feat: support weakKeys in the CacheConfiguration

com.avaloq.tools.ddk/src/com/avaloq/tools/ddk/caching/CacheConfiguration.java

@@ -18,6 +18,7 @@ public class CacheConfiguration {
 
   private boolean arraySize;
   private boolean softValues;
+  private boolean weakKeys;
   private boolean weakValues;
   private boolean statistics;
 
@@ -45,6 +46,16 @@ public CacheConfiguration useWeakValues() {
     return this;
   }
 
+  /**
+   * All keys stored in the cache are wrapped as {@link java.lang.ref.SoftReference WeakReference}, allowing them to be garbage collected as necessary.
+   *
+   * @return the cache configuration
+   */
+  public CacheConfiguration useWeakKeys() {
+    weakKeys = true;
+    return this;
+  }
+
   /**
    * If enabled, the cache will treat the values as arrays and count their total entries when determining the maximum number of allowed entries.
    *
@@ -85,6 +96,10 @@ public boolean isWeakValuesEnabled() {
     return weakValues;
   }
 
+  public boolean isWeakKeysEnabled() {
+    return weakKeys;
+  }
+
   public boolean isStatisticsEnabled() {
     return statistics;
   }

com.avaloq.tools.ddk/src/com/avaloq/tools/ddk/caching/MapCache.java

@@ -57,6 +57,11 @@ private CacheBuilder<Object, Object> configure(final CacheConfiguration config)
     } else if (config.isWeakValuesEnabled()) {
       cacheBuilder.weakValues();
     }
+
+    if (config.isWeakKeysEnabled()) {
+      cacheBuilder.weakKeys();
+    }
+
     if (config.getInitialCapacity() >= 0) {
       cacheBuilder.initialCapacity(config.getInitialCapacity());
     }