@Nullable open fun compile(expression: SpelNodeImpl): CompiledExpression
Attempt compilation of the supplied expression. A check is made to see if it is compilable before compilation proceeds. The check involves visiting all the nodes in the expression Ast and ensuring enough state is known about them that bytecode can be generated for them.
expression - the expression to compile
Return
an instance of the class implementing the compiled expression, or null if compilation is not possible
open static fun compile(expression: Expression): Boolean
Request that an attempt is made to compile the specified expression. It may fail if components of the expression are not suitable for compilation or the data types involved are not suitable for compilation. Used for testing.
Return
true if the expression was successfully compiled