/*
* @(#)$Id: RefExpRemover.java,v 1.2 2001/09/19 02:10:53 Bear Exp $
*
* Copyright 2001 Sun Microsystems, Inc. All Rights Reserved.
*
* This software is the proprietary information of Sun Microsystems, Inc.
* Use is subject to license terms.
*
*/
package com.sun.msv.grammar.util;
import com.sun.msv.grammar.*;
import com.sun.msv.grammar.relax.*;
import com.sun.msv.grammar.trex.*;
import java.util.Iterator;
import java.util.Set;
/**
* removes all ReferenceExp from AGM.
*
* when named expression is nullSet, it cannot be used.
* by replacing ReferenceExp by its definition, those unavailable expressions
* will be properly removed from AGM.
*
* @author <a href="mailto:kohsuke.kawaguchi@eng.sun.com">Kohsuke KAWAGUCHI</a>
*/
public class RefExpRemover
extends ExpressionCloner {
/** set of visited ElementExps */
private final Set visitedElements = new java.util.HashSet();
private final boolean recursive;
/**
* @param _recursive
* <p>
* If true, this object behaves destructively. It recursively
* visits all the reachable expressions and removes ReferenceExps.
* In this process, this object changes the content model of
* ElementExps.
*
* <p>
* If false, this object doesn't visit the content models of child
* elements, therefore, it behaves non-destructively. Nothing in the
* original expression will be touched.
*/
public RefExpRemover( ExpressionPool pool, boolean _recursive ) {
super(pool);
this.recursive = _recursive;
}
public Expression onElement( ElementExp exp ) {
if( !recursive )
// do not touch child elements.
return exp;
if( !visitedElements.contains(exp) ) {
// remove refs from this content model
visitedElements.add(exp);
exp.contentModel = exp.contentModel.visit(this);
}
if(exp.contentModel==Expression.nullSet)
return Expression.nullSet; // this element is not allowed
else
return exp;
}
public Expression onAttribute( AttributeExp exp ) {
Expression content = exp.exp.visit(this);
if( content==Expression.nullSet )
return Expression.nullSet; // this attribute is not allowed
else
return pool.createAttribute( exp.nameClass, content );
}
public Expression onRef( ReferenceExp exp ) {
return exp.exp.visit(this);
}
public Expression onOther( OtherExp exp ) {
return exp.exp.visit(this);
}
}