io.vertx.rx.java.UnmarshallerOperator Maven / Gradle / Ivy

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package io.vertx.rx.java;

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.ObjectCodec;
import com.fasterxml.jackson.core.type.TypeReference;
import io.vertx.core.buffer.Buffer;
import io.vertx.core.json.Json;
import io.vertx.core.json.jackson.JacksonFactory;
import rx.Observable;
import rx.Subscriber;

import static java.util.Objects.nonNull;

/**
 * An operator
 *
 * @author Julien Viet
 */
public abstract class UnmarshallerOperator implements Observable.Operator {

  private final Class mappedType;
  private final TypeReference mappedTypeRef;
  private ObjectCodec mapper;

  public UnmarshallerOperator(Class mappedType) {
    this.mappedType = mappedType;
    this.mapper = null;
    this.mappedTypeRef = null;
  }

  public UnmarshallerOperator(Class mappedType, ObjectCodec mapper) {
    this.mappedType = mappedType;
    this.mapper = mapper;
    this.mappedTypeRef = null;
  }

  public UnmarshallerOperator(TypeReference mappedTypeRef) {
    this.mappedType = null;
    this.mapper = null;
    this.mappedTypeRef = mappedTypeRef;
  }

  public UnmarshallerOperator(TypeReference mappedTypeRef, ObjectCodec mapper) {
    this.mappedType = null;
    this.mapper = mapper;
    this.mappedTypeRef = mappedTypeRef;
  }

  public abstract Buffer unwrap(B buffer);

  @Override
  public Subscriber call(Subscriber subscriber) {
    final Buffer buffer = Buffer.buffer();

    return new Subscriber(subscriber) {

      @Override
      public void onCompleted() {
        try {
          T obj = null;
          if (buffer.length() > 0) {
            if (mapper != null) {
              JsonParser parser = mapper.getFactory().createParser(buffer.getBytes());
              obj = nonNull(mappedType) ? mapper.readValue(parser, mappedType) :
                mapper.readValue(parser, mappedTypeRef);
            } else {
              obj = nonNull(mappedType) ? Json.CODEC.fromBuffer(buffer, mappedType) :
                JacksonFactory.CODEC.fromBuffer(buffer, mappedTypeRef);
            }
          }
          subscriber.onNext(obj);
          subscriber.onCompleted();
        } catch (Exception e) {
          onError(e);
        }
      }

      @Override
      public void onError(Throwable e) {
        subscriber.onError(e);
      }

      @Override
      public void onNext(B item) {
        buffer.appendBuffer(unwrap(item));
      }
    };
  }
}