fix(appengine): removing obsolete symlink from java 8 on java 17 bundle services (#10270)

* Fix removing obsolete symlink from java 8. Also added correct JSTL dependency to avoid JSP compilation failure

* chore: update copyright headers to Google LLC

* fix: sanitize output, update redirect logic, and conditionally display pagination links

* chore: remove Datastore region tags code snippets from test and servlet files

Author: Kef131

appengine-java17-bundled-services/datastore/pom.xml

@@ -126,6 +126,11 @@
       <version>1.4.0</version>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>jstl</groupId>
+      <artifactId>jstl</artifactId>
+      <version>1.2</version>
+    </dependency>
   </dependencies>
 
   <build>

appengine-java17-bundled-services/datastore/src/main/java/com/example/appengine/AbstractGuestbook.java

@@ -0,0 +1,76 @@
+/*
+ * Copyright 2016 Google LLC
+ *
+ * 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.appengine;
+
+import com.example.time.Clock;
+import com.google.appengine.api.datastore.DatastoreService;
+import com.google.appengine.api.datastore.DatastoreServiceFactory;
+import com.google.appengine.api.datastore.Entity;
+import com.google.appengine.api.users.User;
+import com.google.appengine.api.users.UserService;
+import com.google.appengine.api.users.UserServiceFactory;
+import com.google.common.collect.ImmutableList;
+import java.util.Date;
+import java.util.List;
+
+/**
+ * A log of notes left by users.
+ *
+ * <p>This is meant to be subclassed to demonstrate different storage structures in Datastore.
+ */
+abstract class AbstractGuestbook {
+
+  private final DatastoreService datastore;
+  private final UserService userService;
+  private final Clock clock;
+
+  AbstractGuestbook(Clock clock) {
+    this.datastore = DatastoreServiceFactory.getDatastoreService();
+    this.userService = UserServiceFactory.getUserService();
+    this.clock = clock;
+  }
+
+  /**
+   * Appends a new greeting to the guestbook and returns the {@link Entity} that was created.
+   **/
+  public Greeting appendGreeting(String content) {
+    return Greeting.create(
+        createGreeting(datastore, userService.getCurrentUser(), Date.from(clock.now()), content));
+  }
+
+  /**
+   * Write a greeting to Datastore.
+   */
+  protected abstract Entity createGreeting(
+      DatastoreService datastore, User user, Date date, String content);
+
+  /**
+   * Return a list of the most recent greetings.
+   */
+  public List<Greeting> listGreetings() {
+    ImmutableList.Builder<Greeting> greetings = ImmutableList.builder();
+    for (Entity entity : listGreetingEntities(datastore)) {
+      greetings.add(Greeting.create(entity));
+    }
+    return greetings.build();
+  }
+
+  /**
+   * Return a list of the most recent greetings.
+   */
+  protected abstract List<Entity> listGreetingEntities(DatastoreService datastore);
+}

appengine-java17-bundled-services/datastore/src/main/java/com/example/appengine/AbstractGuestbook.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2016 Google LLC
+ *
+ * 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.appengine;
+
+import java.io.IOException;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+abstract class AbstractGuestbookServlet extends HttpServlet {
+
+  private final AbstractGuestbook guestbook;
+
+  public AbstractGuestbookServlet(AbstractGuestbook guestbook) {
+    this.guestbook = guestbook;
+  }
+
+  private void renderGuestbook(HttpServletRequest req, HttpServletResponse resp)
+      throws IOException, ServletException {
+    resp.setContentType("text/html");
+    resp.setCharacterEncoding("UTF-8");
+    req.setAttribute("greetings", guestbook.listGreetings());
+    req.getRequestDispatcher("/guestbook.jsp").forward(req, resp);
+  }
+
+  @Override
+  public void doGet(HttpServletRequest req, HttpServletResponse resp)
+      throws IOException, ServletException {
+    renderGuestbook(req, resp);
+  }
+
+  @Override
+  public void doPost(HttpServletRequest req, HttpServletResponse resp)
+      throws IOException, ServletException {
+    String content = req.getParameter("content");
+    if (content == null || content.isEmpty()) {
+      resp.sendError(HttpServletResponse.SC_BAD_REQUEST, "missing content");
+      return;
+    }
+    guestbook.appendGreeting(content);
+    resp.sendRedirect(req.getRequestURI());
+  }
+}

appengine-java17-bundled-services/datastore/src/main/java/com/example/appengine/AbstractGuestbookServlet.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2016 Google LLC
+ *
+ * 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.appengine;
+
+import com.google.appengine.api.datastore.Entity;
+import com.google.appengine.api.users.User;
+import com.google.auto.value.AutoValue;
+import java.time.Instant;
+import java.util.Date;
+import javax.annotation.Nullable;
+
+@AutoValue
+public abstract class Greeting {
+
+  static Greeting create(Entity entity) {
+    User user = (User) entity.getProperty("user");
+    Instant date = ((Date) entity.getProperty("date")).toInstant();
+    String content = (String) entity.getProperty("content");
+    return new AutoValue_Greeting(user, date, content);
+  }
+
+  @Nullable
+  public abstract User getUser();
+
+  public abstract Instant getDate();
+
+  public abstract String getContent();
+}

appengine-java17-bundled-services/datastore/src/main/java/com/example/appengine/AbstractGuestbookServlet.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright 2016 Google LLC
+ *
+ * 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.appengine;
+
+import com.example.time.Clock;
+import com.google.appengine.api.datastore.DatastoreService;
+import com.google.appengine.api.datastore.Entity;
+import com.google.appengine.api.datastore.FetchOptions;
+import com.google.appengine.api.datastore.Query;
+import com.google.appengine.api.users.User;
+import java.util.Date;
+import java.util.List;
+
+/**
+ * A log of notes left by users.
+ *
+ * <p>This demonstrates the use of Google Cloud Datastore using the App Engine APIs. See the <a
+ * href="https://cloud.google.com/appengine/docs/java/datastore/">documentation</a> for more
+ * information.
+ */
+class Guestbook extends AbstractGuestbook {
+
+  Guestbook(Clock clock) {
+    super(clock);
+  }
+
+  @Override
+  protected Entity createGreeting(
+      DatastoreService datastore, User user, Date date, String content) {
+    // No parent key specified, so Greeting is a root entity.
+    Entity greeting = new Entity("Greeting");
+    greeting.setProperty("user", user);
+    greeting.setProperty("date", date);
+    greeting.setProperty("content", content);
+
+    datastore.put(greeting);
+    return greeting;
+  }
+
+  @Override
+  protected List<Entity> listGreetingEntities(DatastoreService datastore) {
+    Query query = new Query("Greeting").addSort("date", Query.SortDirection.DESCENDING);
+    return datastore.prepare(query).asList(FetchOptions.Builder.withLimit(10));
+  }
+}