Add mr2, the 2nd map/reduce coding style.

libswk/GNUmakefile

@@ -81,6 +81,7 @@ LIBSWK_TESTS += swk_str_split_test
 
 LIBSWK_EXAMPLES =#
 LIBSWK_EXAMPLES += mr1.wordcount
+LIBSWK_EXAMPLES += mr2.wordcount
 
 LIBSWK_STATIC_OBJS = $(foreach item,$(LIBSWK_SRCS),src/$(item).o)
 LIBSWK_SHARED_OBJS = $(foreach item,$(LIBSWK_SRCS),src/$(item).lo)

libswk/example/mr2.wordcount.cpp

@@ -0,0 +1,66 @@
+#include <swk/mr2/mapper.hpp>
+#include <swk/mr2/reducer.hpp>
+#include <swk/mr2/job.hpp>
+#include <swk/fs_local.hpp>
+#include <swk/str_split.hpp>
+#include <string>
+#include <vector>
+#include <stdint.h>
+
+class wordcount_mapper : public swk::mr2::mapper<uint32_t, std::string,
+                                                 std::string, uint32_t>
+{
+public:
+
+	void operator()(const uint32_t& key,
+	                const std::string& value,
+	                context& ctx)
+	{
+		SWK_DOUT << value;
+		std::vector<std::string> tokens = swk::str_split(value);
+		for (std::vector<std::string>::const_iterator it = tokens.begin();
+		     it != tokens.end();
+		     ++it) {
+			SWK_DVAR(*it);
+			ctx.push(*it, uint32_t(1));
+		}
+	}
+
+}; // class wordcount
+
+class wordcount_reducer : public swk::mr2::reducer<std::string, uint32_t,
+                                                   std::string, uint32_t>
+{
+public:
+
+	void operator()(const std::string& key,
+	                const std::vector<uint32_t>& values,
+	                context& ctx)
+	{
+		uint32_t sum = 0;
+		for (std::vector<uint32_t>::const_iterator it = values.begin();
+		     it != values.end();
+		     ++it) {
+			sum += *it;
+		}
+		ctx.push(key, sum);
+	}
+};
+
+int main()
+{
+	try {
+		typedef swk::mr2::job<wordcount_mapper, wordcount_reducer> job_type;
+		job_type wc;
+		wc.add_input_path("data1.txt");
+		wc.add_input_path("data2.txt");
+		wc.add_input_path("data3.txt");
+		wc.set_output_dir("output");
+		wc.run();
+		return 0;
+	}
+	catch (std::exception e) {
+		return 1;
+	}
+}
+

libswk/include/swk/mr2/job.hpp

@@ -0,0 +1,66 @@
+#ifndef SWK_MR2_JOB_HPP_INCLUDED
+#define SWK_MR2_JOB_HPP_INCLUDED
+
+#include <swk/dtool.hpp>
+#include <string>
+#include <vector>
+#include <stdint.h>
+#include <iostream>
+
+namespace swk {
+namespace mr2 {
+
+template <class M, class R, class FS = fs_local>
+class job
+{
+public:
+
+	void add_input_path(const std::string& path)
+	{
+		input_paths.push_back(path);
+	}
+
+	void set_output_dir(const std::string& dir)
+	{
+		output_dir = dir;
+	}
+
+	void run()
+	{
+		M m;
+		typename M::context mc;
+		for (std::vector<std::string>::const_iterator ip = input_paths.begin(); // ip: input path
+		     ip != input_paths.end();
+		     ++ip) {
+			typename FS::ichannel ic(ip->c_str());
+			std::string line;
+			uint32_t no = 0;
+			while (std::getline(ic, line)) {
+				SWK_DOUT << line;
+				++no;
+				m(no, line, mc);
+			}
+		}
+		SWK_DMVEC(mc.outputs_);
+
+		R r;
+		typename R::context rc;
+		for (typename M::context::outputs_type::const_iterator me = mc.outputs_.begin(); // me: map entry
+		     me != mc.outputs_.end();
+		     ++me) {
+			r(me->first, me->second, rc);
+		}
+	}
+
+private:
+
+	std::vector<std::string> input_paths;
+	std::string output_dir;
+
+};
+
+} // namespace swk::mr2
+} // namespace swk
+
+#endif /* SWK_MR2_JOB_HPP_INCLUDED */
+

libswk/include/swk/mr2/mapper.hpp

@@ -0,0 +1,47 @@
+#ifndef SWK_MR2_MAPPER_HPP_INCLUDED
+#define SWK_MR2_MAPPER_HPP_INCLUDED
+
+#include <swk/fs_local.hpp>
+#include <vector>
+#include <map>
+#include <utility>
+
+namespace swk {
+namespace mr2 {
+
+template <class IK, class IV, class OK, class OV>
+class mapper_context
+{
+public:
+
+	typedef std::map<OK, std::vector<OV> > outputs_type;
+
+	void push(const OK& ok, const OV& ov)
+	{
+		std::pair<typename outputs_type::iterator, bool> r
+			= outputs_.insert(make_pair(ok, std::vector<OV>()));
+		r.first->second.push_back(ov);
+	}
+
+	outputs_type outputs_;
+
+}; // class swk::mapper_context
+
+template <class IK, class IV, class OK, class OV>
+class mapper
+{
+public:
+
+	typedef mapper_context<IK, IV, OK, OV> context;
+
+//	virtual void operator()(const IK& key,
+//	                        const IV& value,
+//	                        context& ctx) = 0;
+
+}; // class swk::mapper
+
+} // namespace swk::mr2
+} // namespace swk
+
+#endif /* SWK_MR2_MAPPER_HPP_INCLUDED */
+

libswk/include/swk/mr2/reducer.hpp

@@ -0,0 +1,41 @@
+#ifndef SWK_MR2_REDUCER_HPP_INCLUDED
+#define SWK_MR2_REDUCER_HPP_INCLUDED
+
+#include <swk/dtool.hpp>
+#include <swk/fs_local.hpp>
+#include <vector>
+
+namespace swk {
+namespace mr2 {
+
+template <class IK, class IV, class OK, class OV>
+class reducer_context
+{
+public:
+
+	void push(const OK& ok, const OV& ov)
+	{
+		SWK_DOUT << ov << " <= " << ok;
+	}
+
+}; // class swk::reducer_context
+
+template <class IK, class IV, class OK, class OV>
+class reducer
+{
+public:
+
+	typedef reducer_context<IK, IV, OK, OV> context;
+
+//	virtual void operator()(const IK& key,
+//	                        const std::vector<IV>& values,
+//	                        context& ctx) = 0;
+
+}; // class swk::reducer
+
+} // namespace mr2
+} // namespace swk
+
+#endif /* SWK_MR2_REDUCER_HPP_INCLUDED */
+
+