Tweak jackson polymorphic deserialization - jackson

Question

I have a simple polymorphic model like this
public class Foo {
private Bar bar1;
private Bar bar2;
public Bar getBar1() {
return bar1;
}
public Bar getBar2() {
return bar2;
}
public void setBar1(Bar bar1) {
this.bar1 = bar1;
}
public void setBar2(Bar bar2) {
this.bar2 = bar2;
}
}
#JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, include = JsonTypeInfo.As.PROPERTY, property = "#type")
public class Bar {
}
public class BarExpression extends Bar {
private String expression;
public String getExpression() {
return expression;
}
#JsonIgnore
public Object getValue() {
return null;
}
public void setExpression(String expression) {
this.expression = expression;
}
}
public class BarLiteral extends Bar {
private String value;
private String type;
public String getType() {
return type;
}
public Object getValue() {
return value;
}
public void setType(String type) {
this.type = type;
}
public void setValue(String value) {
this.value = value;
}
}
Serializing a simple example like this
public void run() throws Exception {
Foo foo;
BarLiteral bar1;
BarExpression bar2;
//
foo = new Foo();
bar1 = new BarLiteral();
bar1.setType("java.lang.String");
bar1.setValue("gnu");
foo.setBar1(bar1);
bar2 = new BarExpression();
bar2.setExpression("bean.property * 2");
foo.setBar2(bar2);
//
ObjectMapper mapper = new ObjectMapper();
mapper.enable(SerializationFeature.INDENT_OUTPUT);
StringWriter w = new StringWriter();
mapper.writeValue(w, foo);
System.out.println(w.toString());
}
gives the expected result:
{
"bar1" : {
"#type" : "de.mit.jackson.BarLiteral",
"value" : "gnu",
"type" : "java.lang.String"
},
"bar2" : {
"#type" : "de.mit.jackson.BarExpression",
"expression" : "bean.property * 2"
}
}
The question is now: I want to improve user experience when handwriting this "DSL" by supporting "primitive shortcuts" for the typed "Bar..." classes like this
{
"bar1" : "gnu",
"bar2" : "#{bean.property * 2}"
}
The solution that came closest was using a converter on Foo#bar1 and Foo#bar2, checking for either String or "Bar" input, but this solution requires decoration of every attribute definition.
Creating a deserializer with a comparable behavior did not work, as the #JsonTypeInfo is not compatible in the sense that i can have a #JsonDeserialize implementation that will check for a String event and then delegate to the standard #JsonTypeInfo process. The #JsonTypeInfo standard will check only for the #type and then delegate back to the (subtype) deserializer which is again my wrapper implementation.
The required process is
if input event is string {
parse and return string input
} else {
activate #type parsing delegate;
after #type parsing activate standard BeanDeserializer
(**not** my implementation)
}
Is there another hook i am missing?