/*
* @(#)$Id: Nilled.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.accessor;
import java.util.List;
import xbird.xquery.XQueryException;
import xbird.xquery.dm.NodeKind;
import xbird.xquery.dm.instance.DocumentTableModel.DTMElement;
import xbird.xquery.dm.value.*;
import xbird.xquery.dm.value.node.DMElement;
import xbird.xquery.dm.value.sequence.ValueSequence;
import xbird.xquery.dm.value.xsi.BooleanValue;
import xbird.xquery.expr.XQExpression;
import xbird.xquery.func.*;
import xbird.xquery.func.opt.EagerEvaluated;
import xbird.xquery.meta.DynamicContext;
import xbird.xquery.meta.StaticContext;
import xbird.xquery.type.Type;
import xbird.xquery.type.TypeRegistry;
/**
* fn:nilled($arg as node()?) as xs:boolean?.
* <DIV lang="en">
* Returns an xs:boolean indicating whether the argument node is "nilled".
* </DIV>
* <DIV lang="ja"></DIV>
*
* @author Makoto YUI (yuin405+xbird@gmail.com)
* @link http://www.w3.org/TR/xquery-operators/#func-nilled
*/
public final class Nilled extends BuiltInFunction {
private static final long serialVersionUID = -8644861906953531601L;
public static final String SYMBOL = "fn:nilled";
public Nilled() {
super(SYMBOL, TypeRegistry.safeGet("xs:boolean?"));
}
protected FunctionSignature[] signatures() {
final FunctionSignature[] s = new FunctionSignature[1];
s[0] = new FunctionSignature(getName(), new Type[] { TypeRegistry.safeGet("node()?") });
return s;
}
@Override
public Function staticAnalysis(StaticContext context, List<? extends XQExpression> params) throws XQueryException {
assert (params != null);
if (params.isEmpty()) {
return new EagerEvaluated(this, ValueSequence.EMPTY_SEQUENCE);
}
return this;
}
public Sequence eval(Sequence<? extends Item> contextSeq, ValueSequence argv, DynamicContext dynEnv) throws XQueryException {
assert (argv != null);
if (argv.isEmpty()) {
return ValueSequence.EMPTY_SEQUENCE;
}
assert (argv.size() == 1);
Item arg = argv.getItem(0);
//If the argument is not an element node, returns the empty sequence.
if (arg instanceof XQNode) {
byte kind = ((XQNode) arg).nodeKind();
if (kind == NodeKind.ELEMENT) {
final boolean nilled;
if (arg instanceof DMElement) {
nilled = ((DMElement) arg).nilled();
} else {
// check element attribute value of "xsi:nil"
assert (arg instanceof DTMElement);
nilled = ((DTMElement) arg).nilled();
}
return nilled ? BooleanValue.TRUE : BooleanValue.FALSE;
}
}
return ValueSequence.EMPTY_SEQUENCE;
}
}