Java sample for doing online prediction in Cloud Machine Learning Eng…

…ine. (#868)

* Java sample for online prediction in CMLE.

* update README

* add licence and some comments

* Update README, add license to pom.xml

* fix README

* small fix

mlengine/online-prediction/README.md

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+# Cloud Machine Learning Engine - Online Prediction with Java
+
+## Setup
+This sample demonstrates how to send online prediction requests to your deployed 
+model on CMLE. 
+Follow the [tutorial](https://cloud.google.com/ml-engine/docs/how-tos/deploying-models)
+to deploy your model first.
+
+This sample is using the [Application Default Credential](https://developers.google.com/identity/protocols/application-default-credentials). You can install the Google Cloud SDK and run:
+<pre>gcloud auth application-default login</pre>
+
+## Run
+Modify the OnlinePredictionSample.java with your project/model/version information.
+
+Compile the sample code using Maven by running the following command:
+<pre>mvn compile</pre>
+Execute the sample code using Maven by running the following command:
+<pre>mvn -q exec:java</pre>

mlengine/online-prediction/input.txt

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+{"instances": ["YOUR_INPUT_INSTANCE1", "YOUR_INPUT_INSTANCE2"]}

mlengine/online-prediction/pom.xml

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+<!--
+Copyright 2017 Google Inc.
+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
+      http://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.
+-->
+
+<project>
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>com.google.cloud.samples</groupId>
+  <artifactId>mlengine-online-prediction</artifactId>
+  <version>1</version>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>exec-maven-plugin</artifactId>
+        <version>1.4.0</version>
+        <executions>
+          <execution>
+            <goals>
+              <goal>java</goal>
+            </goals>
+          </execution>
+        </executions>
+        <configuration>
+          <mainClass>OnlinePredictionSample</mainClass>
+          <systemProperties>
+            <systemProperty>
+              <key>java.util.logging.config.file</key>
+              <value>logging.properties</value>
+            </systemProperty>
+          </systemProperties>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
+  <dependencies>
+    <dependency>
+      <groupId>joda-time</groupId>
+      <artifactId>joda-time</artifactId>
+      <version>2.2</version>
+    </dependency>
+    <dependency>
+     <groupId>com.google.api-client</groupId>
+     <artifactId>google-api-client</artifactId>
+     <version>1.22.0</version>
+    </dependency>
+    <dependency>
+      <groupId>com.google.apis</groupId>
+      <artifactId>google-api-services-discovery</artifactId>
+      <version>v1-rev58-1.22.0</version>
+    </dependency>
+  </dependencies>
+</project>

mlengine/online-prediction/src/main/java/OnlinePredictionSample.java

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+/*
+ * Copyright 2017 Google Inc.
+ *
+ * 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
+ *
+ * http://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.
+ */
+
+import com.google.api.client.googleapis.auth.oauth2.GoogleCredential;
+import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport;
+import com.google.api.client.http.FileContent;
+import com.google.api.client.http.GenericUrl;
+import com.google.api.client.http.HttpContent;
+import com.google.api.client.http.HttpRequest;
+import com.google.api.client.http.HttpRequestFactory;
+import com.google.api.client.http.HttpTransport;
+import com.google.api.client.http.UriTemplate;
+import com.google.api.client.json.JsonFactory;
+import com.google.api.client.json.jackson2.JacksonFactory;
+import com.google.api.services.discovery.Discovery;
+import com.google.api.services.discovery.model.JsonSchema;
+import com.google.api.services.discovery.model.RestDescription;
+import com.google.api.services.discovery.model.RestMethod;
+import java.io.File;
+
+/*
+ * Sample code for doing Cloud Machine Learning Engine online prediction in Java.
+ */
+
+public class OnlinePredictionSample {
+  public static void main(String[] args) throws Exception {
+    HttpTransport httpTransport = GoogleNetHttpTransport.newTrustedTransport();
+    JsonFactory jsonFactory = JacksonFactory.getDefaultInstance();
+    Discovery discovery = new Discovery.Builder(httpTransport, jsonFactory, null).build();
+
+    RestDescription api = discovery.apis().getRest("ml", "v1").execute();
+    RestMethod method = api.getResources().get("projects").getMethods().get("predict");
+
+    JsonSchema param = new JsonSchema();
+    String projectId = "YOUR_PROJECT_ID";
+    // You should have already deployed a model and a version.
+    // For reference, see https://cloud.google.com/ml-engine/docs/how-tos/deploying-models.
+    String modelId = "YOUR_MODEL_ID";
+    String versionId = "YOUR_VERSION_ID";
+    param.set(
+        "name", String.format("projects/%s/models/%s/versions/%s", projectId, modelId, versionId));
+
+    GenericUrl url =
+        new GenericUrl(UriTemplate.expand(api.getBaseUrl() + method.getPath(), param, true));
+    System.out.println(url);
+
+    String contentType = "application/json";
+    File requestBodyFile = new File("input.txt");
+    HttpContent content = new FileContent(contentType, requestBodyFile);
+    System.out.println(content.getLength());
+
+    GoogleCredential credential = GoogleCredential.getApplicationDefault();
+    HttpRequestFactory requestFactory = httpTransport.createRequestFactory(credential);
+    HttpRequest request = requestFactory.buildRequest(method.getHttpMethod(), url, content);
+
+    String response = request.execute().parseAsString();
+    System.out.println(response);
+  }
+}
+