C# DBElement类代码示例

     // function to insert into database
 public XElement insert(XElement dbe, DBEngine<int, DBElement<int, string>> db)
 {
     DBElement<int, string> elem = new DBElement<int, string>();
     Console.WriteLine("\n");
     Console.WriteLine("\n----------Insert operation----------");
     elem.name = dbe.Element("name").Value;
     elem.descr = dbe.Element("descr").Value;
     elem.payload = dbe.Element("payload").Value;
     List<int> childrenlist = new List<int>();
     XElement db1 = dbe.Element("children");
     foreach (var v in db1.Elements("dbkey")) childrenlist.Add(Int32.Parse(v.Value));
     elem.children = childrenlist;
     bool result = db.insert(Int32.Parse((dbe.Element("key").Value)), elem);
     db.showDB();
     if (result == true)
     {
         XElement s = new XElement("result", "\n element inserted successfully ");
         return s;
     }
     else
     {
         XElement f = new XElement("result", "Failure");
         return f;
     }
 }

        void TestR3()
        {
            "\n1) Inserting key/value pairs to the database".title();
            DBElement<int, string> elem2 = new DBElement<int, string>();                            //Add new key/value pairs to the database
            elem2.name = "Roger federer";
            elem2.descr = "Tennis player";
            elem2.timeStamp = DateTime.Now;
            elem2.children.AddRange(new List<int> { 3 });
            elem2.payload = "Famous tennis player";
            db.insert(2, elem2);

            DBElement<int, string> elem3 = new DBElement<int, string>();
            elem3.name = "Usain Bolt";
            elem3.descr = "Athelte";
            elem3.timeStamp = DateTime.Now;
            elem3.children.AddRange(new List<int> { 1 });
            elem3.payload = "Fastest in the world";
            db.insert(3, elem3);

            DBElement<int, string> elem4 = new DBElement<int, string>();
            elem4.name = "Saina Nehwal";
            elem4.descr = "Badminton Player";
            elem4.timeStamp = DateTime.Now;
            elem4.children.AddRange(new List<int> { 2 });
            elem4.payload = "Famous badminton player";
            db.insert(4, elem4);
            db.showDB();
            WriteLine();

            "\n2) Removing key 4 from the database".title();
            db.delete(4);
            db.showDB();
            WriteLine();
        }

 /* Defining a query using lambda function to search specific key 
 */
 public void key_value_search(DBEngine<int, DBElement<int, string>> db, IQuery<int, DBElement<int, string>> i_query, QueryEngine<int, DBElement<int, string>> qe )
 {
     "Query for value with specified key (key = 2):".title();
     WriteLine();
     int key_to_search = 2;
     Func<int, string, bool> keyValueSearch = (int key, string search) => //lambda function
     {
         if (!db.Keys().Contains(key))
             return false;
         else
         {
             if (key == int.Parse(search))
             {
                 DBElement<int, string> ele = new DBElement<int, string>();
                 db.getValue(key, out ele);
                 return true;
             }
             else { return false; }
         }
     };
     // pass query to query engine and call simpleQuery to make query on DBEngine
     qe.simpleQuery(keyValueSearch, key_to_search.ToString(), out i_query);
     WriteLine();
     foreach (var key in i_query.Keys())
     {
         DBElement<int, string> temp = new DBElement<int, string>();
         i_query.getValue(key, out temp);
         WriteLine("key : {0}", key);
         temp.showElement();
         WriteLine();
     }
 }

        void TestR2()
        {
            "Demonstrating Requirement #2".title();
            //creating new element of type int and string
            DBElement<int, string> element = new DBElement<int, string>();
            element.name = "first element of db";
            element.descr = "int and string type";
            element.timeStamp = DateTime.Now;
            element.children.AddRange(new List<int> { 0, 2, 4, 8 });
            element.payload = "first element's payload";
            element.showElement();
            db.insert(1, element);
            db.showDB();
            WriteLine();
            //creating new element of type string and list of strings
            DBElement<string, List<string>> element2 = new DBElement<string, List<string>>();
            element2.name = "second element of db";
            element2.descr = "strings and strings of string types";
            element2.timeStamp = DateTime.Now;
            element2.children.AddRange(new List<string> { "SMA", "OOD", "Project2" });
            element2.payload = new List<string> { "second", "SMA", "project" };
            element2.showEnumerableElement();
            db2.insert("2", element2);
            db2.showEnumerableDB();
            WriteLine();

        }

        public void testDBlement()
        {
            Write("\n --- Test DBElement<int,string> ---");
            DBElement<int, string> elem1 = new DBElement<int, string>();
            elem1.payload = "a payload";
            Write(elem1.showElement<int, string>());
            WriteLine();

            DBElement<int, string> elem2 = new DBElement<int, string>("Darth Vader", "Evil Overlord");
            elem2.payload = "The Empire strikes back!";
            Write(elem2.showElement<int, string>());
            WriteLine();

            var elem3 = new DBElement<int, string>("Luke Skywalker", "Young HotShot");
            elem3.children.AddRange(new List<int> { 1, 5, 23 });
            elem3.payload = "X-Wing fighter in swamp - Oh oh!";
            Write(elem3.showElement<int, string>());
            WriteLine();

            Write("\n --- Test DBEngine<int,DBElement<int,string>> ---");

            int key = 0;
            Func<int> keyGen = () => { ++key; return key; };  // anonymous function to generate keys

            DBEngine<int, DBElement<int, string>> db = new DBEngine<int, DBElement<int, string>>();
            bool p1 = db.insert(keyGen(), elem1);
            bool p2 = db.insert(keyGen(), elem2);
            bool p3 = db.insert(keyGen(), elem3);
            if (p1 && p2 && p3)
                Write("\n  all inserts succeeded");
            else
                Write("\n  at least one insert failed");
            db.show<int, DBElement<int, string>, string>();
            WriteLine();
        }

 public Server()
 {
     elem = new DBElement<int, string>();
     strElem = new DBElement<string, List<string>>();
     rh = new RequestHandler();
     tot = new Hashtable();
 }

    public void TestR2()
    {
      "Demonstrating Requirement #2".title('=');
      "Database with string as payload".title();
      DBElement<int, string> elem = new DBElement<int, string>();
      elem.name = "element";
      elem.descr = "test element";
      elem.timeStamp = DateTime.Now;
      elem.children.AddRange(new List<int>{ 1, 2, 3 });
      elem.payload = "elem's payload";
      elem.showElement();
      db.insert(1, elem);
      db.showDB();
      WriteLine();
      "database with list of strings as payload".title();
      DBElement<string, List<string>> element = new DBElement<string, List<string>>();
      element.name = "element2";
      element.descr = "test element for list of strings as value";
      element.timeStamp = DateTime.Now;
      element.children.AddRange(new List<string> { "one","two"});
      element.payload = new List<string> { "element's payload", "2nd payload" };
      element.showEnumerableElement();
      enum_db.insert("enum_one", element);
      enum_db.showEnumerableDB();
      WriteLine();

    }

 public void XMLWrite(DBEngine<int, DBElement<int, string>> db, out string pathname)
 {
     pathname = "xmlDoc.xml";
     // The root element is nosqldb or nosqldbLOS, which we can say, is the name
     // of the database of the corresponding type. The declaration is important
     // from an XML parser point of view.
     DBElement<int, string> Val = new DBElement<int, string>();
     XDocument doc = new XDocument(new XElement("nosqldb"));
     doc.Declaration = new XDeclaration("1.0", "utf - 8", "yes");
     XElement keyType = new XElement("keytype", "int");
     XElement payloadType = new XElement("payloadtype", "string");
     doc.Root.Add(keyType);
     doc.Root.Add(payloadType);
     foreach (var key in db.Keys())
     {
         XElement keyNode = new XElement("key", key);
         db.getValue(key, out Val);
         XElement elementNode = new XElement("element");
         elementNode.Add(new XElement("name", Val.name));
         elementNode.Add(new XElement("descr", Val.descr));
         elementNode.Add(new XElement("timeStamp", Val.timeStamp.ToString()));
         XElement childrenNode = new XElement("children"); //since children is List<Key>
         foreach (var item in Val.children)
         {
             childrenNode.Add(new XElement("key", item));
         }
         elementNode.Add(childrenNode);
         elementNode.Add(new XElement("payload", Val.payload)); //since payload is string for this type of database
         doc.Root.Add(keyNode);
         doc.Root.Add(elementNode);
     }
     doc.Save(pathname);
     
 }

    void TestR3()//addition and deletion of key/value pairs
    {
      "Demonstrating Requirement #3".title();
	  WriteLine();
	  
	  Write("\n --- Test addition of key/value pairs Start---");
	  WriteLine();
	  DBElement<int, string> elem1 = new DBElement<int, string>();
      elem1.name = "element#1";//add a new key/value pairs
      elem1.descr = "test element#1";
      elem1.timeStamp = DateTime.Now;
      elem1.children.AddRange(new List<int>{ 6, 8 });
      elem1.payload = "elem#1's payload";
      elem1.showElement();
      db.insert(2, elem1);
	  Write("\n\n Show key/value pairs in data base:\n");
      db.showDB();
      WriteLine();
	  Write("\n --- Test addition of key/value pairs End---");
	  WriteLine();
	  
	  Write("\n --- Test deletion of key/value pairs Start---");
	  WriteLine();
	  db.delete(1);//delete an existing key/value pairs
	  Write("\n\n Show key/value pairs in data base:\n");
      db.showDB();
      WriteLine();
      db.delete(100);//try to delete a key/value pairs that doesn't exist
	  Write("\n --- Test deletion of key/value pairs End---");
      WriteLine();
    }

 private static void Test2(out DBElement<string, string> newelem1, out DBElement<string, string> newerelem1, out DBElement<string, string> newerelem2)
 {
     newelem1 = new DBElement<string, string>();
     newelem1.name = "newelem1";
     newelem1.descr = "test new type";
     newelem1.payload = "one";
     //Load the second element
     newerelem1 = new DBElement<string, string>();
     newerelem1.name = "newerelem1";
     newerelem1.descr = "better formatting";
     newerelem1.payload = "alpha";
     //Load the third element
     newerelem2 = new DBElement<string, string>();
     newerelem2.name = "newerelem2";
     newerelem2.descr = "better formatting";
     newerelem2.children.AddRange(new List<string> { "first", "second" });
     newerelem2.payload = "a";
     if (verbose)
     {
         Write("\n --- Test DBElement<string,List<string>> ---");
         WriteLine();
         newelem1.showEnumerableElement();       //Display the element
         WriteLine();
         newerelem1.showEnumerableElement();      //Display the element
         WriteLine();
         newerelem2.showEnumerableElement();
         WriteLine();
     }
 }

        static void Main(string[] args)
        {
            WriteLine("Testing DBExtensions Package\n");
            WriteLine();

            //Insert first element
            Write("\n --- Test DBElement<int,string> ---");
            DBElement<int, string> elem1 = new DBElement<int, string>();
            elem1.payload = "a payload";
            Write(elem1.showElement<int, string>());

            //Insert first element into DB
            DBEngine<int, DBElement<int, string>> dbs = new DBEngine<int, DBElement<int, string>>();
            dbs.insert(1, elem1);
            dbs.show<int, DBElement<int, string>, string>();
            WriteLine();

            //Insert first element into String Key/Value DB
            Write("\n --- Test DBElement<string,List<string>> ---");
            DBElement<string, List<string>> newelem1 = new DBElement<string, List<string>>();
            newelem1.name = "newelem1";
            newelem1.descr = "test new type";
            newelem1.children = new List<string> { "Key1", "Key2" };
            newelem1.payload = new List<string> { "one", "two", "three" };
            Write(newelem1.showElement<string, List<string>, string>());
            DBEngine<string, DBElement<string, List<string>>> dbe = new DBEngine<string, DBElement<string, List<string>>>();
            dbe.insert("key1", newelem1);
            dbe.show<string, DBElement<string, List<string>>, List<string>, string>();
            Write("\n\n");
        }

		public void writeXML()
		{
			if(db1.emptyDictionary())
				Write("\n\nThe database is empty.\n");
		
			else{//if the dictionary is not empty store key/value pairs into a XML file
			
					DBElement<int, string> temp = new DBElement<int, string>();
					IEnumerable<int> keys = db1.Keys();
					XDocument xml = new XDocument();
					xml.Declaration = new XDeclaration("1.0", "utf-8", "yes");
					
					XElement noSqlDb = new XElement("noSqlDb");
					xml.Add(noSqlDb);
					
					XElement keytype = new XElement("keytype", "int");
					XElement payloadtype = new XElement("payloadtype", "string");
					noSqlDb.Add(keytype);
					noSqlDb.Add(payloadtype);
					
					foreach(var i in keys)
					{
						db1.getValue(2, out temp);
						XElement key = new XElement("key", ("key"+i));
						noSqlDb.Add(key);//noSqlDb's children
						XElement element = new XElement("element");
						noSqlDb.Add(element);//noSqlDb's children 
						
						XElement name = new XElement("name", temp.name);//name of the element
						element.Add(name);
						XElement descr = new XElement("descr", temp.descr);//description of the element
						element.Add(descr);
						XElement timeStamp = new XElement("timeStamp", temp.timeStamp);//timeStamp of the element
						element.Add(timeStamp);
						
						if(temp.children.Count!=0)//children of the element
						{
							XElement children = new XElement("children");
							element.Add(children);
							foreach(var j in temp.children)
							{
								XElement childkey = new XElement("key", ("key"+j));
								children.Add(childkey);
							}
						}
						
						XElement payload = new XElement("payload", temp.payload);//payload of the element
						element.Add(payload);
				
					}
					
					Console.Write("\n{0}\n", xml.Declaration);
					Console.Write(xml.ToString());
					Console.Write("\n\n");
					xml.Save(@"C:\Users\lxinghe\Downloads\Project2Starter\Test.xml");
					
					db1.emptyDBEngine();//empty DBEngine
				}
		}

 public RequestHandler()
 {
     sb = new StringBuilder();
     db = new DBEngine<int, DBElement<int, string>>();
     query = new QueryEngine<int, DBElement<int, string>>();
     dbString = new DBEngine<string, DBElement<string, List<string>>>();
     strElem = new DBElement<string, List<string>>();
 }

		public void writeXML(string path)
		{	
			if(db1.emptyDictionary())
				Write("\n\nThe database is empty.\n");
		
			else{//if the dictionary is not empty store key/value pairs into a XML file
			
					DBElement<int, string> temp = new DBElement<int, string>();
					IEnumerable<int> keys = db1.Keys();
					
					xml.Declaration = new XDeclaration("1.0", "utf-8", "yes");
					
					XElement noSqlDb = new XElement("noSqlDb");
					xml.Add(noSqlDb);
					
					XElement keytype = new XElement("keytype", "int");
					XElement payloadtype = new XElement("payloadtype", "string");
					noSqlDb.Add(keytype);
					noSqlDb.Add(payloadtype);
					
					foreach(var i in keys)
					{
						db1.getValue(i, out temp);
						XElement key = new XElement("key", ("key"+i));
						noSqlDb.Add(key);//noSqlDb's children
						XElement element = new XElement("element");
						noSqlDb.Add(element);//noSqlDb's children 
						
						XElement name = new XElement("name", temp.name);//name of the element
						element.Add(name);
						XElement descr = new XElement("descr", temp.descr);//description of the element
						element.Add(descr);
						XElement timeStamp = new XElement("timeStamp", temp.timeStamp);//timeStamp of the element
						element.Add(timeStamp);
						
						if(temp.children.Count!=0)//children of the element
						{
							XElement children = new XElement("children");
							element.Add(children);
							foreach(var j in temp.children)
							{
								XElement childkey = new XElement("key", ("key"+j));
								children.Add(childkey);
							}
						}
						
						XElement payload = new XElement("payload", temp.payload);//payload of the element
						element.Add(payload);
					}
					
					
					xml.Save(path);
				}
		}

 /// <summary>
 /// Editing Data while updating.This returns element to be modified
 /// </summary>
 /// <param name="dbStore"></param>
 /// <param name="key"></param>
 /// <param name="element"></param>
 /// <param name="Operation"></param>
 /// <param name="error"></param>
 /// <returns></returns>
 public bool EditData(ref DBEngine<int, DBElement<int, string>> dbStore, int key, out DBElement<int, string> element, string Operation, out string error)
 {
     try
     {
         DBElement<int, string> elem = new DBElement<int, string>();
         error = "success"; bool success = true;
         success = dbStore.getValue(key, out element);
         if (success != true)
         {
             error = "Key not found in DB";
             return false;
         }
         elem = element;
         switch (Operation)
         {
             case "EditName":        //Modify Name 
                 {
                     element.name = elem.name;
                     break;
                 }
             case "EditDescription":      //Modify Description 
                 {
                     element.descr = elem.descr;
                     break;
                 }
             case "EditPayload":         //Modify Payload 
                 {
                     element.payload = elem.payload;
                     break;
                 }
             case "EditChildren":        //Modify Children 
                 {
                     element.children = new List<int>();
                     element.children = elem.children;
                     break;
                 }
             case "EditKeyNotValid":         //Key editing is not valid
                 {
                     error = "Editing of Key is not allowed";
                     return false;
                 }
             default:
                 break;
         }
         return true;
     }
     catch (Exception ex)
     {
         throw new CustomException("error at itemeditor editdata", ex);
     }
 }