public bool IsDependent(DependenceGraphNode n1, DependenceGraphNode n2)
{
if (n1 == null || n2 == null || n1 == n2)
{
return(false);
}
Dictionary <DependenceGraphNode, bool> oldNodes = new Dictionary <DependenceGraphNode, bool>();
Queue <DependenceGraphNode> iterateQueue = new Queue <DependenceGraphNode>();
iterateQueue.Enqueue(n1);
oldNodes[n1] = true;
while (iterateQueue.Count > 0)
{
DependenceGraphNode n = iterateQueue.Dequeue();
foreach (DependenceGraphNode nn in n.NextNodes)
{
if (nn == n2)
{
iterateQueue.Clear();
oldNodes.Clear();
return(true);
}
if (!oldNodes.ContainsKey(nn))
{
iterateQueue.Enqueue(nn);
oldNodes[nn] = true;
}
}
}
return(false);
}
public bool IsAccessed(DependenceGraphNode node)
{
if (accessedNodes.ContainsKey(node))
{
return(accessedNodes[node]);
}
return(false);
}
public DependenceGraphNode NewNode(string id)
{
if (nodes.ContainsKey(id))
{
return(nodes[id]);
}
else
{
DependenceGraphNode node = new DependenceGraphNode(id);
nodes[id] = node;
return(node);
}
}
private DependenceGraphNode PopDeepFirstNode()
{
if (iterateStack.Count <= 0)
{
return(null);
}
DependenceGraphNode node = iterateStack.Peek();
while (node.NextNodes.Count > 0)
{
bool existNext = false;
//每次只扩展一个后继，深度优先
for (int i = 0; i < node.NextNodes.Count; i++)
{
DependenceGraphNode n = node.NextNodes[i];
if (!accessedNodes.ContainsKey(n))
{
iterateStack.Push(n);
PrepareAccessNode(n);
existNext = true;
break;
}
else if (!accessedNodes[n])//依赖一个存于深度优先栈内的节点，表明有循环依赖
{
cyclicDependences.Add(new KeyValuePair <string, string>(node.ID, n.ID));
}
}
if (!existNext)
{
break;
}
else
{
node = iterateStack.Peek();
}
}
node = iterateStack.Pop();
return(node);
}
/// <summary>
/// 设定一个结点为已访问结点，已访问结点是已经由迭代过程返回过的结点。
/// </summary>
/// <param name="node"></param>
private void AccessNode(DependenceGraphNode node)
{
accessedNodes[node] = true;
}
/// <summary>
/// 设定一个结点为待访问结点，同时从未访问集合中删除此结点。
/// </summary>
/// <param name="node"></param>
private void PrepareAccessNode(DependenceGraphNode node)
{
accessedNodes[node] = false;
unaccessedNodes.Remove(node);
}