Here is a flat JSON string that needs to be deserialized in Java using Jackson:
{"ccy":"EUR",
"value1":500,
"value2":200,
"date":"2017-07-25",
"type":"",
... <many other pairs>}
To deserialize this JSON string, we can create the following classes:
public class Data
{
@JsonProperty("ccy")
private String currency;
private Amount value1;
private Amount value2;
@JsonProperty("date")
private String date;
@JsonProperty("type")
private String type;
... <many other members>
}
public class Amount
{
private double value;
private String currency;
public Amount(double value, String currency)
{
this.value = value;
this.currency = currency;
}
}
The challenge is how to correctly fill the value1 and value2 fields in the Data class. One approach is to use custom setters with Jackson annotations:
@JsonSetter("value1")
private void setValue1(double value1)
{
this.value1 = new Amount(value1, this.currency);
}
@JsonSetter("value2")
private void setValue2(double value2)
{
this.value2 = new Amount(value2, this.currency);
}
However, this solution relies on this.currency being deserialized first, which may not always be guaranteed.
Is there a more elegant solution that avoids using a custom constructor like
Data(@JsonProperty("value1") double value1, (@JsonProperty("value2") double value2, (@JsonProperty("ccy") String currency) {...}Note: Using a solution that utilizes Jackson would be preferred.