Add LruCache, a cache implementation using LRU algorithm

src/main/kotlin/io/kamel/core/cache/LruCache.kt

@@ -0,0 +1,29 @@
+package io.kamel.core.cache
+
+private const val LoadFactor = 0.75F
+
+/**
+ * Cache implementation which evicts items using an LRU algorithm.
+ */
+internal class LruCache<K, V>(override val maxSize: Int) : Cache<K, V> {
+
+    private val cache: MutableMap<K, V> = object : LinkedHashMap<K, V>(maxSize, LoadFactor, true) {
+        override fun removeEldestEntry(eldest: MutableMap.MutableEntry<K, V>?): Boolean = size > maxSize
+    }
+
+    override val size: Int
+        get() = cache.size
+
+    init {
+        require(maxSize >= 0) { "Cache max size must be positive number" }
+    }
+
+    override fun get(key: K): V? = cache[key]
+
+    override fun set(key: K, value: V) = cache.set(key, value)
+
+    override fun remove(key: K): Boolean = cache.remove(key) != null
+
+    override fun clear(): Unit = cache.clear()
+
+}