From f92b725b0e2f2a124d4653a5f929a644ff40677e Mon Sep 17 00:00:00 2001
From: =?utf8?q?=EB=B0=95=EC=A2=85=ED=98=84/=EB=8F=99=EC=9E=91=EC=A0=9C?=
 =?utf8?q?=EC=96=B4Lab=28SR=29/Senior=20Engineer/=EC=82=BC=EC=84=B1?=
 =?utf8?q?=EC=A0=84=EC=9E=90?= <jh1302.park@samsung.com>
Date: Fri, 4 May 2018 15:30:11 +0900
Subject: [PATCH] [core] Introduce 'Printable' interface (#199)

This commit introduces 'Printable' interface for printable objects. This
commit also introduces related tests.

Signed-off-by: Jonghyun Park <jh1302.park@samsung.com>
---
 libs/core/include/nncc/core/ADT/Printable.h    | 26 ++++++++++++++++++
 libs/core/src/nncc/core/ADT/Printable.cpp      | 18 +++++++++++++
 libs/core/src/nncc/core/ADT/Printable.test.cpp | 37 ++++++++++++++++++++++++++
 3 files changed, 81 insertions(+)
 create mode 100644 libs/core/include/nncc/core/ADT/Printable.h
 create mode 100644 libs/core/src/nncc/core/ADT/Printable.cpp
 create mode 100644 libs/core/src/nncc/core/ADT/Printable.test.cpp

diff --git a/libs/core/include/nncc/core/ADT/Printable.h b/libs/core/include/nncc/core/ADT/Printable.h
new file mode 100644
index 0000000..7ae903a
--- /dev/null
+++ b/libs/core/include/nncc/core/ADT/Printable.h
@@ -0,0 +1,26 @@
+#ifndef __NNCC_CORE_ADT_PRINTABLE_H__
+#define __NNCC_CORE_ADT_PRINTABLE_H__
+
+#include <ostream>
+
+namespace nncc
+{
+namespace core
+{
+namespace ADT
+{
+
+struct Printable
+{
+  virtual ~Printable() = default;
+
+  virtual void print(std::ostream &os) const = 0;
+};
+
+std::ostream &operator<<(std::ostream &os, const Printable &prn);
+
+} // namespace ADT
+} // namespace core
+} // namespace nncc
+
+#endif // __NNCC_CORE_ADT_PRINTABLE_H__
diff --git a/libs/core/src/nncc/core/ADT/Printable.cpp b/libs/core/src/nncc/core/ADT/Printable.cpp
new file mode 100644
index 0000000..2af3881
--- /dev/null
+++ b/libs/core/src/nncc/core/ADT/Printable.cpp
@@ -0,0 +1,18 @@
+#include "nncc/core/ADT/Printable.h"
+
+namespace nncc
+{
+namespace core
+{
+namespace ADT
+{
+
+std::ostream &operator<<(std::ostream &os, const Printable &prn)
+{
+  prn.print(os);
+  return os;
+}
+
+} // namespace ADT
+} // namespace core
+} // namespace nncc
diff --git a/libs/core/src/nncc/core/ADT/Printable.test.cpp b/libs/core/src/nncc/core/ADT/Printable.test.cpp
new file mode 100644
index 0000000..10d0c22
--- /dev/null
+++ b/libs/core/src/nncc/core/ADT/Printable.test.cpp
@@ -0,0 +1,37 @@
+#include <nncc/core/ADT/Printable.h>
+
+#include <string>
+#include <sstream>
+
+#include <gtest/gtest.h>
+
+namespace
+{
+
+class PrintableObject final : public nncc::core::ADT::Printable
+{
+public:
+  PrintableObject(const std::string &message) : _message{message}
+  {
+    // DO NOTHING
+  }
+
+public:
+  void print(std::ostream &os) const override { os << _message; }
+
+private:
+  const std::string _message;
+};
+}
+
+TEST(ADT_PRINTABLE, shift_operator)
+{
+  const std::string message{"hello"};
+  const ::PrintableObject object{message};
+
+  std::stringstream ss;
+
+  ss << object;
+
+  ASSERT_EQ(ss.str(), message);
+}
-- 
2.7.4