add AbstractCache::forEach()

Foundation/include/Poco/AbstractCache.h

@@ -176,6 +176,23 @@ public:
 		return result;
 	}
 
+	template <typename Fn>
+	void forEach(Fn&& fn) const
+		/// Iterates over all key-value pairs in the
+		/// cache, using a functor or lambda expression.
+		///
+		/// The given functor must take the key and value
+		/// as parameters. Note that the value is passed
+		/// as the actual value (or reference),
+		/// not a Poco::SharedPtr.
+	{
+		typename TMutex::ScopedLock lock(_mutex);
+		for (const auto& p: _data)
+		{
+			fn(p.first, *p.second);
+		}
+	}
+
 protected:
 	mutable FIFOEvent<ValidArgs<TKey>> IsValid;
 	mutable FIFOEvent<KeySet>          Replace;

Foundation/testsuite/src/LRUCacheTest.cpp

@@ -221,6 +221,29 @@ void LRUCacheTest::testUpdate()
 }
 
 
+void LRUCacheTest::testForEach()
+{
+	LRUCache<int, int> aCache(3);
+
+	std::map<int, int> values;
+	aCache.add(1, 100);
+	aCache.add(2, 200);
+	aCache.add(3, 300);
+
+	aCache.forEach(
+		[&values](int key, int value)
+		{
+			values[key] = value;
+		}
+	);
+
+	assertEquals (values.size(), 3);
+	assertEquals (values[1], 100);
+	assertEquals (values[2], 200);
+	assertEquals (values[3], 300);
+}
+
+
 void LRUCacheTest::onUpdate(const void* pSender, const Poco::KeyValueArgs<int, int>& args)
 {
 	++updateCnt;
@@ -260,6 +283,7 @@ CppUnit::Test* LRUCacheTest::suite()
 	CppUnit_addTest(pSuite, LRUCacheTest, testCacheSizeN);
 	CppUnit_addTest(pSuite, LRUCacheTest, testDuplicateAdd);
 	CppUnit_addTest(pSuite, LRUCacheTest, testUpdate);
+	CppUnit_addTest(pSuite, LRUCacheTest, testForEach);
 
 	return pSuite;
 }

Foundation/testsuite/src/LRUCacheTest.h

@@ -31,6 +31,7 @@ public:
 	void testCacheSizeN();
 	void testDuplicateAdd();
 	void testUpdate();
+	void testForEach();
 
 	void setUp();
 	void tearDown();