CE-938 update memoization to say if it should store null values or not

qqq-backend-core/src/main/java/com/kingsrook/qqq/backend/core/utils/memoization/Memoization.java

@@ -43,8 +43,9 @@ public class Memoization<K, V>
 
    private final Map<K, MemoizedResult<V>> map = Collections.synchronizedMap(new LinkedHashMap<>());
 
-   private Duration timeout = Duration.ofSeconds(600);
-   private Integer  maxSize = 1000;
+   private Duration timeout            = Duration.ofSeconds(600);
+   private Integer  maxSize            = 1000;
+   private boolean  mayStoreNullValues = true;
 
 
 
@@ -58,6 +59,40 @@ public class Memoization<K, V>
 
 
 
+   /*******************************************************************************
+    ** Constructor
+    **
+    *******************************************************************************/
+   public Memoization(Integer maxSize)
+   {
+      this.maxSize = maxSize;
+   }
+
+
+
+   /*******************************************************************************
+    ** Constructor
+    **
+    *******************************************************************************/
+   public Memoization(Duration timeout)
+   {
+      this.timeout = timeout;
+   }
+
+
+
+   /*******************************************************************************
+    ** Constructor
+    **
+    *******************************************************************************/
+   public Memoization(Duration timeout, Integer maxSize)
+   {
+      this.timeout = timeout;
+      this.maxSize = maxSize;
+   }
+
+
+
    /*******************************************************************************
     ** Get the memoized Value for a given input Key - computing it if it wasn't previously
     ** memoized (or expired).
@@ -153,6 +188,14 @@ public class Memoization<K, V>
     *******************************************************************************/
    public void storeResult(K key, V value)
    {
+      //////////////////////////////////////////////////////////////////////////////////////////
+      // if the value is null, and we're not supposed to store nulls, then return w/o storing //
+      //////////////////////////////////////////////////////////////////////////////////////////
+      if(value == null && !mayStoreNullValues)
+      {
+         return;
+      }
+
       map.put(key, new MemoizedResult<>(value));
 
       //////////////////////////////////////
@@ -277,4 +320,35 @@ public class Memoization<K, V>
       return (this);
    }
 
+
+
+   /*******************************************************************************
+    ** Getter for mayStoreNullValues
+    *******************************************************************************/
+   public boolean getMayStoreNullValues()
+   {
+      return (this.mayStoreNullValues);
+   }
+
+
+
+   /*******************************************************************************
+    ** Setter for mayStoreNullValues
+    *******************************************************************************/
+   public void setMayStoreNullValues(boolean mayStoreNullValues)
+   {
+      this.mayStoreNullValues = mayStoreNullValues;
+   }
+
+
+
+   /*******************************************************************************
+    ** Fluent setter for mayStoreNullValues
+    *******************************************************************************/
+   public Memoization<K, V> withMayStoreNullValues(boolean mayStoreNullValues)
+   {
+      this.mayStoreNullValues = mayStoreNullValues;
+      return (this);
+   }
+
 }

qqq-backend-core/src/test/java/com/kingsrook/qqq/backend/core/utils/memoization/MemoizationTest.java

@@ -119,6 +119,57 @@ class MemoizationTest extends BaseTest
 
 
 
+   /*******************************************************************************
+    **
+    *******************************************************************************/
+   @Test
+   void testMayNotStoreNull()
+   {
+      Memoization<String, String> memoization = new Memoization<>();
+      memoization.setMayStoreNullValues(false);
+
+      AtomicInteger callCounter = new AtomicInteger();
+      callCounter.set(0);
+      UnsafeFunction<String, String, Exception> supplier = name ->
+      {
+         callCounter.getAndIncrement();
+         if(name.equals("throw"))
+         {
+            throw (new Exception("You asked me to throw"));
+         }
+         else if(name.equals("null"))
+         {
+            return (null);
+         }
+         else
+         {
+            return (name);
+         }
+      };
+
+      assertThat(memoization.getResult("null", supplier)).isEmpty();
+      assertEquals(1, callCounter.get());
+
+      assertThat(memoization.getResult("null", supplier)).isEmpty();
+      assertEquals(2, callCounter.get()); // should re-run the supplier, incrementing the counter
+
+      assertThat(memoization.getResult("throw", supplier)).isEmpty();
+      assertEquals(3, callCounter.get());
+
+      assertThat(memoization.getResult("throw", supplier)).isEmpty();
+      assertEquals(4, callCounter.get()); // should re-run the supplier, incrementing the counter
+
+      //noinspection AssertBetweenInconvertibleTypes
+      assertThat(memoization.getResult("foo", supplier)).isPresent().get().isEqualTo("foo");
+      assertEquals(5, callCounter.get());
+
+      //noinspection AssertBetweenInconvertibleTypes
+      assertThat(memoization.getResult("foo", supplier)).isPresent().get().isEqualTo("foo");
+      assertEquals(5, callCounter.get()); // should NOT re-run the supplier, NOT incrementing the counter
+   }
+
+
+
    /*******************************************************************************
     **
     *******************************************************************************/