In the Couchbase documentation the below is given as an example to configure the environment. What would be done for having more than one bucket ?
#Configuration
public class Config extends AbstractCouchbaseConfiguration {
#Override
protected List<String> getBootstrapHosts() {
return Collections.singletonList("127.0.0.1");
}
#Override
protected String getBucketName() {
return "beer-sample";
}
#Override
protected String getBucketPassword() {
return "";
}
}
For multiple buckets in 2.0.x branch, the way it currently works is that you have to instantiate a second Bucket bean and the associated CouchbaseTemplate (that's the hardest part):
//we want all User objects to be stored in a second bucket
//let's define the bucket reference...
#Bean
public Bucket userBucket() {
return couchbaseCluster().openBucket("users", "");
}
//... then the template (inspired by couchbaseTemplate() method)...
#Bean
public CouchbaseTemplate userTemplate() {
CouchbaseTemplate template = new CouchbaseTemplate(
couchbaseClusterInfo(), //reuse the default bean
userBucket(), //the bucket is non-default
mappingCouchbaseConverter(), translationService() //default beans here as well
);
template.setDefaultConsistency(getDefaultConsistency());
return template;
}
After that, you'll probably also want some of your repositories to use this second template (and bucket). There's currently an implementation for that as well (RepositoryOperationsMapping), but it's probably going to change a bit until upcoming 2.0.0-RC so I won't go into details there.
Related
My data people gave me the http://127.0.0.1:8091/pools url to connect to our Couchbase server and I've been told the pools suffix is the address to all the nodes in the cluster.
I'm using Spring 4.2.0.RELEASE with spring-data-couchbase 2.0.0.M1 against Couchbase 2.5.1 enterprise edition (build-1083)
Now, if I add the above url as is into the getBootstrapHosts list:
#Override
protected List<String> getBootstrapHosts() {
return Collections.singletonList(couchbaseProperties.getHost());
}
I get a number format exception on the 8091/pools value.
But when using the http://127.0.0.1:8091 url I get an invalid password exception.
I reckon the first url is to be used, but not in the way I went for.
There is probably a method I should override in the AbstractCouchbaseConfiguration class, but looking at the source code didn't really enlighten me.
Here is the Couchbase configuration class.
#Configuration
#EnableCouchbaseRepositories(basePackages = { "com.thalasoft.data.couchbase.repository" })
#ComponentScan(nameGenerator = PackageBeanNameGenerator.class, basePackages = { "com.thalasoft.data.couchbase.config" })
#EnableTransactionManagement
public class CouchbaseConfiguration extends AbstractCouchbaseConfiguration {
private static Logger logger = LoggerFactory.getLogger(CouchbaseConfiguration.class);
#Autowired
private CouchbaseProperties couchbaseProperties;
#Override
protected List<String> getBootstrapHosts() {
return Collections.singletonList(couchbaseProperties.getHost());
}
#Override
protected String getBucketName() {
return couchbaseProperties.getBucketName();
}
#Override
protected String getBucketPassword() {
return couchbaseProperties.getBucketPassword();
}
#Bean
public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
return new PropertySourcesPlaceholderConfigurer();
}
#Bean
public LocalValidatorFactoryBean validator() {
return new LocalValidatorFactoryBean();
}
#Bean
public ValidatingCouchbaseEventListener validationEventListener() {
return new ValidatingCouchbaseEventListener(validator());
}
}
The fact that your database administrators gave you 127.0.0.1 as the adress to connect to seem strange, but indeed could be valid if one node of the cluster is running colocated with the client code...
This url-based syntax was the one used for the 1.4.x generation of SDK, and configuration is indeed a bit different in 2.x (reflecting the evolution of the Couchbase SDK between 1.4.x and 2.x): you just need to provide the hostname or ip of each node to bootstrap from, in a list.
You should try with just "127.0.0.1". It is possible also that you need to specify a bucket name and/or a password (ask your administrator). The defaults used by Spring Data Couchbase for each is "default" and "" (empty password), but you can override the getBucketName() and getBucketPassword() methods from AbsctractCouchbaseConfiguration to change that.
PS: the Spring Data Couchbase documentation is available here
My application has configurations which are loaded using parsing annotations into a file using Jackson's fasterxml annotations. For example:
public class RootConfiguration extends Configuration {
#JsonProperty
#NotEmpty
public String foo;
#JsonProperty
public BarConfiguration bar;
public class BarConfiguration extends Configuration {
#JsonProperty
public String baz;
}
}
The configuration is then injected into providers in my Module that help me bind those properties to places in the code that use them. Like so:
#Provides
#Named("config")
public RootConfiguration provideRootConfiguration(RootConfiguration configuration) {
return configuration;
}
#Provides
#Named("config.foo")
public String provideFooConfiguration(RootConfiguration configuration) {
return configuration.foo;
}
#Provides
#Named("config.bar")
public BarConfiguration provideBarConfiguration(RootConfiguration configuration) {
return configuration.bar;
}
And so on.
I'm looking for a framework to help me avoid this tedious work.
I would imagine something that looks like this:
#Configuration(value = "config", bindSubProperties = true)
public class RootConfiguration extends Configuration {
...
That would use Reflection to bind any sub fields in my class as guice Names.
I've looked into Governator's annotations for configurations but as far as I can see they need to be applied to every configuration that I want to bind, which saves me some coding, but is essentially the same (I still have to manually specify the path for each and every configuration I want to bind).
Before I roll out my own implementation for this, is there something that will give me what I need?
Note: I'm using this for a Dropwizard project so the constraint on using Jackson to map the configuration to POJOs is rather tight (unless I move the application configuration outside of the config yaml).
I don't know of any tool that would do this for you, but you could do it yourself pretty easily with something like this:
void bindConfiguration() {
for (Field field : RootConfiguration.class.getFields() {
bindConfiguration(TypeLiteral.get(field.getGenericType()), field);
}
}
<T> void bindConfiguration(TypeLiteral<T> type, Field field) {
bind(type)
.annotatedWith(Names.named("config." + field.getName()))
.toProvider(new ConfigurationProvider<T>(field))
.in(Singleton.class);
}
class ConfigurationProvider<T> implements Provider<T> {
private final Field field;
#Inject RootConfiguration configuration;
ConfigurationProvider(Field field) {
this.field = field;
}
#Override
public T get() {
return (T) field.get(configuration);
}
}
To share data (complexe data ) between pages in my windows phone 8 application I want to implement a singleton, but I want it to be generic, is it possible? I suppose that it creates a new instance for each type isn't it?
public sealed class NavigationContextService<T>
{
private static readonly NavigationContextService<T> instance = new NavigationContextService<T>();
private NavigationContextService()
{
}
public static NavigationContextService<T> Instance
{
get
{
return instance;
}
}
public List<T> ShareList { get; set; }
public T ShareData { get; set; }
}
It is creating a new instance for every type, because it is generic - you want it to be like this (if you start with generics, take a look at some tutorials, blogs or MSDN - you will easily find many in the internet).
It is still a singleton. When you use
NavigationContextService<string>.Instance.ShareList.Add("Text");
then you have one Instance for type string. Generics helps a lot when you want to create same methods/classes that differ in type.
On the other hand if you want to create Singleton that will hold different types then you can for example modify your class to be non Generic like this:
public sealed class NavigationContextServiceNonGeneric
{
private static readonly NavigationContextServiceNonGeneric instance = new NavigationContextServiceNonGeneric();
private NavigationContextServiceNonGeneric() { ShareList = new List<object>(); }
public static NavigationContextServiceNonGeneric Instance
{ get { return instance; } }
public List<object> ShareList { get; set; }
public object ShareData { get; set; }
}
As you can see in the code above I haven't defined the 'exact' type of shared data - it is object type. Then you can easily hold most of data with it:
NavigationContextServiceNonGeneric.Instance.ShareList.Add("Text");
NavigationContextServiceNonGeneric.Instance.ShareList.Add(3);
NavigationContextServiceNonGeneric.Instance.ShareList.Add(3.0f);
It is singleton, which can hold different types of shared data. BUT it has also disavantages - the main is that you have to remember what type of data you hold and in what order. In my opinion Generic version is better because of that fact.
Everything depends on the purpose of your code. There may be easier and better ways that those two approaches.
As for the Page Navigation, you can for example try to use a method from this article - you extend Navigation service to pass the object:
public static class Extensions
{
private static object Data;
public static void Navigate(this NavigationService navigationService, Uri source, object data)
{
Data = data;
navigationService.Navigate(source);
}
public static object GetNavigationData(this NavigationService service) { return Data; }
}
Then you use it:
NavigationService.Navigate(yourUri, DataToPass);
After Navigation you can get your data:
string myTextData = NavigationService.GetNavigationData() as string;
This method has to disadvantages: it is not type-safe and your data won't be preserved in Tombstone mode.
As for the second disadvantage you can easily use PhoneApplicationService.State Property for the purpose of Page Navigation - it is a dictionary (which is preserved while tombstoning):
PhoneApplicationService.Current.State.Add("data", yourData);
Then when you want to get your data:
yourDataType yourData = PhoneApplicationService.Current.State["data"] as yourDataType;
There are also more ways in which you can pass the data.
I've inherited a system that uses the Castle Windsor IRepository pattern to abstract away from the DAL which is LinqToSQL.
The main problem that I can see, is that IRepository only implements IEnumerable. So even the simplest of queries have to load ALL the data from the datatable, to return a single object.
Current usage is as follows
using (IUnitOfWork context2 = IocServiceFactory.Resolve<IUnitOfWork>())
{
KpiFormDocumentEntry entry = context2.GetRepository<KpiFormDocumentEntry>().FindById(id, KpiFormDocumentEntry.LoadOptions.FormItem);
And this uses lambda to filter, like so
public static KpiFormDocumentEntry FindById(this IRepository<KpiFormDocumentEntry> source, int id, KpiFormDocumentEntry.LoadOptions loadOptions)
{
return source.Where( qi => qi.Id == id ).LoadWith( loadOptions ).FirstOrDefault();
}
So it becomes a nice extension method.
My Question is, how can I use this same Interface/pattern etc. but also implement IQueryable to properly support LinqToSQL and get some serious performance improvements?
The current implementation/Interfaces for IRepository are as follows
public interface IRepository<T> : IEnumerable<T> where T : class
{
void Add(T entity);
void AddMany(IEnumerable<T> entities);
void Delete(T entity);
void DeleteMany(IEnumerable<T> entities);
IEnumerable<T> All();
IEnumerable<T> Find(Func<T, bool> predicate);
T FindFirst(Func<T, bool> predicate);
}
and then this is implemented by an SqlClientRepository like so
public sealed class SqlClientRepository<T> : IRepository<T> where T : class
{
private readonly Table<T> _source;
internal SqlClientRepository(Table<T> source)
{
if( source == null ) throw new ArgumentNullException( "source", Gratte.Aurora.SHlib.labelText("All_TableIsNull",1) );
_source = source;
}
//removed add delete etc
public IEnumerable<T> All()
{
return _source;
}
public IEnumerator<T> GetEnumerator()
{
return _source.GetEnumerator();
}
IEnumerator IEnumerable.GetEnumerator()
{
return GetEnumerator();
}
}
The problem at the moment is, in our example above, the .Where is calling 'GetEnumerator', which then loads all rows into memory, and then looks for the one we need.
If I change IRepository to implement IQueryable, I can't implement the three methods needed, as these are not public in the Table class.
I think I should change the SQLClientRepository to be defined like so
public sealed class SqlClientRepository<T> : IQueryable<T>, IRepository<T> where T : class
And then implement the necessary methods, but I can't figure out how to pass the expressions around etc. as they are private members of the Table class, like so
public override Type ElementType
{
get { return _source.ElementType; } //Won't work as ElementType is private
}
public override Expression Expression
{
get { return _source.Expression; } //Won't work as Expression is private
}
public override IQueryProvider Provider
{
get { return _source.Provider; } //Won't work as Provider is private
}
Any help really appreciated to move this from 'iterate through every row in the database after loading it' to 'select x where id=1'!
If you want to expose linq you can stop using the repository pattern and use Linq2Sql directly. The reason to this is that every Linq To Sql provider has it's own custom solutions. So if you expose LINQ you get a leaky abstraction. There is no point in using an abstraction layer then.
Instead of exposing LINQ you got two options:
Implement the specification pattern
Use the repository pattern as I describe here: http://blog.gauffin.org/2013/01/repository-pattern-done-right/
So, while it may not be a true abstraction any longer, the main point was to get the benefit of linq to sql without updating all the queries already written.
so, I made the IRepository implement IQueryable instead of IEnumerable.
then in the SqlClientRepository implementation, I can call AsQueryable() to cast the Table to IQueryable, and then all is good, like so.
Now everywhere somebody has written IRepository().Where(qi => qi.id = id) or similar, it actually passes the ID to sql server and only pulls back one record, instead of all of them, and loops through looking for the correct one.
/// <summary>Provides the ability to query and access entities within a SQL Server data store.</summary>
/// <typeparam name="T">The type of entity in the repository.</typeparam>
public sealed class SqlClientRepository<T> : IRepository<T> where T : class
{
private readonly Table<T> _source;
private readonly IQueryable<T> _sourceQuery;
IQueryable<T> Query()
{
return (IQueryable<T>)_source;
}
public Type ElementType
{
get { return _sourceQuery.GetType(); }
}
public Expression Expression
{
get { return _sourceQuery.Expression; }
}
public IQueryProvider Provider
{
get { return _sourceQuery.Provider; }
}
/// <summary>Initializes a new instance of the <see cref="SqlClientRepository{T}"/> class.</summary>
/// <param name="source">A <see cref="Table{T}"/> to a collection representing the entities from a SQL Server data store.</param>
/// <exception cref="ArgumentNullException"><paramref name="source"/> is a <c>null</c> reference (<c>Nothing</c> in Visual Basic).</exception>
internal SqlClientRepository(Table<T> source)
{
if( source == null ) throw new ArgumentNullException( "source", "All_TableIsNull" ) );
_source = source;
_sourceQuery = _source.AsQueryable();
}
I'm using EF4.1 with MVC3 and I need an override to prevent EF from creating a db if it doesn't exist. Instead of creating a new db I would like to catch the error and report that the initial catalog (the database name) is invalid in the connect string.
However, during development I would like to allow for updates for new classes/properties to create according tables/cols in the database.
Is there a best practice or pattern here?
In my application i am completly disable context initializer and handle database mapping and schema manually.
For example :
public class AppDbContext : DbContext
{
public IDbSet<Account> Accounts { get; set; }
public AppDbContext() : base("connection_string")
{
Database.SetInitializer<AppDbContext>(null); // Important! Dont use entity framework initializer !important
}
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
/* Register custom mapping class */
modelBuilder.Configurations.Add(new AccountMapper());
base.OnModelCreating(modelBuilder);
}
}
And custom mapping :
public class AccountMapper : EntityTypeConfiguration<Account>
{
/// <summary>
/// Employee entity mapper
/// </summary>
public AccountMapper()
{
ToTable("accounts");
HasKey(x => x.Id);
...
}
}
I would suggest looking into the EF database initializer, specifically the IDatabaseInitializer interface.
If you just want it to stop creating the database when it doesn't exist, then just set the Initializer to null. But if you want to log the event or something along those lines then simply create your own IDatabaseInitializer - it's not hard.
You can then set the initializer Application_Start in your global.asax.cs like so:
Database.SetInitializer(new YourCustomInitializer());
As a bonus, here's an example IDatabaseInitializer that I use to run database migrations (using FluentMigrator)... it's extremely handy if I do say so myself!
public class MigrationsDbContextInitializer : IDatabaseInitializer<YourDbContext>
{
private static readonly ILog Logger = LogManager.GetLogger(typeof(MigrationsDbContextInitializer));
public void InitializeDatabase(YourDbContext context)
{
var announcer = new BaseAnnouncer(x => Logger.Info(x));
var runnerContext = new RunnerContext(announcer)
{
Database = "sqlserver2008",
Connection = context.Database.Connection.ConnectionString,
Target = "YourEntitiesNamespace",
PreviewOnly = false,
Task = "migrate"
};
new TaskExecutor(runnerContext).Execute();
}
}