Harmonize the use of Writer rather than Generator

spring-core/src/main/java/org/springframework/aot/nativex/FileNativeConfigurationGenerator.java

@@ -1,136 +0,0 @@
-/*
- * Copyright 2002-2022 the original author or authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      https://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.springframework.aot.nativex;
-
-import java.io.File;
-import java.io.FileWriter;
-import java.io.IOException;
-import java.nio.file.Path;
-
-import org.springframework.aot.hint.JavaSerializationHints;
-import org.springframework.aot.hint.ProxyHints;
-import org.springframework.aot.hint.ReflectionHints;
-import org.springframework.aot.hint.ResourceHints;
-import org.springframework.aot.hint.RuntimeHints;
-import org.springframework.lang.Nullable;
-
-/**
- * Generate the GraalVM native configuration files from runtime hints.
- *
- * @author Sebastien Deleuze
- * @since 6.0
- * @see <a href="https://www.graalvm.org/22.0/reference-manual/native-image/BuildConfiguration/">Native Image Build Configuration</a>
- */
-public class FileNativeConfigurationGenerator implements NativeConfigurationGenerator {
-
-	private final Path basePath;
-
-	private final String groupId;
-
-	private final String artifactId;
-
-	public FileNativeConfigurationGenerator(Path basePath) {
-		this(basePath, null, null);
-	}
-
-	public FileNativeConfigurationGenerator(Path basePath, @Nullable String groupId, @Nullable String artifactId) {
-		this.basePath = basePath;
-		if ((groupId == null && artifactId != null) || (groupId != null && artifactId == null)) {
-			throw new IllegalArgumentException("groupId and artifactId must be both null or both non-null");
-		}
-		this.groupId = groupId;
-		this.artifactId = artifactId;
-	}
-
-	@Override
-	public void generate(RuntimeHints hints) {
-		try {
-			if (hints.javaSerialization().types().findAny().isPresent()) {
-				generateFile(hints.javaSerialization());
-			}
-			if (hints.proxies().jdkProxies().findAny().isPresent()) {
-				generateFile(hints.proxies());
-			}
-			if (hints.reflection().typeHints().findAny().isPresent()) {
-				generateFile(hints.reflection());
-			}
-			if (hints.resources().resourcePatterns().findAny().isPresent() ||
-					hints.resources().resourceBundles().findAny().isPresent()) {
-				generateFile(hints.resources());
-			}
-		}
-		catch (IOException ex) {
-			throw new IllegalStateException("Unexpected I/O error while writing the native configuration", ex);
-		}
-	}
-
-	/**
-	 * Generate the Java serialization native configuration file.
-	 */
-	private void generateFile(JavaSerializationHints hints) throws IOException {
-		JavaSerializationHintsSerializer serializer = new JavaSerializationHintsSerializer();
-		File file = createIfNecessary("serialization-config.json");
-		FileWriter writer = new FileWriter(file);
-		writer.write(serializer.serialize(hints));
-		writer.close();
-	}
-
-	/**
-	 * Generate the proxy native configuration file.
-	 */
-	private void generateFile(ProxyHints hints) throws IOException {
-		ProxyHintsSerializer serializer = new ProxyHintsSerializer();
-		File file = createIfNecessary("proxy-config.json");
-		FileWriter writer = new FileWriter(file);
-		writer.write(serializer.serialize(hints));
-		writer.close();
-	}
-
-	/**
-	 * Generate the reflection native configuration file.
-	 */
-	private void generateFile(ReflectionHints hints) throws IOException {
-		ReflectionHintsSerializer serializer = new ReflectionHintsSerializer();
-		File file = createIfNecessary("reflect-config.json");
-		FileWriter writer = new FileWriter(file);
-		writer.write(serializer.serialize(hints));
-		writer.close();
-	}
-
-	/**
-	 * Generate the resource native configuration file.
-	 */
-	private void generateFile(ResourceHints hints) throws IOException {
-		ResourceHintsSerializer serializer = new ResourceHintsSerializer();
-		File file = createIfNecessary("resource-config.json");
-		FileWriter writer = new FileWriter(file);
-		writer.write(serializer.serialize(hints));
-		writer.close();
-	}
-
-	private File createIfNecessary(String filename) throws IOException {
-		Path outputDirectory = this.basePath.resolve("META-INF").resolve("native-image");
-		if (this.groupId != null && this.artifactId != null) {
-			outputDirectory = outputDirectory.resolve(this.groupId).resolve(this.artifactId);
-		}
-		outputDirectory.toFile().mkdirs();
-		File file = outputDirectory.resolve(filename).toFile();
-		file.createNewFile();
-		return file;
-	}
-
-}

spring-core/src/main/java/org/springframework/aot/nativex/FileNativeConfigurationWriter.java

@@ -0,0 +1,86 @@
+/*
+ * Copyright 2002-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.aot.nativex;
+
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.Writer;
+import java.nio.file.Path;
+import java.util.function.Consumer;
+
+import org.springframework.lang.Nullable;
+
+/**
+ * A {@link NativeConfigurationWriter} implementation that writes the
+ * configuration to disk.
+ *
+ * @author Sebastien Deleuze
+ * @author Stephane Nicoll
+ * @since 6.0
+ * @see <a href="https://www.graalvm.org/22.0/reference-manual/native-image/BuildConfiguration/">Native Image Build Configuration</a>
+ */
+public class FileNativeConfigurationWriter extends NativeConfigurationWriter {
+
+	private final Path basePath;
+
+	private final String groupId;
+
+	private final String artifactId;
+
+	public FileNativeConfigurationWriter(Path basePath) {
+		this(basePath, null, null);
+	}
+
+	public FileNativeConfigurationWriter(Path basePath, @Nullable String groupId, @Nullable String artifactId) {
+		this.basePath = basePath;
+		if ((groupId == null && artifactId != null) || (groupId != null && artifactId == null)) {
+			throw new IllegalArgumentException("groupId and artifactId must be both null or both non-null");
+		}
+		this.groupId = groupId;
+		this.artifactId = artifactId;
+	}
+
+	@Override
+	protected void writeTo(String fileName, Consumer<BasicJsonWriter> writer) {
+		try {
+			File file = createIfNecessary(fileName);
+			try (FileWriter out = new FileWriter(file)) {
+				writer.accept(createJsonWriter(out));
+			}
+		}
+		catch (IOException ex) {
+			throw new IllegalStateException("Failed to write native configuration for " + fileName, ex);
+		}
+	}
+
+	private File createIfNecessary(String filename) throws IOException {
+		Path outputDirectory = this.basePath.resolve("META-INF").resolve("native-image");
+		if (this.groupId != null && this.artifactId != null) {
+			outputDirectory = outputDirectory.resolve(this.groupId).resolve(this.artifactId);
+		}
+		outputDirectory.toFile().mkdirs();
+		File file = outputDirectory.resolve(filename).toFile();
+		file.createNewFile();
+		return file;
+	}
+
+	private BasicJsonWriter createJsonWriter(Writer out) {
+		return new BasicJsonWriter(out);
+	}
+
+}

spring-core/src/main/java/org/springframework/aot/nativex/JavaSerializationHintsWriter.java

@@ -16,7 +16,6 @@
 
 package org.springframework.aot.nativex;
 
-import java.io.StringWriter;
 import java.util.LinkedHashMap;
 import java.util.Map;
 
@@ -24,7 +23,7 @@ import org.springframework.aot.hint.JavaSerializationHints;
 import org.springframework.aot.hint.TypeReference;
 
 /**
- * Serialize a {@link JavaSerializationHints} to the JSON output expected by the
+ * Write a {@link JavaSerializationHints} to the JSON output expected by the
  * GraalVM {@code native-image} compiler, typically named
  * {@code serialization-config.json}.
  *
@@ -33,13 +32,12 @@ import org.springframework.aot.hint.TypeReference;
  * @since 6.0
  * @see <a href="https://www.graalvm.org/22.0/reference-manual/native-image/BuildConfiguration/">Native Image Build Configuration</a>
  */
-class JavaSerializationHintsSerializer {
+class JavaSerializationHintsWriter {
 
-	public String serialize(JavaSerializationHints hints) {
-		StringWriter sw = new StringWriter();
-		BasicJsonWriter writer = new BasicJsonWriter(sw, "  ");
+	public static final JavaSerializationHintsWriter INSTANCE = new JavaSerializationHintsWriter();
+
+	public void write(BasicJsonWriter writer, JavaSerializationHints hints) {
 		writer.writeArray(hints.types().map(this::toAttributes).toList());
-		return sw.toString();
 	}
 
 	private Map<String, Object> toAttributes(TypeReference typeReference) {

spring-core/src/main/java/org/springframework/aot/nativex/NativeConfigurationGenerator.java

@@ -1,36 +0,0 @@
-/*
- * Copyright 2002-2022 the original author or authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      https://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.springframework.aot.nativex;
-
-import org.springframework.aot.hint.RuntimeHints;
-
-/**
- * Generate GraalVM native configuration.
- *
- * @author Sebastien Deleuze
- * @since 6.0
- * @see <a href="https://www.graalvm.org/22.0/reference-manual/native-image/BuildConfiguration/">Native Image Build Configuration</a>
- */
-public interface NativeConfigurationGenerator {
-
-	/**
-	 * Generate the GraalVM native configuration from the provided hints.
-	 * @param hints the hints to serialize
-	 */
-	void generate(RuntimeHints hints);
-
-}

spring-core/src/main/java/org/springframework/aot/nativex/NativeConfigurationWriter.java

@@ -0,0 +1,85 @@
+/*
+ * Copyright 2002-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.aot.nativex;
+
+import java.util.function.Consumer;
+
+import org.springframework.aot.hint.JavaSerializationHints;
+import org.springframework.aot.hint.ProxyHints;
+import org.springframework.aot.hint.ReflectionHints;
+import org.springframework.aot.hint.ResourceHints;
+import org.springframework.aot.hint.RuntimeHints;
+
+/**
+ * Write {@link RuntimeHints} as GraalVM native configuration.
+ *
+ * @author Sebastien Deleuze
+ * @author Stephane Nicoll
+ * @since 6.0
+ * @see <a href="https://www.graalvm.org/22.0/reference-manual/native-image/BuildConfiguration/">Native Image Build Configuration</a>
+ */
+public abstract class NativeConfigurationWriter {
+
+	/**
+	 * Write the GraalVM native configuration from the provided hints.
+	 * @param hints the hints to handle
+	 */
+	public void write(RuntimeHints hints) {
+		if (hints.javaSerialization().types().findAny().isPresent()) {
+			writeJavaSerializationHints(hints.javaSerialization());
+		}
+		if (hints.proxies().jdkProxies().findAny().isPresent()) {
+			writeProxyHints(hints.proxies());
+		}
+		if (hints.reflection().typeHints().findAny().isPresent()) {
+			writeReflectionHints(hints.reflection());
+		}
+		if (hints.resources().resourcePatterns().findAny().isPresent() ||
+				hints.resources().resourceBundles().findAny().isPresent()) {
+			writeResourceHints(hints.resources());
+		}
+	}
+
+	/**
+	 * Write the specified GraalVM native configuration file, using the
+	 * provided {@link BasicJsonWriter}.
+	 * @param fileName the name of the file
+	 * @param writer a consumer for the writer to use
+	 */
+	protected abstract void writeTo(String fileName, Consumer<BasicJsonWriter> writer);
+
+	private void writeJavaSerializationHints(JavaSerializationHints hints) {
+		writeTo("serialization-config.json", writer ->
+				JavaSerializationHintsWriter.INSTANCE.write(writer, hints));
+	}
+
+	private void writeProxyHints(ProxyHints hints) {
+		writeTo("proxy-config.json", writer ->
+				ProxyHintsWriter.INSTANCE.write(writer, hints));
+	}
+
+	private void writeReflectionHints(ReflectionHints hints) {
+		writeTo("reflect-config.json", writer ->
+				ReflectionHintsWriter.INSTANCE.write(writer, hints));
+	}
+
+	private void writeResourceHints(ResourceHints hints) {
+		writeTo("resource-config.json", writer ->
+				ResourceHintsWriter.INSTANCE.write(writer, hints));
+	}
+
+}

spring-core/src/main/java/org/springframework/aot/nativex/ProxyHintsWriter.java

@@ -16,7 +16,6 @@
 
 package org.springframework.aot.nativex;
 
-import java.io.StringWriter;
 import java.util.LinkedHashMap;
 import java.util.Map;
 
@@ -25,7 +24,7 @@ import org.springframework.aot.hint.ProxyHints;
 import org.springframework.aot.hint.TypeReference;
 
 /**
- * Serialize {@link JdkProxyHint}s contained in a {@link ProxyHints} to the JSON
+ * Write {@link JdkProxyHint}s contained in a {@link ProxyHints} to the JSON
  * output expected by the GraalVM {@code native-image} compiler, typically named
  * {@code proxy-config.json}.
  *
@@ -35,13 +34,12 @@ import org.springframework.aot.hint.TypeReference;
  * @see <a href="https://www.graalvm.org/22.0/reference-manual/native-image/DynamicProxy/">Dynamic Proxy in Native Image</a>
  * @see <a href="https://www.graalvm.org/22.0/reference-manual/native-image/BuildConfiguration/">Native Image Build Configuration</a>
  */
-class ProxyHintsSerializer {
+class ProxyHintsWriter {
 
-	public String serialize(ProxyHints hints) {
-		StringWriter sw = new StringWriter();
-		BasicJsonWriter writer = new BasicJsonWriter(sw, "  ");
+	public static final ProxyHintsWriter INSTANCE = new ProxyHintsWriter();
+
+	public void write(BasicJsonWriter writer, ProxyHints hints) {
 		writer.writeArray(hints.jdkProxies().map(this::toAttributes).toList());
-		return sw.toString();
 	}
 
 	private Map<String, Object> toAttributes(JdkProxyHint hint) {

spring-core/src/main/java/org/springframework/aot/nativex/ReflectionHintsWriter.java

@@ -16,7 +16,6 @@
 
 package org.springframework.aot.nativex;
 
-import java.io.StringWriter;
 import java.util.Collection;
 import java.util.LinkedHashMap;
 import java.util.List;
@@ -34,7 +33,7 @@ import org.springframework.aot.hint.TypeReference;
 import org.springframework.lang.Nullable;
 
 /**
- * Serialize {@link ReflectionHints} to the JSON output expected by the GraalV
+ * Write {@link ReflectionHints} to the JSON output expected by the GraalVM
  * {@code native-image} compiler, typically named {@code reflect-config.json}.
  *
  * @author Sebastien Deleuze
@@ -43,13 +42,12 @@ import org.springframework.lang.Nullable;
  * @see <a href="https://www.graalvm.org/22.0/reference-manual/native-image/Reflection/">Reflection Use in Native Images</a>
  * @see <a href="https://www.graalvm.org/22.0/reference-manual/native-image/BuildConfiguration/">Native Image Build Configuration</a>
  */
-class ReflectionHintsSerializer {
+class ReflectionHintsWriter {
 
-	public String serialize(ReflectionHints hints) {
-		StringWriter sw = new StringWriter();
-		BasicJsonWriter writer = new BasicJsonWriter(sw, "  ");
+	public static final ReflectionHintsWriter INSTANCE = new ReflectionHintsWriter();
+
+	public void write(BasicJsonWriter writer, ReflectionHints hints) {
 		writer.writeArray(hints.typeHints().map(this::toAttributes).toList());
-		return sw.toString();
 	}
 
 	private Map<String, Object> toAttributes(TypeHint hint) {

spring-core/src/main/java/org/springframework/aot/nativex/ResourceHintsWriter.java

@@ -16,7 +16,6 @@
 
 package org.springframework.aot.nativex;
 
-import java.io.StringWriter;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.LinkedHashMap;
@@ -32,7 +31,7 @@ import org.springframework.aot.hint.ResourcePatternHint;
 import org.springframework.lang.Nullable;
 
 /**
- * Serialize a {@link ResourceHints} to the JSON output expected by the GraalVM
+ * Write a {@link ResourceHints} to the JSON output expected by the GraalVM
  * {@code native-image} compiler, typically named {@code resource-config.json}.
  *
  * @author Sebastien Deleuze
@@ -41,16 +40,15 @@ import org.springframework.lang.Nullable;
  * @see <a href="https://www.graalvm.org/22.0/reference-manual/native-image/Resources/">Accessing Resources in Native Images</a>
  * @see <a href="https://www.graalvm.org/22.0/reference-manual/native-image/BuildConfiguration/">Native Image Build Configuration</a>
  */
-class ResourceHintsSerializer {
+class ResourceHintsWriter {
 
-	public String serialize(ResourceHints hints) {
-		StringWriter out = new StringWriter();
-		BasicJsonWriter writer = new BasicJsonWriter(out, "\t");
+	public static final ResourceHintsWriter INSTANCE = new ResourceHintsWriter();
+
+	public void write(BasicJsonWriter writer, ResourceHints hints) {
 		Map<String, Object> attributes = new LinkedHashMap<>();
 		attributes.put("resources", toAttributes(hints));
 		handleResourceBundles(attributes, hints.resourceBundles());
 		writer.writeObject(attributes);
-		return out.toString();
 	}
 
 	private Map<String, Object> toAttributes(ResourceHints hint) {