step7
Class postfix

java.lang.Object
  step7.postfix

All Implemented Interfaces:

Visitor

public class postfix
extends Object
implements Visitor

output expr tree in postfix notation.

Field Summary

protected HashMap	_rules maps class to array of Rule.
protected PrintStream	out print action stream.

Constructor Summary

postfix()

Method Summary

protected static String	classname(Object obj) return last component of (inner) classname.
static void	main(String[] args) read an expression from standard input and output it in postorder.
protected PrintStream	out() returns print action stream.
Object	visit(int _action, Object _object) visits an object.
Object	visit(Object object) visits an object.
Object	visit0(Object object) visits an object, ignoring possible descendants.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

out

protected transient PrintStream out

print action stream. Can be replaced to reroute output. BUG: should be a self-flushing PrintWriter.

_rules

protected final HashMap _rules

maps class to array of Rule.

Constructor Detail

postfix

public postfix()

Method Detail

out

protected PrintStream out()

returns print action stream. Defaults to System.out.

visit

public Object visit(Object object)
             throws Exception

visits an object. This is a facade for the class search.

Specified by:

visit in interface Visitor

Parameters:

object - to be visited, not null.

Returns:

result of action.

Throws:

NoRuleException - if no rule can be found.

Exception

See Also:

Rule.visit(jag.Visitor, java.util.HashMap, java.lang.Object, int, java.util.List)

visit0

public Object visit0(Object object)
              throws Exception

visits an object, ignoring possible descendants. This is a facade for the class search with degree zero.

Specified by:

visit0 in interface Visitor

Parameters:

object - to be visited, not null.

Returns:

result of action.

Throws:

NoRuleException - if no rule can be found.

Exception

See Also:

Rule.visit(jag.Visitor, java.util.HashMap, java.lang.Object, int, java.util.List)

visit

public Object visit(int _action,
                    Object _object)
             throws Exception

visits an object.

Specified by:

visit in interface Visitor

Parameters:

_action - index.

_object - to be visited, not null.

Returns:

result of action.

Throws:

NoRuleException - if no rule can be found.

Exception

classname

protected static String classname(Object obj)

return last component of (inner) classname.

main

public static void main(String[] args)
                 throws Exception

read an expression from standard input and output it in postorder.

Throws:

Exception