polyglot.visit
Class FinalLocalExtractor

java.lang.Object
  extended by polyglot.visit.NodeVisitor
      extended by polyglot.visit.FinalLocalExtractor
All Implemented Interfaces:
java.lang.Cloneable, Copy

public class FinalLocalExtractor
extends NodeVisitor

This visitor converts non-final local variables into final local variables. This improves the precision of some analyses.

Author:
nystrom

Nested Class Summary
protected static class FinalLocalExtractor.LocalDeclFixer
           
 
Constructor Summary
FinalLocalExtractor(Job job, TypeSystem ts, NodeFactory nf)
           
 
Method Summary
 NodeVisitor begin()
          The begin method is called before the entire tree is visited.
 NodeVisitor enter(Node parent, Node n)
          Begin normal traversal of a subtree rooted at n.
 void finish()
          The finish method is called after the entire tree has been visited.
 Node leave(Node old, Node n, NodeVisitor v)
          This method is called after all of the children of n have been visited.
 
Methods inherited from class polyglot.visit.NodeVisitor
copy, enter, finish, leave, override, override, toString, visitEdge, visitEdgeNoOverride
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

FinalLocalExtractor

public FinalLocalExtractor(Job job,
                           TypeSystem ts,
                           NodeFactory nf)
Parameters:
job -
ts -
nf -
Method Detail

begin

public NodeVisitor begin()
Description copied from class: NodeVisitor
The begin method is called before the entire tree is visited. This method allows the visitor to perform any initialization that cannot be done when the visitor is created. If null is returned, the ast is not traversed.

Overrides:
begin in class NodeVisitor
Returns:
the NodeVisitor to traverse the ast with. If null is returned, the ast is not traversed.

finish

public void finish()
Description copied from class: NodeVisitor
The finish method is called after the entire tree has been visited. This method allows the visitor to perform any last minute cleanup, including flushing buffers and I/O connections.

Overrides:
finish in class NodeVisitor

enter

public NodeVisitor enter(Node parent,
                         Node n)
Description copied from class: NodeVisitor
Begin normal traversal of a subtree rooted at n. This gives the visitor the option of changing internal state or returning a new visitor which will be used to visit the children of n.

The default implementation of this method is to call enter(n), as most subclasses do not need to know the parent of the node n.

Overrides:
enter in class NodeVisitor
Parameters:
parent - The parent of n, null if n has no parent.
n - The root of the subtree to be traversed.
Returns:
The NodeVisitor which should be used to visit the children of n.

leave

public Node leave(Node old,
                  Node n,
                  NodeVisitor v)
Description copied from class: NodeVisitor
This method is called after all of the children of n have been visited. In this case, these children were visited by the visitor v. This is the last chance for the visitor to modify the tree rooted at n. This method will be called exactly the same number of times as entry is called. That is, for each node that is not overriden, enter and leave are each called exactly once.

Note that if old == n then the vistior should make a copy of n before modifying it. It should then return the modified copy.

This method is typically called by the method leave(parent, old, n v). If a subclass overrides the method leave(parent, old, n v) then this method may not be called.

Overrides:
leave in class NodeVisitor
Parameters:
old - The original state of root of the current subtree.
n - The current state of the root of the current subtree.
v - The NodeVisitor object used to visit the children.
Returns:
The final result of the traversal of the tree rooted at n.