Allow chaining set calls on Configuration and TopicConfiguration

include/cppkafka/configuration.h

@@ -90,47 +90,47 @@ public:
      * \param name The name of the attribute
      * \param value The value of the attribute
      */
-    void set(const std::string& name, const std::string& value);
+    Configuration& set(const std::string& name, const std::string& value);
 
     /**
      * Sets the delivery report callback (invokes rd_kafka_conf_set_dr_msg_cb)
      */
-    void set_delivery_report_callback(DeliveryReportCallback callback);
+    Configuration& set_delivery_report_callback(DeliveryReportCallback callback);
 
     /**
      * Sets the offset commit callback (invokes rd_kafka_conf_set_offset_commit_cb)
      */
-    void set_offset_commit_callback(OffsetCommitCallback callback);
+    Configuration& set_offset_commit_callback(OffsetCommitCallback callback);
 
     /** 
      * Sets the error callback (invokes rd_kafka_conf_set_error_cb)
      */
-    void set_error_callback(ErrorCallback callback);
+    Configuration& set_error_callback(ErrorCallback callback);
 
     /** 
      * Sets the throttle callback (invokes rd_kafka_conf_set_throttle_cb)
      */
-    void set_throttle_callback(ThrottleCallback callback);
+    Configuration& set_throttle_callback(ThrottleCallback callback);
 
     /** 
      * Sets the log callback (invokes rd_kafka_conf_set_log_cb)
      */
-    void set_log_callback(LogCallback callback);
+    Configuration& set_log_callback(LogCallback callback);
 
     /** 
      * Sets the stats callback (invokes rd_kafka_conf_set_stats_cb)
      */
-    void set_stats_callback(StatsCallback callback);
+    Configuration& set_stats_callback(StatsCallback callback);
 
     /** 
      * Sets the socket callback (invokes rd_kafka_conf_set_socket_cb)
      */
-    void set_socket_callback(SocketCallback callback);
+    Configuration& set_socket_callback(SocketCallback callback);
 
     /** 
      * Sets the default topic configuration
      */
-    void set_default_topic_configuration(boost::optional<TopicConfiguration> config);
+    Configuration& set_default_topic_configuration(boost::optional<TopicConfiguration> config);
 
     /**
      * Returns true iff the given property name has been set

include/cppkafka/configuration_base.h

@@ -45,8 +45,8 @@ public:
     /**
      * Sets a bool value
      */
-    void set(const std::string& name, bool value) {
-        proxy_set(name, value ? "true" : "false");
+    Concrete& set(const std::string& name, bool value) {
+        return proxy_set(name, value ? "true" : "false");
     }
 
     /**
@@ -54,15 +54,15 @@ public:
      */
     template <typename T,
               typename = typename std::enable_if<std::is_integral<T>::value>::type>
-    void set(const std::string& name, T value) {
-        proxy_set(name, std::to_string(value));
+    Concrete& set(const std::string& name, T value) {
+        return proxy_set(name, std::to_string(value));
     }
 
     /**
      * Sets a cstring value
      */
-    void set(const std::string& name, const char* value) {
-        proxy_set(name, value);
+    Concrete& set(const std::string& name, const char* value) {
+        return proxy_set(name, value);
     }
 
     /**
@@ -92,8 +92,8 @@ protected:
         return output;
     }
 private:
-    void proxy_set(const std::string& name, const std::string& value) {
-        static_cast<Concrete&>(*this).set(name, value);
+    Concrete& proxy_set(const std::string& name, const std::string& value) {
+        return static_cast<Concrete&>(*this).set(name, value);
     }
 
     static std::string convert(const std::string& value, Type2Type<std::string>) {

include/cppkafka/topic_configuration.h

@@ -77,14 +77,14 @@ public:
      * \param name The name of the option
      * \param value The value of the option
      */
-    void set(const std::string& name, const std::string& value);
+    TopicConfiguration& set(const std::string& name, const std::string& value);
 
     /**
      * \brief Sets the partitioner callback
      *
      * This translates into a call to rd_kafka_topic_conf_set_partitioner_cb
      */
-    void set_partitioner_callback(PartitionerCallback callback);
+    TopicConfiguration& set_partitioner_callback(PartitionerCallback callback);
 
     /**
      * \brief Sets the "this" pointer as the opaque pointer for this handle
@@ -92,7 +92,7 @@ public:
      * This method will be called by consumers/producers when the topic configuration object
      * has been put in a persistent memory location. Users of cppkafka do not need to use this.
      */
-    void set_as_opaque();
+    TopicConfiguration& set_as_opaque();
 
     /** 
      * Gets the partitioner callback

src/configuration.cpp

@@ -125,7 +125,7 @@ Configuration::Configuration(rd_kafka_conf_t* ptr)
 
 }
 
-void Configuration::set(const string& name, const string& value) {
+Configuration& Configuration::set(const string& name, const string& value) {
     char error_buffer[512];
     rd_kafka_conf_res_t result;
     result = rd_kafka_conf_set(handle_.get(), name.data(), value.data(), error_buffer,
@@ -133,45 +133,55 @@ void Configuration::set(const string& name, const string& value) {
     if (result != RD_KAFKA_CONF_OK) {
         throw ConfigException(name, error_buffer);
     }
+    return *this;
 }
 
-void Configuration::set_delivery_report_callback(DeliveryReportCallback callback) {
+Configuration& Configuration::set_delivery_report_callback(DeliveryReportCallback callback) {
     delivery_report_callback_ = move(callback);
     rd_kafka_conf_set_dr_msg_cb(handle_.get(), &delivery_report_callback_proxy);
+    return *this;
 }
 
-void Configuration::set_offset_commit_callback(OffsetCommitCallback callback) {
+Configuration& Configuration::set_offset_commit_callback(OffsetCommitCallback callback) {
     offset_commit_callback_ = move(callback);
     rd_kafka_conf_set_offset_commit_cb(handle_.get(), &offset_commit_callback_proxy);
+    return *this;
 }
 
-void Configuration::set_error_callback(ErrorCallback callback) {
+Configuration& Configuration::set_error_callback(ErrorCallback callback) {
     error_callback_ = move(callback);
     rd_kafka_conf_set_error_cb(handle_.get(), &error_callback_proxy);
+    return *this;
 }
 
-void Configuration::set_throttle_callback(ThrottleCallback callback) {
+Configuration& Configuration::set_throttle_callback(ThrottleCallback callback) {
     throttle_callback_ = move(callback);
     rd_kafka_conf_set_throttle_cb(handle_.get(), &throttle_callback_proxy);
+    return *this;
 }
 
-void Configuration::set_log_callback(LogCallback callback) {
+Configuration& Configuration::set_log_callback(LogCallback callback) {
     log_callback_ = move(callback);
     rd_kafka_conf_set_log_cb(handle_.get(), &log_callback_proxy);
+    return *this;
 }
 
-void Configuration::set_stats_callback(StatsCallback callback) {
+Configuration& Configuration::set_stats_callback(StatsCallback callback) {
     stats_callback_ = move(callback);
     rd_kafka_conf_set_stats_cb(handle_.get(), &stats_callback_proxy);
+    return *this;
 }
 
-void Configuration::set_socket_callback(SocketCallback callback) {
+Configuration& Configuration::set_socket_callback(SocketCallback callback) {
     socket_callback_ = move(callback);
     rd_kafka_conf_set_socket_cb(handle_.get(), &socket_callback_proxy);
+    return *this;
 }
 
-void Configuration::set_default_topic_configuration(optional<TopicConfiguration> config) {
+Configuration&
+Configuration::set_default_topic_configuration(optional<TopicConfiguration> config) {
     default_topic_config_ = std::move(config);
+    return *this;
 }
 
 bool Configuration::has_property(const string& name) const {

src/topic_configuration.cpp

@@ -67,7 +67,7 @@ TopicConfiguration::TopicConfiguration(rd_kafka_topic_conf_t* ptr)
 
 }
 
-void TopicConfiguration::set(const string& name, const string& value) {
+TopicConfiguration& TopicConfiguration::set(const string& name, const string& value) {
     char error_buffer[512];
     rd_kafka_conf_res_t result;
     result = rd_kafka_topic_conf_set(handle_.get(), name.data(), value.data(), error_buffer,
@@ -75,15 +75,18 @@ void TopicConfiguration::set(const string& name, const string& value) {
     if (result != RD_KAFKA_CONF_OK) {
         throw ConfigException(name, error_buffer);
     }
+    return *this;
 }
 
-void TopicConfiguration::set_partitioner_callback(PartitionerCallback callback) {
+TopicConfiguration& TopicConfiguration::set_partitioner_callback(PartitionerCallback callback) {
     partitioner_callback_ = move(callback);
     rd_kafka_topic_conf_set_partitioner_cb(handle_.get(), &partitioner_callback_proxy);
+    return *this;
 }
 
-void TopicConfiguration::set_as_opaque() {
+TopicConfiguration& TopicConfiguration::set_as_opaque() {
     rd_kafka_topic_conf_set_opaque(handle_.get(), this);
+    return *this;
 }
 
 const TopicConfiguration::PartitionerCallback&

tests/configuration_test.cpp

@@ -13,8 +13,9 @@ public:
 
 TEST_F(ConfigurationTest, GetSetConfig) {
     Configuration config;
-    config.set("group.id", "foo");
+    config.set("group.id", "foo").set("metadata.broker.list", "asd:9092");
     EXPECT_EQ("foo", config.get("group.id"));
+    EXPECT_EQ("asd:9092", config.get("metadata.broker.list"));
     EXPECT_EQ("foo", config.get<string>("group.id"));
 
     EXPECT_THROW(config.get("asd"), ConfigOptionNotFound);
@@ -22,8 +23,9 @@ TEST_F(ConfigurationTest, GetSetConfig) {
 
 TEST_F(ConfigurationTest, GetSetTopicConfig) {
     TopicConfiguration config;
-    config.set("auto.commit.enable", true);
+    config.set("auto.commit.enable", true).set("offset.store.method", "broker");
     EXPECT_EQ("true", config.get("auto.commit.enable"));
+    EXPECT_EQ("broker", config.get("offset.store.method"));
     EXPECT_EQ(true, config.get<bool>("auto.commit.enable"));
 
     EXPECT_THROW(config.get("asd"), ConfigOptionNotFound);