public Void unionShape()

in codegen/smithy-ruby-codegen/src/main/java/software/amazon/smithy/ruby/codegen/generators/ParamsGenerator.java [214:259]
44 lines of code
2 McCabe index (conditional complexity)

    public Void unionShape(UnionShape shape) {
        Symbol symbol = symbolProvider.toSymbol(shape);
        String shapeName = symbol.getName();

        writer
                .write("")
                .openBlock("module $L", shapeName)
                .openBlock("def self.build(params, context: '')")
                .write("return params if params.is_a?(Types::$L)", shapeName)
                .write("Seahorse::Validator.validate!(params, ::Hash, Types::$L, context: context)", shapeName)
                .openBlock("unless params.size == 1")
                .write("raise ArgumentError,")
                .indent(3)
                .write("\"Expected #{context} to have exactly one member, got: #{params}\"")
                .dedent(3)
                .closeBlock("end")
                .write("key, value = params.flatten")
                .write("case key"); //start a case statement.  This does NOT indent

        for (MemberShape member : shape.members()) {
            Shape target = model.expectShape(member.getTarget());
            String memberClassName = symbolProvider.toMemberName(member);
            String memberName = RubyFormatter.asSymbol(memberClassName);
            writer.write("when $L", memberName)
                    .indent()
                    .openBlock("Types::$L::$L.new(", shapeName, memberClassName);
            String input = "params[" + memberName + "]";
            String context = "\"#{context}[" + memberName + "]\"";
            target.accept(new MemberBuilder(writer, symbolProvider, "", input, context, member, false));
            writer.closeBlock(")")
                    .dedent();
        }
        String expectedMembers =
                shape.members().stream().map((member) -> RubyFormatter.asSymbol(member.getMemberName()))
                        .collect(Collectors.joining(", "));
        writer.write("else")
                .indent()
                .write("raise ArgumentError,")
                .indent(3)
                .write("\"Expected #{context} to have one of $L set\"", expectedMembers)
                .dedent(4);
        writer.write("end")  //end of case statement, NOT indented
                .closeBlock("end")
                .closeBlock("end");
        return null;
    }