Fix terrain API repo failing if no cache was provided

api/src/main/java/com/seibel/distanthorizons/api/interfaces/data/IDhApiTerrainDataCache.java

@@ -9,12 +9,15 @@ package com.seibel.distanthorizons.api.interfaces.data;
  * @version 2024-7-14
  * @since API 3.0.0
  */
-public interface IDhApiTerrainDataCache
+public interface IDhApiTerrainDataCache // TODO should this be AutoClosable?
 {
 	/**
 	 * Removes any data that's currently stored in this cache.
 	 * This cane be done to free up memory or invalidate 
 	 * the cache so fresh data can be pulled in.
+	 * <br><br>
+	 * This should be called before de-referencing this object
+	 * so DH can handle any necessary cleanup for internal objects.
 	 */
 	void clear();
 	

core/src/main/java/com/seibel/distanthorizons/core/api/external/methods/data/DhApiTerrainDataRepo.java

@@ -197,10 +197,10 @@ public class DhApiTerrainDataRepo implements IDhApiTerrainDataRepo
 		ILevelWrapper coreLevelWrapper = (ILevelWrapper) levelWrapper;
 		
 		
-		if (!(apiDataCache instanceof DhApiTerrainDataCache))
+		// the data cache can be null, but must be our own implementation
+		if (apiDataCache != null
+			&& !(apiDataCache instanceof DhApiTerrainDataCache))
 		{
-			// custom level wrappers aren't supported,
-			// the API user must get a level wrapper from our code somewhere
 			return DhApiResult.createFail("Unsupported [" + IDhApiTerrainDataCache.class.getSimpleName() + "] implementation, only the core class [" + DhApiTerrainDataCache.class.getSimpleName() + "] is a valid parameter.");
 		}
 		DhApiTerrainDataCache dataCache = (DhApiTerrainDataCache) apiDataCache;
@@ -226,10 +226,9 @@ public class DhApiTerrainDataRepo implements IDhApiTerrainDataRepo
 		// get the data source //
 		//=====================//
 		
+		FullDataSourceV2 dataSource = null;
 		try
 		{
-			FullDataSourceV2 dataSource = null;
-			
 			// try using the cached data if possible
 			if (dataCache != null)
 			{
@@ -244,7 +243,12 @@ public class DhApiTerrainDataRepo implements IDhApiTerrainDataRepo
 				{
 					return DhApiResult.createFail("Unable to find/generate any data at the " + DhSectionPos.class.getSimpleName() + " [" + DhSectionPos.toString(sectionPos) + "].");
 				}
-				dataCache.add(sectionPos, dataSource);
+				
+				// save to the cache if present
+				if (dataCache != null)
+				{
+					dataCache.add(sectionPos, dataSource);
+				}
 			}
 			
 			
@@ -316,6 +320,14 @@ public class DhApiTerrainDataRepo implements IDhApiTerrainDataRepo
 			LOGGER.error("Unexpected exception in getTerrainDataColumnArray. Error: [" + e.getMessage() + "]", e);
 			return DhApiResult.createFail("Unexpected exception: [" + e.getMessage() + "].");
 		}
+		finally
+		{
+			if (dataCache == null
+				&& dataSource != null)
+			{
+				dataSource.close();
+			}
+		}
 	}