/*
* eXist Open Source Native XML Database
* Copyright (C) 2001-2007 The eXist Project
* http://exist-db.org
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $Id$
*/
package org.exist.xquery;
import org.exist.xquery.util.ExpressionDumper;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.Type;
import org.exist.xquery.value.ValueSequence;
/**
* An XQuery sequence constructor ",". For example, ($a, $b) constructs a new
* sequence containing items $a and $b.
*
* @author wolf
*/
public class SequenceConstructor extends PathExpr {
/**
* @param context
*/
public SequenceConstructor(XQueryContext context) {
super(context);
}
public void analyze(AnalyzeContextInfo contextInfo) throws XPathException {
contextInfo.setParent(this);
inPredicate = (contextInfo.getFlags() & IN_PREDICATE) > 0;
unordered = (contextInfo.getFlags() & UNORDERED) > 0;
contextId = contextInfo.getContextId();
int staticType = Type.ANY_TYPE;
for (int i = 0 ; i < steps.size() ; i++) {
final Expression expr = steps.get(i);
//Create a new context info because each sequence expression could modify it (add/remove flags...)
final AnalyzeContextInfo info = new AnalyzeContextInfo(contextInfo);
expr.analyze(info);
if (staticType == Type.ANY_TYPE)
{staticType = info.getStaticReturnType();}
else if (staticType != Type.ITEM && staticType != info.getStaticReturnType())
{staticType = Type.ITEM;}
}
contextInfo.setStaticReturnType(staticType);
}
/* (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());}
}
final ValueSequence result = new ValueSequence();
result.keepUnOrdered(unordered);
for(final Expression step : steps) {
context.pushDocumentContext();
try {
final Sequence temp = step.eval(contextSequence, contextItem);
if(temp != null && !temp.isEmpty()) {
result.addAll(temp);
}
} finally {
context.popDocumentContext();
}
}
if (context.getProfiler().isEnabled())
{context.getProfiler().end(this, "", result);}
return result;
}
/* (non-Javadoc)
* @see org.exist.xquery.PathExpr#dump(org.exist.xquery.util.ExpressionDumper)
*/
public void dump(ExpressionDumper dumper) {
dumper.display("(");
dumper.startIndent();
boolean moreThanOne = false;
for(final Expression step : steps) {
if (moreThanOne)
{dumper.display(", ");}
moreThanOne = true;
step.dump(dumper);
}
dumper.endIndent();
dumper.nl().display(")");
}
public String toString() {
final StringBuilder result = new StringBuilder();
result.append("( ");
boolean moreThanOne = false;
for (final Expression step : steps) {
if (moreThanOne)
{result.append(", ");}
moreThanOne = true;
result.append(step.toString());
}
result.append(" )");
return result.toString();
}
/* (non-Javadoc)
* @see org.exist.xquery.Expression#returnsType()
*/
public int returnsType() {
return Type.ITEM;
}
/* (non-Javadoc)
* @see org.exist.xquery.AbstractExpression#getCardinality()
*/
public int getCardinality() {
return Cardinality.ZERO_OR_MORE;
}
@Override
public boolean allowMixedNodesInReturn() {
return true;
}
/* (non-Javadoc)
* @see org.exist.xquery.AbstractExpression#resetState()
*/
public void resetState(boolean postOptimization) {
super.resetState(postOptimization);
}
}