package net.sf.saxon.expr;
import net.sf.saxon.type.BuiltInAtomicType;
import net.sf.saxon.type.TypeHierarchy;
import net.sf.saxon.type.ItemType;
import net.sf.saxon.value.AtomicValue;
import net.sf.saxon.value.NumericValue;
import net.sf.saxon.value.UntypedAtomicValue;
import net.sf.saxon.value.DoubleValue;
import net.sf.saxon.trans.XPathException;
/**
* Expression that performs numeric promotion to xs:double
*/
public class PromoteToFloat extends NumericPromoter {
public PromoteToFloat(Expression exp) {
super(exp);
}
/**
* Determine the data type of the items returned by the expression, if possible
* @return a value such as Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE,
* or Type.ITEM (meaning not known in advance)
* @param th the type hierarchy cache
*/
public ItemType getItemType(TypeHierarchy th) {
return BuiltInAtomicType.FLOAT;
}
/**
* Copy an expression. This makes a deep copy.
*
* @return the copy of the original expression
*/
public Expression copy() {
return new PromoteToFloat(getBaseExpression().copy());
}
/**
* Perform the promotion
* @param value the numeric or untyped atomic value to be promoted
* @param context the XPath dynamic evaluation context
* @return the value that results from the promotion
*/
protected AtomicValue promote(AtomicValue value, XPathContext context) throws XPathException {
if (!(value instanceof NumericValue || value instanceof UntypedAtomicValue)) {
final TypeHierarchy th = context.getConfiguration().getTypeHierarchy();
XPathException err = new XPathException(
"Cannot promote non-numeric value to " + getItemType(th).toString(), "XPTY0004", context);
err.setLocator(this);
throw err;
}
if (value instanceof DoubleValue) {
XPathException err = new XPathException(
"Cannot promote from xs:double to xs:float", "XPTY0004", context);
err.setLocator(this);
throw err;
}
return value.convert(BuiltInAtomicType.FLOAT, true, context).asAtomic();
}
}
//
// The contents of this file are subject to the Mozilla Public License Version
// 1.0 (the "License");
// you may not use this file except in compliance with the License. You may
// obtain a copy of the
// License at http://www.mozilla.org/MPL/
//
// Software distributed under the License is distributed on an "AS IS" basis,
// WITHOUT WARRANTY OF ANY KIND, either express or implied.
// See the License for the specific language governing rights and limitations
// under the License.
//
// The Original Code is: all this file.
//
// The Initial Developer of the Original Code is Michael Kay,
//
// Portions created by (your name) are Copyright (C) (your legal entity). All
// Rights Reserved.
//
// Contributor(s): none.
//