Add avaje-jsonb JsonOutput as performance option

avaje-jex/src/main/java/io/avaje/jex/core/BufferedOutStream.java

@@ -15,7 +15,6 @@ final class BufferedOutStream extends OutputStream {
   private long count;
 
   BufferedOutStream(JdkContext context, int initial, long max) {
-
     this.context = context;
     this.max = max;
     this.buffer = new ByteArrayOutputStream(initial);

avaje-jex/src/main/java/io/avaje/jex/core/JdkContext.java

@@ -503,6 +503,16 @@ public void write(byte[] bytes) {
     }
   }
 
+  @Override
+  public void write(byte[] bufferBytes, int length) {
+    try (var os = exchange.getResponseBody()) {
+      exchange.sendResponseHeaders(statusCode(), length == 0 ? -1 : length);
+      os.write(bufferBytes, 0, length);
+    } catch (IOException e) {
+      throw new UncheckedIOException(e);
+    }
+  }
+
   @Override
   public void write(InputStream is) {
     try (is; var os = outputStream()) {

avaje-jex/src/main/java/io/avaje/jex/core/json/JsonbOutput.java

@@ -0,0 +1,64 @@
+package io.avaje.jex.core.json;
+
+import io.avaje.jex.http.Context;
+import io.avaje.json.stream.JsonOutput;
+
+import java.io.IOException;
+import java.io.OutputStream;
+
+/**
+ * avaje-jsonb output that allows for writing fixed length content
+ * straight from the avaje-jsonb buffer, avoiding the jex side buffer.
+ */
+public final class JsonbOutput implements JsonOutput {
+
+  private final Context context;
+  private OutputStream os;
+
+  public static JsonOutput of(Context context) {
+    return new JsonbOutput(context);
+  }
+
+  private JsonbOutput(Context context) {
+    this.context = context;
+  }
+
+  @Override
+  public void write(byte[] content, int offset, int length) throws IOException {
+    if (os == null) {
+      // exceeds the avaje-jsonb buffer size
+      os = context.outputStream();
+    }
+    os.write(content, offset, length);
+  }
+
+  @Override
+  public void writeLast(byte[] content, int offset, int length) throws IOException {
+    if (os == null) {
+      // write as fixed length content straight from the avaje-jsonb buffer
+      context.write(content, length);
+    } else {
+      os.write(content, offset, length);
+    }
+  }
+
+  @Override
+  public void flush() throws IOException {
+    if (os != null) {
+      os.flush();
+    }
+  }
+
+  @Override
+  public void close() throws IOException {
+    if (os != null) {
+      os.close();
+    }
+  }
+
+  @Override
+  public OutputStream unwrapOutputStream() {
+    return context.outputStream();
+  }
+
+}

avaje-jex/src/main/java/io/avaje/jex/http/Context.java

@@ -449,6 +449,16 @@ default String userAgent() {
    */
   void write(byte[] bytes);
 
+  /**
+   * Writes the first bytes from this buffer directly to the response.
+   *
+   * <p>The bytes written will be from position 0 to length.
+   *
+   * @param bufferBytes The byte array to write.
+   * @param length The number of bytes to write from the buffer.
+   */
+  void write(byte[] bufferBytes, int length);
+
   /**
    * Writes the content from the given InputStream directly to the response body.
    *

avaje-jex/src/test/java/io/avaje/jex/core/JsonTest.java

@@ -11,6 +11,7 @@
 import java.util.concurrent.locks.LockSupport;
 import java.util.stream.Stream;
 
+import io.avaje.jex.core.json.JsonbOutput;
 import io.avaje.jsonb.Json;
 import io.avaje.jsonb.JsonType;
 import io.avaje.jsonb.Jsonb;
@@ -58,6 +59,13 @@ static TestPair init() {
                   var result = HelloDto.rob();
                   jsonTypeHelloDto.toJson(result, ctx.outputStream());
                 })
+            .get(
+              "/usingJsonOutput",
+              ctx -> {
+                ctx.status(200).contentType("application/json");
+                var result = HelloDto.fi();
+                jsonTypeHelloDto.toJson(result, JsonbOutput.of(ctx));
+              })
             .get("/iterate", ctx -> ctx.jsonStream(ITERATOR))
             .get("/stream", ctx -> ctx.jsonStream(HELLO_BEANS.stream()))
             .post("/", ctx -> ctx.text("bean[" + ctx.bodyAsClass(HelloDto.class) + "]"));
@@ -118,6 +126,21 @@ void usingOutputStream() {
     assertThat(bean.name).isEqualTo("rob");
   }
 
+  @Test
+  void usingJsonOutput() {
+    var hres = pair.request().path("usingJsonOutput")
+      .GET()
+      .as(HelloDto.class);
+
+    assertThat(hres.statusCode()).isEqualTo(200);
+    final HttpHeaders headers = hres.headers();
+    assertThat(headers.firstValue("Content-Type").orElseThrow()).isEqualTo("application/json");
+
+    var bean = hres.body();
+    assertThat(bean.id).isEqualTo(45);
+    assertThat(bean.name).isEqualTo("fi");
+  }
+
 
   @Test
   void stream_viaIterator() {