/*
* @(#)$Id: CompositeSequence.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.dm.value.sequence;
import java.util.Iterator;
import xbird.xquery.XQRTException;
import xbird.xquery.XQueryException;
import xbird.xquery.dm.value.*;
import xbird.xquery.expr.XQExpression;
import xbird.xquery.meta.*;
import xbird.xquery.type.Type;
/**
*
* <DIV lang="en"></DIV>
* <DIV lang="ja"></DIV>
*
* @author Makoto YUI (yuin405+xbird@gmail.com)
*/
public final class CompositeSequence<T extends Item> extends AbstractSequence<T> {
private static final long serialVersionUID = 100110868711189545L;
private final Sequence<? extends Item> _src;
private final XQExpression _filterStepExpr;
private final DynamicContext _dynEnv;
public CompositeSequence(Sequence<? extends Item> src, XQExpression filterExpr, DynamicContext dynEnv) {
super(dynEnv);
if(src == null || filterExpr == null) {
throw new IllegalArgumentException("src: " + src + ", filterExpr: " + filterExpr);
}
this._src = src;
this._filterStepExpr = filterExpr;
this._dynEnv = dynEnv;
}
@Override
public CompositeFocus<T> iterator() {
final CompositeFocus<T> focus = new CompositeFocus<T>(this, _src.iterator(), _dynEnv);
return focus;
}
public boolean next(final IFocus focus) throws XQueryException {
final CompositeFocus<T> cfocus = (CompositeFocus<T>) focus;
Iterator<T> filterItor = cfocus.getFilterIterator();
final Iterator<? extends Item> srcItor = cfocus.getBaseFocus();
while(true) {
if(filterItor != null && filterItor.hasNext()) { // false if filteredExpr is not evaled
T n = filterItor.next();
focus.setContextItem(n);
return true;
}
if(!srcItor.hasNext()) { // src sequence has no more elements
return false;
}
final Item nextit = srcItor.next();
final Sequence<? extends Item> filtered;
try {
filtered = _filterStepExpr.eval(nextit, _dynEnv);
} catch (XQueryException e) {
throw new XQRTException(e.getErrCode(), "failed at path evaluation: "
+ _filterStepExpr, e);
}
filterItor = (Iterator<T>) filtered.iterator();
cfocus.setFilterIterator(filterItor);
}
}
public Type getType() {
return _filterStepExpr.getType();
}
private static final class CompositeFocus<T extends Item> extends Focus<T> {
private static final long serialVersionUID = -4933948644036633051L;
private Iterator<T> filterItor = null;
public CompositeFocus(Sequence<T> src, Iterator<? extends Item> base, DynamicContext dynEnv) {
super(src, base, dynEnv);
}
public Iterator<T> getFilterIterator() {
return filterItor;
}
public void setFilterIterator(Iterator<T> filterItor) {
this.filterItor = filterItor;
}
}
}