When a message routing pattern is used, messages get routed through several systems based on the fulfillment of certain criteria or rules. But when messages pass through several systems, there is a likelihood that they get out of order. In these situations, the resequencer pattern comes in handy. The diagram depicting the resequencer pattern is given as follows:

The resequencer is a stateful filter that can be used to reorder messages so that they can be published in a specific sequence to the output channel. The resequencer contains an internal buffer that stores a sequence of messages until the complete sequence is obtained. The in-sequence messages are published immediately to the output channel. The out-of-sequence messages are kept in the internal buffer until they are placed in sequence and then they are sent to the output channel. The resequencer just...