com.google.cloud.dataflow.sdk.coders.TableRowJsonCoder Maven / Gradle / Ivy

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Google Cloud Dataflow Java SDK provides a simple, Java-based interface for processing virtually any size data using Google cloud resources. This artifact includes entire Dataflow Java SDK.

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/*
 * Copyright (C) 2015 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

package com.google.cloud.dataflow.sdk.coders;

import com.google.api.services.bigquery.model.TableRow;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * A {@link Coder} that encodes BigQuery {@link TableRow} objects in their native JSON format.
 */
public class TableRowJsonCoder extends AtomicCoder {

  @JsonCreator
  public static TableRowJsonCoder of() {
    return INSTANCE;
  }

  @Override
  public void encode(TableRow value, OutputStream outStream, Context context)
      throws IOException {
    String strValue = MAPPER.writeValueAsString(value);
    StringUtf8Coder.of().encode(strValue, outStream, context);
  }

  @Override
  public TableRow decode(InputStream inStream, Context context)
      throws IOException {
    String strValue = StringUtf8Coder.of().decode(inStream, context);
    return MAPPER.readValue(strValue, TableRow.class);
  }

  @Override
  protected long getEncodedElementByteSize(TableRow value, Context context)
      throws Exception {
    String strValue = MAPPER.writeValueAsString(value);
    return StringUtf8Coder.of().getEncodedElementByteSize(strValue, context);
  }

  /////////////////////////////////////////////////////////////////////////////

  // FAIL_ON_EMPTY_BEANS is disabled in order to handle null values in
  // TableRow.
  private static final ObjectMapper MAPPER =
      new ObjectMapper().disable(SerializationFeature.FAIL_ON_EMPTY_BEANS);

  private static final TableRowJsonCoder INSTANCE = new TableRowJsonCoder();

  private TableRowJsonCoder() { }

  /**
   * {@inheritDoc}
   *
   * @throws NonDeterministicException always. A {@link TableRow} can hold arbitrary
   *         {@link Object} instances, which makes the encoding non-deterministic.
   */
  @Override
  public void verifyDeterministic() throws NonDeterministicException {
    throw new NonDeterministicException(this,
        "TableCell can hold arbitrary instances, which may be non-deterministic.");
  }
}