package org.pdf4j.saxon.expr;
import org.pdf4j.saxon.om.Item;
import org.pdf4j.saxon.om.SequenceIterator;
import org.pdf4j.saxon.trace.ExpressionPresenter;
import org.pdf4j.saxon.trans.XPathException;
import org.pdf4j.saxon.type.BuiltInAtomicType;
import org.pdf4j.saxon.type.ItemType;
import org.pdf4j.saxon.type.TypeHierarchy;
import org.pdf4j.saxon.value.*;
/**
* A NumericPromoter performs numeric promotion on each item in a supplied sequence
*/
public final class NumericPromoter extends UnaryExpression {
private BuiltInAtomicType requiredType; // always xs:float or xs:double
/**
* Constructor
* @param sequence this must be a sequence of atomic values. This is not checked; a ClassCastException
* will occur if the precondition is not satisfied.
* @param requiredType the item type to which all items in the sequence should be converted,
* using the rules for "cast as".
*/
public NumericPromoter(Expression sequence, BuiltInAtomicType requiredType) {
super(sequence);
this.requiredType = requiredType;
ExpressionTool.copyLocationInfo(sequence, this);
}
/**
* Simplify an expression
* @param visitor an expression visitor
*/
public Expression simplify(ExpressionVisitor visitor) throws XPathException {
operand = visitor.simplify(operand);
if (operand instanceof Literal) {
if (((Literal)operand).getValue() instanceof AtomicValue) {
return Literal.makeLiteral(
promote(((AtomicValue)((Literal)operand).getValue()), null));
} else {
return Literal.makeLiteral(
((Value)SequenceExtent.makeSequenceExtent(
iterate(visitor.getStaticContext().makeEarlyEvaluationContext()))).reduce());
}
}
return this;
}
/**
* Type-check the expression
*/
public Expression typeCheck(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException {
operand = visitor.typeCheck(operand, contextItemType);
return this;
}
/**
* Optimize the expression
*/
public Expression optimize(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException {
operand = visitor.optimize(operand, contextItemType);
return this;
}
/**
* Iterate over the sequence of values
*/
public SequenceIterator iterate(final XPathContext context) throws XPathException {
SequenceIterator base = operand.iterate(context);
ItemMappingFunction promoter = new ItemMappingFunction() {
public Item map(Item item) throws XPathException {
return promote(((AtomicValue)item), context);
}
};
return new ItemMappingIterator(base, promoter);
}
/**
* Copy an expression. This makes a deep copy.
*
* @return the copy of the original expression
*/
public Expression copy() {
return new NumericPromoter(getBaseExpression().copy(), requiredType);
}
/**
* Evaluate as an Item. This should only be called if the expression has cardinality zero-or-one
*/
public Item evaluateItem(XPathContext context) throws XPathException {
Item item = operand.evaluateItem(context);
if (item==null) return null;
return promote(((AtomicValue)item), context);
}
/**
* 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
*/
private 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 (requiredType.equals(BuiltInAtomicType.FLOAT) && 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(requiredType, true, context).asAtomic();
}
/**
* Get the required type. Always StandardNames.XS_DOUBLE or StandardNames.XS_FLOAT
* @return the fingerprint of the name of the required type
*/
public int getRequiredType() {
return requiredType.getFingerprint();
}
/**
* 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) {
if (requiredType.equals(BuiltInAtomicType.DOUBLE)) {
return BuiltInAtomicType.DOUBLE;
} else {
return BuiltInAtomicType.FLOAT;
}
}
/**
* Is this expression the same as another expression?
*/
public boolean equals(Object other) {
return super.equals(other) &&
requiredType == ((NumericPromoter)other).requiredType;
}
/**
* Diagnostic print of expression structure. The abstract expression tree
* is written to the supplied output destination.
*/
public void explain(ExpressionPresenter out) {
out.startElement("promoteNumeric");
out.emitAttribute("to", getItemType(out.getTypeHierarchy()).toString(out.getConfiguration().getNamePool()));
operand.explain(out);
out.endElement();
}
}
//
// 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.
//