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https://issues.apache.org/jira/browse/AVRO-2115?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16287765#comment-16287765
]
Miguel edited comment on AVRO-2115 at 12/13/17 8:05 AM:
--------------------------------------------------------
This should do the job:
{code:java}
public class ReflectDataAllowingUnionsInMember extends ReflectData {
@Override
protected Schema createSchema(final Type type, final Map<String,
Schema> names) {
if (type instanceof Class<?>) {
Class<?> cl = (Class<?>) type;
if (cl.isAnnotationPresent(Union.class)) {
Union annotation =
cl.getAnnotation(Union.class);
Class<?>[] list = annotation.value();
if (list != null) {
List<Schema> branches = new
ArrayList<>();
for (Class<?> branch : list) {
final Schema schema;
if (branch == null) {
schema =
Schema.create(Schema.Type.NULL);
} else {
schema =
createSchema(branch, names);
}
branches.add(schema);
}
return Schema.createUnion(branches);
}
}
}
return super.createSchema(type, names);
}
}
{code}
I think this must be inside the createSchema method within the ReflectData
class.
*#edit*
I omitted that also need to add the ElementType.FIELD target in @Union.
{code:java}
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE, ElementType.PARAMETER, ElementType.METHOD,
ElementType.FIELD})
@Documented
public @interface Union {
/** The instantiable classes that compose this union. */
Class[] value();
}
{code}
was (Author: elmendavies):
This should do the job:
{code:java}
public class ReflectDataAllowingUnionsInMember extends ReflectData {
@Override
protected Schema createSchema(final Type type, final Map<String,
Schema> names) {
if (type instanceof Class<?>) {
Class<?> cl = (Class<?>) type;
if (cl.isAnnotationPresent(Union.class)) {
Union annotation =
cl.getAnnotation(Union.class);
Class<?>[] list = annotation.value();
if (list != null) {
List<Schema> branches = new
ArrayList<>();
for (Class<?> branch : list) {
final Schema schema;
if (branch == null) {
schema =
Schema.create(Schema.Type.NULL);
} else {
schema =
createSchema(branch, names);
}
branches.add(schema);
}
return Schema.createUnion(branches);
}
}
}
return super.createSchema(type, names);
}
}
{code}
I think this must be inside the createSchema method within the ReflectData
class.
> Support @Union in members too
> -----------------------------
>
> Key: AVRO-2115
> URL: https://issues.apache.org/jira/browse/AVRO-2115
> Project: Avro
> Issue Type: Improvement
> Reporter: Miguel
> Priority: Minor
>
> Allow defining unions in members:
> {code:java}
> class MyDatum {
> @Nullable
> @Union({String.class, Long.class, Other.class,...})
> Object o;
> }
> {code}
> It can currently be implemented using @AvroSchema like this, but it is seems
> in my oppinion more verbose and more difficult to maintain:
> {code:java}
> @AvroSchema("[\"null\",\"string\",...")
> {code}
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