/// <summary>
/// On a left activation
/// (when there is a new match for all the earlier conditions), we build and store a new token, perform
/// a join for the token, store the join results in the token structure, and pass the token onto any
/// successor nodes if there were no join results.
/// </summary>
/// <param name="node">The node.</param>
/// <param name="t">The t.</param>
/// <param name="w">The w.</param>
private void negative_node_left_activation(NegativeNode node, Token t, WME w)
{
// *** Right Unlinking ***
if (node.Items.Count == 0)
relink_to_alpha_memory(node);
// *** End Right Unlinking ***
Token new_token = make_token(node, t, w);
node.Items.AddToFront(new_token);
foreach (ItemInAlphaMemory item in node.AlphaMemory.Items)
{
if (perform_join_tests(node.Tests, new_token, item.WME))
{
NegativeJoinResult jr = new NegativeJoinResult();
jr.Owner = new_token;
jr.WME = w;
new_token.JoinResults.AddToFront(jr);
w.NegativeJoinResults.AddToFront(jr);
}
}
if (new_token.JoinResults.Count == 0)
{
foreach (ReteNode child in node.Children)
{
left_activation(child, new_token, null);
}
}
}
/// <summary>
/// Builtin_node_left_activations the specified memory.
/// </summary>
/// <param name="memory">The memory.</param>
/// <param name="tok">The tok.</param>
/// <param name="w">The w.</param>
private void builtin_node_left_activation(BuiltinMemory memory, Token tok, WME w)
{
Token new_token = make_token(memory, tok, w);
memory.Items.AddToFront(new_token);
if (memory.PerformEvaluation(new_token))
{
foreach (ReteNode child in memory.Children)
{
left_activation(child, new_token, w);
}
}
}
/// <summary>
/// Adds the fact.
/// </summary>
/// <param name="fact">The fact to the initial facts list.</param>
public void AddFact(WME fact)
{
_initialFacts.Add(fact);
}
/// <summary>
/// Now, to remove a WME, we just remove it from each alpha memory containing it (these
/// alpha memories are now conveniently on a list) and call the helper routine delete-token-and-
/// descendents to delete all the tokens involving it (all the necessary "root" tokens involving it are
/// also conveniently on a list):
/// </summary>
/// <param name="wme">The wme.</param>
public void RemoveWME(WME wme)
{
int pos = _working_memory.IndexOf(wme);
if (pos < 0)
return;
WME w = _working_memory[pos];
foreach (ItemInAlphaMemory item in w.AlphaMemoryItems)
{
item.AlphaMemory.Items.Remove(item);
// *** Left Unlinking ***
if (item.AlphaMemory.Items.Count == 0)
{
foreach (ReteNode node in item.AlphaMemory.Successors)
{
if (node.Type == ReteNodeType.Join)
{
node.Parent.Children.Remove(node);
((JoinNode) node).IsLeftUnlinked = true;
}
}
}
// *** End Left Unlinking ***
}
while (w.Tokens.Count > 0)
{
delete_token_and_descendents(w.Tokens[0]);
}
foreach (NegativeJoinResult jr in w.NegativeJoinResults)
{
jr.Owner.JoinResults.Remove(jr);
if (jr.Owner.JoinResults.Count == 0)
{
foreach (ReteNode child in jr.Owner.Node.Children)
{
left_activation(child, jr.Owner, null);
}
}
}
_working_memory.Remove(w);
}
/// <summary>
/// Whenever a new WME is filtered through the alpha network and reaches an alpha memory, we
/// simply add it to the list of other WMEs in that memory, and inform each of the attached join
/// nodes:
/// </summary>
/// <param name="node">The node.</param>
/// <param name="w">The w.</param>
private void alpha_memory_activation(AlphaMemory node, WME w)
{
ItemInAlphaMemory new_item = new ItemInAlphaMemory();
new_item.WME = w;
new_item.AlphaMemory = node;
node.Items.Add(new_item);
w.AlphaMemoryItems.AddToFront(new_item);
// *** Neo Integration ***
if (w.Value.TermType == TermType.EntityObject)
{
IFactProvider eo = (IFactProvider) w.Value.Value;
if (eo.MyFactsHaveBeenAsserted == false)
{
foreach (WME wme in eo.GenerateFactsForRelatedObject(w.Attribute.Value.ToString(), w.Identifier.Value as IFactProvider))
{
AddWME(wme);
}
}
}
if (w.Value.TermType == TermType.ObjectRelation)
{
ObjectRelationBase orb = (ObjectRelationBase) w.Value.Value;
foreach (RulesEnabledEntityObject eo in orb)
{
if (eo.MyFactsHaveBeenAsserted == false)
{
foreach (WME wme in eo.GenerateFactsForObjectInCollection(w.Attribute.Value.ToString(), orb))
{
AddWME(wme);
}
}
}
}
// *** End Neo Integration ***
//The unlinking process changes the underlying collection so we need a new collection...
BigList<ReteNode> successors = node.Successors.Clone();
foreach (ReteNode successor in successors)
{
right_activation(successor, w);
}
}
/// <summary>
/// P_node_activations the specified node.
/// </summary>
/// <param name="node">The node.</param>
/// <param name="tok">The tok.</param>
/// <param name="w">The w.</param>
private void p_node_activation(ProductionNode node, Token tok, WME w)
{
Token new_token = make_token(node, tok, w);
node.Items.AddToFront(new_token);
int lhsCnt = node.Production.Lhs.Count - 1;
foreach (RightHandSideCondition rhsCondition in node.Production.Rhs)
{
WME newfact = new WME();
for (int f = 0; f < 3; f++)
{
Term term = rhsCondition.Fields[f];
if (term.TermType == TermType.Variable)
{
for (int i = lhsCnt; i >= 0; i--)
{
Condition lhsCondition = node.Production.Lhs[i];
if (lhsCondition.ConditionType == ConditionType.Positive)
{
int pos = lhsCondition.Contains(term);
if (pos >= 0)
{
Token tok2 = new_token.GetTokenUp(lhsCnt - i);
newfact.Fields[f] = tok2.WME[pos];
i = -1;
}
}
}
}
else
{
newfact.Fields[f] = term;
}
}
Activation newact = new Activation(newfact, rhsCondition.ConditionType);
if (node.Production.InferredFacts.Contains(newact) == false)
{
node.Production.InferredFacts.Add(newact);
}
}
}
/// <summary>
/// Controls the activation flow based on node type
/// </summary>
/// <param name="child">The child.</param>
/// <param name="w">The w.</param>
private void right_activation(ReteNode child, WME w)
{
switch (child.Type)
{
case ReteNodeType.Join:
join_node_right_activation(child as JoinNode, w);
break;
case ReteNodeType.Negative:
negative_node_right_activation(child as NegativeNode, w);
break;
default:
throw new ApplicationException("???");
}
}
/// <summary>
/// Initializes a new instance of the <see cref="DummyTopToken"/> class.
/// </summary>
public DummyTopToken()
{
_wme = new WME("null");
}
/// <summary>
/// Initializes a new instance of the <see cref="DummyTopToken"/> class.
/// </summary>
public DummyTopToken()
{
_wme = new WME("null");
}
/// <summary>
/// Binds the RHS.
/// </summary>
private void BindRHS(List<Activation> items)
{
int lhsCnt = _lhs.Count - 1;
foreach (Activation act in items)
{
foreach (RightHandSideCondition condition in _rhs)
{
WME newfact = new WME();
for (int f = 0; f < 3; f++)
{
Term term = condition.Fields[f];
if (term.TermType == TermType.Variable)
{
for (int i = lhsCnt; i >= 0; i--)
{
Condition rh = _lhs[i];
if (rh.ConditionType == ConditionType.Positive)
{
int pos = rh.Contains(term);
if (pos >= 0)
{
newfact.Fields[f] = act.InferredFact[pos];
i = -1;
}
}
}
}
else
{
newfact.Fields[f] = term;
}
}
Activation newact = new Activation(newfact, condition.ConditionType);
if (_inferredFacts.Contains(newact) == false)
{
_inferredFacts.Add(newact);
}
}
}
}
/// <summary>
/// Initializes a new instance of the <see cref="Activation"/> class.
/// </summary>
/// <param name="prod">The prod.</param>
/// <param name="tok">The tok.</param>
public Activation(WME prod, ConditionType tok)
{
_fact = prod;
_conditionType = tok;
}
/// <summary>
/// Sets the specified fact.
/// </summary>
/// <param name="fact">The fact.</param>
private void Set(WME fact)
{
IFactProvider eo = fact.Identifier.Value as IFactProvider;
if (eo == null)
{
return;
}
try
{
eo.SetProperty(fact.Attribute.Value.ToString(), fact.Value.Value);
_actionsTaken.Add(fact);
}
catch
{
_actionsSkipped.Add(fact);
}
}
/// <summary>
/// Retracts the specified fact.
/// </summary>
/// <param name="fact">The fact.</param>
private void Retract(WME fact)
{
_inferredFacts.Remove(fact);
_rete.RemoveWME(fact);
}
/// <summary>
/// Asserts the specified fact.
/// </summary>
/// <param name="fact">The fact.</param>
private void Assert(WME fact)
{
_inferredFacts.Add(fact);
_rete.AddWME(fact);
}
/// <summary>
/// On a right activation of a negative node (when a WME is added to its alpha memory),
/// we look for any tokens in its memory consistent with the WME; for each such token, we add
/// this WME to its local result memory. Also, if the number of results changes from zero to
/// one - indicating that the negated condition was previously true but is now false - then we
/// call the delete-descendents-of-token helper function to delete any tokens lower in the network
/// that depend on this token.
/// </summary>
/// <param name="node">The node.</param>
/// <param name="w">The w.</param>
private void negative_node_right_activation(NegativeNode node, WME w)
{
foreach (Token t in node.Items)
{
if (perform_join_tests(node.Tests, t, w))
{
if (t.JoinResults.Count == 0)
{
delete_descendents_of_token(t);
}
NegativeJoinResult jr = new NegativeJoinResult();
jr.Owner = t;
jr.WME = w;
t.JoinResults.AddToFront(jr);
w.NegativeJoinResults.AddToFront(jr);
}
}
}
/// <summary>
/// Upon a right activation (when a new WME w is added to the alpha memory), we look
/// through the beta memory and find any token(s) t for which all these t-versus-w tests succeed.
/// Any successful (t;w) combinations are passed on to the join node's children.
/// </summary>
/// <param name="node">The node.</param>
/// <param name="w">The w.</param>
private void join_node_right_activation(JoinNode node, WME w)
{
// *** Left Unlinking ***
if (node.IsLeftUnlinked)
{
relink_to_beta_memory(node);
if (((BetaMemory) node.Parent).Items.Count == 0)
{
node.AlphaMemory.Successors.Remove(node);
node.IsRightUnlinked = true;
}
}
// *** End Left Unlinking ***
foreach (Token t in ((BetaMemory) node.Parent).Items)
{
if (perform_join_tests(node.Tests, t, w))
{
foreach (ReteNode child in node.Children)
{
left_activation(child, t, w);
}
}
}
}
/// <summary>
/// Performs the specified tests.
/// </summary>
/// <param name="tests">The tests.</param>
/// <param name="t">The t.</param>
/// <param name="w">The w.</param>
/// <returns></returns>
private bool perform_join_tests(IEnumerable<TestAtJoinNode> tests, Token t, WME w)
{
foreach (TestAtJoinNode this_test in tests)
{
Term arg1 = w[this_test.FieldOfArg1];
WME wme2 = t[this_test.NumberOfLevelsUp];
Term arg2 = wme2[this_test.FieldOfArg2];
if (this_test.Evaluator.Evaluate(arg1, arg2) == false)
return false;
}
return true;
}
/// <summary>
/// Left_activations the specified new_node.
/// </summary>
/// <param name="new_node">The new_node.</param>
/// <param name="tok">The tok.</param>
/// <param name="w">The w.</param>
private void left_activation(ReteNode new_node, Token tok, WME w)
{
switch (new_node.Type)
{
case ReteNodeType.BetaMemory:
beta_memory_left_activation(new_node as BetaMemory, tok, w);
break;
case ReteNodeType.Negative:
negative_node_left_activation(new_node as NegativeNode, tok, w);
break;
case ReteNodeType.Builtin:
builtin_node_left_activation(new_node as BuiltinMemory, tok, w);
break;
case ReteNodeType.NCCPartner:
ncc_partner_node_left_activation(new_node as NCCPartnerNode, tok, w);
break;
case ReteNodeType.NCC:
ncc_node_left_activation(new_node as NCCNode, tok, w);
break;
case ReteNodeType.Join:
join_node_left_activation(new_node as JoinNode, tok);
break;
case ReteNodeType.Production:
p_node_activation(new_node as ProductionNode, tok, w);
break;
case ReteNodeType.Mutex:
mutex_node_activation(new_node as MutexNode, tok, w);
break;
case ReteNodeType.Aggregator:
aggregator_node_activation(new_node as AggregatorNode, tok, w);
break;
default:
throw new ApplicationException("Unknown left_activation type: " + new_node.GetType().Name);
}
}
/// <summary>
/// Adds the WME.
/// </summary>
/// <param name="w">The WME.</param>
public void AddWME(WME w)
{
int v1 = w.Fields[0].GetHashCode();
int v2 = w.Fields[1].GetHashCode();
int v3 = w.Fields[2].GetHashCode();
_working_memory.Add(w);
AlphaMemory alpha_mem;
alpha_mem = lookup_in_hash_table(0, 0, 0);
if (alpha_mem != null)
alpha_memory_activation(alpha_mem, w);
alpha_mem = lookup_in_hash_table(0, 0, v3);
if (alpha_mem != null)
alpha_memory_activation(alpha_mem, w);
alpha_mem = lookup_in_hash_table(0, v2, 0);
if (alpha_mem != null)
alpha_memory_activation(alpha_mem, w);
alpha_mem = lookup_in_hash_table(0, v2, v3);
if (alpha_mem != null)
alpha_memory_activation(alpha_mem, w);
alpha_mem = lookup_in_hash_table(v1, 0, 0);
if (alpha_mem != null)
alpha_memory_activation(alpha_mem, w);
alpha_mem = lookup_in_hash_table(v1, 0, v3);
if (alpha_mem != null)
alpha_memory_activation(alpha_mem, w);
alpha_mem = lookup_in_hash_table(v1, v2, 0);
if (alpha_mem != null)
alpha_memory_activation(alpha_mem, w);
alpha_mem = lookup_in_hash_table(v1, v2, v3);
if (alpha_mem != null)
alpha_memory_activation(alpha_mem, w);
}
/// <summary>
/// Similarly, whenever a new token tok = ht;wi is added to a beta memory, we add tok to
/// t.children and to w.tokens. We also fill in the new node field on the token. To simplify our
/// pseudocode, it is convenient to define a "helper" function make-token which builds a new token
/// and initializes its various fields as necessary for tree-based removal. Although we write this as
/// a separate function, it would normally be coded "inline" for efficiency.
/// </summary>
/// <param name="node">The node.</param>
/// <param name="parent">The parent.</param>
/// <param name="w">The w.</param>
/// <returns></returns>
private Token make_token(ReteNode node, Token parent, WME w)
{
Token tok = new Token();
tok.Parent = parent;
tok.WME = w;
tok.Node = node;
parent.Children.AddToFront(tok);
if (w != null)
{
w.Tokens.AddToFront(tok);
}
return tok;
}
/// <summary>
/// Modifies an existing WME.
/// </summary>
/// <param name="oldWME">The old WME.</param>
/// <param name="newWME">The new WME.</param>
public virtual void ModifyWME(WME oldWME, WME newWME)
{
RemoveWME(oldWME);
AddWME(newWME);
}
/// <summary>
/// Mutex_node_activations the specified node.
/// </summary>
/// <param name="node">The node.</param>
/// <param name="tok">The tok.</param>
/// <param name="w">The w.</param>
private void mutex_node_activation(MutexNode node, Token tok, WME w)
{
Token new_token = make_token(node, tok, w);
node.Items.Add(new_token);
}
private void aggregator_node_activation(AggregatorNode node, Token tok, WME w)
{
Token new_token = make_token(node, tok, w);
node.Items.AddToFront(new_token);
}
/// <summary>
/// Ncc_node_left_activations the specified node.
/// </summary>
/// <remarks>
/// Our ncc-node-left-activation procedure is similar to the negative-node-left-activation procedure
/// (page 42). In both cases, we need to find the join results for a new token. For negative
/// nodes, we compute these join results by scanning the WMEs in an alpha memory and performing
/// the join tests on them. For NCC nodes, the join results have already been computed by the
/// subnetwork, so we simply look at the new-result-buffer in the NCC partner node to find them.
/// </remarks>
/// <param name="node">The node.</param>
/// <param name="t">The t.</param>
/// <param name="w">The w.</param>
private void ncc_node_left_activation(NCCNode node, Token t, WME w)
{
Token new_token = make_token(node, t, w);
node.Items.AddToFront(new_token);
foreach (Token result in node.Partner.NewResultBuffer)
{
node.Partner.NewResultBuffer.Remove(result);
new_token.NCCResults.AddToFront(result);
result.Owner = new_token;
}
if (new_token.NCCResults.Count == 0)
{
foreach (ReteNode child in node.Children)
{
left_activation(child, new_token, null);
}
}
}
/// <summary>
/// Whenever a beta memory is informed of a new match (consisting of an existing token and some
/// WME), we build a token, add it to the list in the beta memory, and inform each of the beta
/// memory's children:
/// </summary>
/// <param name="node">The node.</param>
/// <param name="t">The token.</param>
/// <param name="w">The wme.</param>
private void beta_memory_left_activation(BetaMemory node, Token t, WME w)
{
Token new_token = make_token(node, t, w);
node.Items.Add(new_token);
//The unlinking process changes the underlying collection so we need a new collection...
BigList<ReteNode> children = node.Children.Clone();
foreach (ReteNode child in children)
{
left_activation(child, new_token, null);
}
}
/// <summary>
/// Ncc_partner_node_left_activations the specified partner.
/// </summary>
/// <remarks>
/// To handle an NCC partner node (left) activation, we take the new match from the subnetwork
/// and build a "result" token to store it. (The pseudocode for this is shown in Figure 2.8.) Next we
/// try to find the appropriate owner token in the NCC node's memory. (There might be one there,
/// if this is a new subconditions match for an old preceding-conditions match, or there might not
/// be one there, if this is an initial subconditions match for a new preceding-conditions match.)
/// If we find an appropriate owner token, then we add the new result token to its local memory;
/// if the number of results in the local memory changes from zero to one | indicating that the
/// NCC was previously true but is now false | then we call the delete-descendents-of-token helper
/// function to delete any tokens lower in the network that depend on this owner token. (This is
/// similar to the negative-node-right-activation procedure on page 43.) On the other hand, if there
/// isn't an appropriate owner token already in the NCC node's memory, then this new result token
/// is placed in the new-result-buffer. (The NCC node will soon be activated and collect any new
/// results from the buffer.)
/// </remarks>
/// <param name="partner">The partner.</param>
/// <param name="t">The t.</param>
/// <param name="w">The w.</param>
private void ncc_partner_node_left_activation(NCCPartnerNode partner, Token t, WME w)
{
NCCNode nccNode = partner.NCCNode;
Token new_result = make_token(partner, t, w);
Token owners_t = t;
WME owners_w = w;
for (int i = 0; i < partner.NumberOfConjuncts; i++)
{
owners_w = owners_t.WME;
owners_t = owners_t.Parent;
}
foreach (Token owner in nccNode.Items)
{
if (owner.Parent == owners_t && owner.WME == owners_w)
{
owner.NCCResults.Add(new_result);
new_result.Owner = owner;
delete_descendents_of_token(owner);
}
else
{
partner.NewResultBuffer.AddToFront(new_result);
}
}
}
/// <summary>
/// Check_constant_testses the specified w.
/// </summary>
/// <param name="w">The w.</param>
/// <param name="c">The c.</param>
/// <returns></returns>
private bool check_constant_tests(WME w, Condition c)
{
foreach (Term o in c.Fields)
{
if ((o is Variable) == false)
{
if (w.Contains(o) == false)
return false;
}
}
return true;
}
/// <summary>
/// Initializes a new instance of the <see cref="Activation"/> class.
/// </summary>
/// <param name="prod">The prod.</param>
/// <param name="tok">The tok.</param>
public Activation(WME prod, ConditionType tok)
{
_fact = prod;
_conditionType = tok;
}
