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Fig. 10.5 Resource Service internal architecture

maximizes response times while minimizing load on the interface and persisted data
sources. Modifications made to the internal YAWL org model are written to both
cache and the persistent source (at times of low load). If the org model is loaded
from an external source, then as stated in Sect. 10.3, it is treated as read-only, and
so modifications to the data are assumed to be also carried out externally. While it
is only necessary to load internal organizational data into the cache once on start-
up, a service configuration value may be set for external sources so that the caches
are updated at a regular, specified interval to enable synchronization with external
modifications.