Allow NoSuchFileException to indicate missing

ezkv-kvs/src/main/java/io/jstach/ezkv/kvs/DefaultKeyValuesSourceLoader.java

@@ -2,6 +2,7 @@
 
 import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.nio.file.NoSuchFileException;
 import java.util.ArrayList;
 import java.util.EnumSet;
 import java.util.HashSet;
@@ -216,7 +217,7 @@ KeyValues load(Node node, InternalKeyValuesResource resource, Set<LoadFlag> flag
 		catch (KeyValuesException e) {
 			throw new IOException("Resource has key value errors. resource: " + describe(node), e);
 		}
-		catch (FileNotFoundException e) {
+		catch (FileNotFoundException | NoSuchFileException e) {
 			logger.missing(resource, e);
 			if (LoadFlag.NO_REQUIRE.isSet(flags)) {
 				return KeyValues.empty();

ezkv-kvs/src/main/java/io/jstach/ezkv/kvs/KeyValuesEnvironment.java

@@ -224,7 +224,7 @@ default void loaded(KeyValuesResource resource) {
 		 * @param resource the resource that was not found
 		 * @param exception the exception that occurred when the resource was not found
 		 */
-		default void missing(KeyValuesResource resource, FileNotFoundException exception) {
+		default void missing(KeyValuesResource resource, Exception exception) {
 			debug(KeyValueReference.describe(new StringBuilder("Missing "), resource, false).toString());
 		}
 
@@ -294,7 +294,7 @@ public void loaded(KeyValuesResource resource) {
 	}
 
 	@Override
-	public void missing(KeyValuesResource resource, FileNotFoundException exception) {
+	public void missing(KeyValuesResource resource, Exception exception) {
 	}
 
 }

ezkv-kvs/src/main/java/io/jstach/ezkv/kvs/KeyValuesLoader.java

@@ -3,6 +3,7 @@
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.net.URI;
+import java.nio.file.NoSuchFileException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.function.Consumer;
@@ -150,10 +151,15 @@ public KeyValuesLoader build() {
 		 * Loads key-values using the current builder configuration.
 		 * @return a {@link KeyValues} instance containing the loaded key-value pairs
 		 * @throws IOException if an I/O error occurs during loading
-		 * @throws FileNotFoundException if a specified resource is not found
+		 * @throws FileNotFoundException if a specified resource is not found. This
+		 * exception gets special treatment if thrown if the resource is optional it will
+		 * not be an error.
+		 * @throws NoSuchFileException if a specified resource is not found. This
+		 * exception gets special treatment if thrown if the resource is optional it will
+		 * not be an error.
 		 */
 		@Override
-		public KeyValues load() throws IOException, FileNotFoundException {
+		public KeyValues load() throws IOException, FileNotFoundException, NoSuchFileException {
 			return build().load();
 		}
 

ezkv-kvs/src/main/java/io/jstach/ezkv/kvs/KeyValuesResource.java

@@ -1,7 +1,9 @@
 package io.jstach.ezkv.kvs;
 
+import java.io.FileNotFoundException;
 import java.net.URI;
 import java.nio.charset.StandardCharsets;
+import java.nio.file.NoSuchFileException;
 import java.util.ArrayList;
 import java.util.Base64;
 import java.util.EnumSet;
@@ -210,7 +212,13 @@ public sealed interface KeyValuesResource extends NamedKeyValuesSource, KeyValue
 
 	/**
 	 * Indicates that the resource is optional and no error should occur if it is not
-	 * found.
+	 * found. {@linkplain KeyValuesLoader Loaders} can indicate not found by throwing
+	 * either {@link FileNotFoundException} or {@link NoSuchFileException}. If the
+	 * resource is missing during a full load it will be logged with
+	 * {@link KeyValuesEnvironment.Logger#missing(KeyValuesResource, Exception)}. Note
+	 * that a resource may just not have any key values but is still found. By default
+	 * resources are normally required to exist.
+	 * @see #FLAG_NO_EMPTY
 	 */
 	public static final String FLAG_NO_REQUIRE = "NO_REQUIRE";
 
@@ -226,7 +234,9 @@ public sealed interface KeyValuesResource extends NamedKeyValuesSource, KeyValue
 
 	/**
 	 * Indicates that the resource should not be empty. Typically used to enforce that the
-	 * resource contains at least one key-value pair.
+	 * resource contains at least one key-value pair. This is different than
+	 * {@link #FLAG_NO_REQUIRE} which is if the resource does not exist at all. By default
+	 * empty resources are normally allowed.
 	 */
 	public static final String FLAG_NO_EMPTY = "NO_EMPTY";
 

ezkv-kvs/src/main/java/io/jstach/ezkv/kvs/KeyValuesServiceProvider.java

@@ -2,6 +2,7 @@
 
 import java.io.FileNotFoundException;
 import java.net.URI;
+import java.nio.file.NoSuchFileException;
 import java.util.Optional;
 import java.util.function.BiConsumer;
 
@@ -103,9 +104,9 @@ default KeyValuesMedia.Parser requireParser(KeyValuesResource resource) throws K
 		 * Finds a {@link KeyValuesLoader} capable of loading the specified
 		 * {@link KeyValuesResource} using the provided {@link LoaderContext}. <strong>If
 		 * the resource cannot be found the returned {@link KeyValuesLoader} should throw
-		 * a {@link FileNotFoundException} to indicate not found and not Optional.empty
-		 * which conversely means no matching loader could be found based on the resource.
-		 * </strong>
+		 * a {@link FileNotFoundException} or {@link NoSuchFileException} to indicate not
+		 * found and not Optional.empty which conversely means no matching loader could be
+		 * found based on the resource. </strong>
 		 * @param context the context containing dependencies and services
 		 * @param resource the resource for which a loader is sought
 		 * @return an {@link Optional} containing the loader if found, or empty if not