Add MessageBuilder and use it on producer classes

include/cppkafka/message_builder.h

@@ -0,0 +1,126 @@
+/*
+ * Copyright (c) 2016, Matias Fontanini
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following disclaimer
+ *   in the documentation and/or other materials provided with the
+ *   distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef CPPKAFKA_MESSAGE_BUILDER_H
+#define CPPKAFKA_MESSAGE_BUILDER_H
+
+#include <boost/optional.hpp>
+#include "buffer.h"
+#include "topic.h"
+#include "partition.h"
+
+namespace cppkafka {
+
+/**
+ * \brief Message builder class
+ * 
+ * Allows building a message including topic, partition, key, payload, etc.
+ *
+ * Example:
+ *
+ * \code
+ * Producer producer(...);
+ * Topic topic = producer.get_topic("test");
+ * 
+ * string payload = "hello world";
+ * producer.produce(MessageBuilder(topic).partition(5).payload(payload));
+ * \endcode
+ */
+class MessageBuilder {
+public:
+    /**
+     * Construct a MessageBuilder
+     *
+     * \param topic The topic into which this message would be produced
+     */
+    MessageBuilder(const Topic& topic);
+
+    /**
+     * Sets the partition into which this message will be produced
+     *
+     * \param value The partition to be used  
+     */
+    MessageBuilder& partition(Partition value);
+
+    /**
+     * Sets the message's key
+     *
+     * \param value The key to be used
+     */
+    MessageBuilder& key(const Buffer& value);
+
+    /**
+     * Sets the message's payload
+     *
+     * \param value The payload to be used
+     */
+    MessageBuilder& payload(const Buffer& value);
+
+    /**
+     * Sets the message's user data pointer
+     *
+     * \param value Pointer to the user data to be used on the produce call
+     */
+    MessageBuilder& user_data(void* value);
+
+    /**
+     * Gets the topic this message will be produced into
+     */
+    const Topic& topic() const;
+
+    /**
+     * Gets the partition this message will be produced into
+     */
+    const Partition& partition() const;
+
+    /**
+     * Gets the message's key
+     */
+    const Buffer& key() const;
+
+    /**
+     * Gets the message's payload
+     */
+    const Buffer& payload() const;
+
+    /**
+     * Gets the message's user data pointer
+     */
+    void* user_data() const;
+private:
+    const Topic& topic_;
+    Partition partition_;
+    Buffer key_;
+    Buffer payload_;
+    void* user_data_;
+};
+
+} // cppkafka
+
+#endif // CPPKAFKA_MESSAGE_BUILDER_H