/*
* 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.DocumentSet;
import org.exist.xquery.util.ExpressionDumper;
import org.exist.xquery.value.BooleanValue;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.Type;
/**
* Implements the "castable as" XQuery expression.
*
* @author wolf
*/
public class CastableExpression extends AbstractExpression {
private Expression expression;
private int requiredCardinality;
private final int requiredType;
/**
*
*
* @param requiredCardinality
* @param context
* @param expr
* @param requiredType
*/
public CastableExpression(XQueryContext context, Expression expr, int requiredType, int requiredCardinality) {
super(context);
this.expression = expr;
this.requiredType = requiredType;
this.requiredCardinality = requiredCardinality;
if (!Type.subTypeOf(expression.returnsType(), Type.ATOMIC))
expression = new Atomize(context, expression);
}
/* (non-Javadoc)
* @see org.exist.xquery.CastExpression#returnsType()
*/
public int returnsType() {
return Type.BOOLEAN;
}
/* (non-Javadoc)
* @see org.exist.xquery.AbstractExpression#getCardinality()
*/
public int getCardinality() {
return Cardinality.EXACTLY_ONE;
}
public int getDependencies() {
return Dependency.CONTEXT_SET + Dependency.CONTEXT_ITEM;
}
/* (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);
}
/* (non-Javadoc)
* @see org.exist.xquery.AbstractExpression#eval(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 (requiredType == Type.ATOMIC || (requiredType == Type.NOTATION && expression.returnsType() != Type.NOTATION))
throw new XPathException(this, "err:XPST0080: cannot convert 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, "err:XPST0051: cannot convert to " + Type.getTypeName(requiredType));
Sequence result;
//See : http://article.gmane.org/gmane.text.xml.xquery.general/1413
//... for the rationale
//may be more complicated : let's see with following XQTS versions
if (requiredType == Type.QNAME && Dependency.dependsOnVar(expression))
result = BooleanValue.FALSE;
else {
Sequence seq = expression.eval(contextSequence, contextItem);
if(seq.isEmpty()) {
//If ? is specified after the target type, the result of the cast expression is an empty sequence.
if (Cardinality.checkCardinality(requiredCardinality, Cardinality.ZERO))
result = BooleanValue.TRUE;
//If ? is not specified after the target type, a type error is raised [err:XPTY0004].
else
//TODO : raise the error ?
result = BooleanValue.FALSE;
}
else {
try {
seq.itemAt(0).convertTo(requiredType);
//If ? is specified after the target type, the result of the cast expression is an empty sequence.
if (Cardinality.checkCardinality(requiredCardinality, seq.getCardinality()))
result = BooleanValue.TRUE;
//If ? is not specified after the target type, a type error is raised [err:XPTY0004].
else
result = BooleanValue.FALSE;
//TODO : improve by *not* using a costly exception ?
} catch(XPathException e) {
result = BooleanValue.FALSE;
}
}
}
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(" castable as ");
dumper.display(Type.getTypeName(requiredType));
}
public String toString() {
StringBuilder result = new StringBuilder();
result.append(expression.toString());
result.append(" castable as ");
result.append(Type.getTypeName(requiredType));
return result.toString();
}
public void setContextDocSet(DocumentSet contextSet) {
super.setContextDocSet(contextSet);
expression.setContextDocSet(contextSet);
}
public void resetState(boolean postOptimization) {
super.resetState(postOptimization);
expression.resetState(postOptimization);
}
}