FilterVisitor (Apache LDAP API 2.1.1 API Documentation)

All Known Implementing Classes:

BranchNormalizedVisitor
```
public interface FilterVisitor
```
Filter expression tree node visitor interface. Note that this is a variation of the extrinsic visitor variation. It has the following advantages over the standard visitor pattern:
- Visitor takes responsibility that a visitor can visit a node
- Each visitor knows which types of concrete classes it can visit
- New visitors can be created without changing the node class
- New node classes can be added without having to change old visitors
- Visitation order can be controled in every respect:
- - Visitation rejection with canVisit() and/or getOrder()
  - Recursive visitation ordering with isPrefix()
  - Child visitation ordering with getOrder()
Author:

Apache Directory Project

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`boolean`	`canVisit(ExprNode node)`	Checks to see if a node can be visited.
`List<ExprNode>`	`getOrder(BranchNode node, List<ExprNode> children)`	Get the array of children to visit sequentially to determine the order of child visitations.
`boolean`	`isPrefix()`	Determines whether the visitation order is prefix or postfix.
`Object`	`visit(ExprNode node)`	Visits a filter expression AST using a specific visitation order.

- Method Detail
  - visit
```
Object visit(ExprNode node)
```
    Visits a filter expression AST using a specific visitation order.
    
    Parameters:
    
    node - the node to visit
    
    Returns:
    
    node the resulting modified node
  - canVisit
```
boolean canVisit(ExprNode node)
```
    Checks to see if a node can be visited.
    
    Parameters:
    
    node - the node to be visited
    
    Returns:
    
    whether or node the node should be visited
  - isPrefix
```
boolean isPrefix()
```
    Determines whether the visitation order is prefix or postfix.
    
    Returns:
    
    true if the visitation is in prefix order, false otherwise.
  - getOrder
```
List<ExprNode> getOrder(BranchNode node,
                        List<ExprNode> children)
```
    Get the array of children to visit sequentially to determine the order of child visitations. Some children may not be returned at all if canVisit() returns false on them.
    
    Parameters:
    
    node - the parent branch node
    
    children - the child node array
    
    Returns:
    
    the new reordered array of children