/*
* @(#)$Id: Root.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.node;
import xbird.xquery.DynamicError;
import xbird.xquery.XQueryException;
import xbird.xquery.dm.value.*;
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.node.NodeType;
/**
* fn:root.
* <DIV lang="en">
* Returns the root of the tree to which $arg belongs.
* This will usually, but not necessarily, be a document node.
* <ul>
* <li>fn:root() as node()</li>
* <li>fn:root($arg as node()?) as node()?</li>
* </ul>
* </DIV>
* <DIV lang="ja"></DIV>
*
* @author Makoto YUI (yuin405+xbird@gmail.com)
* @link http://www.w3.org/TR/xquery-operators/#func-root
*/
public final class Root extends BuiltInFunction {
private static final long serialVersionUID = -6777771959484142261L;
public static final String SYMBOL = "fn:root";
public Root() {
super(SYMBOL, NodeType.ANYNODE);
}
protected FunctionSignature[] signatures() {
final FunctionSignature[] s = new FunctionSignature[2];
s[0] = new FunctionSignature(getName());
s[1] = new FunctionSignature(getName(), new Type[] { TypeRegistry.safeGet("node()?") });
return s;
}
public Sequence eval(Sequence<? extends Item> contextSeq, ValueSequence argv, DynamicContext dynEnv) throws XQueryException {
if(argv == null) {
// If the function is called without an argument, the context item is used
// as the default argument.
Item i = dynEnv.contextItem();
if(i == null) {
throw new DynamicError("err:XPDY0002", "ContextItem is not set");
}
if(i instanceof XQNode) {
((XQNode) i).getRoot();
} else {
throw new DynamicError("err:XPTY0004", "context item is not a node");
}
} else if(argv.size() == 1) {
Item i = argv.getItem(0);
if(i.isEmpty()) {
return ValueSequence.EMPTY_SEQUENCE;
}
if(i instanceof XQNode) {
return ((XQNode) i).getRoot();
}
}
throw new DynamicError("Arguments size of " + SYMBOL + " must be 0 or 1, but was "
+ argv.size());
}
}