make http client autocloseable (#512)

http-client/pom.xml

@@ -66,7 +66,7 @@
     <dependency>
       <groupId>io.avaje</groupId>
       <artifactId>avaje-http-api</artifactId>
-      <version>2.9-SNAPSHOT</version>
+      <version>${project.version}</version>
       <scope>test</scope>
     </dependency>
 

http-client/src/main/java/io/avaje/http/client/DHttpClientContext.java

@@ -1,5 +1,7 @@
 package io.avaje.http.client;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodType;
 import java.lang.reflect.Type;
 import java.net.http.HttpHeaders;
 import java.net.http.HttpRequest;
@@ -9,6 +11,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutorService;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.concurrent.atomic.LongAccumulator;
 import java.util.concurrent.atomic.LongAdder;
@@ -340,4 +343,17 @@ private String authToken() {
   String maxResponseBody(String body) {
     return body.length() > 1_000 ? body.substring(0, 1_000) + " <truncated> ..." : body;
   }
+
+  @Override
+  public void close() {
+    if (Integer.getInteger("java.specification.version") >= 21) {
+      try {
+        MethodHandles.lookup()
+            .findVirtual(java.net.http.HttpClient.class, "close", MethodType.methodType(void.class))
+            .invokeExact(httpClient);
+      } catch (Throwable t) {
+        throw new IllegalStateException("Failed to close java.net.http.HttpClient instance");
+      }
+    }
+  }
 }

http-client/src/main/java/io/avaje/http/client/HttpClient.java

@@ -3,7 +3,6 @@
 import java.net.Authenticator;
 import java.net.CookieHandler;
 import java.net.ProxySelector;
-import java.net.http.HttpRequest;
 import java.time.Duration;
 import java.util.Map;
 import java.util.concurrent.Executor;
@@ -33,7 +32,7 @@
  *
  * }</pre>
  */
-public interface HttpClient {
+public interface HttpClient extends AutoCloseable {
 
   /**
    * Return the builder to config and build the client context.
@@ -93,6 +92,19 @@ static Builder builder() {
    */
   HttpClient.Metrics metrics(boolean reset);
 
+  /**
+   * Note: invoking this method has no effect on JDK versions less than 21.
+   *
+   * <p>Initiates an orderly shutdown in which http requests previously submitted are run to
+   * completion, but no new requests will be accepted. Running a request to completion may involve
+   * running several operations in the background, including waiting for responses to be delivered.
+   * This method waits until all operations have completed execution and the client has terminated.
+   *
+   * @see {@linkplain java.net.http.HttpClient#close}
+   */
+  @Override
+  void close();
+
   /**
    * Builds the HttpClient.
    *

http-generator-client/src/main/java/io/avaje/http/generator/client/ClientWriter.java

@@ -1,5 +1,6 @@
 package io.avaje.http.generator.client;
 
+import io.avaje.http.generator.core.APContext;
 import io.avaje.http.generator.core.BaseControllerWriter;
 import io.avaje.http.generator.core.ControllerReader;
 import io.avaje.http.generator.core.MethodReader;
@@ -62,12 +63,17 @@ private void writeMethods() {
     for (final ClientMethodWriter methodWriter : methodList) {
       methodWriter.write();
     }
+    writer.append("  @Override").eol();
+    writer.append("  public void close() {").eol();
+    writer.append("    this.client.close();").eol();
+    writer.append("  }").eol();
   }
 
   private void writeClassStart() {
     writer.append(AT_GENERATED).eol();
     AnnotationUtil.writeAnnotations(writer, reader.beanType());
-    writer.append("public class %s%s implements %s {", shortName, suffix, shortName).eol().eol();
+
+    writer.append("public class %s%s implements %s, AutoCloseable {", shortName, suffix, shortName).eol().eol();
 
     writer.append("  private final HttpClient client;").eol().eol();