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/*
* eXist-db Open Source Native XML Database
* Copyright (C) 2001 The eXist-db Authors
*
* [email protected]
* http://www.exist-db.org
*
* 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.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 Cardinality cardinality;
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 current context
* @param expr expression to cast
* @param requiredType the {@link Type} expected
* @param cardinality the {@link Cardinality} expected
*/
public CastExpression(final XQueryContext context, final Expression expr, final int requiredType, final Cardinality cardinality) {
super(context);
this.requiredType = requiredType;
this.cardinality = cardinality;
setExpression(expr);
}
protected Expression getInnerExpression() {
return expression;
}
public void setExpression(Expression expr) {
this.expression = expr;
}
@Override
public void analyze(AnalyzeContextInfo contextInfo) throws XPathException {
contextInfo.setParent(this);
expression.analyze(contextInfo);
contextInfo.setStaticReturnType(requiredType);
}
@Override
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.atLeastOne())
{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() | Dependency.CONTEXT_ITEM;
}
@Override
public Cardinality 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 String typeName = Type.getTypeName(CastExpression.this.requiredType);
try {
final QName qname = QName.parse(context, typeName);
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(this, signature);
} catch (final QName.IllegalQNameException e) {
throw new XPathException(ErrorCodes.XPST0081, "No namespace defined for prefix " + typeName);
}
}
private static class FunctionWrapper extends Function {
private final CastExpression castExpression;
protected FunctionWrapper(final CastExpression castExpression, final FunctionSignature signature) throws XPathException {
super(castExpression.getContext(), signature);
final List args = new ArrayList<>(1);
args.add(new Function.Placeholder(castExpression.getContext()));
super.setArguments(args);
this.castExpression = castExpression;
}
@Override
public void setArguments(final List arguments) throws XPathException {
castExpression.setExpression(arguments.get(0));
}
@Override
public Sequence eval(Sequence contextSequence, Item contextItem) throws XPathException {
return castExpression.eval(contextSequence);
}
}
}
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