/*
* 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.dom.persistent.DocumentSet;
import org.exist.dom.QName;
import org.exist.xquery.util.ExpressionDumper;
import org.exist.xquery.value.*;
import java.util.ArrayList;
import java.util.List;
/**
* CastExpression represents cast expressions as well as all type
* constructors.
*
* @author wolf
*/
public class CastExpression extends AbstractExpression {
private Expression expression;
private int cardinality = Cardinality.EXACTLY_ONE;
private final int requiredType;
/**
* Constructor. When calling {@link #eval(Sequence, Item)}
* the passed expression will be cast into the required type and cardinality.
*
* @param context
*/
public CastExpression(XQueryContext context, Expression expr, int requiredType, int cardinality) {
super(context);
this.requiredType = requiredType;
this.cardinality = cardinality;
setExpression(expr);
}
protected Expression getInnerExpression() {
return expression;
}
public void setExpression(Expression expr) {
this.expression = expr;
}
/* (non-Javadoc)
* @see org.exist.xquery.Expression#analyze(org.exist.xquery.Expression)
*/
public void analyze(AnalyzeContextInfo contextInfo) throws XPathException {
contextInfo.setParent(this);
expression.analyze(contextInfo);
contextInfo.setStaticReturnType(requiredType);
}
/* (non-Javadoc)
* @see org.exist.xquery.Expression#eval(org.exist.dom.persistent.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());}
}
//Should be handled by the parser
if (requiredType == Type.ATOMIC || (requiredType == Type.NOTATION && expression.returnsType() != Type.NOTATION)) {
throw new XPathException(this, ErrorCodes.XPST0080, "cannot cast to " +
Type.getTypeName(requiredType));
}
if (requiredType == Type.ANY_SIMPLE_TYPE || expression.returnsType() == Type.ANY_SIMPLE_TYPE || requiredType == Type.UNTYPED || expression.returnsType() == Type.UNTYPED) {
throw new XPathException(this, ErrorCodes.XPST0051, "cannot cast to " +
Type.getTypeName(requiredType));
}
Sequence result;
final Sequence seq = Atomize.atomize(expression.eval(contextSequence, contextItem));
if (seq.isEmpty()) {
if ((cardinality & Cardinality.ZERO) == 0)
{throw new XPathException(this, "Type error: empty sequence is not allowed here");}
else
{result = Sequence.EMPTY_SEQUENCE;}
} else {
final Item item = seq.itemAt(0);
if (seq.hasMany() && Type.subTypeOf(requiredType, Type.ATOMIC))
{throw new XPathException(this,
ErrorCodes.XPTY0004,
"cardinality error: sequence with more than one item is not allowed here");}
try {
// casting to QName needs special treatment
if(requiredType == Type.QNAME) {
if (item.getType() == Type.QNAME)
{result = item.toSequence();}
else if(item.getType() == Type.ATOMIC || Type.subTypeOf(item.getType(), Type.STRING)) {
result = new QNameValue(context, item.getStringValue());
} else {
throw new XPathException(this,
ErrorCodes.XPTY0004,
"Cannot cast " + Type.getTypeName(item.getType()) + " to xs:QName");
}
} else
{result = item.convertTo(requiredType);}
} catch(final XPathException e) {
e.setLocation(e.getLine(), e.getColumn());
throw e;
}
}
if (context.getProfiler().isEnabled())
{context.getProfiler().end(this, "", result);}
return result;
}
/* (non-Javadoc)
* @see org.exist.xquery.Expression#dump(org.exist.xquery.util.ExpressionDumper)
*/
public void dump(ExpressionDumper dumper) {
expression.dump(dumper);
dumper.display(" cast as ");
dumper.display(Type.getTypeName(requiredType));
}
public String toString() {
return expression.toString() + " cast as " + Type.getTypeName(requiredType);
}
/* (non-Javadoc)
* @see org.exist.xquery.Expression#returnsType()
*/
public int returnsType() {
return requiredType;
}
/* (non-Javadoc)
* @see org.exist.xquery.AbstractExpression#getDependencies()
*/
public int getDependencies() {
// return expression.getDependencies();
return Dependency.CONTEXT_SET | Dependency.CONTEXT_ITEM;
}
/* (non-Javadoc)
* @see org.exist.xquery.AbstractExpression#getCardinality()
*/
public int getCardinality() {
return Cardinality.ZERO_OR_ONE;
}
public void setContextDocSet(DocumentSet contextSet) {
super.setContextDocSet(contextSet);
expression.setContextDocSet(contextSet);
}
/* (non-Javadoc)
* @see org.exist.xquery.AbstractExpression#resetState()
*/
public void resetState(boolean postOptimization) {
super.resetState(postOptimization);
expression.resetState(postOptimization);
}
public void accept(ExpressionVisitor visitor) {
visitor.visitCastExpr(this);
}
public Function toFunction() throws XPathException {
final QName qname = QName.parse(context, Type.getTypeName(CastExpression.this.requiredType));
final FunctionSignature signature = new FunctionSignature(qname);
final SequenceType argType = new SequenceType(Type.ITEM, Cardinality.EXACTLY_ONE);
signature.setArgumentTypes(new SequenceType[] { argType });
signature.setReturnType(new SequenceType(CastExpression.this.requiredType, CastExpression.this.cardinality));
return new FunctionWrapper(context, signature);
}
private class FunctionWrapper extends Function {
protected FunctionWrapper(XQueryContext context, FunctionSignature signature) throws XPathException {
super(context, signature);
final List<Expression> args = new ArrayList<Expression>(1);
args.add(new Function.Placeholder(context));
super.setArguments(args);
}
@Override
public void setArguments(List<Expression> arguments) throws XPathException {
CastExpression.this.setExpression(arguments.get(0));
}
@Override
public Sequence eval(Sequence contextSequence, Item contextItem) throws XPathException {
return CastExpression.this.eval(contextSequence);
}
}
}