/*
* @(#)$Id: RoundHalfToEven.java 3619 2008-03-26 07:23:03Z yui $
*
* Copyright 2006-2008 Makoto YUI
*
* Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Contributors:
* Makoto YUI - initial implementation
*/
package xbird.xquery.func.math;
import java.util.Iterator;
import xbird.xquery.DynamicError;
import xbird.xquery.XQueryException;
import xbird.xquery.dm.value.Item;
import xbird.xquery.dm.value.Sequence;
import xbird.xquery.dm.value.literal.XInteger;
import xbird.xquery.dm.value.literal.XNumber;
import xbird.xquery.dm.value.sequence.ValueSequence;
import xbird.xquery.dm.value.xsi.UntypedAtomicValue;
import xbird.xquery.func.BuiltInFunction;
import xbird.xquery.func.FunctionSignature;
import xbird.xquery.meta.DynamicContext;
import xbird.xquery.type.Type;
import xbird.xquery.type.TypeRegistry;
import xbird.xquery.type.xs.DoubleType;
import xbird.xquery.type.xs.IntegerType;
/**
* The value returned is the nearest (that is, numerically closest) numeric to $arg
* that is a multiple of ten to the power of minus $precision.
* <DIV lang="en">
* <ul>
* <li>fn:round-half-to-even($arg as numeric?) as numeric?</li>
* <li>fn:round-half-to-even($arg as numeric?, $precision as xs:integer) as numeric?</li>
* </ul>
* </DIV>
* <DIV lang="ja"></DIV>
*
* @author Makoto YUI (yuin405+xbird@gmail.com)
*/
public final class RoundHalfToEven extends BuiltInFunction {
private static final long serialVersionUID = 2605509627310272142L;
public static final String SYMBOL = "fn:round-half-to-even";
public RoundHalfToEven() {
super(SYMBOL, TypeRegistry.safeGet("xs:numeric?"));
}
protected FunctionSignature[] signatures() {
final FunctionSignature[] t = new FunctionSignature[2];
t[0] = new FunctionSignature(getName(), new Type[] { TypeRegistry.safeGet("xs:numeric?") });
t[1] = new FunctionSignature(getName(), new Type[] { TypeRegistry.safeGet("xs:numeric?"),
IntegerType.INTEGER });
return t;
}
protected XNumber promote(XNumber value, int scale) {
final double v = value.getNumber().doubleValue();
if(Double.isNaN(v)) {
return value;
}
return value.roundHalfToEven(scale);
}
public Sequence eval(Sequence<? extends Item> contextSeq, ValueSequence argv, DynamicContext dynEnv)
throws XQueryException {
Item arg = argv.getItem(0);
Iterator<? extends Item> argItor = arg.iterator();
if(!argItor.hasNext()) {
return ValueSequence.EMPTY_SEQUENCE;
}
Item firstItem = argItor.next();
if(firstItem instanceof UntypedAtomicValue) {
firstItem = ((UntypedAtomicValue) firstItem).castAs(DoubleType.DOUBLE, dynEnv);
}
if(firstItem instanceof XNumber) {
XNumber num = (XNumber) firstItem;
final int scale;
final int args = argv.size();
if(args > 1) {
Item precision = argv.getItem(1);
if(!(precision instanceof XInteger)) {
throw new DynamicError("err:FORG0006", "second argument type for precision is invalid: "
+ precision.getType());
}
scale = ((XInteger) precision).getNumber().intValue();
} else {
scale = 0;
}
XNumber promoted = promote(num, scale);
return promoted;
} else {
throw new DynamicError("err:FORG0006", "Invalid argument type: " + firstItem.getType());
}
}
}