Add async native Java Client (#4721)

* Add async native Java Client

* UPDATE: Reformat the samples

* test java native async in drone.io

* update test count

Co-authored-by: William Cheng <wing328hk@gmail.com>

CI/.drone.yml

@@ -26,6 +26,7 @@ steps:
   - ./mvnw --quiet verify -Psamples.droneio -Dorg.slf4j.simpleLogger.defaultLogLevel=error
   # test java native client
   - ./mvnw clean test -f samples/client/petstore/java/native/pom.xml
+  - ./mvnw clean test -f samples/client/petstore/java/native-async/pom.xml
   # test all generators with fake petstore spec (2.0, 3.0)
   - /bin/bash bin/utils/test-fake-petstore-for-all.sh
   # generate test scripts

bin/java-petstore-native-async.sh

@@ -0,0 +1,35 @@
+#!/bin/sh
+
+SCRIPT="$0"
+echo "# START SCRIPT: $SCRIPT"
+
+while [ -h "$SCRIPT" ] ; do
+  ls=`ls -ld "$SCRIPT"`
+  link=`expr "$ls" : '.*-> \(.*\)$'`
+  if expr "$link" : '/.*' > /dev/null; then
+    SCRIPT="$link"
+  else
+    SCRIPT=`dirname "$SCRIPT"`/"$link"
+  fi
+done
+
+if [ ! -d "${APP_DIR}" ]; then
+  APP_DIR=`dirname "$SCRIPT"`/..
+  APP_DIR=`cd "${APP_DIR}"; pwd`
+fi
+
+executable="./modules/openapi-generator-cli/target/openapi-generator-cli.jar"
+
+if [ ! -f "$executable" ]
+then
+  mvn -B clean package
+fi
+
+# if you've executed sbt assembly previously it will use that instead.
+export JAVA_OPTS="${JAVA_OPTS} -Xmx1024M -DloggerPath=conf/log4j.properties"
+ags="generate -t modules/openapi-generator/src/main/resources/Java/libraries/native -i modules/openapi-generator/src/test/resources/2_0/petstore-with-fake-endpoints-models-for-testing.yaml -g java -c bin/java-petstore-native.json -o samples/client/petstore/java/native-async --additional-properties hideGenerationTimestamp=true,asyncNative=true $@"
+
+echo "Removing files and folders under samples/client/petstore/java/httpclient/src/main"
+rm -rf samples/client/petstore/java/native-async/src/main
+find samples/client/petstore/java/native-async -maxdepth 1 -type f ! -name "README.md" -exec rm {} +
+java $JAVA_OPTS -jar $executable $ags

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaClientCodegen.java

@@ -55,6 +55,7 @@ public class JavaClientCodegen extends AbstractJavaCodegen
     public static final String USE_PLAY_WS = "usePlayWS";
     public static final String PLAY_VERSION = "playVersion";
     public static final String FEIGN_VERSION = "feignVersion";
+    public static final String ASYNC_NATIVE = "asyncNative";
     public static final String PARCELABLE_MODEL = "parcelableModel";
     public static final String USE_RUNTIME_EXCEPTION = "useRuntimeException";
     public static final String USE_REFLECTION_EQUALS_HASHCODE = "useReflectionEqualsHashCode";
@@ -95,6 +96,7 @@ public class JavaClientCodegen extends AbstractJavaCodegen
     protected boolean usePlayWS = false;
     protected String playVersion = PLAY_25;
     protected String feignVersion = FEIGN_10;
+    protected boolean asyncNative = false;
     protected boolean parcelableModel = false;
     protected boolean useBeanValidation = false;
     protected boolean performBeanValidation = false;
@@ -139,6 +141,7 @@ public JavaClientCodegen() {
         cliOptions.add(CliOption.newBoolean(PERFORM_BEANVALIDATION, "Perform BeanValidation"));
         cliOptions.add(CliOption.newBoolean(USE_GZIP_FEATURE, "Send gzip-encoded requests"));
         cliOptions.add(CliOption.newBoolean(USE_RUNTIME_EXCEPTION, "Use RuntimeException instead of Exception"));
+        cliOptions.add(CliOption.newBoolean(ASYNC_NATIVE, "If true, async handlers will be used, instead of the sync version"));
         cliOptions.add(CliOption.newBoolean(FEIGN_VERSION, "Version of OpenFeign: '10.x' (default), '9.x' (deprecated)"));
         cliOptions.add(CliOption.newBoolean(USE_REFLECTION_EQUALS_HASHCODE, "Use org.apache.commons.lang3.builder for equals and hashCode in the models. WARNING: This will fail under a security manager, unless the appropriate permissions are set up correctly and also there's potential performance impact."));
         cliOptions.add(CliOption.newBoolean(CASE_INSENSITIVE_RESPONSE_HEADERS, "Make API response's headers case-insensitive. Available on " + OKHTTP_GSON + ", " + JERSEY2 + " libraries"));
@@ -249,6 +252,10 @@ public void processOpts() {
         }
         additionalProperties.put(FEIGN_VERSION, feignVersion);
 
+        if (additionalProperties.containsKey(ASYNC_NATIVE)) {
+            this.setAsyncNative(convertPropertyToBooleanAndWriteBack(ASYNC_NATIVE));
+        }
+
         if (additionalProperties.containsKey(PARCELABLE_MODEL)) {
             this.setParcelableModel(Boolean.valueOf(additionalProperties.get(PARCELABLE_MODEL).toString()));
         }
@@ -850,6 +857,8 @@ public void setFeignVersion(String feignVersion) {
         this.feignVersion = feignVersion;
     }
 
+    public void setAsyncNative(boolean asyncNative) { this.asyncNative = asyncNative; }
+
     public void setParcelableModel(boolean parcelableModel) {
         this.parcelableModel = parcelableModel;
     }

modules/openapi-generator/src/main/resources/Java/libraries/native/api.mustache

@@ -28,6 +28,10 @@ import java.util.List;
 import java.util.Map;
 {{/fullJavaUtil}}
 
+{{#asyncNative}}
+import java.util.concurrent.CompletableFuture;
+{{/asyncNative}}
+
 {{>generatedAnnotation}}
 {{#operations}}
 public class {{classname}} {
@@ -73,14 +77,19 @@ public class {{classname}} {
   {{#isDeprecated}}
   @Deprecated
   {{/isDeprecated}}
-  public {{#returnType}}{{{returnType}}} {{/returnType}}{{^returnType}}void {{/returnType}}{{operationId}}({{#allParams}}{{{dataType}}} {{paramName}}{{#hasMore}}, {{/hasMore}}{{/allParams}}) throws ApiException {
+  public {{#returnType}}{{#asyncNative}}CompletableFuture<{{{returnType}}}>{{/asyncNative}}{{^asyncNative}}{{{returnType}}}{{/asyncNative}}{{/returnType}}{{^returnType}}{{#asyncNative}}CompletableFuture<Void>{{/asyncNative}}{{^asyncNative}}void{{/asyncNative}}{{/returnType}} {{operationId}} ({{#allParams}}{{{dataType}}} {{paramName}}{{#hasMore}}, {{/hasMore}}{{/allParams}}) throws ApiException {
     {{#allParams}}
-      {{#required}}
+    {{#required}}
     // verify the required parameter '{{paramName}}' is set
     if ({{paramName}} == null) {
-      throw new ApiException(400, "Missing the required parameter '{{paramName}}' when calling {{operationId}}");
+    {{#asyncNative}}
+        return CompletableFuture.failedFuture(new ApiException(400, "Missing the required parameter '{{paramName}}' when calling {{operationId}}"));
+    {{/asyncNative}}
+    {{^asyncNative}}
+        throw new ApiException(400, "Missing the required parameter '{{paramName}}' when calling {{operationId}}");
+    {{/asyncNative}}
     }
-      {{/required}}
+    {{/required}}
     {{/allParams}}
 
     HttpRequest.Builder localVarRequestBuilder = HttpRequest.newBuilder();
@@ -122,7 +131,14 @@ public class {{classname}} {
     {{/bodyParam}}
     localVarRequestBuilder.header("Accept", "application/json");
 
+    {{^asyncNative}}
+    try {
+    {{/asyncNative}}
+    {{#asyncNative}}
+      {{#bodyParam}}
     try {
+      {{/bodyParam}}
+    {{/asyncNative}}
       {{#bodyParam}}
       byte[] localVarPostBody = memberVarObjectMapper.writeValueAsBytes({{paramName}});
       localVarRequestBuilder.method("{{httpMethod}}", HttpRequest.BodyPublishers.ofByteArray(localVarPostBody));
@@ -136,29 +152,63 @@ public class {{classname}} {
       if (memberVarInterceptor != null) {
         memberVarInterceptor.accept(localVarRequestBuilder);
       }
-
+      {{^asyncNative}}
       HttpResponse<InputStream> localVarResponse = memberVarHttpClient.send(
-          localVarRequestBuilder.build(),
-          HttpResponse.BodyHandlers.ofInputStream());
+      localVarRequestBuilder.build(),
+      HttpResponse.BodyHandlers.ofInputStream());
       if (memberVarResponseInterceptor != null) {
         memberVarResponseInterceptor.accept(localVarResponse);
       }          
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "{{operationId}} call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+          throw new ApiException(localVarResponse.statusCode(),
+              "{{operationId}} call received non-success response",
+              localVarResponse.headers(),
+              localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
       }
-
       {{#returnType}}
       return memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<{{{returnType}}}>() {});
       {{/returnType}}
+      {{/asyncNative}}
+      {{#asyncNative}}
+      return memberVarHttpClient.sendAsync(
+              localVarRequestBuilder.build(),
+              HttpResponse.BodyHandlers.ofString()).thenComposeAsync(localVarResponse -> {
+          if (localVarResponse.statusCode()/ 100 != 2) {
+              return CompletableFuture.failedFuture(new ApiException(localVarResponse.statusCode(),
+                  "{{operationId}} call received non-success response",
+                  localVarResponse.headers(),
+                  localVarResponse.body())
+              );
+          } else {
+              return CompletableFuture.completedFuture(
+                  {{#returnValue}}
+                      memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<{{{returnType}}}>() {})
+                  {{/returnValue}}
+                  {{^returnValue}}
+                      null
+                  {{/returnValue}}
+              );
+          }
+      });
+      {{/asyncNative}}
+    {{#asyncNative}}
+    {{#bodyParam}}
+    } catch (IOException e) {
+      return CompletableFuture.failedFuture(new ApiException(e));
+    }
+    {{/bodyParam}}
+    {{/asyncNative}}
+    {{^asyncNative}}
     } catch (IOException e) {
       throw new ApiException(e);
-    } catch (InterruptedException e) {
+    }
+    {{/asyncNative}}
+    {{^asyncNative}}
+    catch (InterruptedException e) {
       Thread.currentThread().interrupt();
       throw new ApiException(e);
     }
+    {{/asyncNative}}
   }
   {{/operation}}
 }

modules/openapi-generator/src/test/java/org/openapitools/codegen/java/JavaClientCodegenTest.java

@@ -433,6 +433,45 @@ public void testJdkHttpClient() throws Exception {
         assertTrue(apiClientContent.contains("import java.net.http.HttpRequest;"));
     }
 
+    @Test
+    public void testJdkHttpAsyncClient() throws Exception {
+        Map<String, Object> properties = new HashMap<>();
+        properties.put(JavaClientCodegen.JAVA8_MODE, true);
+        properties.put(CodegenConstants.API_PACKAGE, "xyz.abcdef.api");
+        properties.put(JavaClientCodegen.ASYNC_NATIVE, true);
+
+        File output = Files.createTempDirectory("test").toFile();
+        output.deleteOnExit();
+
+        final CodegenConfigurator configurator = new CodegenConfigurator()
+                .setGeneratorName("java")
+                .setLibrary(JavaClientCodegen.NATIVE)
+                .setAdditionalProperties(properties)
+                .setInputSpec("src/test/resources/3_0/pingSomeObj.yaml")
+                .setOutputDir(output.getAbsolutePath().replace("\\", "/"));
+
+        final ClientOptInput clientOptInput = configurator.toClientOptInput();
+        MockDefaultGenerator generator = new MockDefaultGenerator();
+        generator.opts(clientOptInput).generate();
+
+        Map<String, String> generatedFiles = generator.getFiles();
+        Assert.assertEquals(generatedFiles.size(), 29);
+        validateJavaSourceFiles(generatedFiles);
+        String defaultApiFilename = new File(output, "src/main/java/xyz/abcdef/api/PingApi.java").getAbsolutePath().replace("\\", "/");
+        String defaultApiContent = generatedFiles.get(defaultApiFilename);
+        assertTrue(defaultApiContent.contains("public class PingApi"));
+        assertTrue(defaultApiContent.contains("import java.net.http.HttpClient;"));
+        assertTrue(defaultApiContent.contains("import java.net.http.HttpRequest;"));
+        assertTrue(defaultApiContent.contains("import java.net.http.HttpResponse;"));
+        assertTrue(defaultApiContent.contains("import java.util.concurrent.CompletableFuture;"));
+
+        String apiClientFilename = new File(output, "src/main/java/xyz/abcdef/ApiClient.java").getAbsolutePath().replace("\\", "/");
+        String apiClientContent = generatedFiles.get(apiClientFilename);
+        assertTrue(apiClientContent.contains("public class ApiClient"));
+        assertTrue(apiClientContent.contains("import java.net.http.HttpClient;"));
+        assertTrue(apiClientContent.contains("import java.net.http.HttpRequest;"));
+    }
+
     @Test
     public void testReferencedHeader() {
         final OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/3_0/issue855.yaml");

samples/client/petstore/java/native-async/.gitignore

@@ -0,0 +1,21 @@
+*.class
+
+# Mobile Tools for Java (J2ME)
+.mtj.tmp/
+
+# Package Files #
+*.jar
+*.war
+*.ear
+
+# exclude jar for gradle wrapper
+!gradle/wrapper/*.jar
+
+# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
+hs_err_pid*
+
+# build files
+**/target
+target
+.gradle
+build

samples/client/petstore/java/native-async/.openapi-generator-ignore

@@ -0,0 +1,23 @@
+# OpenAPI Generator Ignore
+# Generated by openapi-generator https://github.com/openapitools/openapi-generator
+
+# Use this file to prevent files from being overwritten by the generator.
+# The patterns follow closely to .gitignore or .dockerignore.
+
+# As an example, the C# client generator defines ApiClient.cs.
+# You can make changes and tell OpenAPI Generator to ignore just this file by uncommenting the following line:
+#ApiClient.cs
+
+# You can match any string of characters against a directory, file or extension with a single asterisk (*):
+#foo/*/qux
+# The above matches foo/bar/qux and foo/baz/qux, but not foo/bar/baz/qux
+
+# You can recursively match patterns against a directory, file or extension with a double asterisk (**):
+#foo/**/qux
+# This matches foo/bar/qux, foo/baz/qux, and foo/bar/baz/qux
+
+# You can also negate patterns with an exclamation (!).
+# For example, you can ignore all files in a docs folder with the file extension .md:
+#docs/*.md
+# Then explicitly reverse the ignore rule for a single file:
+#!docs/README.md

samples/client/petstore/java/native-async/.openapi-generator/VERSION

@@ -0,0 +1 @@
+4.3.1-SNAPSHOT

samples/client/petstore/java/native-async/.travis.yml

@@ -0,0 +1,16 @@
+#
+# Generated by: https://openapi-generator.tech
+#
+language: java
+jdk:
+  - oraclejdk11
+before_install:
+  # ensure gradlew has proper permission
+  - chmod a+x ./gradlew
+script:
+  # test using maven
+  - mvn test
+  # uncomment below to test using gradle
+  # - gradle test
+  # uncomment below to test using sbt 
+  # - sbt test