Internationalization context
An internationalization context is a distributable collection of internationalization information containing an ordered list, or chain, of locales and a single time zone, where the locales and time zone are instances of the java.util.Locale and java.util.TimeZone Java SDK types, respectively. A locale chain is ordered according to the user's preference.
The internationalization service manages and makes available two varieties of internationalization context: the caller context, which represents the caller's localization environment, and the invocation context, which represents the localization environment under which a business method runs. Server application components use elements of the caller and invocation internationalization contexts to appropriately tailor locale-sensitive and time zone-sensitive computations.
The internationalization service does not support time zone types other than the java.util.SimpleTimeZone type that is found in the Java SDK. Unsupported time zone types silently map to the default time zone of the JVM when supplied to internationalization context API methods. For a complete description of the java.util.Locale, java.util.TimeZone and java.util.SimpleTimeZone types, refer the Java SDK API documentation.
Caller context
Caller internationalization context contains the locale chain and time zone received on incoming EJB business method and servlet service method invocations; it is the internationalization context propagated from the calling process. Use caller context elements within server application components to localize computations to the calling component. Caller context is read-only and can be accessed by all application components by using the Internationalization interface of the internationalization context API.
Caller context is computed in the following manner: On an EJB business method or servlet service method invocation, the internationalization service extracts the internationalization context from the incoming request and scopes this context to the method as the caller context. For any missing or null context element, the service inserts the corresponding default element of the JVM (for example, java.util.Locale.getDefault() or java.util.TimeZone.getDefault().) The service performs a similar insertion whenever missing or null Caller context elements are encountered on invocations of stateless session beans that are enabled for Web services.
Formally, caller context is the invocation context of the calling business method or application component.
Invocation context
Invocation internationalization context contains the locale chain and time zone under which EJB business methods and servlet service methods run. It is managed by either the hosting container or the application component, depending on the applicable internationalization policy. On outgoing business method requests, it is the context that propagates to the target process. Use invocation context elements to localize computations under the specified settings of the current application component.
Invocation context is computed in the following manner: On an incoming business method or servlet service method invocation, the internationalization service queries the associated context management policy. If the policy is container-managed internationalization (CMI), the container scopes the context designated by the policy to the invocation; otherwise the policy is application-managed internationalization (AMI), and the container scopes an empty context to the invocation that can be altered by the method implementation.
Application components can access invocation context elements through both the Internationalization and InvocationInternationalization interfaces of the internationalization context API. Invocation context elements can be set (overwritten) under the application-managed internationalization policy only.
On an outgoing business method request, the service obtains the currently scoped invocation context and attaches it to the request. This outgoing exported context becomes the caller context of the target invocation. When supplying invocation context elements, either for export on outgoing requests or through the API, the internationalization service always provides the most recent element set using the API; the service also supplies the corresponding default element of the JVM for any null invocation context element.
Because the internationalization context that is propagated over Web services (SOAP) requests contains a time zone ID rather than the entire state of a java.lang.SimpleTimeZone object, time zone information might be lost when a Web service-enabled client program or session bean becomes involved in remote business computation.
Related concepts
Internationalization context: Propagation and scope
Related tasks
Use the internationalization context API
Related Reference
Internationalization context API: Programming reference