/* eXist Native XML Database
* Copyright (C) 2000-03, Wolfgang M. Meier (wolfgang@exist-db.org)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public License
* as published by the Free Software Foundation; either version 2
* 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 Library General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* $Id$
*/
package org.exist.xquery;
import org.exist.dom.persistent.DocumentSet;
import org.exist.dom.memtree.MemTreeBuilder;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.Type;
/**
* Abstract base class for all node constructors.
*
* @author wolf
*/
public abstract class NodeConstructor extends AbstractExpression {
protected MemTreeBuilder builder = null;
protected boolean newDocumentContext = false;
public NodeConstructor(XQueryContext context) {
super(context);
}
public void setDocumentBuilder(MemTreeBuilder builder) {
this.builder = builder;
}
public void analyze(AnalyzeContextInfo contextInfo) throws XPathException {
newDocumentContext = (contextInfo.getFlags() & IN_NODE_CONSTRUCTOR) == 0;
}
/* (non-Javadoc)
* @see org.exist.xquery.Expression#eval(org.exist.xquery.StaticContext, org.exist.dom.persistent.DocumentSet, org.exist.xquery.value.Sequence, org.exist.xquery.value.Item)
*/
public abstract Sequence eval(Sequence contextSequence, Item contextItem)
throws XPathException;
/* (non-Javadoc)
* @see org.exist.xquery.Expression#preselect(org.exist.dom.persistent.DocumentSet, org.exist.xquery.StaticContext)
*/
public DocumentSet preselect(DocumentSet in_docs) throws XPathException {
return in_docs;
}
@Override
public int getDependencies() {
// if this is a top-level node constructor, it must depend on the context item, so
// an expression like //foo/<x/> will generate one <x> for every foo. However, if the
// constructor appears inside another constructor, we don't want it to be called once
// for every context item, so we just return a dependency on context set:
if (newDocumentContext)
{return Dependency.CONTEXT_SET | Dependency.CONTEXT_ITEM;}
else
{return Dependency.CONTEXT_SET;}
}
/* (non-Javadoc)
* @see org.exist.xquery.Expression#returnsType()
*/
public int returnsType() {
return Type.NODE;
}
/* (non-Javadoc)
* @see org.exist.xquery.AbstractExpression#resetState()
*/
public void resetState(boolean postOptimization) {
super.resetState(postOptimization);
}
}