/*
* @(#)$Id: Remove.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 java.util.Iterator;
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.XInteger;
import xbird.xquery.dm.value.sequence.ProxySequence;
import xbird.xquery.dm.value.sequence.ValueSequence;
import xbird.xquery.expr.XQExpression;
import xbird.xquery.func.BuiltInFunction;
import xbird.xquery.func.FunctionSignature;
import xbird.xquery.meta.DynamicContext;
import xbird.xquery.meta.IFocus;
import xbird.xquery.type.SequenceType;
import xbird.xquery.type.Type;
import xbird.xquery.type.xs.IntegerType;
/**
* fn:remove($target as item()*, $position as xs:integer) as item()*.
* <DIV lang="en">
* Returns a new sequence constructed from the value of $target with the item
* at the position specified by the value of $position removed.
* </DIV>
* <DIV lang="ja"></DIV>
*
* @author Makoto YUI (yuin405+xbird@gmail.com)
* @link http://www.w3.org/TR/xquery-operators/#func-remove
*/
public final class Remove extends BuiltInFunction {
private static final long serialVersionUID = -5504658491131019824L;
public static final String SYMBOL = "fn:remove";
public Remove() {
super(SYMBOL, SequenceType.ANY_ITEMS);
}
protected FunctionSignature[] signatures() {
final FunctionSignature[] s = new FunctionSignature[1];
s[0] = new FunctionSignature(getName(), new Type[] { SequenceType.ANY_ITEMS,
IntegerType.INTEGER });
return s;
}
@Override
public Type getReturnType(List<XQExpression> params) {
XQExpression target = params.get(0);
Type targetType = target.getType();
return targetType;
}
public Sequence eval(Sequence<? extends Item> contextSeq, ValueSequence argv, DynamicContext dynEnv)
throws XQueryException {
assert (argv != null && argv.size() == 2);
final Item target = argv.getItem(0);
if(target.isEmpty()) {
return ValueSequence.EMPTY_SEQUENCE;
}
Item secondItem = argv.getItem(1);
assert (secondItem instanceof XInteger);
final int pos = (int) ((XInteger) secondItem).getValue();
return pos > 0 ? new RemoveEmuration(target, pos, dynEnv) : target;
}
private static final class RemoveEmuration extends ProxySequence {
private static final long serialVersionUID = -737597888736351350L;
private final int _removePos;
public RemoveEmuration(final Sequence src, final int removePos, final DynamicContext dynEnv) {
super(src, dynEnv);
assert (removePos > 0);
this._removePos = removePos;
}
public boolean next(IFocus focus) throws XQueryException {
final int cpos = focus.getContextPosition();
Iterator<? extends Item> itor = focus.getBaseFocus();
boolean removed = false;
while(itor.hasNext()) {
Item next = itor.next();
if(!removed && cpos == _removePos - 1) {
removed = true;
continue;
}
focus.setContextItem(next);
return true;
}
return false;
}
}
}