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• GraphJsonUtils.java

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com.datastax.driver.dse.graph.GraphJsonUtils Maven / Gradle / Ivy

/*
 * Copyright DataStax, Inc.
 *
 * This software can be used solely with DataStax Enterprise. Please consult the license at
 * http://www.datastax.com/terms/datastax-dse-driver-license-terms
 */
package com.datastax.driver.dse.graph;

import static com.datastax.driver.core.ClasspathUtil.isJavaTimeAvailable;

import com.datastax.driver.core.Row;
import com.datastax.driver.core.VersionNumber;
import com.datastax.driver.core.exceptions.DriverException;
import com.datastax.driver.dse.DseCluster;
import com.fasterxml.jackson.core.Version;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.base.Function;
import com.google.common.base.Throwables;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/** Utility static methods and objects useful in the DSE Driver's execution chain. */
public class GraphJsonUtils {

  private static final Logger LOGGER = LoggerFactory.getLogger(GraphJsonUtils.class);

  private static final ObjectMapper GRAPHSON1_OBJECT_MAPPER;
  private static final ObjectMapper GRAPHSON2_OBJECT_MAPPER;

  /**
   * Function that transforms a Row from the wrapped Cassandra driver, into a {@link
   * com.datastax.driver.dse.graph.GraphNode}. The GraphNode created will be directly exposed to the
   * user when iterating over the {@link com.datastax.driver.dse.graph.GraphResultSet} returned from
   * a Graph query.
   */
  public static final Function ROW_TO_GRAPHSON2_OBJECTGRAPHNODE =
      new Function() {
        @Override
        public GraphNode apply(Row input) {
          try {
            if (input == null) {
              return null;
            } else if (input.getColumnDefinitions().contains("gremlin")) {
              // some results do not contain the "row" gremlin.
              return readStringAsTreeGraphson20(input.getString("gremlin"));
            } else {
              return null;
            }
          } catch (Exception e) {
            throw new DriverException("Could not deserialize the response of this Graph query.", e);
          }
        }
      };

  static {
    GRAPHSON1_OBJECT_MAPPER = new ObjectMapper();
    Version dseDriverVersion = dseDriverVersion();
    GRAPHSON1_OBJECT_MAPPER.registerModule(
        new GraphSON1DefaultModule("graph-graphson1default", dseDriverVersion));

    GraphSON2Mapper.Builder graphSON2MapperBuilder =
        GraphSON2Mapper.build()
            .addCustomModule(new GraphSON2GremlinDriverModule())
            .addCustomModule(new GraphSON2GremlinXDriverModule())
            .addCustomModule(new GraphSON2GremlinGraphDriverModule())
            .addCustomModule(new GraphSON2DseGraphDriverModule())
            .addCustomModule(new GraphSON2TinkerDriverModule())
            .addCustomModule(new GraphSON2DriverObjectsModule());

    if (isJavaTimeAvailable()) {
      LOGGER.debug(
          "JSR 310 found on the classpath, registering serializers for java.time temporal types");
      GRAPHSON1_OBJECT_MAPPER.registerModule(
          new GraphSON1JavaTimeModule("graph-graphson1javatime", dseDriverVersion));
      GRAPHSON1_OBJECT_MAPPER.registerModule(
          new GraphSON1DriverTimeModule("graph-graphson1drivertime", dseDriverVersion));
      graphSON2MapperBuilder.addCustomModule(new GraphSON2JavaTimeModule());
    } else {
      LOGGER.debug(
          "JSR 310 not found on the classpath, not registering serializers for java.time temporal types");
      GRAPHSON1_OBJECT_MAPPER.registerModule(
          new GraphSON1DriverTimeModule("graph-graphson1drivertime", dseDriverVersion));
      graphSON2MapperBuilder.addCustomModule(new GraphSON2DriverTimeModule());
    }
    GRAPHSON2_OBJECT_MAPPER = graphSON2MapperBuilder.create().createMapper();
  }

  private static Version dseDriverVersion() {
    String versionStr = DseCluster.getDseDriverVersion();
    VersionNumber version = VersionNumber.parse(versionStr);
    return new Version(
        version.getMajor(),
        version.getMinor(),
        version.getPatch(),
        // version.getPreReleaseLabels() throws NPE, see JAVA-1160
        versionStr.contains("-SNAPSHOT") ? "SNAPSHOT" : null,
        "com.datastax.cassandra",
        "dse-driver");
  }

  /**
   * If JDK 8 is available, then node properties in the returned tree can be coerced into JDK 8
   * temporal types ({@code java.time.Instant}, {@code java.time.ZonedDateTime}, and {@code
   * java.time.Duration}).
   *
   * 
Example:
   *
   * 
{@code
   * GraphNode result = session.executeGraph("g.V().has('name', 'robert').next()").one();
   * Vertex robert = result.asVertex();
   * VertexProperty birthday = robert.getProperty("birthday");
   * Instant t = birthday.getValue().as(Instant.class);
   * }
   */
  static GraphNode readStringAsTree(String content) {
    try {
      return new DefaultGraphNode(
          GRAPHSON1_OBJECT_MAPPER.readTree(content), GRAPHSON1_OBJECT_MAPPER);
    } catch (Exception e) {
      throw Throwables.propagate(e);
    }
  }

  /**
   * If JDK 8 is available, then the following temporal types can be serialized: ({@code
   * java.time.Instant}, {@code java.time.ZonedDateTime}, and {@code java.time.Duration}).
   */
  static String writeValueAsString(Object value) {
    try {
      return GRAPHSON1_OBJECT_MAPPER.writeValueAsString(value);
    } catch (Exception e) {
      throw Throwables.propagate(e);
    }
  }

  static GraphNode readStringAsTreeGraphson20(String content) {
    try {
      return new ObjectGraphNode(GRAPHSON2_OBJECT_MAPPER.readValue(content, Object.class));
    } catch (Exception e) {
      throw Throwables.propagate(e);
    }
  }

  /**
   * If JDK 8 is available, then the following temporal types can be serialized: ({@code
   * java.time.Instant}, {@code java.time.ZonedDateTime}, and {@code java.time.Duration}).
   */
  static String writeValueAsStringGraphson20(Object value) {
    try {
      return GRAPHSON2_OBJECT_MAPPER.writeValueAsString(value);
    } catch (Exception e) {
      throw Throwables.propagate(e);
    }
  }
}