Support ReadPreference Option For Find

src/main/generated/io/vertx/ext/mongo/FindOptionsConverter.java

@@ -36,6 +36,11 @@ public static void fromJson(Iterable<java.util.Map.Entry<String, Object>> json,
             obj.setLimit(((Number)member.getValue()).intValue());
           }
           break;
+        case "readPreference":
+          if (member.getValue() instanceof String) {
+            obj.setReadPreference((String)member.getValue());
+          }
+          break;
         case "skip":
           if (member.getValue() instanceof Number) {
             obj.setSkip(((Number)member.getValue()).intValue());
@@ -63,6 +68,9 @@ public static void toJson(FindOptions obj, java.util.Map<String, Object> json) {
       json.put("hint", obj.getHint());
     }
     json.put("limit", obj.getLimit());
+    if (obj.getReadPreference() != null) {
+      json.put("readPreference", obj.getReadPreference());
+    }
     json.put("skip", obj.getSkip());
     if (obj.getSort() != null) {
       json.put("sort", obj.getSort());

src/main/java/io/vertx/ext/mongo/FindOptions.java

@@ -1,8 +1,11 @@
 package io.vertx.ext.mongo;
 
+import com.mongodb.ReadPreference;
 import io.vertx.codegen.annotations.DataObject;
 import io.vertx.core.json.JsonObject;
 
+import java.util.Objects;
+
 /**
  * Options used to configure find operations.
  *
@@ -32,6 +35,7 @@ public class FindOptions {
   private int skip;
   private int batchSize;
   private String hint;
+  private ReadPreference readPreference;
 
   /**
    * Default constructor
@@ -43,6 +47,7 @@ public FindOptions() {
     this.skip = DEFAULT_SKIP;
     this.batchSize = DEFAULT_BATCH_SIZE;
     this.hint = new String();
+    this.readPreference = null;
   }
 
   /**
@@ -57,6 +62,7 @@ public FindOptions(FindOptions options) {
     this.skip = options.skip;
     this.batchSize = options.batchSize;
     this.hint = options.hint;
+    this.readPreference = options.readPreference;
   }
 
   /**
@@ -197,6 +203,33 @@ public FindOptions setHint(String hint) {
     return this;
   }
 
+  /**
+   * Get the readPreference. This determines the operation readPreference to use.
+   *
+   * @return the readPreference
+   */
+  public ReadPreference getReadPreference(boolean returnObj) {
+    return readPreference;
+  }
+  public String getReadPreference() {
+    return readPreference == null ? null : readPreference.getName();
+  }
+
+  /**
+   * Set the readPreference
+   *
+   * @param readPreference the readPreference
+   * @return reference to this, for fluency
+   */
+  public FindOptions setReadPreference(ReadPreference readPreference) {
+    this.readPreference = readPreference;
+    return this;
+  }
+  public FindOptions setReadPreference(String readPreferenceName) {
+    this.readPreference = (readPreferenceName == null ? null : ReadPreference.valueOf(readPreferenceName));
+    return this;
+  }
+
   @Override
   public boolean equals(Object o) {
     if (this == o) return true;
@@ -209,6 +242,7 @@ public boolean equals(Object o) {
     if (batchSize != that.batchSize) return false;
     if (fields != null ? !fields.equals(that.fields) : that.fields != null) return false;
     if (hint != null ? !hint.equals(that.hint) : that.hint != null) return false;
+    if (!Objects.equals(readPreference, that.readPreference)) return false;
     return sort != null ? sort.equals(that.sort) : that.sort == null;
   }
 
@@ -220,6 +254,7 @@ public int hashCode() {
     result = 31 * result + skip;
     result = 31 * result + batchSize;
     result = 31 * result + (hint != null ? hint.hashCode() : 0);
+    result = 31 * result + (readPreference != null ? readPreference.hashCode() : 0);
     return result;
   }
 }

src/main/java/io/vertx/ext/mongo/MongoClient.java

@@ -1,6 +1,7 @@
 package io.vertx.ext.mongo;
 
 import com.mongodb.MongoClientSettings;
+import com.mongodb.ReadPreference;
 import com.mongodb.client.model.changestream.ChangeStreamDocument;
 import io.vertx.codegen.annotations.Fluent;
 import io.vertx.codegen.annotations.GenIgnore;
@@ -311,6 +312,19 @@ MongoClient bulkWriteWithOptions(String collection, List<BulkOperation> operatio
    */
   Future<@Nullable JsonObject> findOne(String collection, JsonObject query, @Nullable JsonObject fields);
 
+  /**
+   * Like {@link #findOne(String, JsonObject, JsonObject, Handler)} but give an option to set ReadPreference
+   */
+  @GenIgnore(GenIgnore.PERMITTED_TYPE)
+  @Fluent
+  MongoClient findOne(String collection, JsonObject query, @Nullable JsonObject fields, @Nullable ReadPreference readPreference, Handler<AsyncResult<@Nullable JsonObject>> resultHandler);
+
+  /**
+   * Like {@link #findOne(String, JsonObject, JsonObject)} but give an option to set ReadPreference
+   */
+  @GenIgnore(GenIgnore.PERMITTED_TYPE)
+  Future<@Nullable JsonObject> findOne(String collection, JsonObject query, @Nullable JsonObject fields, @Nullable ReadPreference readPreference);
+
   /**
    * Find a single matching document in the specified collection and update it.
    * <p>

src/main/java/io/vertx/ext/mongo/impl/MongoClientImpl.java

@@ -17,6 +17,7 @@
 package io.vertx.ext.mongo.impl;
 
 import com.mongodb.MongoClientSettings;
+import com.mongodb.ReadPreference;
 import com.mongodb.WriteConcern;
 import com.mongodb.bulk.BulkWriteResult;
 import com.mongodb.client.model.*;
@@ -353,15 +354,32 @@ public io.vertx.ext.mongo.MongoClient findOne(String collection, JsonObject quer
 
   @Override
   public Future<@Nullable JsonObject> findOne(String collection, JsonObject query, @Nullable JsonObject fields) {
+    return findOne(collection, query, fields, (ReadPreference) null);
+  }
+
+  @Override
+  public MongoClient findOne(String collection, JsonObject query, @Nullable JsonObject fields, @Nullable ReadPreference readPreference, Handler<AsyncResult<@Nullable JsonObject>> resultHandler) {
+    Future<JsonObject> future = findOne(collection, query, fields, readPreference);
+    setHandler(future, resultHandler);
+    return this;
+  }
+
+  @Override
+  public Future<@Nullable JsonObject> findOne(String collection, JsonObject query, @Nullable JsonObject fields, @Nullable ReadPreference readPreference) {
     requireNonNull(collection, "collection cannot be null");
     requireNonNull(query, "query cannot be null");
 
     JsonObject encodedQuery = encodeKeyWhenUseObjectId(query);
 
     Bson bquery = wrap(encodedQuery);
     Bson bfields = wrap(fields);
+
     Promise<JsonObject> promise = vertx.promise();
-    getCollection(collection).find(bquery).projection(bfields).first().subscribe(new SingleResultSubscriber<>(promise));
+    MongoCollection<JsonObject> coll = getCollection(collection);
+    if (readPreference != null) {
+      coll = coll.withReadPreference(readPreference);
+    }
+    coll.find(bquery).projection(bfields).first().subscribe(new SingleResultSubscriber<>(promise));
     return promise.future().map(object -> object == null ? null : decodeKeyWhenUseObjectId(object));
   }
 
@@ -983,6 +1001,9 @@ private JsonObject decodeKeyWhenUseObjectId(JsonObject json) {
   private FindPublisher<JsonObject> doFind(String collection, JsonObject query, FindOptions options) {
     MongoCollection<JsonObject> coll = getCollection(collection);
     Bson bquery = wrap(encodeKeyWhenUseObjectId(query));
+    if (options.getReadPreference() != null) {
+      coll = coll.withReadPreference(options.getReadPreference(true));
+    }
     FindPublisher<JsonObject> find = coll.find(bquery, JsonObject.class);
     if (options.getLimit() != -1) {
       find.limit(options.getLimit());