Deserializing JSON with missing field fails using @JsonbCreator #237
Description
When I attempt to deserialize a JSON document with missing fields as a Java type using @JsonbCreator I get the following exception:
javax.json.bind.JsonbException: JsonbCreator parameter PARAM_NAME is missing in json document.
Looking into the source, I found this which indicates that the error condition is mandated by the spec. However, I can't find anything in the spec that requires all parameters in a creator to be present. Am I missing it?
Here's a test class that illustrates the issue:
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNull;
import javax.json.bind.Jsonb;
import javax.json.bind.annotation.JsonbCreator;
import javax.json.bind.annotation.JsonbProperty;
import org.eclipse.yasson.internal.JsonBindingBuilder;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
public class JsonbCreatorTest {
public static class Mutable {
private String test = "default";
public String getTest() {
return test;
}
public void setTest(String test) {
this.test = test;
}
}
public static class Immutable {
private final String test;
@JsonbCreator
public Immutable(@JsonbProperty("test") String test) {
this.test = test;
}
public String getTest() {
return test;
}
}
private static final String OBJECT_WITH_FIELD = "{\"test\":\"test\"}";
private static final String EMPTY_OBJECT = "{}";
private Jsonb jsonb;
@BeforeEach
public void createJsonBuilder() {
jsonb = new JsonBindingBuilder().build();
}
@Test
public void testDeserializeMutableFromObjectWithField() {
Mutable mutable = jsonb.fromJson(OBJECT_WITH_FIELD, Mutable.class);
assertEquals("test", mutable.getTest());
}
@Test
public void testDeserializeImmutableFromObjectWithField() {
Immutable immutable = jsonb.fromJson(OBJECT_WITH_FIELD, Immutable.class);
assertEquals("test", immutable.getTest());
}
@Test
public void testDeserializeMutableFromEmptyOBject() {
Mutable mutable = jsonb.fromJson(EMPTY_OBJECT, Mutable.class);
// spec says the setter MUST NOT be called when the property is absent
assertEquals("default", mutable.getTest());
}
@Test
public void testDeserializeImmutableFromEmptyOBject() {
Immutable immutable = jsonb.fromJson(EMPTY_OBJECT, Immutable.class);
// spec does not seem to mention how to handle this - null seems like the only sane choice
assertNull(immutable.getTest());
}
}Ultimately, I think this needs to be clarified in the spec, so I will raise it there as well, but I would like a way to get null passed in to creators when fields are missing instead of exceptions. I don't want to have to resort to mutable POJOs just to support this use case.