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Viewing changes to src/org/hibernate/hql/ast/util/ASTIterator.java

  • Committer: Bazaar Package Importer
  • Author(s): Torsten Werner
  • Date: 2007-10-14 14:43:34 UTC
  • Revision ID: james.westby@ubuntu.com-20071014144334-eamc8i0q10gs1aro
Tags: upstream-3.2.5
Import upstream version 3.2.5

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src/org/hibernate/hql/ast/util/ASTIterator.java
 
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// $Id: ASTIterator.java 7460 2005-07-12 20:27:29Z steveebersole $
 
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package org.hibernate.hql.ast.util;
 
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import java.util.Iterator;
 
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import java.util.LinkedList;
 
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import antlr.collections.AST;
 
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/**
 
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 * Depth first iteration of an ANTLR AST.
 
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 *
 
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 * @author josh Sep 25, 2004 7:44:39 AM
 
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 */
 
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public class ASTIterator implements Iterator {
 
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        private AST next, current;
 
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        private LinkedList parents = new LinkedList();
 
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        public void remove() {
 
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                throw new UnsupportedOperationException( "remove() is not supported" );
 
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        }
 
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        public boolean hasNext() {
 
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                return next != null;
 
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        }
 
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        public Object next() {
 
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                return nextNode();
 
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        }
 
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        public ASTIterator(AST tree) {
 
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                next = tree;
 
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                down();
 
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        }
 
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        public AST nextNode() {
 
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                current = next;
 
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                if ( next != null ) {
 
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                        AST nextSibling = next.getNextSibling();
 
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                        if ( nextSibling == null ) {
 
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                                next = pop();
 
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                        }
 
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                        else {
 
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                                next = nextSibling;
 
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                                down();
 
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                        }
 
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                }
 
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                return current;
 
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        }
 
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        private void down() {
 
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                while ( next != null && next.getFirstChild() != null ) {
 
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                        push( next );
 
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                        next = next.getFirstChild();
 
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                }
 
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        }
 
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        private void push(AST parent) {
 
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                parents.addFirst( parent );
 
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        }
 
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        private AST pop() {
 
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                if ( parents.size() == 0 ) {
 
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                        return null;
 
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                }
 
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                else {
 
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                        return ( AST ) parents.removeFirst();
 
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                }
 
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        }
 
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}