com.smartgwt.client.docs

Interface DsRequestEquivalence

public interface DsRequestEquivalence

Various subsystems have a need to compare DataSource requests and understand if they are equivalent or affect the same data (examples include automatic cache synchronization and offline caching and synchronization).

Aside from basic properties that would clearly make two DSRequests non-equivalent (dataSource, operationType and data, as well as sortBy, startRow, endRow and textMatchStyle for a "fetch"), operationId is the only property that will cause two DSRequests to be considered distinct (non-equivalent) requests.

Bearing this in mind, the best practice is:

• everything that will be treated as criteria or as values on the server side should be part of data. Do not "smuggle" data that will ultimately be used as criteria or values in other dsRequest properties, such as HTTP parameters.
• use operationId as the sole piece of information in the request that modifies how the request as a whole is executed. If two or more pieces of information are required, combine or encode them into a single operationId String. If this becomes awkward because there are many operation variants, consider including additional fields in data instead.

DataSource.cloneDSRequest() can be used to create an equivalent DSRequest.