Java 类com.mongodb.client.model.BsonField 实例源码

private static List<Bson> getServerQuery(Bson filter) {

    final List<Bson> pipeline = new ArrayList<>(6);
    if (filter != ALL) {
      pipeline.add(Aggregates.match(filter));
    }
    pipeline.add(Aggregates.unwind("$deployments", new UnwindOptions().preserveNullAndEmptyArrays(true)));
    pipeline.add(Aggregates.lookup(Collections.APPLICATIONS, "deployments.applicationId", "id", "applications"));
    pipeline.add(Aggregates.unwind("$applications", new UnwindOptions().preserveNullAndEmptyArrays(true)));
    pipeline.add(Aggregates.group(
      new Document().append("hostname", "$hostname").append("environment", "$environment"),
      new BsonField("fqdn", new Document("$first", "$fqdn")),
      new BsonField("description", new Document("$first", "$description")),
      new BsonField("os", new Document("$first", "$os")),
      new BsonField("network", new Document("$first", "$network")),
      new BsonField("meta", new Document("$first", "$meta")),
      new BsonField("attributes", new Document("$first", "$attributes")),
      new BsonField("applications", new Document("$push", "$applications")),
      new BsonField("deployments", new Document("$push", "$deployments"))));
    pipeline.add(Aggregates.sort(Sorts.ascending("_id")));
    return pipeline;
  }

/**
 * Add a $group step to filter out redundant solutions.
 * @return True if the distinct operation was successfully appended.
 */
public boolean distinct() {
    List<String> key = new LinkedList<>();
    for (String varName : bindingNames) {
        key.add(hashFieldExpr(varName));
    }
    List<BsonField> reduceOps = new LinkedList<>();
    for (String field : FIELDS) {
        reduceOps.add(new BsonField(field, new Document("$first", "$" + field)));
    }
    pipeline.add(Aggregates.group(new Document("$concat", key), reduceOps));
    return true;
}

public List<BsonField> getAccumulators() {
    return accumulators;
}

public MongoAccumulator setAccumulators(List<BsonField> accumulators) {
    this.accumulators = accumulators;
    return this;
}