Move all samples to the root dir

Signed-off-by: Anca Iordache <anca.iordache@docker.com>

sparkjava-mysql/backend/src/main/java/App.java

@@ -0,0 +1,78 @@
+import com.google.gson.Gson;
+import com.mysql.cj.jdbc.exceptions.CommunicationsException;
+
+import static spark.Spark.*;
+
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.sql.*;
+import java.util.ArrayList;
+import java.util.List;
+
+public class App {
+
+    public static void main(String[] args) throws Exception {
+        Class.forName("com.mysql.cj.jdbc.Driver");
+
+        prepare();
+
+        port(8080);
+
+        get("/", (req, res) -> new Gson().toJson(titles()));
+    }
+
+    private static List<String> titles() {
+        try (Connection conn = connect()) {
+            List<String> titles = new ArrayList<>();
+            try (Statement stmt = conn.createStatement()) {
+                try (ResultSet rs = stmt.executeQuery("SELECT title FROM blog")) {
+                    while (rs.next()) {
+                        titles.add(rs.getString("title"));
+                    }
+                }
+            }
+            return titles;
+        } catch (Exception ex) {
+            return new ArrayList<>();
+        }
+    }
+
+    public static void prepare() throws Exception {
+        try (Connection conn = connect()) {
+            recreateTable(conn);
+            insertData(conn);
+        }
+    }
+
+    private static void insertData(Connection conn) throws SQLException {
+        for (int i = 0; i < 5; i++) {
+            try (PreparedStatement stmt = conn.prepareStatement("INSERT INTO blog (title) VALUES (?);")) {
+                stmt.setString(1, "Blog post #" + i);
+                stmt.execute();
+            }
+        }
+    }
+
+    private static void recreateTable(Connection conn) throws SQLException {
+        try (Statement stmt = conn.createStatement()) {
+            stmt.execute("DROP TABLE IF EXISTS blog");
+            stmt.execute("CREATE TABLE IF NOT EXISTS blog (id int NOT NULL AUTO_INCREMENT, title varchar(255), PRIMARY KEY (id))");
+        }
+    }
+
+
+    private static Connection connect() throws Exception {
+        for (int i = 0; i < 60; i++) {
+            try {
+                return DriverManager.getConnection("jdbc:mysql://db/example?useSSL=false", "root", Files.lines(Paths.get("/run/secrets/db-password")).findFirst().get());
+            } catch (CommunicationsException ex) {
+                Thread.sleep(1000L);
+                continue;
+            } catch (Exception ex) {
+                throw ex;
+            }
+        }
+        throw new RuntimeException("Unable to connect to MySQL");
+    }
+}
+