samples: Add NL quickstart sample. Fix some other quickstarts. (#438)

Author: jmdobry

language/snippets/src/main/java/com/example/language/QuickstartSample.java

@@ -0,0 +1,44 @@
+/*
+  Copyright 2016, 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.
+*/
+
+package com.example.language;
+
+// [START language_quickstart]
+// Imports the Google Cloud client library
+import com.google.cloud.language.spi.v1.LanguageServiceClient;
+
+import com.google.cloud.language.v1.Document;
+import com.google.cloud.language.v1.Document.Type;
+import com.google.cloud.language.v1.Sentiment;
+
+public class QuickstartSample {
+  public static void main(String... args) throws Exception {
+    // Instantiates a client
+    LanguageServiceClient language = LanguageServiceClient.create();
+
+    // The text to analyze
+    String text = "Hello, world!";
+    Document doc = Document.newBuilder()
+            .setContent(text).setType(Type.PLAIN_TEXT).build();
+
+    // Detects the sentiment of the text
+    Sentiment sentiment = language.analyzeSentiment(doc).getDocumentSentiment();
+
+    System.out.printf("Text: %s%n", text);
+    System.out.printf("Sentiment: %s, %s%n", sentiment.getScore(), sentiment.getMagnitude());
+  }
+}
+// [END language_quickstart]

language/snippets/src/test/java/com/example/language/QuickstartSampleIT.java

@@ -0,0 +1,61 @@
+/*
+  Copyright 2016, 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.
+*/
+
+package com.example.language;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+
+/**
+ * Tests for quickstart sample.
+ */
+@RunWith(JUnit4.class)
+@SuppressWarnings("checkstyle:abbreviationaswordinname")
+public class QuickstartSampleIT {
+  private ByteArrayOutputStream bout;
+  private PrintStream out;
+
+  @Before
+  public void setUp() {
+    bout = new ByteArrayOutputStream();
+    out = new PrintStream(bout);
+    System.setOut(out);
+  }
+
+  @After
+  public void tearDown() {
+    System.setOut(null);
+  }
+
+  @Test
+  public void testQuickstart() throws Exception {
+    // Act
+    QuickstartSample.main();
+
+    // Assert
+    String got = bout.toString();
+    assertThat(got).contains("Text: Hello, world!");
+    assertThat(got).contains("Sentiment: ");
+  }
+}