Expose Context.outputStream() such that outputStream can be used dire…

…ctly (#109)

For example, with Jsonb we can obtain the specific type once and then
write directly to the outputSteam like:

           ctx.status(200).contentType("application/json");
           var result = HelloDto.rob();
           jsonTypeHelloDto.toJson(result, ctx.outputStream());

... where jsonTypeHelloDto is obtained like:

  static final Jsonb jsonb = Jsonb.builder().build();
  static final JsonType<HelloDto> jsonTypeHelloDto = jsonb.type(HelloDto.class);

With this approach, it effectively bypasses the underlying io.avaje.jex.spi.JsonService with the view that this can be more flexible and more efficient.

avaje-jex/pom.xml

@@ -48,6 +48,12 @@
       <optional>true</optional>
     </dependency>
 
+    <dependency>
+      <groupId>io.avaje</groupId>
+      <artifactId>avaje-jsonb-generator</artifactId>
+      <version>2.3</version>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
 
   <build>

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

@@ -4,6 +4,7 @@
 import static java.util.Collections.emptyMap;
 
 import java.io.InputStream;
+import java.io.OutputStream;
 import java.time.Duration;
 import java.time.ZonedDateTime;
 import java.util.Iterator;
@@ -294,6 +295,15 @@ default String userAgent() {
    */
   Context write(InputStream is);
 
+  /**
+   * Return the outputStream to write content. It is expected that
+   * the {@link #contentType(String)} has been set prior to obtaining
+   * and writing to the outputStream.
+   *
+   * @return The outputStream to write content to.
+   */
+  OutputStream outputStream();
+
   /**
    * Render a template typically as html.
    *

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

@@ -477,6 +477,7 @@ public String protocol() {
     return exchange.getProtocol();
   }
 
+  @Override
   public OutputStream outputStream() {
     var out = mgr.createOutputStream(this);
     if (compressionConfig.compressionEnabled()) {

avaje-jex/src/test/java/io/avaje/jex/jdk/HelloDto.java

@@ -1,5 +1,8 @@
 package io.avaje.jex.jdk;
 
+import io.avaje.jsonb.Json;
+
+@Json
 public class HelloDto {
 
   public long id;

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

@@ -11,6 +11,8 @@
 import java.util.concurrent.locks.LockSupport;
 import java.util.stream.Stream;
 
+import io.avaje.jsonb.JsonType;
+import io.avaje.jsonb.Jsonb;
 import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.Test;
 
@@ -26,12 +28,19 @@ private static AutoCloseIterator<HelloDto> createBeanIterator() {
     return new AutoCloseIterator<>(HELLO_BEANS.iterator());
   }
 
-  static TestPair pair = init();
+  static final TestPair pair = init();
+  static final Jsonb jsonb = Jsonb.builder().build();
+  static final JsonType<HelloDto> jsonTypeHelloDto = jsonb.type(HelloDto.class);
 
   static TestPair init() {
     Jex app = Jex.create()
       .routing(routing -> routing
-        .get("/", ctx -> ctx.json(HelloDto.rob()).status(200))
+        .get("/", ctx -> ctx.status(200).json(HelloDto.rob()))
+        .get("/usingOutputStream", ctx -> {
+          ctx.status(200).contentType("application/json");
+          var result = HelloDto.rob();
+          jsonTypeHelloDto.toJson(result, ctx.outputStream());
+        })
         .get("/iterate", ctx -> ctx.jsonStream(ITERATOR))
         .get("/stream", ctx -> ctx.jsonStream(HELLO_BEANS.stream()))
         .post("/", ctx -> ctx.text("bean[" + ctx.bodyAsClass(HelloDto.class) + "]")));
@@ -58,9 +67,33 @@ void get() {
       .GET().asString();
 
     final HttpHeaders headers = hres.headers();
-    assertThat(headers.firstValue("Content-Type").get()).isEqualTo("application/json");
+    assertThat(headers.firstValue("Content-Type").orElseThrow()).isEqualTo("application/json");
   }
 
+  @Test
+  void usingOutputStream() {
+
+    var bean = pair.request().path("usingOutputStream")
+      .GET()
+      .bean(HelloDto.class);
+
+    assertThat(bean.id).isEqualTo(42);
+    assertThat(bean.name).isEqualTo("rob");
+
+    final HttpResponse<String> hres = pair.request()
+      .GET().asString();
+
+    final HttpHeaders headers = hres.headers();
+    assertThat(headers.firstValue("Content-Type").orElseThrow()).isEqualTo("application/json");
+
+    bean = pair.request().path("usingOutputStream")
+      .GET()
+      .bean(HelloDto.class);
+    assertThat(bean.id).isEqualTo(42);
+    assertThat(bean.name).isEqualTo("rob");
+  }
+
+
   @Test
   void stream_viaIterator() {
     final Stream<HelloDto> beanStream = pair.request()