Class QueryNodeProcessor

This is a default implementation for the IQueryNodeProcessor interface, it's an abstract class, so it should be extended by classes that want to process a IQueryNode tree.

This class process IQueryNodes from left to right in the tree. While it's walking down the tree, for every node, PreProcessNode(IQueryNode) is invoked. After a node's children are processed, PostProcessNode(IQueryNode) is invoked for that node. SetChildrenOrder(IList<IQueryNode>) is invoked before PostProcessNode(IQueryNode) only if the node has at least one child, in SetChildrenOrder(IList<IQueryNode>) the implementor might redefine the children order or remove any children from the children list.

Here is an example about how it process the nodes:

     a
    / \
   b   e
  / \
 c   d

Here is the order the methods would be invoked for the tree described above:

    PreProcessNode( a );
    PreProcessNode( b );
    PreProcessNode( c );
    PostProcessNode( c );
    PreProcessNode( d );
    PostProcessNode( d );
    SetChildrenOrder( bChildrenList );
    PostProcessNode( b );
    PreProcessNode( e );
    PostProcessNode( e );
    SetChildrenOrder( aChildrenList );
    PostProcessNode( a )