/*
* 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.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.List;
import org.teiid.designer.query.sql.IElementCollectorVisitor;
import org.teiid.designer.runtime.version.spi.ITeiidServerVersion;
import org.teiid.query.parser.LanguageVisitor;
import org.teiid.query.sql.lang.LanguageObject;
import org.teiid.query.sql.navigator.DeepPreOrderNavigator;
import org.teiid.query.sql.navigator.PreOrderNavigator;
import org.teiid.query.sql.symbol.ElementSymbol;
import org.teiid.query.sql.symbol.MultipleElementSymbol;
import org.teiid.runtime.client.Messages;
/**
* <p>This visitor class will traverse a language object tree and collect all element
* symbol references it finds. It uses a collection to collect the elements in so
* different collections will give you different collection properties - for instance,
* using a Set will remove duplicates.</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 ElementCollectorVisitor extends LanguageVisitor
implements IElementCollectorVisitor<LanguageObject, ElementSymbol> {
private Collection<? super ElementSymbol> elements;
private boolean aggsOnly;
/**
* Construct a new visitor with a default returning collection
* @param teiidVersion
* @param removeDuplicates
*/
public ElementCollectorVisitor(ITeiidServerVersion teiidVersion, boolean removeDuplicates) {
this(teiidVersion, removeDuplicates ? new HashSet<ElementSymbol>() : new ArrayList<ElementSymbol>());
}
/**
* Construct a new visitor with the specified collection, which should
* be non-null.
* @param teiidVersion
* @param elements Collection to use for elements
* @throws IllegalArgumentException If elements is null
*/
public ElementCollectorVisitor(ITeiidServerVersion teiidVersion, Collection<? super ElementSymbol> elements) {
super(teiidVersion);
if(elements == null) {
throw new IllegalArgumentException(Messages.getString(Messages.ERR.ERR_015_010_0021));
}
this.elements = elements;
}
/**
* Visit a language object and collect symbols. This method should <b>NOT</b> be
* called directly.
* @param obj Language object
*/
@Override
public void visit(ElementSymbol obj) {
if (!aggsOnly || obj.isAggregate()) {
this.elements.add(obj);
}
}
/**
* Visit a language object and collect symbols. This method should <b>NOT</b> be
* called directly.
* @param obj Language object
*/
@Override
public void visit(MultipleElementSymbol obj) {
List<ElementSymbol> elementSymbols = obj.getElementSymbols();
if(elementSymbols != null) {
for (int i = 0; i < elementSymbols.size(); i++) {
visit(elementSymbols.get(i));
}
}
}
/**
* Helper to quickly get the elements from obj in the elements collection
* @param obj Language object
* @param elements Collection to collect elements in
*/
public static final void getElements(LanguageObject obj, Collection<? super ElementSymbol> elements) {
if(obj == null) {
return;
}
ElementCollectorVisitor visitor = new ElementCollectorVisitor(obj.getTeiidVersion(), elements);
PreOrderNavigator.doVisit(obj, visitor);
}
/**
* @param objs
* @param elements
*/
public static final void getElements(Collection<? extends LanguageObject> objs, Collection<ElementSymbol> elements) {
if(objs == null) {
return;
}
LanguageObject obj = objs.iterator().next();
ElementCollectorVisitor visitor = new ElementCollectorVisitor(obj.getTeiidVersion(), elements);
for (LanguageObject object : objs) {
PreOrderNavigator.doVisit(object, visitor);
}
}
/**
* Helper to quickly get the elements from obj in a collection. The
* removeDuplicates flag affects whether duplicate elements will be
* filtered out.
* @param obj Language object
* @param removeDuplicates True to remove duplicates
* @return Collection of {@link ElementSymbol}
*/
public static final Collection<ElementSymbol> getElements(LanguageObject obj, boolean removeDuplicates) {
return ElementCollectorVisitor.getElements(obj, removeDuplicates, false);
}
/**
* Helper to quickly get the elements from obj in a collection. The
* removeDuplicates flag affects whether duplicate elements will be
* filtered out.
* @param obj Language object
* @param removeDuplicates True to remove duplicates
* @param useDeepIteration indicates whether or not to iterate into nested
* subqueries of the query
* @return Collection of {@link ElementSymbol}
*/
public static final Collection<ElementSymbol> getElements(LanguageObject obj, boolean removeDuplicates, boolean useDeepIteration) {
return getElements(obj, removeDuplicates, useDeepIteration, false);
}
/**
* @param obj
* @param removeDuplicates
* @param useDeepIteration
* @param aggsOnly
* @return Collection of {@link ElementSymbol}
*/
public static final Collection<ElementSymbol> getElements(LanguageObject obj, boolean removeDuplicates, boolean useDeepIteration, boolean aggsOnly) {
if(obj == null) {
return Collections.emptyList();
}
Collection<ElementSymbol> elements = null;
if(removeDuplicates) {
elements = new LinkedHashSet<ElementSymbol>();
} else {
elements = new ArrayList<ElementSymbol>();
}
ElementCollectorVisitor visitor = new ElementCollectorVisitor(obj.getTeiidVersion(), elements);
visitor.aggsOnly = aggsOnly;
if (useDeepIteration){
DeepPreOrderNavigator.doVisit(obj, visitor);
} else {
PreOrderNavigator.doVisit(obj, visitor);
}
return elements;
}
/**
* @param obj
* @param removeDuplicates
* @return aggregates from given object
*/
public static final Collection<ElementSymbol> getAggregates(LanguageObject obj, boolean removeDuplicates) {
return getElements(obj, removeDuplicates, false, true);
}
@Override
public Collection<? super ElementSymbol> findElements(LanguageObject obj) {
return findElements(obj, false);
}
@Override
public Collection<? super ElementSymbol> findElements(LanguageObject obj, boolean useDeepIteration) {
return findElements(obj, useDeepIteration, false);
}
@Override
public Collection<? super ElementSymbol> findElements(LanguageObject obj, boolean useDeepIteration, boolean aggsOnly) {
this.aggsOnly = aggsOnly;
if (useDeepIteration){
DeepPreOrderNavigator.doVisit(obj, this);
} else {
PreOrderNavigator.doVisit(obj, this);
}
return elements;
}
}