Deserializing fails when using builder classes with Iterable Collection setters #646
Description
When using builder classes with method signatures like Builder orderLines(Iterable<? extends OrderLine> lines) for
collections, deserialization fails with the following.
com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot construct instance of `com.example.OrderLine$Builder` (although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value ('1')
at [Source: (BufferedInputStream); line: 5, column: 14] (through reference chain: com.example.Order$Builder["line"]->java.util.ArrayList[0])
A reproducer can be found at https://github.com/bpasson/jackson-dataformat-xml-issue-646
This concerns jackson-dataformat-xml version 2.17.0.
Detailed Example
Consider the following objects:
@JsonDeserialize(builder = Order.Builder.class)
@JsonIgnoreProperties(ignoreUnknown = true)
@JacksonXmlRootElement(localName="order")
public class Order {
private final Long id;
private final List<OrderLine> lines;
private Order(Long id, List<OrderLine> lines) {
this.id = id;
this.lines = lines;
}
@JsonProperty("id")
public Long getId() {
return id;
}
@JsonProperty("line")
List<OrderLine> getOrderLines() {
return lines;
}
public Builder builder() {
return new Builder();
}
public static class Builder {
private Long id;
private List<OrderLine> lines = new ArrayList<>();
@JsonProperty("id")
public Builder id(Long id) {
this.id = id;
return this;
}
@JsonProperty("line")
public Builder lines(Iterable<? extends OrderLine> lines) { // fails
//public Builder lines(Collection<? extends OrderLine> lines) { // works
this.lines.clear();
for (OrderLine line : lines) {
this.lines.add(line);
}
return this;
}
public Order build() {
return new Order(id, lines);
}
}
}@JsonDeserialize(builder = OrderLine.Builder.class)
@JsonIgnoreProperties(ignoreUnknown = true)
@JacksonXmlRootElement(localName = "line")
public class OrderLine {
private final Long id;
private final String description;
@JsonProperty("id")
public Long getId() {
return id;
}
@JsonProperty("description")
String description() {
return description;
}
private OrderLine(Long id, String description) {
this.id = id;
this.description = description;
}
public Builder builder() {
return new Builder();
}
public static class Builder {
private Long id;
private String description;
@JsonProperty("id")
public Builder id(Long id) {
this.id = id;
return this;
}
@JsonProperty("description")
public Builder description(String description) {
this.description = description;
return this;
}
public OrderLine build() {
return new OrderLine(id, description);
}
}
}When deserializing the following XMl document:
<?xml version="1.0" encoding="UTF-8" ?>
<order>
<id>1</id>
<line>
<id>1</id>
<description>order line 1</description>
</line>
<line>
<id>2</id>
<description>order line 2</description>
</line>
</order>Deserializing fails with:
com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot construct instance of `com.example.OrderLine$Builder` (although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value ('1')
at [Source: (BufferedInputStream); line: 5, column: 14] (through reference chain: com.example.Order$Builder["line"]->java.util.ArrayList[0])
This is caused by the following builder method:
@JsonProperty("line")
public Builder lines(Iterable<? extends OrderLine> lines) { // fails
//public Builder lines(Collection<? extends OrderLine> lines) { // works
this.lines.clear();
for (OrderLine line : lines) {
this.lines.add(line);
}
return this;
}If you use Iterable<? extends OrderLine> as method parameter it fails. If you use Collection<? extends OrderLine>, see commented line above, it works. I expected both to work as is the case for Json binding.