Android chat crashes on DataSnapshot.getValue() for timestamp

Question

I\'m trying to modify Firebase\'s Android chat example to include Firebase timestamp values. I can send the timestamp just fine using ServerValue.TIMESTAMP; but

Answer 1

I know this thread is quite old, but for anyone trying to implement a similar timestamp now, instead of using @JsonIgnore from the Jackson annotations, you can use the Firebase native @Exclude now.

Answer 2

Firebase.ServerValue.TIMESTAMP is set as a Map (containing {.sv: "timestamp"}) which tells Firebase to populate that field with the server's time. When that data is read back, it is the actual unix time stamp which is a Long. When Firebase (using Jackson) tries to deserialize that returned value, it fails since it is not a Map.

You could use Jackson annotations to control how your class is converted to JSON.

For example, something like this should work:

import com.fasterxml.jackson.annotation.JsonIgnore;
import com.firebase.client.ServerValue;

public class Thing {
    private String id;
    private Long creationDate;

    public Thing() {

    }

    public Thing(String id) {
        this.id = id;
    }

    public String getId() {
        return id;
    }

    public java.util.Map<String, String> getCreationDate() {
        return ServerValue.TIMESTAMP;
    }

    @JsonIgnore
    public Long getCreationDateLong() {
       return creationDate;
    }

    public void setId(String id) {
        this.id = id;
    }

    public void setCreationDate(Long creationDate) {
        this.creationDate = creationDate;
    }
}