CUBA Platform Developers Manual

EntityManager mostly resembles the standard javax.persistence.EntityManager. The interface helps to obtain references to configuration interfaces. This section describes some of the JMX beans available in the platform.

Time to plan your summer in Montenegro with ANEX Tour online travel agency

However, if the cuba.useEntityDataStoreForIdSequence application property is set to true, sequences are created in the data store the entity belongs to. At screen commit, non-empty attribute values defined in the editor, are set for all the entity instances. In addition to cuba.dbmsType application property, there is an optional cuba.dbmsVersion property. It affects the choice of interface implementations for DbmsFeatures, SequenceSupport, DbTypeConverter, and the search for database init and update scripts.

4.3. The Persistence Interface

Therefore the code will be executed with the existing session and the subsequent call to the end() method will not clear the thread. Query cache stores identifiers of entity instances returned by JPQL queries, so it naturally complements the entity cache. With this in mind, we recommend using declarative transaction management only for simple cases like a service method reading a certain object and returning it to the client. OnBeforeAttach() method is called before the object is attached to the persistence context as a result of EntityManager.merge() operation. OnBeforeDetach() method is called before the object is detached from EntityManager on transaction commit. Behavior of SQL queries returning entities and modifying queries (update, delete) in relation to the current persistence context is similar to that of JPQL queries described above.

• DataManager can select data from the results of previous requests.
• If you have any performance issues with the database access, the first thing to check is what SQL statements are actually executed.
• Defines a reference attribute with one-to-one relationship type.
• Datatype of an entity attribute can be obtained from the corresponding meta-property using getRange().asDatatype() call.
• Therefore we recommend to use only @Component annotation from Spring Framework.
• The fragment element can be added to any UI-container of the screen, including the top-level layout element.
• Belongs to a EntityManager instance, i.e. is contained in its persistence context.

4.2. Data Stores

The event is sent only for entities annotated with @PublishEntityChangedEvents. Do not forget to add this annotation to entities for which you want to listen to EntityChangedEvent. The listener can be used to enforce complex business rules involving multiple entities. The getTransaction() method either creates a new transaction or attaches to an existing one. However calling end() without a prior call to commit() will mark current transaction as RollbackOnly. This section covers various aspects of transaction management in CUBA applications.

5.2. Visual Components Library

It is possible to group update scripts into subdirectories, however, the path to the script with the subdirectory should not break the chronological sequence. For example, subdirectories can be created by using year, or by year and month. On Microsoft SQL Server, providing a connection property is not enough, you have to link the schema with the database user. Below is an example of creating a new database and using a non-default schema in it.

• You can create you own domain-specific constraints with programmatic or declarative validation.
• Defines the inheritance strategy to be used for an entity class hierarchy.
• These interfaces are implemented using the Vaadin framework components.
• By default, in EntityManager, a view affects only reference attributes, i.e. all local attributes are loaded.
• For example, you may want to force a user to enter a value for an entity attribute, but at the same time to have an ability to set this attribute to null by some internal mechanism.
• This section describes some of the JMX beans available in the platform.
• The default implementation of AuthenticationManager is AuthenticationManagerBean, which delegates authentication to a chain of AuthenticationProvider instances.

See the step-by-step guide to working with a custom application component in the Example of Application Component section. A module is the smallest structural part of a CUBA application. It is a single module of an application project and the corresponding JAR file with executable code. User interface can be implemented by one or several blocks, such as Web Client and Web Portal. A block is a separate executable program interacting with other blocks of the application. This chapter contains detailed description of the platform architecture, components and mechanisms.

Websites may show extra security checks when they detect proxy traffic. Instead, you type those URLs into the proxy website’s search box. Think of the proxy as a middleman that visits the site for you.

Integration of QUIC into the platform

• If you want to return a single violation, annotate the annotation class with @ReportAsSingleViolation.
• However, certain DB servers (PostgreSQL in particular) have performance problems when executing SQL queries with distinct if the number of returned records is large (more than 10000).
• Technically, the core framework is also an application component called cuba.
• Some offer mobile apps too, but honestly, the browser versions usually work fine on phones anyway.
• Screens is not a Spring bean, so you can only inject it to screen controllers or obtain using ComponentsHelper.getScreenContext(component).getScreens() static method.

Script sorting is performed by path, starting with the first subdirectory of the type or type-version directory, i.e. regardless of the directory where the script is located (versioned or not). Usually, all the work to convert the data between the database and the Java code is performed by the ORM layer in conjunction with the appropriate JDBC driver. It means that no manual conversion is required when working with the data using DataManager, EntityManager and JPQL queries; you should simply use Java types listed in the left column of the table. Database-related components belong to the Middleware block; other blocks of the application do not have direct access to the database. Generic UI components connected to a datasource get an instance of BeanValidator to check the field value.

• If your application uses only Web or Portal clients, you can safely keep default values of these properties.
• A block is a separate executable program interacting with other blocks of the application.
• The primary attribute is used to set the highlighting for the button.
• When one stops working (and they all do eventually), you can quickly switch to another.
• Based on experimentation, tail lags are still large even though proxies are used to terminate TCP and QUIC close to users.
• Events.publish() notifies all matching listeners registered with this application of an application event.

JPQL query text can include macros, which are processed before the query is executed. They are converted into the executable JPQL and can additionally modify the set of query parameters. The methods of Query mainly correspond to the methods of the standard JPA javax.persistence.Query interface. An instance loaded from the database, or a new one passed to EntityManager.persist(). Belongs to a EntityManager instance, i.e. is contained in its persistence context. You can force EntityManager to load partial entities if you set the loadPartialEntities attribute of the view to true (for example, DataManager does this).

CUBA Platform. Developer’s Manual

The execution of scripts essentially comes down to running a special Gradle task defined in the build.gradle build script. It can be done from the command line or via the Studio interface. The platform contains a special unchecked exception class SilentException. It can be used to interrupt execution without showing any messages to the user or writing them to the log.

4.8. EntityPersistingEvent

The only difference is that it is mandatory for any application. All other components depend on cuba and can also have dependencies between each other. Unlike Web Portal, it is a client-side application (for example, a JavaScript application executed in the web browser). It communicates with the middleware via REST API running either in Web Client or in Web Portal blocks. After you click OK, your configuration will be saved and your Web browser will automatically connect through that proxy on all future connections. If you get an error message such as, “The proxy server is refusing connections” or “Unable to find the proxy server”, there is a problem with your proxy configuration.

TCP performance analysis

• If the screen has unsaved changes in DataContext, a dialog with a corresponding message will be displayed before the screen is closed.
• Setting up the TCP stack on our heterogeneous edge servers was difficult, as TCP has disparate implementations across OS versions.
• You can also set flush mode explicitly using the setFlushMode() method of the Query interface.
• And also attacked with 32 Shahed-type strike drones and various types of simulator drones from the northeast.
• A wave of new Russian TV dramas has hit domestic streaming platforms this spring, pushing aggressive state propaganda.
• Of course, application components can be reusable and provide a domain-specific layer of abstraction on top of the framework.
• This will happen because ORM will run the SQL query with the condition lower(C.NAME) like ?.

Cache of the compiled classes can be cleaned at runtime using CachingFacadeMBean JMX bean. If you need to listen to an event in a bean with interface, implement the ApplicationListener interface instead. On the middle tier, you can use TransactionalDataManager if you need to implement complex transactional behavior.

Common Proxy Website Issues and Solutions

However, these queries can be simpler and faster if related entities are in cache. For example, if you query for Orders together with related Customers and do not use cache, the SQL query will contain a JOIN for customers table. If Customer entities are cached, the SQL query will select only orders, and related customers will be retrieved from the cache.

Note that access group constraints (row-level security) are always applied regardless of the above conditions. You have to open a transaction before working with EntityManager. It is recommended to give descriptive names to the shared views. Defines a reference attribute with one-to-one relationship type.

The web interface of the platform-based applications supports all popular browsers, including Google Chrome, Mozilla Firefox, Safari, Opera 15+, Internet Explorer 11, Microsoft Edge. The service allows you to make a logo in just 5 minutes and absolutely free. You will receive not just a https://keyproxy.net/en logo, but a complete packagefiles, as from the designer.

Then the parameters will be available in InitEvent and AfterInitEvent handlers of the fragment controller. The recommended way of passing parameters to an opened screen is to use public setters of the screen controller, as demonstrated in the example above. In this case, the editor will update the entity, but the caller screen will not receive the updated instance. Screens is not a Spring bean, so you can only inject it to screen controllers or obtain using ComponentsHelper.getScreenContext(component).getScreens() static method.

This annotation is useful when the object being deleted has no attribute that can be checked before deletion. Typically, the object being checked has a reference to the object being deleted, and this is the attribute that should be annotated with @OnDeleteInverse. CUBA platform supports soft deletion mode, when the records are not deleted from the database, but instead, marked in a special way, so that they become inaccessible for common use. Later, these records can be either completely removed from the database using some kind of scheduled procedure or restored.

• The operation of all platform mechanisms is guaranteed when you use these types.
• Detection of database constraint violation errors is done by the UniqueConstraintViolationHandler class which uses regular expressions depending on your database type.
• This confusing behavior is disabled by default and can be enabled using the cuba.enableDeleteStatementInSoftDeleteMode application property.
• Recommendations for usage of the server DB update mechanism can be found in Creating and Updating Database in Production.
• When working with DataManager, query hints can be provided to the query using LoadContext.setHint() method.
• Defines DB column that determines the relationship between entities.

CUBA Studio automatically creates database migration scripts for your changing data model, see its documentation. The information below can be helpful for better understanding of the process and for creating Groovy-based migration scripts not supported in Studio. This section provides information on how to configure database connections and work with particular types of DBMS. It also describes a database migration mechanism, which enables creating a new database and keeping it up-to-date throughout the entire cycle of the development and operation of the application.

This section describes some access control aspects from the developer’s point of view. For complete information on configuring user data access restrictions, see Security Subsystem. They can only be obtained through explicit interface injection or via Configuration.getConfig() but not through AppBeans.get().

If the query is supposed to be used to load entities, we recommend calling createQuery() with the result type as a parameter. An instance loaded from the database and detached from its persistence context (as a result of the transaction end or serialization). Managed beans are Spring beans that contain the business logic of the application.

It is represented by a separate web application running on a Java servlet container. To determine how TCP worked in our applications, we monitored TCP packets using tcpdump for a week on combat traffic coming from the Indian edge servers. Additionally, we created an Android application that sends emulated traffic to a test server, imitating real traffic as much as possible. Smartphones with this application were distributed to several employees who collected logs over several days. The way the data is displayed in columns can be customized using parameterized declarative renderers.

See the Validation in Java applications article in our blog for more details. The sample application described in this article is available on GitHub. The MethodParametersValidationException and MethodResultValidationException exceptions are thrown on validation errors.

Events bean is a simple facade for ApplicationEventPublisher of the Spring Framework. The load(), loadList(), loadValues() and getCount() methods check user’s READ permission for entities being loaded. Additionally, loading entities from the database is subject for access group constraints. Please note that the changes to property values stored in files are not persistent, and are valid only until restart of the application block. Such field is required when an entity class implements the Versioned interface (StandardEntity base class already contains such field). If decimalSeparator and/or groupingSeparator are not specified, the framework uses corresponding values from the format strings for the current user’s locale.

This object can be used to check additional permissions, read User properties and session attributes. The SYS_QUERY_RESULT table is periodically cleaned of old query results left by terminated user sessions. This is done by the deleteForInactiveSessions() method of the QueryResultsManagerAPI bean which is invoked by a Spring scheduler defined in cuba-spring.xml. By default, it is done once in 10 minutes, but you can set a desired interval in milliseconds using the cuba.deleteOldQueryResultsInterval application property of the core module. The table below describes the recommended mapping of data types between entity attributes in Java and table columns in different DBMS. CUBA Studio automatically chooses these types when generates scripts to create and update the database.

The 11 Best Proxy Websites That Actually Work in 2025

Allows you to use a fully qualified enum constant name instead of its database identifier. This simplifies searching for enum usages throughout the application code. If you pass the string (?i)%doe% as a value of the name parameter, the search will return John Doe, if such record exists in the database, even though the case of symbols is different. This will happen because ORM will run the SQL query with the condition lower(C.NAME) like ?. Any changes of the instance in Managed state will be saved to the database when the transaction that the EntityManager belongs to is committed. Reference to EntityManager may be obtained via the Persistence interface by calling its getEntityManager() method.

We are actively looking for ways to improve congestion management and increase the efficiency of QUIC loss recovery algorithms. Inspired by experiments, we have implemented QUIC support in our Android and iOS apps. We conducted A/B testing to determine the impact of QUIC in cities where Uber operates. In general, we saw a significant reduction in tail delays in the context of both regions and telecom operators and network type. We first integrated Cronet into our Android apps to add QUIC support. The integration was carried out in such a way as to minimize the cost of migration.

They are called by services, other beans or via the optional JMX interface. Services are Spring beans that form the application boundary and provide the interface to the client tier. Services may contain the business logic themselves or delegate the execution to managed beans. The search for database init and update scripts prioritizes the type-version directory over the type directory. This means that the scripts in the type-version directory replace the scripts with the same name in the type directory. The type-version directory can also contain some scripts with unique names; they will be added to the common set of scripts for execution, too.