Used to lookup meta data concerning a particular component. The primary source of meta data is the meta data defined for the component, accessed via {@link org.apache.tapestry5.model.ComponentModel#getMeta(String)}. This includes meta data defined by base classes. When meta-data for a particular component can not be found, a search works up the containment hierarchy (to the component's container, and the container's container, and so on). If
that proves unfruitful, a system of defaults is provided by configuration and matched against the containing page's logical name.
Finally, if no metadata is available, then {@link org.apache.tapestry5.ioc.services.SymbolSource#valueForSymbol(String)}is used to obtain a value. Generally speaking, if you are going to use this service to look up meta data, your should also make a contribution to the FactoryDefaults service; otherwise, you risk a runtime exception if a meta-data key can not be resolved.