/*
* @(#)$Id: PrefixFromQName.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.qname;
import java.util.List;
import xbird.xquery.XQueryException;
import xbird.xquery.dm.value.Item;
import xbird.xquery.dm.value.Sequence;
import xbird.xquery.dm.value.literal.XString;
import xbird.xquery.dm.value.sequence.ValueSequence;
import xbird.xquery.dm.value.xsi.QNameValue;
import xbird.xquery.expr.XQExpression;
import xbird.xquery.func.*;
import xbird.xquery.meta.DynamicContext;
import xbird.xquery.meta.StaticContext;
import xbird.xquery.misc.QNameTable.QualifiedName;
import xbird.xquery.type.Type;
import xbird.xquery.type.TypeRegistry;
import xbird.xquery.type.xs.NCNameType;
/**
* fn:prefix-from-QName($arg as xs:QName?) as xs:NCName?
* <DIV lang="en"></DIV>
* <DIV lang="ja"></DIV>
*
* @author Makoto YUI (yuin405+xbird@gmail.com)
* @link http://www.w3.org/TR/xquery-operators/#func-prefix-from-QName
*/
public final class PrefixFromQName extends BuiltInFunction {
private static final long serialVersionUID = 4809594696986732057L;
public static final String SYMBOL = "fn:prefix-from-QName";
public PrefixFromQName() {
super(SYMBOL, TypeRegistry.safeGet("xs:NCName?"));
}
protected FunctionSignature[] signatures() {
final FunctionSignature[] s = new FunctionSignature[1];
s[0] = new FunctionSignature(getName(), new Type[] { TypeRegistry.safeGet("xs:QName?") });
return s;
}
@Override
public PrefixFromQName staticAnalysis(StaticContext context, List<? extends XQExpression> params) throws XQueryException {
strictCheckArguments(context, params);
return this;
}
public Sequence eval(Sequence<? extends Item> contextSeq, ValueSequence argv, DynamicContext dynEnv)
throws XQueryException {
assert (argv != null && argv.size() == 1);
Item firstItem = argv.getItem(0);
if(firstItem.isEmpty()) {
return ValueSequence.EMPTY_SEQUENCE;
}
QNameValue arg = (QNameValue) firstItem;
QualifiedName qname = arg.getValue();
String prefix = qname.getPrefix();
if(prefix.length() == 0) {
return ValueSequence.EMPTY_SEQUENCE;
}
return new XString(prefix, NCNameType.NCNAME);
}
}