The FIX adapter exchanges FIX messages with datasources such as files and socket connections, as well as other FIX engines.
Files and socket connections are handled by the Connection Manager. Sessions with other FIX engines are handled by the Session Manager.
Adapters are one-directional. You can use each adapter to receive messages from (or send them to) a single source of FIX data, such as a file, a client socket connection, or a server socket connection. By default, file and socket adapters validate the checksum and body length tags of all input messages. You can turn validation off in the adapter configuration file.
Sessions with other FIX engines are two-directional. Input messages received via sessions are always validated. You cannot turn off validation for sessions. Session management (login, logout, message sequence numbers, resending of messages, and so on), as well as message validation, is performed by the QuickFIX API.
Invalid input messages are discarded and any errors are logged. Otherwise, messages are parsed and published to stream clusters even if their checksum or body length tags are absent or have incorrect values.
Before sending an output message, the adapter recalculates its checksum and body length and updates the appropriate tags.