w88

src/w8/W88/Cache.java

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+package w8.W88;
+
+import java.util.concurrent.ConcurrentHashMap;
+
+public class Cache<K, V> {
+    private ConcurrentHashMap<K, V> cache;
+    private long defaultTTL;
+
+    public Cache() {
+        this.cache = new ConcurrentHashMap<>();
+        this.defaultTTL = 60000;
+    }
+
+    public Cache(long ttlMillis) {
+        this.cache = new ConcurrentHashMap<>();
+        this.defaultTTL = ttlMillis;
+    }
+
+    public void put(K key, V value) {
+        if (key == null) {
+            System.out.println("Error: Key cannot be null");
+            return;
+        }
+        cache.put(key, value);
+        System.out.println("Cache put: " + key + " = " + value);
+    }
+
+    public V get(K key) {
+        if (key == null) {
+            System.out.println("Error: Key cannot be null");
+            return null;
+        }
+        V value = cache.get(key);
+        if (value == null) {
+            System.out.println("Cache miss: " + key + " not found");
+            return null;
+        }
+        System.out.println("Cache hit: " + key + " = " + value);
+        return value;
+    }
+
+    public void remove(K key) {
+        cache.remove(key);
+        System.out.println("Cache removed: " + key);
+    }
+
+    public void clear() {
+        cache.clear();
+        System.out.println("Cache cleared");
+    }
+
+    public int size() {
+        return cache.size();
+    }
+
+    public boolean containsKey(K key) {
+        return cache.containsKey(key);
+    }
+}

src/w8/W88/GenericReflectionExample.java

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+package w8.W88;
+
+import java.lang.reflect.ParameterizedType;
+import java.lang.reflect.Type;
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.List;
+
+public class GenericReflectionExample {
+
+    public static void getGenericInfo() {
+        List<String> list = new ArrayList<String>() {};
+
+        Type type = list.getClass().getGenericSuperclass();
+        if (type instanceof ParameterizedType) {
+            ParameterizedType pt = (ParameterizedType) type;
+            Type[] actualTypes = pt.getActualTypeArguments();
+            for (Type t : actualTypes) {
+                System.out.println("Generic type: " + t.getTypeName());
+            }
+        }
+    }
+
+    public static void getFieldGenericInfo() throws NoSuchFieldException {
+        class MyClass {
+            public List<String> names;
+        }
+
+        Field field = MyClass.class.getField("names");
+        ParameterizedType type = (ParameterizedType) field.getGenericType();
+        Type[] types = type.getActualTypeArguments();
+        System.out.println("Field generic type: " + types[0].getTypeName());
+    }
+
+    public static void getMethodGenericInfo() throws NoSuchMethodException {
+        class MyClass {
+            public void process(List<Integer> numbers) {}
+        }
+
+        Method method = MyClass.class.getMethod("process", List.class);
+        Type[] paramTypes = method.getGenericParameterTypes();
+        ParameterizedType pt = (ParameterizedType) paramTypes[0];
+        System.out.println("Method parameter generic: " + pt.getActualTypeArguments()[0]);
+    }
+
+    public static void main(String[] args) throws Exception {
+        System.out.println("=== Reflection Generic Info ===");
+        getGenericInfo();
+        getFieldGenericInfo();
+        getMethodGenericInfo();
+    }
+}

src/w8/W88/Main.java

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+package w8.W88;
+
+import w8.Cache;
+import w8.Pair;
+
+public class Main {
+    public static void main(String[] args) {
+        System.out.println("=== Pair Test ===");
+        Pair<String, Integer> pair = new Pair<>("age", 25);
+        System.out.println("Original: " + pair);
+        System.out.println("Swap: " + pair.swap());
+
+        System.out.println("\n=== Cache Test ===");
+        Cache<String, String> cache = new Cache<>(3000);
+        cache.put("name", "Ahmed");
+        cache.put("city", "Cairo");
+
+        System.out.println("\n=== Get Values ===");
+        System.out.println("Get name: " + cache.get("name"));
+        System.out.println("Get city: " + cache.get("city"));
+        System.out.println("Get country: " + cache.get("country"));
+
+        System.out.println("\n=== Remove ===");
+        cache.remove("city");
+        System.out.println("Get city after remove: " + cache.get("city"));
+
+        System.out.println("\n=== Size ===");
+        System.out.println("Cache size: " + cache.size());
+
+        cache.clear();
+        System.out.println("After clear, size: " + cache.size());
+    }
+}

src/w8/W88/Pair.java

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+package w8.W88;
+
+public class Pair<K, V> {
+    private K key;
+    private V value;
+
+    public Pair(K key, V value) {
+        this.key = key;
+        this.value = value;
+    }
+
+    public K getKey() {
+        return key;
+    }
+
+    public V getValue() {
+        return value;
+    }
+
+    public void setKey(K key) {
+        this.key = key;
+    }
+
+    public void setValue(V value) {
+        this.value = value;
+    }
+
+    public Pair<V, K> swap() {
+        return new Pair<>(value, key);
+    }
+
+    @Override
+    public String toString() {
+        return "Pair{" + key + ", " + value + "}";
+    }
+}