package net.sf.saxon.functions;
import net.sf.saxon.expr.*;
import net.sf.saxon.om.Item;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.type.BuiltInAtomicType;
import net.sf.saxon.type.ConversionResult;
import net.sf.saxon.type.ValidationFailure;
import net.sf.saxon.type.ItemType;
import net.sf.saxon.value.*;
/**
* Implements the XPath number() function. This can also be used as a mapping function
* in a MappingIterator to map a sequence of values to numbers.
*/
public class NumberFn extends SystemFunction implements ItemMappingFunction {
/**
* Simplify and validate.
* This is a pure function so it can be simplified in advance if the arguments are known
* @param visitor an expression visitor
*/
public Expression simplify(ExpressionVisitor visitor) throws XPathException {
useContextItemAsDefault();
argument[0].setFlattened(true);
return simplifyArguments(visitor);
}
/**
* Type-check the expression. This also calls preEvaluate() to evaluate the function
* if all the arguments are constant; functions that do not require this behavior
* can override the preEvaluate method.
*/
public Expression typeCheck(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException {
Expression e2 = super.typeCheck(visitor, contextItemType);
if (e2 != this) {
return e2;
}
if (argument[0] instanceof NumberFn) {
// happens through repeated rewriting
argument[0] = ((NumberFn)argument[0]).argument[0];
}
return this;
}
/**
* Add a representation of a doc() call or similar function to a PathMap.
* This is a convenience method called by the addToPathMap() methods for doc(), document(), collection()
* and similar functions. These all create a new root expression in the path map.
*
* @param pathMap the PathMap to which the expression should be added
* @param pathMapNodes the node in the PathMap representing the focus at the point where this expression
* is called. Set to null if this expression appears at the top level.
* @return the pathMapNode representing the focus established by this expression, in the case where this
* expression is the first operand of a path expression or filter expression
*/
public PathMap.PathMapNodeSet addDocToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodes) {
PathMap.PathMapNodeSet result = argument[0].addToPathMap(pathMap, pathMapNodes);
if (result != null) {
result.setAtomized();
}
return null;
}
/**
* Evaluate in a general context
*/
public Item evaluateItem(XPathContext context) throws XPathException {
Item arg0 = argument[0].evaluateItem(context);
if (arg0==null) {
return DoubleValue.NaN;
}
if (arg0 instanceof BooleanValue || arg0 instanceof NumericValue) {
ConversionResult result = ((AtomicValue)arg0).convert(BuiltInAtomicType.DOUBLE, true, context);
if (result instanceof ValidationFailure) {
return DoubleValue.NaN;
} else {
return (AtomicValue)result;
}
}
if (arg0 instanceof StringValue && !(arg0 instanceof AnyURIValue)) {
CharSequence s = arg0.getStringValueCS();
try {
return new DoubleValue(Value.stringToNumber(s));
} catch (NumberFormatException e) {
return DoubleValue.NaN;
}
}
return DoubleValue.NaN;
}
/**
* Static method to perform the same conversion as the number() function. This is different from the
* convert(Type.DOUBLE) in that it produces NaN rather than an error for non-numeric operands.
* @param value the value to be converted
* @return the result of the conversion
*/
public static DoubleValue convert(AtomicValue value) {
try {
if (value==null) {
return DoubleValue.NaN;
}
if (value instanceof BooleanValue || value instanceof NumericValue) {
ConversionResult result = value.convert(BuiltInAtomicType.DOUBLE, true, null);
if (result instanceof ValidationFailure) {
return DoubleValue.NaN;
} else {
return (DoubleValue)result;
}
}
if (value instanceof StringValue && !(value instanceof AnyURIValue)) {
CharSequence s = value.getStringValueCS();
return new DoubleValue(Value.stringToNumber(s));
}
return DoubleValue.NaN;
} catch (NumberFormatException e) {
return DoubleValue.NaN;
}
}
/**
* Mapping function for use when converting a sequence of atomic values to doubles
* using the rules of the number() function
*/
public Item map(Item item) throws XPathException {
return convert((AtomicValue)item);
}
}
//
// 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 H. Kay.
//
// Portions created by (your name) are Copyright (C) (your legal entity). All Rights Reserved.
//
// Contributor(s): none.
//