public function getFullName() : String {
return firstName + " " + lastName;
}
}
Check out the Granite Data Services project for Java -> AS3 code generation.
http://www.graniteds.org
Adding or removing generally works.
You'll get runtime warnings in your trace about properties either being missing or not found, but any data that is transferred and has a place to go will still get there. You need to keep this in mind while developing as not all your fields might have valid data.
Changing types, doesn't work so well and will often result in run time exceptions.
I like to use explicit data transfer objects and not to persist my actual data model that's used throughout the app. Then your translation from DTO->Model can take version differences into account.