public virtual object DeleteKeyForLeafNode(IKeyAndValue keyAndValue)
{
var position = GetPositionOfKey(keyAndValue.GetKey());
if (position < 0)
return null;
var realPosition = position - 1;
var value = Values[realPosition];
LeftShiftFrom(realPosition, false);
NbKeys--;
BTreeValidator.ValidateNode(this);
return value;
}
public virtual object DeleteKeyForLeafNode(IKeyAndValue keyAndValue)
{
var position = GetPositionOfKey(keyAndValue.GetKey());
if (position < 0)
{
return(null);
}
var realPosition = position - 1;
var value = Values[realPosition];
LeftShiftFrom(realPosition, false);
NbKeys--;
BTreeValidator.ValidateNode(this);
return(value);
}
public override object DeleteKeyForLeafNode(IKeyAndValue keyAndValue)
{
var objectHasBeenFound = false;
var positionOfKey = GetPositionOfKey(keyAndValue.GetKey());
if (positionOfKey < 0)
{
return(null);
}
var realPosition = positionOfKey - 1;
// In Multiple Values per key, the value is a list
var value = (IList)Values[realPosition];
// Here we must search for the right object. The list can contains more than 1 object
var size = value.Count;
for (var i = 0; i < size && !objectHasBeenFound; i++)
{
if (!value[i].Equals(keyAndValue.GetValue()))
{
continue;
}
value.Remove(i);
objectHasBeenFound = true;
}
if (!objectHasBeenFound)
{
return(null);
}
// If after removal, the list is empty, then remove the key from the node
if (value.Count == 0)
{
// If we get there
LeftShiftFrom(realPosition, false);
NbKeys--;
}
BTreeValidator.ValidateNode(this);
return(keyAndValue.GetValue());
}
private static void CheckValuesOfChild(IKeyAndValue key, IBTreeNode node)
{
if (!OdbConfiguration.IsBTreeValidationEnabled())
{
return;
}
if (node == null)
{
return;
}
for (int i = 0; i < node.GetNbKeys(); i++)
{
if (node.GetKeyAndValueAt(i).GetKey().CompareTo(key.GetKey()) >= 0)
{
throw new BTreeNodeValidationException("Left child with values bigger than pivot " + key + " : " +
node);
}
}
}
public override object DeleteKeyForLeafNode(IKeyAndValue keyAndValue)
{
var objectHasBeenFound = false;
var positionOfKey = GetPositionOfKey(keyAndValue.GetKey());
if (positionOfKey < 0)
return null;
var realPosition = positionOfKey - 1;
// In Multiple Values per key, the value is a list
var value = (IList) Values[realPosition];
// Here we must search for the right object. The list can contains more than 1 object
var size = value.Count;
for (var i = 0; i < size && !objectHasBeenFound; i++)
{
if (!value[i].Equals(keyAndValue.GetValue()))
continue;
value.Remove(i);
objectHasBeenFound = true;
}
if (!objectHasBeenFound)
{
return null;
}
// If after removal, the list is empty, then remove the key from the node
if (value.Count == 0)
{
// If we get there
LeftShiftFrom(realPosition, false);
NbKeys--;
}
BTreeValidator.ValidateNode(this);
return keyAndValue.GetValue();
}
/// <summary>
/// Returns the value of the deleted key
/// </summary>
/// <param name="node"> </param>
/// <param name="keyAndValue"> </param>
/// <returns> </returns>
/// <exception cref="System.Exception">System.Exception</exception>
private object InternalDelete(IBTreeNode node, IKeyAndValue keyAndValue)
{
var positionOfKey = node.GetPositionOfKey(keyAndValue.GetKey());
var keyIsHere = positionOfKey > 0;
if (node.IsLeaf())
{
if (keyIsHere)
{
var deletedValue = node.DeleteKeyForLeafNode(keyAndValue);
GetPersister().SaveNode(node);
return(deletedValue);
}
// key does not exist
return(null);
}
int realPosition;
if (!keyIsHere)
{
// descend
realPosition = -positionOfKey - 1;
var childTreeNode = node.GetChildAt(realPosition, true);
if (childTreeNode.GetNbKeys() == _degree - 1)
{
node = PrepareForDelete(node, childTreeNode, realPosition);
return(InternalDelete(node, keyAndValue));
}
return(InternalDelete(childTreeNode, keyAndValue));
}
// Here,the node is not a leaf and contains the key
realPosition = positionOfKey - 1;
var currentKey = node.GetKeyAt(realPosition);
var currentValue = node.GetValueAsObjectAt(realPosition);
// case 2a
var leftNode = node.GetChildAt(realPosition, true);
if (leftNode.GetNbKeys() >= _degree)
{
var prevKeyAndValue = GetBiggest(leftNode, true);
node.SetKeyAndValueAt(prevKeyAndValue, realPosition);
BTreeValidator.ValidateNode(node, node == _root);
GetPersister().SaveNode(node);
return(currentValue);
}
// case 2b
var rightNode = node.GetChildAt(realPosition + 1, true);
if (rightNode.GetNbKeys() >= _degree)
{
var nextKeyAndValue = GetSmallest(rightNode, true);
node.SetKeyAndValueAt(nextKeyAndValue, realPosition);
BTreeValidator.ValidateNode(node, node == _root);
GetPersister().SaveNode(node);
return(currentValue);
}
// case 2c
// Here, both left and right part have degree-1 keys
// remove the element to be deleted from node (shifting left all
// right
// elements, link to right link does not exist anymore)
// insert the key to be deleted in left child and merge the 2 nodes.
// rightNode should be deleted
// if node is root, then leftNode becomes the new root and node
// should be deleted
//
node.DeleteKeyAndValueAt(realPosition, true);
leftNode.InsertKeyAndValue(currentKey, currentValue);
leftNode.MergeWith(rightNode);
// If node is the root and is empty
if (!node.HasParent() && node.GetNbKeys() == 0)
{
_persister.DeleteNode(node);
_root = leftNode;
leftNode.SetParent(null);
// The height has been decreased. No need to save btree here.
// The calling delete method will save it.
_height--;
}
else
{
node.SetChildAt(leftNode, realPosition);
// Node must only be validated if it is not the root
BTreeValidator.ValidateNode(node, node == _root);
}
_persister.DeleteNode(rightNode);
BTreeValidator.ValidateNode(leftNode, leftNode == _root);
GetPersister().SaveNode(node);
GetPersister().SaveNode(leftNode);
return(InternalDelete(leftNode, keyAndValue));
}
public virtual void SetKeyAndValueAt(IKeyAndValue keyAndValue, int index, bool shiftIfAlreadyExist, bool incrementNbKeys)
{
SetKeyAndValueAt(keyAndValue.GetKey(), keyAndValue.GetValue(), index, shiftIfAlreadyExist, incrementNbKeys);
}
public virtual void SetKeyAndValueAt(IKeyAndValue keyAndValue, int index)
{
SetKeyAndValueAt(keyAndValue.GetKey(), keyAndValue.GetValue(), index);
}
private static void CheckValuesOfChild(IKeyAndValue key, IBTreeNode node)
{
if (!OdbConfiguration.IsBTreeValidationEnabled())
return;
if (node == null)
return;
for (var i = 0; i < node.GetNbKeys(); i++)
{
if (node.GetKeyAndValueAt(i).GetKey().CompareTo(key.GetKey()) >= 0)
throw new BTreeNodeValidationException("Left child with values bigger than pivot " + key + " : " +
node);
}
}
public virtual void SetKeyAndValueAt(IKeyAndValue keyAndValue, int index, bool shiftIfAlreadyExist, bool incrementNbKeys)
{
SetKeyAndValueAt(keyAndValue.GetKey(), keyAndValue.GetValue(), index, shiftIfAlreadyExist, incrementNbKeys);
}
public virtual void SetKeyAndValueAt(IKeyAndValue keyAndValue, int index)
{
SetKeyAndValueAt(keyAndValue.GetKey(), keyAndValue.GetValue(), index);
}