feat: my-widget-service example for Java (#172)

* my-widget-service java example

* cleaned up output.json

* Updated Readme for my-widget-service

* Updated pom.xml fix the build

* removed org.codehaus.mojo plugin from pom.xml

* updated the reference to app class in pom.xml

* updated cdk.json to point to App class, cleaned up the stack code with consistent formatting

* updated gitignore for bin directory

* format updates to  stack class

* updated cdk version to 1.18.0

* add .class to gitignore

* java syntax updates

updated to use "Builder" syntax for construct library

java/my-widget-service/.gitignore

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+.classpath.txt
+target
+.classpath
+.project
+.idea
+.settings
+.vscode
+*.iml
+
+# CDK asset staging directory
+.cdk.staging
+cdk.out
+
+#Java bin directory
+*.class
+

java/my-widget-service/README.md

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+# My Widget Service
+
+This example uses lambda to serve-up widgets.
+
+## Building
+
+To build this app, run `mvn compile`. This will download the required
+dependencies to compile the Java code.
+
+You can use your IDE to write code and unit tests, but you will need to use the
+CDK toolkit if you wish to synthesize/deploy stacks.
+
+## CDK Toolkit
+
+The [`cdk.json`](./cdk.json) file in the root of this repository includes
+instructions for the CDK toolkit on how to execute this program.
+
+Specifically, it will tell the toolkit to use the `mvn exec:java` command as the
+entry point of your application. After changing your Java code, you will be able
+to run the CDK toolkit commands as usual (Maven will recompile as needed):
+
+    $ cdk ls
+    <list all stacks in this program>
+
+    $ cdk synth
+    <cloudformation template>
+
+    $ cdk deploy
+    <deploy stack to your account>
+
+    $ cdk diff
+    <diff against deployed stack>

java/my-widget-service/cdk.json

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+{
+  "app": "mvn exec:java -Dexec.mainClass=software.amazon.awscdk.examples.MyWidgetServiceApp"
+}

java/my-widget-service/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
+	xmlns="http://maven.apache.org/POM/4.0.0"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+	<modelVersion>4.0.0</modelVersion>
+
+	<groupId>com.amazonaws.cdk</groupId>
+	<artifactId>my-widget-service</artifactId>
+	<version>1.0.0</version>
+
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+	</properties>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-compiler-plugin</artifactId>
+				<version>3.8.1</version>
+				<configuration>
+					<source>1.8</source>
+					<target>1.8</target>
+				</configuration>
+			</plugin>
+
+			<plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-assembly-plugin</artifactId>
+                <version>3.1.0</version>
+                <configuration>
+                    <descriptorRefs>
+                        <descriptorRef>jar-with-dependencies</descriptorRef>
+                    </descriptorRefs>
+                    <archive>
+                        <manifest>
+                            <mainClass>com.amazonaws.cdk.examples.MyWidgetServiceApp</mainClass>
+                        </manifest>
+                    </archive>
+                </configuration>
+                <executions>
+                    <execution>
+                        <id>make-assembly</id> <!-- this is used for inheritance merges -->
+                        <phase>package</phase> <!-- bind to the packaging phase -->
+                            <goals>
+                            <goal>single</goal>
+                        </goals>
+                    </execution>
+              </executions>
+            </plugin>
+
+		</plugins>
+	</build>
+
+	<dependencies>
+		<!-- AWS Cloud Development Kit -->
+		<dependency>
+			<groupId>software.amazon.awscdk</groupId>
+			<artifactId>core</artifactId>
+			<version>1.18.0</version>
+		</dependency>
+		<dependency>
+			<groupId>software.amazon.awscdk</groupId>
+			<artifactId>s3</artifactId>
+			<version>1.18.0</version>
+		</dependency>
+		<dependency>
+			<groupId>software.amazon.awscdk</groupId>
+			<artifactId>apigateway</artifactId>
+			<version>1.18.0</version>
+		</dependency>
+		<dependency>
+			<groupId>software.amazon.awscdk</groupId>
+			<artifactId>iam</artifactId>
+			<version>1.18.0</version>
+		</dependency>
+		<!-- https://mvnrepository.com/artifact/junit/junit -->
+		 <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.12</version>
+            <scope>test</scope>
+            <exclusions>
+                <exclusion>
+                    <groupId>org.hamcrest</groupId>
+                    <artifactId>hamcrest-core</artifactId>
+                </exclusion>
+            </exclusions>
+        </dependency>
+        <dependency>
+            <groupId>org.hamcrest</groupId>
+            <artifactId>hamcrest-library</artifactId>
+            <version>1.3</version>
+            <scope>test</scope>
+        </dependency>
+	</dependencies>
+</project>

java/my-widget-service/resources/widgets.js

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+//snippet-comment:[These are tags for the AWS doc team's sample catalog. Do not remove.]
+//snippet-comment:[This should be in the resources/ directory]
+//snippet-comment:[and only works with my_widget_service.ts in the bin/ directory]
+//snippet-comment:[and widget_service.ts in the lib/ directory.]
+//snippet-sourceauthor:[Doug-AWS]
+//snippet-sourcedescription:[Lambda function to handle GET, POST, and DELETE.]
+//snippet-keyword:[CDK V0.24.1]
+//snippet-keyword:[S3.deleteObject function]
+//snippet-keyword:[S3.getObject function]
+//snippet-keyword:[S3.listObjectsV2 function]
+//snippet-keyword:[S3.putObject function]
+//snippet-keyword:[JavaScript]
+//snippet-service:[cdk]
+//snippet-sourcetype:[full-example]
+//snippet-sourcedate:[2019-2-8]
+// Copyright 2010-2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+//
+// This file is licensed under the Apache License, Version 2.0 (the "License").
+// You may not use this file except in compliance with the License. A copy of the
+// License is located at
+//
+// http://aws.amazon.com/apache2.0/
+//
+// This file 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.
+//snippet-start:[cdk.typescript.widgets]
+//snippet-start:[cdk.typescript.widgets.imports]
+const AWS = require('aws-sdk');
+const S3 = new AWS.S3();
+//snippet-end:[cdk.typescript.widgets.imports]
+
+const bucketName = process.env.BUCKET;
+
+//snippet-start:[cdk.typescript.widgets.exports_main]
+exports.main = async function(event, context) {
+  try {
+    var method = event.httpMethod;
+    // Get name, if present
+    var widgetName = event.path.startsWith('/') ? event.path.substring(1) : event.path;
+
+    if (method === "GET") {
+      // GET / to get the names of all widgets
+      if (event.path === "/") {
+        const data = await S3.listObjectsV2({ Bucket: bucketName }).promise();
+        var body = {
+          widgets: data.Contents.map(function(e) { return e.Key })
+        };
+        return {
+          statusCode: 200,
+          headers: {},
+          body: JSON.stringify(body)
+        };
+      }
+
+      if (widgetName) {
+        // GET /name to get info on widget name
+        const data = await S3.getObject({ Bucket: bucketName, Key: widgetName}).promise();
+        var body = data.Body.toString('utf-8');
+
+        return {
+          statusCode: 200,
+          headers: {},
+          body: JSON.stringify(body)
+        };
+      }
+    }
+
+    if (method === "POST") {
+      // POST /name
+      // Return error if we do not have a name
+      if (!widgetName) {
+        return {
+          statusCode: 400,
+          headers: {},
+          body: "Widget name missing"
+        };
+      }
+
+      // Create some dummy data to populate object
+      const now = new Date();
+      var data = widgetName + " created: " + now;
+
+      var base64data = new Buffer(data, 'binary');
+
+      await S3.putObject({
+        Bucket: bucketName,
+        Key: widgetName,
+        Body: base64data,
+        ContentType: 'application/json'
+      }).promise();
+
+      return {
+        statusCode: 200,
+        headers: {},
+        body: JSON.stringify(event.widgets)
+      };
+    }
+
+    if (method === "DELETE") {
+      // DELETE /name
+      // Return an error if we do not have a name
+      if (!widgetName) {
+        return {
+          statusCode: 400,
+          headers: {},
+          body: "Widget name missing"
+        };
+      }
+
+      await S3.deleteObject({
+        Bucket: bucketName, Key: widgetName
+      }).promise();
+
+      return {
+        statusCode: 200,
+        headers: {},
+        body: "Successfully deleted widget " + widgetName
+      };
+    }
+
+    // We got something besides a GET, POST, or DELETE
+    return {
+      statusCode: 400,
+      headers: {},
+      body: "We only accept GET, POST, and DELETE, not " + method
+    };
+  } catch(error) {
+    var body = error.stack || JSON.stringify(error, null, 2);
+    return {
+      statusCode: 400,
+      headers: {},
+      body: body
+    }
+  }
+}
+//snippet-end:[cdk.typescript.widgets.exports_main]
+//snippet-end:[cdk.typescript.widgets]

java/my-widget-service/src/main/java/software/amazon/awscdk/examples/MyWidgetServiceApp.java

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+package software.amazon.awscdk.examples;
+
+import software.amazon.awscdk.core.App;
+
+
+
+import java.util.Arrays;
+
+public class MyWidgetServiceApp {
+    public static void main(final String argv[]) {
+        App app = new App();
+
+        new MyWidgetServiceStack(app, "MyWidgetServiceStack");
+
+        app.synth();
+    }
+}

java/my-widget-service/src/main/java/software/amazon/awscdk/examples/MyWidgetServiceStack.java

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+package software.amazon.awscdk.examples;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import software.amazon.awscdk.core.Construct;
+import software.amazon.awscdk.core.Duration;
+import software.amazon.awscdk.core.Stack;
+import software.amazon.awscdk.services.apigateway.LambdaIntegration;
+import software.amazon.awscdk.services.apigateway.LambdaIntegrationOptions;
+import software.amazon.awscdk.services.apigateway.Resource;
+import software.amazon.awscdk.services.apigateway.RestApi;
+import software.amazon.awscdk.services.apigateway.RestApiProps;
+import software.amazon.awscdk.services.iam.IManagedPolicy;
+import software.amazon.awscdk.services.iam.ManagedPolicy;
+import software.amazon.awscdk.services.iam.Role;
+import software.amazon.awscdk.services.iam.RoleProps;
+import software.amazon.awscdk.services.iam.ServicePrincipal;
+import software.amazon.awscdk.services.lambda.Code;
+import software.amazon.awscdk.services.lambda.Function;
+import software.amazon.awscdk.services.lambda.FunctionProps;
+import software.amazon.awscdk.services.lambda.Runtime;
+import software.amazon.awscdk.services.s3.Bucket;
+
+public class MyWidgetServiceStack extends Stack {
+	public MyWidgetServiceStack(final Construct scope, final String id) {
+		super(scope, id, null);
+
+		Bucket bucket = Bucket.Builder.create(this, "WidgetStore").build();
+
+		RestApi api = RestApi.Builder.create(this, "widgets-api")
+				.restApiName("Widget Service")
+				.description("This service serves widgets.")
+				.build();
+
+		List<IManagedPolicy> managedPolicyArray = new ArrayList<IManagedPolicy>();
+		managedPolicyArray.add((IManagedPolicy) ManagedPolicy.fromAwsManagedPolicyName("AmazonS3FullAccess"));
+
+		Role restApiRole = Role.Builder.create(this, "RestAPIRole")
+				.assumedBy(new ServicePrincipal("apigateway.amazonaws.com"))
+				.managedPolicies(managedPolicyArray)
+				.build();
+
+		Map<String, String> environmentVariables = new HashMap<String, String>();
+		environmentVariables.put("BUCKET", bucket.getBucketName());
+
+		Function lambdaFunction = Function.Builder.create(this, "WidgetHandler")
+				.code(Code.fromAsset("resources"))
+				.handler("widgets.main")
+				.timeout(Duration.seconds(300))
+				.runtime(Runtime.NODEJS_10_X)
+				.environment(environmentVariables)
+				.build();
+
+		bucket.grantReadWrite(lambdaFunction);
+
+		Map<String, String> lambdaIntegrationMap = new HashMap<String, String>();
+		lambdaIntegrationMap.put("application/json", "{ \"statusCode\": \"200\" }");
+
+		LambdaIntegration getWidgetIntegration = LambdaIntegration.Builder.create(lambdaFunction)
+				.requestTemplates(lambdaIntegrationMap)
+				.build();
+
+		api.getRoot().addMethod("GET", getWidgetIntegration);
+
+		LambdaIntegration postWidgetIntegration = new LambdaIntegration(lambdaFunction);
+		LambdaIntegration deleteWidgetIntegration = new LambdaIntegration(lambdaFunction);
+
+		Resource widget = api.getRoot().addResource("{id}");
+
+		widget.addMethod("POST", postWidgetIntegration);
+		widget.addMethod("GET", getWidgetIntegration);
+		widget.addMethod("DELETE", deleteWidgetIntegration);
+
+	}
+}