/*
* @(#)$Id: InsertBefore.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 xbird.xquery.XQueryException;
import xbird.xquery.dm.value.*;
import xbird.xquery.dm.value.literal.XInteger;
import xbird.xquery.dm.value.sequence.ProxySequence;
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.meta.IFocus;
import xbird.xquery.type.SequenceType;
import xbird.xquery.type.Type;
import xbird.xquery.type.xs.IntegerType;
/**
* fn:insert-before($target as item()*, $position as xs:integer, $inserts as item()*) as item()*.
* <DIV lang="en"></DIV>
* <DIV lang="ja"></DIV>
*
* @author Makoto YUI (yuin405+xbird@gmail.com)
* @link http://www.w3.org/TR/xquery-operators/#func-insert-before
*/
public final class InsertBefore extends BuiltInFunction {
private static final long serialVersionUID = 2696152358059415990L;
public static final String SYMBOL = "fn:insert-before";
public InsertBefore() {
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, SequenceType.ANY_ITEMS });
return s;
}
public Sequence eval(Sequence<? extends Item> contextSeq, ValueSequence argv, DynamicContext dynEnv) throws XQueryException {
assert (argv != null && argv.size() == 3);
final Item target = argv.getItem(0);
if(target.isEmpty()) {
return ValueSequence.EMPTY_SEQUENCE;
}
Item secondItem = argv.getItem(1);
assert (secondItem instanceof XInteger);
int pos = (int) ((XInteger) secondItem).getValue();
// If $position is less than one (1), the first position, the effective value of $position is one (1).
if(pos < 1) {
pos = 1;
}
Item inserts = argv.getItem(2);
if(target instanceof ValueSequence) {
ValueSequence vs = (ValueSequence) target;
final int last = vs.size();
if(pos > last) {
pos = last;
}
vs.addSequence(pos - 1, inserts);
return vs;
} else {
return new InsertEmuration(target, inserts, pos, dynEnv);
}
}
private static final class InsertEmuration extends ProxySequence {
private static final long serialVersionUID = 4748828736062203534L;
private final Sequence<Item> _inserts;
private final int _insertPos;
private IFocus<Item> _insertItor;
private boolean _reachedEnd = false;
private InsertEmuration(Sequence src, Sequence<Item> inserts, int insertPos, DynamicContext dynEnv) {
super(src, dynEnv);
assert (insertPos >= 1);
this._inserts = inserts;
this._insertPos = insertPos;
}
@Override
public IFocus iterator() {
final IFocus focus = super.iterator();
this._insertItor = _inserts.iterator();
this._reachedEnd = false;
return focus;
}
public boolean next(IFocus focus) throws XQueryException {
if(_reachedEnd) {
return false;
}
final int cpos = focus.getContextPosition();
Iterator<Item> itor = focus.getBaseFocus();
if(itor.hasNext()) {
if(cpos >= (_insertPos - 1)) {
if(_insertItor.hasNext()) {
Item next = _insertItor.next();
focus.setContextItem(next);
return true;
}
}
Item next = itor.next();
focus.setContextItem(next);
return true;
} else {
if(_insertItor.hasNext()) {
Item next = _insertItor.next();
focus.setContextItem(next);
return true;
} else {
this._reachedEnd = false;
return false;
}
}
}
}
}