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A driver for DataStax Enterprise (DSE) and Apache Cassandra 1.2+ clusters that works exclusively with the Cassandra Query Language version 3 (CQL3) and Cassandra's binary protocol, supporting DSE-specific features such as geospatial types, DSE Graph and DSE authentication.
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/*
 * 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.google.common.base.Preconditions.checkNotNull;

import com.datastax.driver.core.ConsistencyLevel;
import com.datastax.driver.core.SimpleStatement;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
import java.nio.ByteBuffer;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.atomic.AtomicBoolean;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/** A simple graph statement implementation. */
public class SimpleGraphStatement extends RegularGraphStatement {

  private static final Logger logger = LoggerFactory.getLogger(SimpleGraphStatement.class);

  @VisibleForTesting static final AtomicBoolean WARNED_GRAPHSON1 = new AtomicBoolean(false);

  private final String query;

  private final Map valuesMap;

  private boolean needsRebuild = true;

  protected SimpleStatement statement;

  private ConsistencyLevel nativeConsistencyLevel;

  private long defaultTimestamp = Long.MIN_VALUE;

  private volatile int readTimeoutMillis = Integer.MIN_VALUE;

  private String authorizationId;

  private static final String GRAPHSON1_WARN_MESSAGE =
      "GraphSON1 is being used for a graph query, however it is recommended "
          + "to switch to GraphSON2 when executing a graph query to maintain "
          + "type information in requests and responses to the DSE Graph server. "
          + "Enabling GraphSON2 can be done via the DseCluster's GraphOptions, "
          + "see https://goo.gl/EAUBUv for more information.";

  public SimpleGraphStatement(String query) {
    this(query, new HashMap());
  }

  public SimpleGraphStatement(String query, Map valuesMap) {
    checkNotNull(valuesMap, "Parameter valuesMap cannot be null");
    this.query = query;
    this.valuesMap = valuesMap;
  }

  @Override
  public String getQueryString() {
    return query;
  }

  /**
   * Sets a parameter on this statement.
   *
   * Note that, contrary to CQL parameters, which are identified either by a bind marker "?" or
   * by the sign ":" in front of a parameter name, parameters in Gremlin queries are simply
   * referenced by their names. Please refer to Gremlin's documentation for more information.
   *
   * Parameter values can be of any type supported by the subprotocol in use: Boolean, Integer,
   * Long, Float, Double, String, Map, List, {@link GraphNode}, {@link Element}, any geospatial
   * type.
   *
   * @param name the parameter name, as referenced in the graph query.
   * @param value the parameter value.
   */
  public SimpleGraphStatement set(String name, Object value) {
    this.valuesMap.put(name, value);
    needsRebuild = true;
    return this;
  }

  @Override
  public GraphStatement setConsistencyLevel(ConsistencyLevel consistencyLevel) {
    needsRebuild = true;
    this.nativeConsistencyLevel = consistencyLevel;
    return this;
  }

  @Override
  public ConsistencyLevel getConsistencyLevel() {
    return nativeConsistencyLevel;
  }

  @Override
  public GraphStatement setDefaultTimestamp(long defaultTimestamp) {
    needsRebuild = true;
    this.defaultTimestamp = defaultTimestamp;
    return this;
  }

  @Override
  public int getReadTimeoutMillis() {
    return this.readTimeoutMillis;
  }

  @Override
  public GraphStatement setReadTimeoutMillis(int readTimeoutMillis) {
    Preconditions.checkArgument(readTimeoutMillis >= 0, "read timeout must be >= 0");
    this.readTimeoutMillis = readTimeoutMillis;
    needsRebuild = true;
    return this;
  }

  @Override
  public long getDefaultTimestamp() {
    return defaultTimestamp;
  }

  @Override
  @Deprecated
  public SimpleStatement unwrap() {
    return unwrap(GraphProtocol.GRAPHSON_1_0);
  }

  @Override
  @Deprecated
  public SimpleStatement unwrap(GraphProtocol graphProtocol) {
    return unwrap(new GraphOptions().setGraphSubProtocol(graphProtocol));
  }

  @Override
  public SimpleStatement unwrap(GraphOptions graphOptions) {
    maybeRebuildCache(graphOptions.getGraphSubProtocol());

    Map payload = graphOptions.buildPayloadWithDefaults(this);
    // if the language set is the default language (gremlin-groovy)
    if (PayloadHelper.asString(payload.get(GraphOptions.GRAPH_LANGUAGE_KEY))
        .equals(GraphOptions.DEFAULT_GRAPH_LANGUAGE)) {
      // if the graph options are left unset (default) or GraphSON1 is explicitly set
      if (graphOptions.getGraphSubProtocol() == null
          || graphOptions.getGraphSubProtocol() == GraphProtocol.GRAPHSON_1_0) {
        if (WARNED_GRAPHSON1.compareAndSet(false, true)) {
          logger.warn(GRAPHSON1_WARN_MESSAGE);
        }
        setTransformResultFunction(GraphResultSet.ROW_TO_DEFAULTGRAPHNODE);
      }
      // if the graph options explicitly set to GraphSON2
      else if (graphOptions.getGraphSubProtocol() == GraphProtocol.GRAPHSON_2_0) {
        setTransformResultFunction(GraphJsonUtils.ROW_TO_GRAPHSON2_OBJECTGRAPHNODE);
      }
    }
    // if another language is used (bytecode-json for example)
    else {
      // if GraphSON1 is forced by the user
      if (graphOptions.getGraphSubProtocol() == GraphProtocol.GRAPHSON_1_0) {
        if (WARNED_GRAPHSON1.compareAndSet(false, true)) {
          logger.warn(GRAPHSON1_WARN_MESSAGE);
        }
        // we may need to re-enforce GraphSON1 GraphNode because it may have been
        // overridden
        setTransformResultFunction(GraphResultSet.ROW_TO_DEFAULTGRAPHNODE);
      }
    }
    return statement;
  }

  @Override
  public GraphStatement executingAs(String userOrRole) {
    this.authorizationId = userOrRole;
    needsRebuild = true;
    return this;
  }

  private void maybeRebuildCache(GraphProtocol graphProtocol) {
    if (needsRebuild) {
      if (valuesMap.isEmpty()) {
        statement = new SimpleStatement(query);
      } else {
        String values =
            graphProtocol == GraphProtocol.GRAPHSON_1_0 || graphProtocol == null
                ? GraphJsonUtils.writeValueAsString(valuesMap)
                : GraphJsonUtils.writeValueAsStringGraphson20(valuesMap);

        statement = new SimpleStatement(query, values);
      }
      if (getConsistencyLevel() != null) statement.setConsistencyLevel(nativeConsistencyLevel);
      if (getDefaultTimestamp() != Long.MIN_VALUE) statement.setDefaultTimestamp(defaultTimestamp);
      if (getReadTimeoutMillis() != Integer.MIN_VALUE)
        statement.setReadTimeoutMillis(readTimeoutMillis);
      if (this.authorizationId != null) statement.executingAs(authorizationId);

      needsRebuild = false;
    }
  }
}