new maven jar called flatbuffers-java-grpc which contains utility … (#4558)

* new maven jar called flatbuffers-java-grpc which contains utility class supporting generated code for grpc over flatbuffers; grpc java unit test based on maven and junit (maven is used only for simplicity of testing); removed straneous namespace_test/NamespaceA/TableInC.java which is not longer used in the test and no longer generated but contains complilation errors if java compiler picks it up

* moved java grpc tests files according to review request

* Added missing generated code for Java gRPC.

Change-Id: Iada090fe2e99b80a4b7c2f8e39c838a992a1feae

* added missing name and url

6 files changed, 568 insertions, 0 deletions

diff --git a/grpc/flatbuffers-java-grpc/pom.xml b/grpc/flatbuffers-java-grpc/pom.xml
new file mode 100644
index 00000000..11aa0bd1
--- /dev/null
+++ b/grpc/flatbuffers-java-grpc/pom.xml
@@ -0,0 +1,42 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>com.google.flatbuffers</groupId>
+        <artifactId>flatbuffers-parent</artifactId>
+        <version>1.8.0</version>
+    </parent>
+    <artifactId>flatbuffers-java-grpc</artifactId>
+    <name>${project.artifactId}</name>
+    <packaging>bundle</packaging>
+    <description>
+        Utilities supporting generated code for GRPC
+    </description>
+    <developers>
+        <developer>
+            <name>Wouter van Oortmerssen</name>
+        </developer>
+        <developer>
+            <name>Yuri Finkelstein</name>
+            <url>https://github.com/yfinkelstein</url>
+        </developer>
+    </developers>
+    <properties>
+        <gRPC.version>1.8.0</gRPC.version>
+    </properties>
+    <dependencies>
+        <dependency>
+            <groupId>com.google.flatbuffers</groupId>
+            <artifactId>flatbuffers-java</artifactId>
+            <version>${project.parent.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>io.grpc</groupId>
+            <artifactId>grpc-core</artifactId>
+            <version>${gRPC.version}</version>
+        </dependency>
+  </dependencies>
+</project>
+
diff --git a/grpc/flatbuffers-java-grpc/src/main/java/com/google/flatbuffers/grpc/FlatbuffersUtils.java b/grpc/flatbuffers-java-grpc/src/main/java/com/google/flatbuffers/grpc/FlatbuffersUtils.java
new file mode 100644
index 00000000..768708b1
--- /dev/null
+++ b/grpc/flatbuffers-java-grpc/src/main/java/com/google/flatbuffers/grpc/FlatbuffersUtils.java
@@ -0,0 +1,117 @@
+/*
+ * Copyright 2014 Google Inc. All rights reserved.
+ *
+ * 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.
+ */
+package com.google.flatbuffers.grpc;
+
+import com.google.flatbuffers.Table;
+import io.grpc.Drainable;
+import io.grpc.KnownLength;
+import io.grpc.MethodDescriptor;
+
+import javax.annotation.Nullable;
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.nio.ByteBuffer;
+
+public class FlatbuffersUtils {
+    abstract public static class FBExtactor  <T extends Table> {
+        T extract (InputStream stream) throws IOException {
+            if (stream instanceof KnownLength) {
+                int size = stream.available();
+                ByteBuffer buffer = ByteBuffer.allocate(size);
+                stream.read(buffer.array());
+                return extract(buffer);
+            } else
+                throw new RuntimeException("The class " + stream.getClass().getCanonicalName() + " does not extend from KnownLength ");
+        }
+
+        public abstract T extract(ByteBuffer buffer);
+
+    }
+
+    static class FBInputStream extends InputStream implements Drainable, KnownLength {
+        private final ByteBuffer buffer;
+        private final int size;
+        @Nullable private ByteArrayInputStream inputStream;
+
+        FBInputStream(ByteBuffer buffer) {
+            this.buffer = buffer;
+            this.size = buffer.remaining();
+        }
+
+        private void makeStreamIfNotAlready() {
+            if (inputStream == null)
+                inputStream = new ByteArrayInputStream(buffer.array(), buffer.position(), size);
+        }
+
+        @Override
+        public int drainTo(OutputStream target) throws IOException {
+            target.write(buffer.array(), buffer.position(), size);
+            return size;
+        }
+
+        @Override
+        public int read() throws IOException {
+            makeStreamIfNotAlready();
+            return inputStream.read();
+        }
+
+        @Override
+        public int read(byte[] b, int off, int len) throws IOException {
+            makeStreamIfNotAlready();
+            if (inputStream == null) {
+                if (len >= size) {
+                    System.arraycopy(buffer.array(), buffer.position(), b, off, size);
+                    return size;
+                } else {
+                    makeStreamIfNotAlready();
+                    return inputStream.read(b, off, len);
+                }
+            } else
+                return inputStream.read(b, off, len);
+        }
+
+        @Override
+        public int available() throws IOException {
+            return inputStream == null ? size : inputStream.available();
+        }
+
+    }
+
+    public static <T extends Table> MethodDescriptor.Marshaller<T> marshaller(final Class<T> clazz, final FBExtactor<T> extractor) {
+        return new MethodDescriptor.ReflectableMarshaller<T>() {
+            @Override
+            public Class<T> getMessageClass() {
+                return clazz;
+            }
+
+            @Override
+            public InputStream stream(T value) {
+                return new FBInputStream (value.getByteBuffer());
+            }
+
+            @Override
+            public T parse(InputStream stream) {
+                try {
+                    return extractor.extract(stream);
+                } catch (IOException e) {
+                    throw new RuntimeException(e);
+                }
+            }
+        };
+    }
+}
diff --git a/grpc/pom.xml b/grpc/pom.xml
new file mode 100644
index 00000000..b43369e3
--- /dev/null
+++ b/grpc/pom.xml
@@ -0,0 +1,213 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.google.flatbuffers</groupId>
+    <artifactId>flatbuffers-parent</artifactId>
+    <packaging>pom</packaging>
+    <version>1.8.0</version>
+    <name>flatbuffers-parent</name>
+    <description>parent pom for flatbuffers java artifacts</description>
+    <properties>
+        <scm.url>https://github.com/google/flatbuffers</scm.url>
+        <scm.connection>scm:git:${scm.url}.git</scm.connection>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+
+    <licenses>
+        <license>
+            <name>The Apache Software License, Version 2.0</name>
+            <url>http://www.apache.org/licenses/LICENSE-2.0.txt</url>
+            <distribution>repo</distribution>
+        </license>
+    </licenses>
+
+    <issueManagement>
+        <system>GitHub</system>
+        <url>https://github.com/google/flatbuffers/issues</url>
+    </issueManagement>
+
+    <developers>
+        <developer>
+            <name>Wouter van Oortmerssen</name>
+        </developer>
+    </developers>
+
+    <url>${scm.url}</url>
+
+    <scm>
+        <connection>${scm.connection}</connection>
+        <developerConnection>${scm.connection}</developerConnection>
+        <url>${scm.url}</url>
+        <tag>HEAD</tag>
+    </scm>
+
+    <distributionManagement>
+        <snapshotRepository>
+            <id>ossrh</id>
+            <url>https://oss.sonatype.org/content/repositories/snapshots</url>
+        </snapshotRepository>
+    </distributionManagement>
+
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.12</version>
+            <scope>test</scope>
+        </dependency>
+
+    </dependencies>
+    <build>
+        <extensions>
+            <extension>
+                <!--
+                    os-maven-plugin is a Maven extension/plugin that generates various useful platform-dependent
+                    project properties normalized from ${os.detected.name} and ${os.detected.arch}.
+                -->
+                <groupId>kr.motd.maven</groupId>
+                <artifactId>os-maven-plugin</artifactId>
+                <version>1.5.0.Final</version>
+            </extension>
+        </extensions>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <artifactId>maven-compiler-plugin</artifactId>
+                    <version>3.6.1</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-jar-plugin</artifactId>
+                    <version>3.0.2</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-source-plugin</artifactId>
+                    <version>3.0.1</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-surefire-plugin</artifactId>
+                    <version>2.19.1</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-javadoc-plugin</artifactId>
+                    <version>2.10.4</version>
+                </plugin>
+                <plugin>
+                    <groupId>org.codehaus.mojo</groupId>
+                    <artifactId>build-helper-maven-plugin</artifactId>
+                    <version>1.12</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-dependency-plugin</artifactId>
+                    <version>2.8</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-deploy-plugin</artifactId>
+                    <version>2.7</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-gpg-plugin</artifactId>
+                    <version>1.5</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-release-plugin</artifactId>
+                    <version>2.5.3</version>
+                </plugin>
+
+                <plugin>
+                    <groupId>org.codehaus.mojo</groupId>
+                    <artifactId>exec-maven-plugin</artifactId>
+                    <version>1.5.0</version>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+
+        <plugins>
+            <plugin>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>1.6</source>
+                    <target>1.6</target>
+                </configuration>
+            </plugin>
+            <plugin>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <configuration>
+                    <includes>
+                        <include>**/*Test.java</include>
+                    </includes>
+                </configuration>
+            </plugin>
+            <plugin>
+                <artifactId>maven-source-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <id>attach-sources</id>
+                        <goals>
+                            <goal>jar</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <artifactId>maven-javadoc-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <id>attach-javadocs</id>
+                        <goals>
+                            <goal>jar</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.felix</groupId>
+                <artifactId>maven-bundle-plugin</artifactId>
+                <version>3.0.1</version>
+                <extensions>true</extensions>
+            </plugin>
+            <plugin>
+                <groupId>org.sonatype.plugins</groupId>
+                <artifactId>nexus-staging-maven-plugin</artifactId>
+                <version>1.6.7</version>
+                <extensions>true</extensions>
+                <configuration>
+                    <serverId>ossrh</serverId>
+                    <nexusUrl>https://oss.sonatype.org/</nexusUrl>
+                    <autoReleaseAfterClose>true</autoReleaseAfterClose>
+                </configuration>
+            </plugin>
+            <plugin>
+                <artifactId>maven-gpg-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <id>sign-artifacts</id>
+                        <phase>verify</phase>
+                        <goals>
+                            <goal>sign</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <artifactId>maven-release-plugin</artifactId>
+                <configuration>
+                    <autoVersionSubmodules>true</autoVersionSubmodules>
+                    <useReleaseProfile>false</useReleaseProfile>
+                    <releaseProfiles>release</releaseProfiles>
+                    <goals>deploy</goals>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <modules>
+<!-- consider the benefits of publishing all maven artifacts in this project 
+
+        <module>flatbuffers-compiler</module>
+        <module>flatbuffers-java</module>
+
+-->
+        <module>flatbuffers-java-grpc</module>
+    </modules>
+
+</project>
diff --git a/grpc/tests/JavaGrpcTest.java b/grpc/tests/JavaGrpcTest.java
new file mode 100644
index 00000000..6ae6995b
--- /dev/null
+++ b/grpc/tests/JavaGrpcTest.java
@@ -0,0 +1,119 @@
+/*
+ * Copyright 2014 Google Inc. All rights reserved.
+ *
+ * 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 MyGame.Example.Monster;
+import MyGame.Example.MonsterStorageGrpc;
+import MyGame.Example.Stat;
+import com.google.flatbuffers.FlatBufferBuilder;
+import io.grpc.ManagedChannel;
+import io.grpc.ManagedChannelBuilder;
+import io.grpc.Server;
+import io.grpc.ServerBuilder;
+import org.junit.Assert;
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.util.Iterator;
+
+
+/**
+ * Demonstrates basic client-server interaction using grpc-java over netty.
+ */
+public class JavaGrpcTest {
+    static final String BIG_MONSTER_NAME = "big-monster";
+    static final short nestedMonsterHp = 600;
+    static final short nestedMonsterMana = 1024;
+    static final int numStreamedMsgs = 10;
+
+    static class MyService extends MonsterStorageGrpc.MonsterStorageImplBase {
+        @Override
+        public void store(Monster request, io.grpc.stub.StreamObserver<Stat> responseObserver) {
+            Assert.assertEquals(request.name(), BIG_MONSTER_NAME);
+            Assert.assertEquals(request.hp(), nestedMonsterHp);
+            Assert.assertEquals(request.mana(), nestedMonsterMana);
+            System.out.println("Received store request from " + request.name());
+            // Create a response from the incoming request name.
+            FlatBufferBuilder builder = new FlatBufferBuilder();
+            int statOffset = Stat.createStat(builder, builder.createString("Hello " + request.name()), 100, 10);
+            builder.finish(statOffset);
+            Stat stat = Stat.getRootAsStat(builder.dataBuffer());
+            responseObserver.onNext(stat);
+            responseObserver.onCompleted();
+        }
+
+        @Override
+        public void retrieve(Stat request, io.grpc.stub.StreamObserver<Monster> responseObserver) {
+            // Create 10 monsters for streaming response.
+            for (int i=0; i<numStreamedMsgs; i++) {
+                FlatBufferBuilder builder = new FlatBufferBuilder();
+                int i1 = builder.createString(request.id() + " No." + i);
+                Monster.startMonster(builder);
+                Monster.addName(builder, i1);
+                int i2 = Monster.endMonster(builder);
+                Monster.finishMonsterBuffer(builder, i2);
+                Monster monster = Monster.getRootAsMonster(builder.dataBuffer());
+                responseObserver.onNext(monster);
+            }
+            responseObserver.onCompleted();
+        }
+    }
+
+
+    private static int startServer() throws IOException {
+        Server server = ServerBuilder.forPort(0).addService(new MyService()).build().start();
+        return server.getPort();
+    }
+
+    @org.junit.Test
+    public void testMonster() throws IOException {
+        int port = startServer();
+        ManagedChannel channel = ManagedChannelBuilder.forAddress("localhost", port)
+                // Channels are secure by default (via SSL/TLS). For the example we disable TLS to avoid
+                // needing certificates.
+                .usePlaintext(true)
+                .directExecutor()
+                .build();
+
+        MonsterStorageGrpc.MonsterStorageBlockingStub stub = MonsterStorageGrpc.newBlockingStub(channel);
+
+        FlatBufferBuilder builder = new FlatBufferBuilder();
+
+        int o_string = builder.createString(BIG_MONSTER_NAME);
+        Monster.startMonster(builder);
+        Monster.addName(builder, o_string);
+        Monster.addHp(builder, nestedMonsterHp);
+        Monster.addMana(builder, nestedMonsterMana);
+        int monster1 = Monster.endMonster(builder);
+        Monster.finishMonsterBuffer(builder, monster1);
+
+        ByteBuffer buffer = builder.dataBuffer();
+        Monster monsterRequest = Monster.getRootAsMonster(buffer);
+        Stat stat = stub.store(monsterRequest);
+        Assert.assertEquals(stat.id(), "Hello " + BIG_MONSTER_NAME);
+        System.out.println("Received stat response from service: " + stat.id());
+
+
+        Iterator<Monster> iterator = stub.retrieve(stat);
+        int counter = 0;
+        while(iterator.hasNext()) {
+            Monster m = iterator.next();
+            System.out.println("Received monster " + m.name());
+            counter ++;
+        }
+        Assert.assertEquals(counter, numStreamedMsgs);
+        System.out.println("FlatBuffers GRPC client/server test: completed successfully");
+    }
+}
diff --git a/grpc/tests/java-grpc-test.sh b/grpc/tests/java-grpc-test.sh
new file mode 100755
index 00000000..ec429605
--- /dev/null
+++ b/grpc/tests/java-grpc-test.sh
@@ -0,0 +1,4 @@
+#!/bin/sh
+
+# NOTE: make sure `mvn install` in /gprc is executed before running this test
+mvn test
diff --git a/grpc/tests/pom.xml b/grpc/tests/pom.xml
new file mode 100644
index 00000000..cfd908b5
--- /dev/null
+++ b/grpc/tests/pom.xml
@@ -0,0 +1,73 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>com.google.flatbuffers</groupId>
+        <artifactId>flatbuffers-parent</artifactId>
+        <version>1.8.0</version>
+    </parent>
+    <artifactId>grpc-test</artifactId>
+    <description>Example/Test project demonstrating usage of flatbuffers with GRPC-Java instead of protobufs
+    </description>
+    <properties>
+        <gRPC.version>1.8.0</gRPC.version>
+    </properties>
+    <dependencies>
+        <dependency>
+            <groupId>com.google.flatbuffers</groupId>
+            <artifactId>flatbuffers-java</artifactId>
+            <version>${project.parent.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.google.flatbuffers</groupId>
+            <artifactId>flatbuffers-java-grpc</artifactId>
+            <version>${project.parent.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.grpc</groupId>
+            <artifactId>grpc-stub</artifactId>
+            <version>${gRPC.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.grpc</groupId>
+            <artifactId>grpc-netty</artifactId>
+            <version>${gRPC.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.12</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>build-helper-maven-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <id>add-source</id>
+                        <phase>generate-sources</phase>
+                        <goals>
+                            <goal>add-test-source</goal>
+                        </goals>
+                        <configuration>
+                            <sources>
+                                <source>${project.basedir}</source>
+				<source>${project.basedir}/../../tests</source>
+                            </sources>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+        <!--<testSourceDirectory>${project.basedir}</testSourceDirectory>-->
+    </build>
+</project>
+