/*
* JBoss, Home of Professional Open Source.
* See the COPYRIGHT.txt file distributed with this work for information
* regarding copyright ownership. Some portions may be licensed
* to Red Hat, Inc. under one or more contributor license agreements.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301 USA.
*/
package org.teiid.query.sql.visitor;
import java.util.ArrayList;
import java.util.List;
import org.teiid.query.sql.LanguageObject;
import org.teiid.query.sql.LanguageVisitor;
import org.teiid.query.sql.navigator.DeepPreOrderNavigator;
import org.teiid.query.sql.symbol.Reference;
/**
* <p>This visitor class will traverse a language object tree and collect all
* references it finds. </p>
*
* <p>The easiest way to use this visitor is to call the static methods which create
* the visitor (and possibly the collection), run the visitor, and return the collection.
* The public visit() methods should NOT be called directly.</p>
*/
public class ReferenceCollectorVisitor extends LanguageVisitor {
private List<Reference> references = new ArrayList<Reference>();
/**
* Get the references collected by the visitor. This should best be called
* after the visitor has been run on the language object tree.
* @return Collection of {@link org.teiid.query.sql.symbol.ElementSymbol}
*/
public List<Reference> getReferences() {
return this.references;
}
/**
* Visit a language object and collect symbols. This method should <b>NOT</b> be
* called directly.
* @param obj Language object
*/
public void visit(Reference obj) {
this.references.add(obj);
}
/**
* Helper to quickly get the references from obj in a collection.
* @param obj Language object
* @return List of {@link org.teiid.query.sql.symbol.Reference}
*/
public static List<Reference> getReferences(LanguageObject obj) {
ReferenceCollectorVisitor visitor = new ReferenceCollectorVisitor();
DeepPreOrderNavigator.doVisit(obj, visitor);
return visitor.getReferences();
}
}