Hexagonal pattern: Add separate class for Mongo connection properties

hexagonal/src/main/java/com/iluwatar/hexagonal/banking/MongoBank.java

@@ -22,6 +22,7 @@
  */
 package com.iluwatar.hexagonal.banking;
 
+import com.iluwatar.hexagonal.mongo.MongoConnectionProperties;
 import com.mongodb.MongoClient;
 import com.mongodb.client.MongoCollection;
 import com.mongodb.client.MongoDatabase;
@@ -35,8 +36,6 @@ import java.util.ArrayList;
  */
 public class MongoBank implements WireTransfers {
 
-  private static final String DEFAULT_HOST = "localhost";
-  private static final int DEFAULT_PORT = 27017;
   private static final String DEFAULT_DB = "lotteryDB";
   private static final String DEFAULT_ACCOUNTS_COLLECTION = "accounts";
 
@@ -54,25 +53,26 @@ public class MongoBank implements WireTransfers {
   /**
    * Constructor accepting parameters
    */
-  public MongoBank(String host, int port, String dbName, String accountsCollectionName) {
+  public MongoBank(String dbName, String accountsCollectionName) {
-    connect(host, port, dbName, accountsCollectionName);
+    connect(dbName, accountsCollectionName);
   }
 
   /**
    * Connect to database with default parameters
    */
   public void connect() {
-    connect(DEFAULT_HOST, DEFAULT_PORT, DEFAULT_DB, DEFAULT_ACCOUNTS_COLLECTION);
+    connect(DEFAULT_DB, DEFAULT_ACCOUNTS_COLLECTION);
   }
 
   /**
    * Connect to database with given parameters
    */
-  public void connect(String host, int port, String dbName, String accountsCollectionName) {
+  public void connect(String dbName, String accountsCollectionName) {
     if (mongoClient != null) {
       mongoClient.close();
     }
-    mongoClient = new MongoClient(host , port);
+    MongoConnectionProperties properties = new MongoConnectionProperties().load();
+    mongoClient = new MongoClient(properties.getHost(), properties.getPort());
     database = mongoClient.getDatabase(dbName);
     accountsCollection = database.getCollection(accountsCollectionName);
   }

hexagonal/src/main/java/com/iluwatar/hexagonal/database/MongoTicketRepository.java

@@ -26,6 +26,7 @@ import com.iluwatar.hexagonal.domain.LotteryNumbers;
 import com.iluwatar.hexagonal.domain.LotteryTicket;
 import com.iluwatar.hexagonal.domain.LotteryTicketId;
 import com.iluwatar.hexagonal.domain.PlayerDetails;
+import com.iluwatar.hexagonal.mongo.MongoConnectionProperties;
 import com.mongodb.MongoClient;
 import com.mongodb.client.MongoCollection;
 import com.mongodb.client.MongoDatabase;
@@ -43,8 +44,6 @@ import java.util.Optional;
  */
 public class MongoTicketRepository implements LotteryTicketRepository {
 
-  private static final String DEFAULT_HOST = "localhost";
-  private static final int DEFAULT_PORT = 27017;
   private static final String DEFAULT_DB = "lotteryDB";
   private static final String DEFAULT_TICKETS_COLLECTION = "lotteryTickets";
   private static final String DEFAULT_COUNTERS_COLLECTION = "counters";
@@ -64,27 +63,28 @@ public class MongoTicketRepository implements LotteryTicketRepository {
   /**
    * Constructor accepting parameters
    */
-  public MongoTicketRepository(String host, int port, String dbName, String ticketsCollectionName,
+  public MongoTicketRepository(String dbName, String ticketsCollectionName,
                                String countersCollectionName) {
-    connect(host, port, dbName, ticketsCollectionName, countersCollectionName);
+    connect(dbName, ticketsCollectionName, countersCollectionName);
   }
 
   /**
    * Connect to database with default parameters
    */
   public void connect() {
-    connect(DEFAULT_HOST, DEFAULT_PORT, DEFAULT_DB, DEFAULT_TICKETS_COLLECTION, DEFAULT_COUNTERS_COLLECTION);
+    connect(DEFAULT_DB, DEFAULT_TICKETS_COLLECTION, DEFAULT_COUNTERS_COLLECTION);
   }
 
   /**
    * Connect to database with given parameters
    */
-  public void connect(String host, int port, String dbName, String ticketsCollectionName,
+  public void connect(String dbName, String ticketsCollectionName,
                       String countersCollectionName) {
     if (mongoClient != null) {
       mongoClient.close();
     }
-    mongoClient = new MongoClient(host , port);
+    MongoConnectionProperties properties = new MongoConnectionProperties().load();
+    mongoClient = new MongoClient(properties.getHost(), properties.getPort());
     database = mongoClient.getDatabase(dbName);
     ticketsCollection = database.getCollection(ticketsCollectionName);
     countersCollection = database.getCollection(countersCollectionName);

hexagonal/src/main/java/com/iluwatar/hexagonal/mongo/MongoConnectionProperties.java

@@ -0,0 +1,80 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.hexagonal.mongo;
+
+import java.io.FileInputStream;
+import java.util.Properties;
+
+/**
+ * Mongo connection properties
+ */
+public class MongoConnectionProperties {
+
+  private static final String DEFAULT_HOST = "localhost";
+  private static final int DEFAULT_PORT = 27017;
+
+  private String host;
+  private int port;
+
+  /**
+   * Constructor
+   */
+  public MongoConnectionProperties() {
+    this.host = DEFAULT_HOST;
+    this.port = DEFAULT_PORT;
+  }
+
+  /**
+   * @return host name
+   */
+  public String getHost() {
+    return host;
+  }
+
+  /**
+   * @return port number
+   */
+  public int getPort() {
+    return port;
+  }
+
+  /**
+   * Try to load connection properties from file.
+   * Fall back to default connection properties.
+   */
+  public MongoConnectionProperties load() {
+    String path = System.getProperty("hexagonal.properties.path");
+    Properties properties = new Properties();
+    if (path != null) {
+      try (FileInputStream fin = new FileInputStream(path)) {
+        properties.load(fin);
+        this.host = properties.getProperty("host");
+        this.port = Integer.parseInt(properties.getProperty("port"));
+      } catch (Exception e) {
+        // error occurred, use default properties
+        e.printStackTrace();
+      }
+    }
+    return this;
+  }
+}

hexagonal/src/test/java/com/iluwatar/hexagonal/banking/MongoBankTest.java

@@ -22,6 +22,7 @@
  */
 package com.iluwatar.hexagonal.banking;
 
+import com.iluwatar.hexagonal.mongo.MongoConnectionProperties;
 import com.mongodb.MongoClient;
 import org.junit.Before;
 import org.junit.Ignore;
@@ -35,8 +36,6 @@ import static org.junit.Assert.assertEquals;
 @Ignore
 public class MongoBankTest {
 
-  private static final String TEST_HOST = "localhost";
-  private static final int TEST_PORT = 27017;
   private static final String TEST_DB = "lotteryDBTest";
   private static final String TEST_ACCOUNTS_COLLECTION = "testAccounts";
 
@@ -44,10 +43,11 @@ public class MongoBankTest {
 
   @Before
   public void init() {
-    MongoClient mongoClient = new MongoClient(TEST_HOST, TEST_PORT);
+    MongoConnectionProperties properties = new MongoConnectionProperties().load();
+    MongoClient mongoClient = new MongoClient(properties.getHost(), properties.getPort());
     mongoClient.dropDatabase(TEST_DB);
     mongoClient.close();
-    mongoBank = new MongoBank(TEST_HOST, TEST_PORT, TEST_DB, TEST_ACCOUNTS_COLLECTION);
+    mongoBank = new MongoBank(TEST_DB, TEST_ACCOUNTS_COLLECTION);
   }
 
   @Test

hexagonal/src/test/java/com/iluwatar/hexagonal/database/MongoTicketRepositoryTest.java

@@ -26,6 +26,7 @@ import com.iluwatar.hexagonal.domain.LotteryNumbers;
 import com.iluwatar.hexagonal.domain.LotteryTicket;
 import com.iluwatar.hexagonal.domain.LotteryTicketId;
 import com.iluwatar.hexagonal.domain.PlayerDetails;
+import com.iluwatar.hexagonal.mongo.MongoConnectionProperties;
 import com.mongodb.MongoClient;
 import org.junit.Before;
 import org.junit.Ignore;
@@ -42,8 +43,6 @@ import static org.junit.Assert.assertTrue;
 @Ignore
 public class MongoTicketRepositoryTest {
 
-  private static final String TEST_HOST = "localhost";
-  private static final int TEST_PORT = 27017;
   private static final String TEST_DB = "lotteryTestDB";
   private static final String TEST_TICKETS_COLLECTION = "lotteryTestTickets";
   private static final String TEST_COUNTERS_COLLECTION = "testCounters";
@@ -52,10 +51,11 @@ public class MongoTicketRepositoryTest {
 
   @Before
   public void init() {
-    MongoClient mongoClient = new MongoClient(TEST_HOST, TEST_PORT);
+    MongoConnectionProperties properties = new MongoConnectionProperties().load();
+    MongoClient mongoClient = new MongoClient(properties.getHost(), properties.getPort());
     mongoClient.dropDatabase(TEST_DB);
     mongoClient.close();
-    repository = new MongoTicketRepository(TEST_HOST, TEST_PORT, TEST_DB, TEST_TICKETS_COLLECTION,
+    repository = new MongoTicketRepository(TEST_DB, TEST_TICKETS_COLLECTION,
         TEST_COUNTERS_COLLECTION);
   }