//----< process children query using queryPredicate >-----------------------------------
public bool processChildrenQuery <Key, Value, Data>(Func <Key, bool> queryPredicate,
out List <Key> keyCollection, Key searchKey, DBEngine <Key, Value> db)
{
keyCollection = new List <Key>();
Value value;
if (db.Keys().Contains(searchKey))
{
db.getValue(searchKey, out value);
DBElement <Key, Data> elem = value as DBElement <Key, Data>;
foreach (Key child in elem.children)
{
if (queryPredicate(child))
{
keyCollection.Add(child);
}
}
}
if (keyCollection.Count() > 0)
{
return(true);
}
return(false);
}
//----< build queryPredicate for timestamp query >---------------------------------------
public Func <Key, bool> queryTimestamp <Key, Value, Data>(DBEngine <Key, Value> db,
DateTime initial, DateTime final = default(DateTime))
{
Func <Key, bool> queryPredicate = (Key key) =>
{
Value value;
db.getValue(key, out value);
DBElement <Key, Data> elem = value as DBElement <Key, Data>;
int init = elem.timeStamp.CompareTo(initial);
if (final == default(DateTime))
{
final = DateTime.Now;
}
int fin = elem.timeStamp.CompareTo(final);
if (init >= 0 && fin <= 0)
{
return(true);
}
return(false);
};
return(queryPredicate);
}
//----< build queryPredicate for metadata query >---------------------------------------
/*
* Query returns true if query(key) condition is satisfied.
* In this example the query is checking to see if the query
* parameter, the captured string, test, is a substring of
* the database element referenced by key.
*/
public Func <Key, bool> queryMetadata <Key, Value, Data>(string queryParam, DBEngine <Key, Value> db)
{
// Func<int, bool> is delegate that binds to
// functions of the form bool query(int key).
Func <Key, bool> queryPredicate = (Key key) =>
{
Value value;
db.getValue(key, out value);
DBElement <Key, Data> elem = value as DBElement <Key, Data>;
if (elem.name.Contains(queryParam))
{
return(true);
}
if (elem.descr.Contains(queryParam))
{
return(true);
}
if (elem.timeStamp.ToString().Contains(queryParam))
{
return(true);
}
foreach (Key child in elem.children)
{
if (child.ToString().Contains(queryParam))
{
return(true);
}
}
return(false);
};
return(queryPredicate);
}
//----< Public Constructor >-----------------------------------------------------
public DBFactory(DBEngine <Key, Value> db)
{
dbStore = new Dictionary <Key, Value>();
foreach (Key key in db.Keys())
{
Value value;
db.getValue(key, out value);
dbStore[key] = value;
}
}
//----< write simple db elements out to Console >------------------
public static void show <Key, Value, Data>(this DBEngine <Key, Value> db)
{
foreach (Key key in db.Keys())
{
Value value;
db.getValue(key, out value);
DBElement <Key, Data> elem = value as DBElement <Key, Data>;
Write("\n\n -- key = {0} --", key);
Write(elem.showElement());
}
}
//----< Convert Enumerable DB to XML file format >---------------------------------
public static XDocument PersistToXML <Key, Value, Data, T>(this DBEngine <Key, Value> dbStore) where Data : IEnumerable <T>
{
XDocument xDocument = new XDocument();
xDocument.Declaration = new XDeclaration("1.0", "utf-8", "yes");
xDocument.Add(new XComment("Persisting DB to XML at " + DateTime.Now.ToString()));
XElement root = new XElement("NoSqlDb");
root.Add(new XElement("KeyType", typeof(Key).ToString()));
root.Add(new XElement("PayloadType", typeof(Data).ToString()));
foreach (Key key in dbStore.Keys())
{
XElement dbEntry = new XElement("DBEntry");
root.Add(dbEntry);
dbEntry.Add(new XElement("Key", key.ToString()));
Value element;
dbStore.getValue(key, out element);
DBElement <Key, Data> dbElement = element as DBElement <Key, Data>;
XElement xmlElement = new XElement("element");
xmlElement.Add(new XElement("name", dbElement.name));
xmlElement.Add(new XElement("descr", dbElement.descr));
xmlElement.Add(new XElement("timestamp", dbElement.timeStamp));
XElement children = new XElement("children");
if (dbElement.children.Count > 0)
{
foreach (Key child in dbElement.children)
{
children.Add(new XElement("key", child.ToString()));
}
}
xmlElement.Add(children);
XElement payload = new XElement("payload");
Data data = dbElement.payload;
foreach (T item in data)
{
payload.Add(new XElement("item", item.ToString()));
}
xmlElement.Add(payload);
dbEntry.Add(xmlElement);
}
xDocument.Add(root);
return(xDocument);
}
//----< Query for value of a given key >------------------------------------------------
public static Value queryValue <Key, Value, Data>(Key key, DBEngine <Key, Value> db)
{
Value value = default(Value);
if (db.Keys().Contains(key))
{
db.getValue(key, out value);
DBElement <Key, Data> elem = value as DBElement <Key, Data>;
return(value);
}
else
{
"Key doesn't exist!".error();
return(value);
}
}
//----< show query results >-------------------------------------------------------------
public DBFactory <Key, Value> queryResults <Key, Value, Data>(bool result,
List <Key> keyCollection, DBEngine <Key, Value> db)
{
DBEngine <Key, Value> newDb = new DBEngine <Key, Value>();
if (result) // query succeeded for at least one key
{
Value value;
foreach (Key key in keyCollection)
{
db.getValue(key, out value);
newDb.insert(key, value);
}
DBFactory <Key, Value> dbFactory = new DBFactory <Key, Value>(newDb);
return(dbFactory);
}
else
{
DBFactory <Key, Value> dbFactory = new DBFactory <Key, Value>(newDb);
return(dbFactory);
}
}
//----< Convert primitive DB to XML format >---------------------------------------
public static XDocument ToXML <Key, Value, Data>(this DBEngine <Key, Value> dbStore)
{
XDocument xDocument = new XDocument();
XElement root = new XElement("NoSqlDb");
foreach (Key key in dbStore.Keys())
{
XElement dbEntry = new XElement("DBEntry");
root.Add(dbEntry);
dbEntry.Add(new XElement("Key", key.ToString()));
Value element;
dbStore.getValue(key, out element);
DBElement <Key, Data> dbElement = element as DBElement <Key, Data>;
XElement xmlElement = new XElement("element");
xmlElement.Add(new XElement("name", dbElement.name));
xmlElement.Add(new XElement("descr", dbElement.descr));
xmlElement.Add(new XElement("timestamp", dbElement.timeStamp));
XElement children = new XElement("children");
if (dbElement.children.Count > 0)
{
foreach (Key child in dbElement.children)
{
children.Add(new XElement("key", child.ToString()));
}
}
xmlElement.Add(children);
XElement payload = new XElement("payload");
payload.Add(new XElement("item", dbElement.payload.ToString()));
xmlElement.Add(payload);
dbEntry.Add(xmlElement);
}
xDocument.Add(root);
return(xDocument);
}
static void Main(string[] args)
{
"Testing DBEngine Package".title('=');
WriteLine();
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();
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.payload = new List <string> {
"one", "two", "three"
};
Write(newelem1.showElement <string, List <string> >());
WriteLine();
Write("\n --- Test DBElement<string,List<string>> ---");
DBElement <string, List <string> > newerelem1 = new DBElement <string, List <string> >();
newerelem1.name = "newerelem1";
newerelem1.descr = "better formatting";
newerelem1.payload = new List <string> {
"alpha", "beta", "gamma"
};
newerelem1.payload.Add("delta");
newerelem1.payload.Add("epsilon");
Write(newerelem1.showElement <string, List <string>, string>());
WriteLine();
DBElement <string, List <string> > newerelem2 = new DBElement <string, List <string> >();
newerelem2.name = "newerelem2";
newerelem2.descr = "better formatting";
newerelem1.children.AddRange(new[] { "first", "second" });
newerelem2.payload = new List <string> {
"a", "b", "c"
};
newerelem2.payload.Add("d");
newerelem2.payload.Add("e");
Write(newerelem2.showElement <string, List <string>, string>());
WriteLine();
Write("\n --- Test DBEngine<string,DBElement<string,List<string>>> ---");
int seed = 0;
string skey = seed.ToString();
Func <string> skeyGen = () => {
++seed;
skey = "string" + seed.ToString();
skey = skey.GetHashCode().ToString();
return(skey);
};
DBEngine <string, DBElement <string, List <string> > > newdb =
new DBEngine <string, DBElement <string, List <string> > >();
newdb.insert(skeyGen(), newerelem1);
newdb.insert(skeyGen(), newerelem2);
newdb.show <string, DBElement <string, List <string> >, List <string>, string>();
WriteLine();
"testing edits".title();
db.show <int, DBElement <int, string>, string>();
DBElement <int, string> editElement = new DBElement <int, string>();
db.getValue(1, out editElement);
editElement.showElement <int, string>();
editElement.name = "editedName";
editElement.descr = "editedDescription";
db.show <int, DBElement <int, string>, string>();
Write("\n\n");
}
