Assignment Singleton - Soorya

src/main/java/com/scaler/lld/design/assignments/builder/DatabaseConfigurationBuilder.java

@@ -1,6 +1,80 @@
 package com.scaler.lld.design.assignments.builder;
 
+import lombok.Getter;
+
 @WithBuilder
+@Getter
 public class DatabaseConfigurationBuilder {
+    private String databaseUrl;
+    private String username;
+    private String password;
+    private int maxConnections;
+    private boolean enableCache;
+    private boolean isReadOnly;
+
+    public DB_builer Builder()
+    {
+        return new DB_builer();
+    }
+
+    // Step 1: create static inner class
+    public static class DB_builer
+    {
+        // Step 2: copy all fields into builder class
+        private DatabaseConfigurationBuilder dbConfig;
+
+        public DB_builer()
+        {
+            this.dbConfig = new DatabaseConfigurationBuilder();
+        }
+
+        // Step 2:
+        // expose setter (fluent interfaces)
+
+
+        public DB_builer setDatabaseUrl(String databaseUrl) {
+            this.dbConfig.databaseUrl = databaseUrl;
+            return this;
+        }
+
+        public DB_builer setEnableCache(boolean enableCache) {
+            this.dbConfig.enableCache = enableCache;
+            return this;
+        }
+
+        public DB_builer setMaxConnections(int maxConnections) {
+            this.dbConfig.maxConnections = maxConnections;
+            return this;
+        }
+
+        public DB_builer setPassword(String password) {
+            this.dbConfig.password = password;
+            return this;
+        }
+
+        public DB_builer setReadOnly(boolean readOnly) {
+            this.dbConfig.isReadOnly = readOnly;
+            return this;
+        }
+
+        public DB_builer setUsername(String username) {
+            this.dbConfig.username = username;
+            return this;
+        }
+
+        // Step 4: build method
+        public DatabaseConfigurationBuilder build()
+        {
+            DatabaseConfigurationBuilder db = new DatabaseConfigurationBuilder();
+
+            db.databaseUrl = dbConfig.databaseUrl;
+            db.isReadOnly = dbConfig.isReadOnly;
+            db.enableCache = dbConfig.enableCache;
+            db.maxConnections = dbConfig.maxConnections;
+            db.password = dbConfig.password;
+            db.username = dbConfig.username;
 
+            return db;
+        }
+    }
 }

src/main/java/com/scaler/lld/design/assignments/prototype/ClonableObject.java

@@ -1,5 +1,5 @@
 package com.scaler.lld.design.assignments.prototype;
-
+// Step 1 : Cloneable interface
 public interface ClonableObject<T> {
     T cloneObject();
 }

src/main/java/com/scaler/lld/design/assignments/prototype/Configuration.java

@@ -1,6 +1,11 @@
 package com.scaler.lld.design.assignments.prototype;
 
-public class Configuration {
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+// Step 2: implement clone method
+@Getter
+public class Configuration implements ClonableObject<Configuration>{
     private String themeColor;
     private Boolean autoSave;
     private String language;
@@ -19,31 +24,8 @@ public Configuration(String themeColor, Boolean autoSave, String language, Boole
         this.type = type;
     }
 
-    public String getThemeColor() {
-        return themeColor;
-    }
-
-    public Boolean getAutoSave() {
-        return autoSave;
-    }
-
-    public String getLanguage() {
-        return language;
-    }
-
-    public Boolean getDarkMode() {
-        return darkMode;
-    }
-
-    public Integer getFontSize() {
-        return fontSize;
-    }
-
-    public String getFontFamily() {
-        return fontFamily;
-    }
-
-    public ConfigurationType getType() {
-        return type;
+    @Override
+    public Configuration cloneObject() {
+        return new Configuration(this.themeColor, this.autoSave, this.language, this.darkMode, this.fontSize, this.fontFamily, this.type);
     }
 }

src/main/java/com/scaler/lld/design/assignments/prototype/ConfigurationRegistryImpl.java

@@ -0,0 +1,24 @@
+package com.scaler.lld.design.assignments.prototype;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class ConfigurationRegistryImpl implements ConfigurationPrototypeRegistry{
+    private Map<ConfigurationType, Configuration> registry = new HashMap<>();
+
+    @Override
+    public void addPrototype(Configuration user)
+    {
+        registry.put(user.getType(), user);
+    }
+
+    @Override
+    public Configuration getPrototype(ConfigurationType type) {
+        return registry.get(type);
+    }
+
+    @Override
+    public Configuration clone(ConfigurationType type) {
+        return getPrototype(type).cloneObject();
+    }
+}

src/main/java/com/scaler/lld/design/assignments/singleton/FileBasedConfigurationManagerImpl.java

@@ -2,49 +2,75 @@
 
 public class FileBasedConfigurationManagerImpl extends FileBasedConfigurationManager {
 
+    // Step 3: static attribute
+    static FileBasedConfigurationManager INSTANCE = null;
+
+    // Step 1: Private constructor
+    private FileBasedConfigurationManagerImpl()
+    {
+        super();
+    }
     @Override
     public String getConfiguration(String key) {
-        // TODO Auto-generated method stub
-        throw new UnsupportedOperationException("Unimplemented method 'getConfiguration'");
+        if(properties.containsKey(key)) {
+            return properties.getProperty(key);
+        }
+        return null;
     }
 
     @Override
     public <T> T getConfiguration(String key, Class<T> type) {
         // TODO Auto-generated method stub
-        throw new UnsupportedOperationException("Unimplemented method 'getConfiguration'");
+        if(properties.containsKey(key)) {
+            return convert(properties.getProperty(key), type);
+        }
+        return null;
     }
 
     @Override
     public void setConfiguration(String key, String value) {
-        // TODO Auto-generated method stub
-        throw new UnsupportedOperationException("Unimplemented method 'setConfiguration'");
+
+        properties.setProperty(key, value);
     }
 
     @Override
     public <T> void setConfiguration(String key, T value) {
         // TODO Auto-generated method stub
-        throw new UnsupportedOperationException("Unimplemented method 'setConfiguration'");
+        properties.setProperty(key, value.toString());
     }
 
     @Override
     public void removeConfiguration(String key) {
-        // TODO Auto-generated method stub
-        throw new UnsupportedOperationException("Unimplemented method 'removeConfiguration'");
+        properties.remove(key);
     }
 
     @Override
     public void clear() {
-        // TODO Auto-generated method stub
-        throw new UnsupportedOperationException("Unimplemented method 'clear'");
+        properties.clear();
     }
 
+    // Step 2: global access point for instance
     public static FileBasedConfigurationManager getInstance() {
-        // TODO Auto-generated method stub
-        return null;
+         // Step 4: Double-checked locking
+        if(INSTANCE == null)
+        {
+            synchronized (FileBasedConfigurationManagerImpl.class)
+            {
+                if(INSTANCE == null)
+                {
+                    INSTANCE = new FileBasedConfigurationManagerImpl();
+                }
+            }
+        }
+
+        return INSTANCE;
     }
 
     public static void resetInstance() {
-        // TODO Auto-generated method stub
+        synchronized (FileBasedConfigurationManagerImpl.class)
+        {
+            INSTANCE = null;
+        }
     }
 
 }