Add Kotlin extensions for Cache and CacheManager

See gh-23927

spring-context/src/main/kotlin/org/springframework/cache/CacheExtensions.kt

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2002-2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cache
+
+
+/**
+ * Extension for [Cache.get] providing a `get<Foo>()` variant.
+ *
+ * @author Mikhael Sokolov
+ * @since 5.2
+ */
+@Suppress("EXTENSION_SHADOWED_BY_MEMBER")
+inline fun <reified T : Any> Cache.get(key: Any): T? = get(key, T::class.java)
+
+/**
+ * Extension for [Cache.get] providing a `foo[key]` variant.
+ *
+ * @author Mikhael Sokolov
+ * @since 5.2
+ */
+@Suppress("EXTENSION_SHADOWED_BY_MEMBER")
+operator fun Cache.get(key: Any): Cache.ValueWrapper? = get(key)
+
+/**
+ * Extension for [Cache.put] providing a `foo[key]` variant.
+ *
+ * @author Mikhael Sokolov
+ * @since 5.2
+ */
+operator fun Cache.set(key: Any, value: Any?) = put(key, value)

spring-context/src/main/kotlin/org/springframework/cache/CacheManagerExtensions.kt

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+package org.springframework.cache
+
+/**
+ * Extension for [CacheManager.getCache(name)] providing a `cm[name]` variant.
+ *
+ * @author Mikhael Sokolov
+ * @since 5.2
+ */
+operator fun CacheManager.get(name: String): Cache? = getCache(name)

spring-context/src/test/kotlin/org/springframework/cache/CacheExtensionsTest.kt

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+package org.springframework.cache
+
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+import org.springframework.cache.concurrent.ConcurrentMapCacheManager
+
+class CacheExtensionsTest {
+
+	@Test
+	fun `Check inline get variant`() {
+		val cache = createCache()
+		cache.put("k", "v")
+		assertEquals("v", cache.get<String>("k"))
+	}
+
+	@Test
+	fun `Check operator get variant`() {
+		val cache = createCache()
+		cache.put("k", "v")
+		assertEquals("v", cache["k"]?.get() as String?)
+	}
+
+	@Test
+	fun `Check operator set variant`() {
+		val cache = createCache()
+		cache["k"] = "v"
+		assertEquals("v", cache.get("k", String::class.java))
+	}
+
+	private fun createCache(cacheName: String = "c"): Cache = ConcurrentMapCacheManager(cacheName).getCache(cacheName)!!
+}

spring-context/src/test/kotlin/org/springframework/cache/CacheManagerExtensionsTest.kt

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+package org.springframework.cache
+
+import org.junit.jupiter.api.Assertions.assertNotEquals
+import org.junit.jupiter.api.Test
+import org.springframework.cache.concurrent.ConcurrentMapCacheManager
+
+class CacheManagerExtensionsTest {
+
+	@Test
+	fun `Check operator get variant`() {
+		val cm = createCacheManager("c")
+		assertNotEquals(null, cm["c"])
+	}
+
+	private fun createCacheManager(cacheName: String = "c"): CacheManager = ConcurrentMapCacheManager(cacheName)
+}