Read properties definition from a separate config file, and rename example file to reflect database-agnostic functionality

---------

Co-authored-by: Roberto Luna Rojas <rberoj+sns@amazon.com>

Author: 2 people

.env.example

@@ -0,0 +1,5 @@
+DB_CONNECTION_STRING=jdbc:aws-wrapper:postgresql://localhost:5432/dbname
+CACHE_RW_SERVER_ADDR=localhost:6379
+CACHE_RO_SERVER_ADDR=localhost:6380
+DB_USERNAME=postgres
+DB_PASSWORD=admin

…amazon/PgConnectionWithCacheExample.java …/DatabaseConnectionWithCacheExample.javaexamples/AWSDriverExample/src/main/java/software/amazon/PgConnectionWithCacheExample.java renamed to examples/AWSDriverExample/src/main/java/software/amazon/DatabaseConnectionWithCacheExample.java examples/AWSDriverExample/src/main/java/software/amazon/PgConnectionWithCacheExample.java renamed to examples/AWSDriverExample/src/main/java/software/amazon/DatabaseConnectionWithCacheExample.java

@@ -1,15 +1,19 @@
 package software.amazon;
 
+import software.amazon.util.EnvLoader;
 import java.sql.*;
 import java.util.*;
 
-public class PgConnectionWithCacheExample {
+public class DatabaseConnectionWithCacheExample {
 
-  private static final String CONNECTION_STRING = "jdbc:aws-wrapper:postgresql://dev-dsk-quchen-2a-3a165932.us-west-2.amazon.com:5432/postgres";
-  private static final String CACHE_RW_SERVER_ADDR = "dev-dsk-quchen-2a-3a165932.us-west-2.amazon.com:6379";
-  private static final String CACHE_RO_SERVER_ADDR = "dev-dsk-quchen-2a-3a165932.us-west-2.amazon.com:6380";
-  private static final String USERNAME = "postgres";
-  private static final String PASSWORD = "admin";
+  private static final EnvLoader env = new EnvLoader();
+
+  private static final String DB_CONNECTION_STRING = env.get("DB_CONNECTION_STRING");
+  private static final String CACHE_RW_SERVER_ADDR = env.get("CACHE_RW_SERVER_ADDR");
+  private static final String CACHE_RO_SERVER_ADDR = env.get("CACHE_RO_SERVER_ADDR");
+  private static final String USERNAME = env.get("DB_USERNAME");
+  private static final String PASSWORD = env.get("DB_PASSWORD");
+  private static final String USE_SSL = env.get("USE_SSL");
 
   public static void main(String[] args) throws SQLException {
     final Properties properties = new Properties();
@@ -22,14 +26,15 @@ public static void main(String[] args) throws SQLException {
     properties.setProperty("wrapperPlugins", "dataRemoteCache");
     properties.setProperty("cacheEndpointAddrRw", CACHE_RW_SERVER_ADDR);
     properties.setProperty("cacheEndpointAddrRo", CACHE_RO_SERVER_ADDR);
+    properties.setProperty("cacheUseSSL", USE_SSL); // "true" or "false"
     properties.setProperty("wrapperLogUnclosedConnections", "true");
     String queryStr = "select * from cinemas";
     String queryStr2 = "SELECT * from cinemas";
 
     for (int i = 0 ; i < 5; i++) {
       // Create a new database connection and issue queries to it
       try {
-        Connection conn = DriverManager.getConnection(CONNECTION_STRING, properties);
+        Connection conn = DriverManager.getConnection(DB_CONNECTION_STRING, properties);
         Statement stmt = conn.createStatement();
         ResultSet rs = stmt.executeQuery(queryStr);
         ResultSet rs2 = stmt.executeQuery(queryStr2);
@@ -40,5 +45,4 @@ public static void main(String[] args) throws SQLException {
       }
     }
   }
-
 }

examples/AWSDriverExample/src/main/java/software/amazon/util/EnvLoader.java

@@ -0,0 +1,83 @@
+package software.amazon.util;
+
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * A simple utility class to load environment variables from a .env file.
+ */
+public class EnvLoader {
+  private final Map<String, String> envVars = new HashMap<>();
+
+  /**
+   * Loads environment variables from a .env file in the current directory.
+   */
+  public EnvLoader() {
+    this(Paths.get(".env"));
+  }
+
+  /**
+   * Loads environment variables from the specified file path.
+   *
+   * @param envPath Path to the .env file
+   */
+  public EnvLoader(Path envPath) {
+    if (Files.exists(envPath)) {
+      try (BufferedReader reader = new BufferedReader(new FileReader(envPath.toFile()))) {
+        String line;
+        while ((line = reader.readLine()) != null) {
+          parseLine(line);
+        }
+      } catch (IOException e) {
+        System.err.println("Error reading .env file: " + e.getMessage());
+      }
+    }
+  }
+
+  private void parseLine(String line) {
+    line = line.trim();
+    // Skip empty lines and comments
+    if (line.isEmpty() || line.startsWith("#")) {
+      return;
+    }
+
+    // Split on the first equals sign
+    int delimiterPos = line.indexOf('=');
+    if (delimiterPos > 0) {
+      String key = line.substring(0, delimiterPos).trim();
+      String value = line.substring(delimiterPos + 1).trim();
+      
+      // Remove quotes if present
+      if ((value.startsWith("\"") && value.endsWith("\"")) || 
+          (value.startsWith("'") && value.endsWith("'"))) {
+        value = value.substring(1, value.length() - 1);
+      }
+      
+      envVars.put(key, value);
+    }
+  }
+
+  /**
+   * Gets the value of an environment variable.
+   *
+   * @param key The name of the environment variable
+   * @return The value of the environment variable, or null if not found
+   */
+  public String get(String key) {
+    // First check the loaded .env file
+    String value = envVars.get(key);
+    
+    // If not found, check system environment variables
+    if (value == null) {
+      value = System.getenv(key);
+    }
+    
+    return value;
+  }
+}