/*
* @(#)$Id: DistinctValues.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.seq;
import xbird.xquery.XQueryException;
import xbird.xquery.dm.value.Item;
import xbird.xquery.dm.value.Sequence;
import xbird.xquery.dm.value.sequence.DistinctSequence;
import xbird.xquery.dm.value.sequence.ValueSequence;
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.StringType;
/**
* fn:distinct-values.
* <DIV lang="en">
* Returns the sequence that results from removing from $arg all but one of
* a set of values that are eq to one other.
* <ul>
* <li>fn:distinct-values($arg as xdt:anyAtomicType*) as xdt:anyAtomicType*</li>
* <li>fn:distinct-values($arg as xdt:anyAtomicType*, $collation as xs:string) as xdt:anyAtomicType*</li>
* </ul>
* </DIV>
* <DIV lang="ja"></DIV>
*
* @author Makoto YUI (yuin405+xbird@gmail.com)
* @link http://www.w3.org/TR/xquery-operators/#func-distinct-values
*/
public final class DistinctValues extends BuiltInFunction {
private static final long serialVersionUID = 8071229137218293533L;
public static final String SYMBOL = "fn:distinct-values";
public DistinctValues() {
super(SYMBOL, TypeRegistry.safeGet("xs:anyAtomicType*"));
}
protected FunctionSignature[] signatures() {
final FunctionSignature[] s = new FunctionSignature[2];
Type anyatom = TypeRegistry.safeGet("xs:anyAtomicType*");
s[0] = new FunctionSignature(getName(), new Type[] { anyatom });
s[1] = new FunctionSignature(getName(), new Type[] { anyatom, StringType.STRING });
return s;
}
public Sequence eval(Sequence<? extends Item> contextSeq, ValueSequence argv, DynamicContext dynEnv) throws XQueryException {
if (argv == null) {
throw new IllegalArgumentException();
}
// NaN does not equal itself, if $arg contains multiple NaN values
// a single NaN is returned.
// TODO handle collation
Item arg = argv.getItem(0);
return DistinctSequence.<Item> wrap(arg, dynEnv);
}
}