How to use

copyType

method

in

org.apache.calcite.rel.type.RelDataTypeFactory

/**
 * Returns an implementation of
 * {@link RelProtoDataType}
 * that copies a given type using the given type factory.
 */
public static RelProtoDataType proto(final RelDataType protoType) {
 assert protoType != null;
 return typeFactory -> typeFactory.copyType(protoType);
}

/**
 * Returns an implementation of
 * {@link RelProtoDataType}
 * that copies a given type using the given type factory.
 */
public static RelProtoDataType proto(final RelDataType protoType) {
 assert protoType != null;
 return typeFactory -> typeFactory.copyType(protoType);
}

public RelDataType copyOf(RelDataType type) {
 return cluster.getTypeFactory().copyType(type);
}

private RelDataType copy(RelDataType type) {
 return builder.getTypeFactory().copyType(type);
}

private RelDataType copy(RelDataType type) {
 return builder.getTypeFactory().copyType(type);
}

@Override
public T read(final Kryo kryo, final Input input, final Class<T> type) {
 // do not use delegate.read because we do not want it to cache the object. Rather, we will cache the normalized type.
 final T dataType = kryo.newInstance(type);
 final FieldSerializer.CachedField[] fields = delegate.getFields();
 for (int i = 0, n = fields.length; i < n; i++) {
  fields[i].read(input, dataType);
 }
 // be gentle to calcite and normalize the returned data type. normalization here means to use same type instances.
 final T result = (T) typeFactory.copyType(dataType);
 kryo.reference(result);
 return result;
}