Some cleanup of appender providers logging.file

core/src/main/java/io/jstach/rainbowgum/LogAppender.java

@@ -8,6 +8,7 @@
 
 import io.jstach.rainbowgum.LogAppender.AbstractLogAppender;
 import io.jstach.rainbowgum.LogAppender.ThreadSafeLogAppender;
+import io.jstach.rainbowgum.LogConfig.Provider;
 import io.jstach.rainbowgum.LogEncoder.Buffer;
 
 /**
@@ -16,7 +17,7 @@
  *
  * The only exception is if an Appender implements {@link ThreadSafeLogAppender}.
  */
-public interface LogAppender extends LogLifecycle, LogEventConsumer {
+public interface LogAppender extends LogLifecycle, LogEventConsumer, LogConfig.Provider<LogAppender> {
 
 	/**
 	 * Default Console appender name.
@@ -53,27 +54,9 @@ default void append(LogEvent[] events, int count) {
 
 	public void append(LogEvent event);
 
-	/**
-	 * A factor of appenders.
-	 */
-	public interface AppenderProvider {
-
-		/**
-		 * Creates an appender from config.
-		 * @param config config.
-		 * @return appender.
-		 */
-		LogAppender provide(LogConfig config);
-
-		/**
-		 * Creates a builder to create an appender provider.
-		 * @param name name of appender.
-		 * @return builder.
-		 */
-		public static Builder builder(String name) {
-			return LogAppender.builder(name);
-		}
-
+	@Override
+	default LogAppender provide(LogConfig config) {
+		return this;
 	}
 
 	/**
@@ -109,9 +92,9 @@ public static LogAppender of(List<? extends LogAppender> appenders) {
 	 */
 	public static final class Builder {
 
-		protected @Nullable LogOutput output;
+		protected @Nullable Provider<LogOutput> output;
 
-		protected @Nullable LogEncoder encoder;
+		protected @Nullable Provider<LogEncoder> encoder;
 
 		private final String name;
 
@@ -128,11 +111,11 @@ public String name() {
 		}
 
 		/**
-		 * Sets output. If not set defaults to {@link LogOutput#ofStandardOut()}.
+		 * Sets output.
 		 * @param output output.
 		 * @return builder.
 		 */
-		public Builder output(LogOutput output) {
+		public Builder output(Provider<LogOutput> output) {
 			this.output = output;
 			return this;
 		}
@@ -164,7 +147,7 @@ public Builder formatter(LogFormatter.EventFormatter formatter) {
 		 * @param encoder encoder not <code>null</code>.
 		 * @return builder.
 		 */
-		public Builder encoder(LogEncoder encoder) {
+		public Builder encoder(Provider<LogEncoder> encoder) {
 			this.encoder = encoder;
 			return this;
 		}
@@ -173,12 +156,16 @@ public Builder encoder(LogEncoder encoder) {
 		 * Builds.
 		 * @return an appender factory.
 		 */
-		public AppenderProvider build() {
+		public Provider<LogAppender> build() {
 			/*
 			 * We need to capture parameters since appender creation needs to be lazy.
 			 */
-			AppenderConfig a = new AppenderConfig(name, output, encoder);
+			var _name = name;
+			var _output = output;
+			var _encoder = encoder;
 			return config -> {
+				AppenderConfig a = new AppenderConfig(_name, Provider.provideOrNull(_output, config),
+						Provider.provideOrNull(_encoder, config));
 				return DefaultAppenderRegistry.appender(a, config);
 			};
 		}

core/src/main/java/io/jstach/rainbowgum/LogAppenderRegistry.java

@@ -9,7 +9,7 @@
 
 import org.eclipse.jdt.annotation.Nullable;
 
-import io.jstach.rainbowgum.LogAppender.AppenderProvider;
+import io.jstach.rainbowgum.LogConfig.Provider;
 import io.jstach.rainbowgum.LogProperties.Property;
 
 /**
@@ -22,14 +22,14 @@ public sealed interface LogAppenderRegistry permits DefaultAppenderRegistry {
 	 * @param name name of the appender.
 	 * @return appender provider to be used for creating the appender.
 	 */
-	Optional<AppenderProvider> appender(String name);
+	Optional<Provider<LogAppender>> appender(String name);
 
 	/**
 	 * Registers an appender provider by name.
 	 * @param name of the appender.
 	 * @param appenderProvider factory to be used for creating appenders.
 	 */
-	void register(String name, AppenderProvider appenderProvider);
+	void register(String name, Provider<LogAppender> appenderProvider);
 
 	/**
 	 * Creates a log appender registry.
@@ -68,7 +68,7 @@ final class DefaultAppenderRegistry implements LogAppenderRegistry {
 	 * properties is complicated particularly because we want to support Spring Boots
 	 * configuration OOB.
 	 */
-	private final Map<String, AppenderProvider> providers = new ConcurrentHashMap<>();
+	private final Map<String, Provider<LogAppender>> providers = new ConcurrentHashMap<>();
 
 	static final Property<URI> fileProperty = Property.builder().toURI().build(LogProperties.FILE_PROPERTY);
 
@@ -101,12 +101,14 @@ private static LogAppender defaultConsoleAppender(LogConfig config) {
 	}
 
 	static Optional<LogAppender> fileAppender(LogConfig config) {
-		String name = LogAppender.FILE_APPENDER_NAME;
-		var outputProperty = outputProperty(LogAppender.APPENDER_OUTPUT_PROPERTY, name, config);
+		final String name = LogAppender.FILE_APPENDER_NAME;
+		var outputProperty = fileProperty //
+			.map(u -> config.outputRegistry().output(u, name, config.properties()));
 		var encoderProperty = encoderProperty(LogAppender.APPENDER_ENCODER_PROPERTY, name, config);
+
 		return fileProperty //
-			.map(u -> appender(name, config, outputProperty, encoderProperty))
-			.get(config.properties())
+			.map(u -> appender(name, config, outputProperty, encoderProperty)) //
+			.get(config.properties()) //
 			.optional();
 	}
 
@@ -198,12 +200,12 @@ private static Property<LogEncoder> encoderProperty(String propertyName, String
 	}
 
 	@Override
-	public Optional<AppenderProvider> appender(String name) {
+	public Optional<Provider<LogAppender>> appender(String name) {
 		return Optional.ofNullable(providers.get(name));
 	}
 
 	@Override
-	public void register(String name, AppenderProvider appenderProvider) {
+	public void register(String name, Provider<LogAppender> appenderProvider) {
 		providers.put(name, appenderProvider);
 
 	}

core/src/main/java/io/jstach/rainbowgum/LogConfig.java

@@ -104,6 +104,40 @@ public static Builder builder() {
 	 */
 	public ServiceRegistry serviceRegistry();
 
+	/**
+	 * A factory that may need config to provide. <strong>Most components implements this
+	 * interface so that you can use already created instances</strong>.
+	 *
+	 * @param <T> component
+	 */
+	@FunctionalInterface
+	public interface Provider<T> {
+
+		/**
+		 * Creates the component from config. The component is not always guaranteed to be
+		 * new object.
+		 * @param config config.
+		 * @return component.
+		 */
+		T provide(LogConfig config);
+
+		/**
+		 * Convenience for flattening nullable providers.
+		 * @param <U> component
+		 * @param provider nullable provider
+		 * @param config config used to provide if not null.
+		 * @return maybe null component.
+		 */
+		@SuppressWarnings("exports")
+		public static <U> @Nullable U provideOrNull(@Nullable Provider<U> provider, LogConfig config) {
+			if (provider == null) {
+				return null;
+			}
+			return provider.provide(config);
+		}
+
+	}
+
 	/**
 	 * Config Change Publisher.
 	 */

core/src/main/java/io/jstach/rainbowgum/LogEncoder.java

@@ -43,7 +43,7 @@
  * @see LogAppender
  * @see StringBuilderBuffer
  */
-public interface LogEncoder {
+public interface LogEncoder extends LogConfig.Provider<LogEncoder> {
 
 	/**
 	 * Creates a <strong>new</strong> buffer. The encoder should not try to reuse buffers
@@ -86,6 +86,11 @@ public interface EncoderProvider {
 
 	}
 
+	@Override
+	default LogEncoder provide(LogConfig config) {
+		return this;
+	}
+
 	/**
 	 * Encoders buffer.
 	 */

core/src/main/java/io/jstach/rainbowgum/LogOutput.java

@@ -31,7 +31,7 @@
  * @see LogOutput.OutputProvider
  * @see Buffer
  */
-public interface LogOutput extends LogLifecycle, Flushable {
+public interface LogOutput extends LogLifecycle, Flushable, LogConfig.Provider<LogOutput> {
 
 	/**
 	 * {@link FileDescriptor#err} URI scheme.
@@ -70,6 +70,10 @@ private static URI uri(String s) {
 		}
 	}
 
+	default LogOutput provide(LogConfig config) {
+		return this;
+	}
+
 	/**
 	 * Finds output based on URI.
 	 */

core/src/main/java/io/jstach/rainbowgum/LogProperties.java

@@ -468,16 +468,6 @@ static String concatKey(String prefix, String name) {
 	 * @return interpolated property name.
 	 */
 	static String interpolateKey(String name, Map<String, String> parameters) {
-
-		// if (validate) {
-		// StringBuilder error = new StringBuilder();
-		// for (Map.Entry<String, String> entry : parameters.entrySet()) {
-		// String key = entry.getKey();
-		// String p = "{" + key + "}";
-		// if (! name.contains(p)) {
-		// }
-		// }
-		// }
 		for (Map.Entry<String, String> entry : parameters.entrySet()) {
 			name = name.replace("{" + entry.getKey() + "}", entry.getValue());
 		}

core/src/main/java/io/jstach/rainbowgum/LogRouter.java

@@ -4,7 +4,6 @@
 
 import java.lang.System.Logger;
 import java.lang.System.Logger.Level;
-import java.net.URI;
 import java.text.MessageFormat;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -19,8 +18,6 @@
 
 import org.eclipse.jdt.annotation.Nullable;
 
-import io.jstach.rainbowgum.LogAppender.AppenderProvider;
-import io.jstach.rainbowgum.LogProperties.Property;
 import io.jstach.rainbowgum.LogPublisher.PublisherProvider;
 import io.jstach.rainbowgum.LogRouter.RootRouter;
 import io.jstach.rainbowgum.LogRouter.Route;
@@ -181,7 +178,7 @@ public final class Builder extends LevelResolver.AbstractBuilder<Builder> {
 
 			private final LogConfig config;
 
-			private List<AppenderProvider> appenders = new ArrayList<>();
+			private List<LogConfig.Provider<LogAppender>> appenders = new ArrayList<>();
 
 			private Builder(LogConfig config) {
 				this.config = config;
@@ -216,7 +213,7 @@ public Builder appender(String name, Consumer<LogAppender.Builder> consumer) {
 			 * @param appender appender provider.
 			 * @return this builder.
 			 */
-			public Builder appender(AppenderProvider appender) {
+			public Builder appender(LogConfig.Provider<LogAppender> appender) {
 				this.appenders.add(appender);
 				return self();
 			}
@@ -238,11 +235,10 @@ public Builder publisher(PublisherProvider publisher) {
 			Router build() {
 				var levelResolver = buildLevelResolver(config.levelResolver());
 				var publisher = this.publisher;
-				List<AppenderProvider> appenders = new ArrayList<>(this.appenders);
+				List<LogConfig.Provider<LogAppender>> appenders = new ArrayList<>(this.appenders);
 				if (appenders.isEmpty()) {
 					DefaultAppenderRegistry.defaultAppenders(config) //
 						.stream() //
-						.<AppenderProvider>map(a -> (c -> a)) //
 						.forEach(appenders::add);
 				}
 				if (publisher == null) {