package com.atlassian.vcache.internal.legacy;
   
   import com.atlassian.cache.Cache;
   import com.atlassian.vcache.JvmCache;
   import com.atlassian.vcache.internal.core.RecursionDetector;
   import com.atlassian.vcache.internal.core.service.LocalCacheUtils;
   
   import java.util.Arrays;
   import java.util.HashSet;
  import java.util.Map;
  import java.util.Optional;
  import java.util.Set;
  import java.util.concurrent.locks.ReentrantLock;
  import java.util.function.Function;
  import java.util.function.Supplier;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * Implementation of {@link JvmCache} that backs onto a legacy {@link Cache}.
   *
   * @param <K> the key type
   * @param <V> the value type
   * @since 1.0.0
   */
  class LegacyJvmCache<K, V> implements JvmCache<K, V> {
      private final ReentrantLock globalLock = new ReentrantLock();
      private final Cache<K, V> delegate;
      private final RecursionDetector<K> recursionDetector = new RecursionDetector<>();
  
      LegacyJvmCache(Cache<K, V> delegate) {
          this.delegate = requireNonNull(delegate);
      }
  
      @Override
      public Set<K> getKeys() {
          return withLock(() -> new HashSet<>(delegate.getKeys()));
      }
  
      @Override
      public Optional<V> get(K key) {
          return withLock(() -> Optional.ofNullable(delegate.get(key)));
      }
  
      @Override
      public V get(K key, Supplier<? extends V> supplier) {
          try (RecursionDetector.Guard<K> ignored = recursionDetector.guardOn(key)) {
              return withLock(() -> delegate.get(key, supplier::get));
          }
      }
  
      @SafeVarargs
      @Override
      public final Map<K, V> getBulk(Function<Set<K>, Map<K, V>> factory, K... keys) {
          // This method needs to be final to prevent subclasses bypassing the locking enforced by this class.
          return getBulk(factory, Arrays.asList(keys));
      }
  
      @Override
      public Map<K, V> getBulk(Function<Set<K>, Map<K, V>> factory, Iterable<K> keys) {
          return withLock(() -> LocalCacheUtils.getBulk(
                  factory,
                  keys,
                  this::get,
                  args -> put(args.key, args.value),
                  recursionDetector));
      }
  
      @Override
      public void put(K key, V value) {
          withLock(() -> delegate.put(key, value));
      }
  
      @Override
      public Optional<V> putIfAbsent(K key, V value) {
          return withLock(() -> Optional.ofNullable(delegate.putIfAbsent(key, value)));
      }
  
      @Override
      public boolean replaceIf(K key, V currentValue, V newValue) {
          return withLock(() -> delegate.replace(key, currentValue, newValue));
      }
  
      @Override
      public boolean removeIf(K key, V value) {
          return withLock(() -> delegate.remove(key, value));
      }
  
      @Override
      public void remove(K key) {
          withLock(() -> delegate.remove(key));
      }
  
      @Override
      public void removeAll() {
          withLock(delegate::removeAll);
      }
  
      @Override
     public String getName() {
         return delegate.getName();
     }
 
     private <R> R withLock(Supplier<R> supplier) {
         globalLock.lock();
         try {
             return supplier.get();
         } finally {
             globalLock.unlock();
         }
     }
 
     private void withLock(Runnable runner) {
         globalLock.lock();
         try {
             runner.run();
         } finally {
             globalLock.unlock();
         }
     }
 }