jackson Deserializer.tryInOrder

Deserializers.java

package com.goswiftly.services.gtfspoller.jacksonutil;

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonDeserializer;
import io.vavr.control.Try;

import java.util.NoSuchElementException;

public class Deserializers {

  /**
   * Makes a new json deserializer that tries the delegates in order. Returns the first one that was
   * successful or throws the last one's exception
   */
  public static <T> JsonDeserializer<T> tryInOrder(JsonDeserializer<? extends T>... delegates) {
    return new JsonDeserializer<T>() {
      @Override
      public T deserialize(JsonParser p, DeserializationContext ctxt) {
        Try<? extends T> thisTry = Try.failure(new NoSuchElementException());
        // Basically Try.sequence but succeed for one success instead of fail for one error
        for (JsonDeserializer<? extends T> d : delegates) {
          thisTry = Try.of(() -> d.deserialize(p, ctxt));
          if (thisTry.isSuccess()) {
            return thisTry.get();
          }
        }
        return thisTry.get(); // throws the last exception
      }
    };
  }
}