/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2010, Red Hat, Inc. and/or its affiliates or third-party contributors as
* indicated by the @author tags or express copyright attribution
* statements applied by the authors. All third-party contributions are
* distributed under license by Red Hat, Inc.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*/
package org.hibernate.search.query.hibernate.impl;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;
import org.hibernate.search.query.engine.spi.EntityInfo;
/**
* @author Emmanuel Bernard
*/
//TODO load the next batch-size elements to benefit from batch-size
public class IteratorImpl implements Iterator<Object> {
private final List<EntityInfo> entityInfos;
private int index = 0;
private final int size;
private Object next;
private int nextObjectIndex = -1;
private final Loader loader;
public IteratorImpl(List<EntityInfo> entityInfos, Loader loader) {
this.entityInfos = entityInfos;
this.size = entityInfos.size();
this.loader = loader;
}
//side effect is to set up next
public boolean hasNext() {
if ( nextObjectIndex == index ) return next != null;
next = null;
nextObjectIndex = -1;
do {
if ( index >= size ) {
nextObjectIndex = index;
next = null;
return false;
}
next = loader.load( entityInfos.get( index ) );
if ( next == null ) {
index++;
}
else {
nextObjectIndex = index;
}
}
while ( next == null );
return true;
}
public Object next() {
//hasNext() has side effect
if ( !hasNext() ) throw new NoSuchElementException( "Out of boundaries" );
index++;
return next;
}
public void remove() {
//TODO this is theoretically doable
throw new UnsupportedOperationException( "Cannot remove from a lucene query iterator" );
}
}