Functional approach

Since Content Integration Framework does not initiate and manage the outgoing connections in case of Functional services, it cannot keep track of end to end success.

Hence, it provides certain standard exceptions, which the service implementations can throw to convey relevant failure conditions. These exceptions are related to communication with the target system and are present within the com.hcl.unica.system.integration.exception package.

• SystemNotFoundException

  This exception must be used when the target system or content repository cannot be located. Alternatively, java.net.UnknownHostException can also be used. This exception is conveyed as 404 HTTP response to the client.

• ServiceNotFoundException

  This exception must be used when the remote endpoint returns 404, or if the target service no longer exists. Absence of the target system and the absence of the required service are considered as different things. Hence, the ServiceNotFoundException conveys presence of the target system and the absence of the required service, or feature, on the target system. For example, in case of content fetched from the database, the absence of the required table (or the absence of the permission to access it) can be conveyed using this exception. This exception is conveyed as 404 HTTP response to the client.

• UnreachableSystemException

  This exception must be used to convey unreachable or inaccessible target systems, such as connection timeout. Alternatively, java.net.ConnectException can also be used. This exception is conveyed as 503 HTTP response to the client.

• SluggishSystemException

  When the response from the target system is not received within expected time, this exception must be used to convey the slowness of the target system. Alternatively, java.net.SocketTimeoutException can also be used. This exception is conveyed as 504 HTTP response to the client.

• InternalSystemError

  This exception must be used if the plugin receives a temporary, or unexpected, error from the target system to convey the problems in it. This exception is conveyed as 502 HTTP response to the client.

Any other exceptions are conveyed as 502 HTTP response to the client. In any case, the message in the exception is never returned to the client. Each HTTP response code carries a fixed, generic, and localized message.

Content Integration Framework wraps the exceptions received from service implementations into com.hcl.unica.system.integration.exception.ServiceExecutionException or its subtype. Exceptions received from REST-based services or HTTP-based services are wrapped in com.hcl.unica.system.integration.exception.HttpServiceExecutionException, whereas the ones received from Functional services are wrapped in com.hcl.unica.system.integration.exception.ServiceExecutionException.

As explained in Service invocation, HttpServiceExecutionException provides a method to obtain an Optional<HttpResponse> object. If the service execution fails before initiating an HTTP call, then this Optional object will not contain any HttpResponse.