/*
* eXist Open Source Native XML Database
* Copyright (C) 2001-06 Wolfgang M. Meier
* wolfgang@exist-db.org
* http://exist.sourceforge.net
*
* This program 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
* of the License, or (at your option) any later version.
*
* This program 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 program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* $Id$
*/
package org.exist.xquery;
import org.exist.dom.DocumentSet;
import org.exist.dom.NodeSet;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.MemoryNodeSet;
/**
* Represents a primary expression in a simple path step like
* foo//$x. The class is mainly used to wrap variable references inside
* a path expression.
*
* @author Wolfgang Meier (wolfgang@exist-db.org)
*/
public class SimpleStep extends Step {
private final Expression expression;
/**
* @param context
* @param axis
*/
public SimpleStep(XQueryContext context, int axis, Expression expression) {
super(context, axis);
this.expression = expression;
this.expression.setPrimaryAxis(axis);
}
/* (non-Javadoc)
* @see org.exist.xquery.Expression#analyze(org.exist.xquery.AnalyzeContextInfo)
*/
public void analyze(AnalyzeContextInfo contextInfo) throws XPathException {
contextInfo.setParent(this);
expression.analyze(contextInfo);
super.analyze(contextInfo);
}
/* (non-Javadoc)
* @see org.exist.xquery.Expression#eval(org.exist.dom.DocumentSet, org.exist.xquery.value.Sequence, org.exist.xquery.value.Item)
*/
public Sequence eval(Sequence contextSequence, Item contextItem) throws XPathException {
if (context.getProfiler().isEnabled()) {
context.getProfiler().start(this);
context.getProfiler().message(this, Profiler.DEPENDENCIES, "DEPENDENCIES", Dependency.getDependenciesName(this.getDependencies()));
if (contextSequence != null)
{context.getProfiler().message(this, Profiler.START_SEQUENCES, "CONTEXT SEQUENCE", contextSequence);}
if (contextItem != null)
{context.getProfiler().message(this, Profiler.START_SEQUENCES, "CONTEXT ITEM", contextItem.toSequence());}
}
if (contextItem != null)
{contextSequence = contextItem.toSequence();}
Sequence result = Sequence.EMPTY_SEQUENCE;
final Sequence set = expression.eval(contextSequence);
if (!set.isEmpty()) {
if (set.isPersistentSet()) {
final NodeSet nodeSet = set.toNodeSet();
switch(axis) {
case Constants.DESCENDANT_SELF_AXIS:
result = nodeSet.selectAncestorDescendant(contextSequence.toNodeSet(), NodeSet.DESCENDANT,
true, contextId, true);
break;
case Constants.CHILD_AXIS:
result = nodeSet.selectParentChild(contextSequence.toNodeSet(), NodeSet.DESCENDANT, contextId);
break;
default:
throw new XPathException(this, "Wrong axis specified");
}
} else {
final MemoryNodeSet ctxNodes = contextSequence.toMemNodeSet();
final MemoryNodeSet nodes = set.toMemNodeSet();
switch(axis) {
case Constants.DESCENDANT_SELF_AXIS:
result = ctxNodes.selectDescendants(nodes);
break;
case Constants.CHILD_AXIS:
result = ctxNodes.selectChildren(nodes);
break;
}
}
}
if (context.getProfiler().isEnabled())
{context.getProfiler().end(this, "", result);}
//actualReturnType = result.getItemType();
return result;
}
/* (non-Javadoc)
* @see org.exist.xquery.Step#resetState()
*/
public void resetState(boolean postOptimization) {
super.resetState(postOptimization);
expression.resetState(postOptimization);
}
public void setContextDocSet(DocumentSet contextSet) {
super.setContextDocSet(contextSet);
expression.setContextDocSet(contextSet);
}
/* (non-Javadoc)
* @see org.exist.xquery.AbstractExpression#setPrimaryAxis(int)
*/
public void setPrimaryAxis(int axis) {
expression.setPrimaryAxis(axis);
}
public int getPrimaryAxis() {
return expression.getPrimaryAxis();
}
}