Though only a single ELResolver is associated with an ELContext, there are usually multiple resolvers considered for any given variable or property resolution. ELResolvers are combined together using a CompositeELResolver, to define rich semantics for evaluating an expression.

For the getValue(ELContext, Object, Object) , getType(ELContext, Object, Object) , setValue(ELContext, Object, Object, Object) and isReadOnly(ELContext, Object, Object) methods, an ELResolver is not responsible for resolving all possible (base, property) pairs. In fact, most resolvers will only handle a base of a single type. To indicate that a resolver has successfully resolved a particular (base, property) pair, it must set the propertyResolved property of the ELContext to true. If it could not handle the given pair, it must leave this property alone. The caller must ignore the return value of the method if propertyResolved is false.

The CompositeELResolver initializes the ELContext.propertyResolved flag to false, and uses it as a stop condition for iterating through its component resolvers.

The ELContext.propertyResolved flag is not used for the design-time methods getFeatureDescriptors(ELContext, Object) and getCommonPropertyType(ELContext, Object) . Instead, results are collected and combined from all child ELResolvers for these methods.