package org.pdf4j.saxon.expr;
import org.pdf4j.saxon.om.Item;
import org.pdf4j.saxon.om.SequenceIterator;
import org.pdf4j.saxon.trans.XPathException;
/**
* Iterator that concatenates the results of two supplied iterators
*/
public class AppendIterator implements SequenceIterator {
private SequenceIterator first;
private SequenceIterable second;
private XPathContext context;
private SequenceIterator currentIterator;
private int position = 0;
/**
* This form of constructor is designed to delay getting an iterator for the second
* expression until it is actually needed. This gives savings in cases where the
* iteration is aborted prematurely.
* @param first Iterator over the first operand
* @param second The second operand
* @param context The dynamic context for evaluation of the second operand
*/
public AppendIterator(SequenceIterator first, SequenceIterable second, XPathContext context) {
this.first = first;
this.second = second;
this.context = context;
this.currentIterator = first;
}
public Item next() throws XPathException {
Item n = currentIterator.next();
if (n == null && currentIterator==first) {
currentIterator = second.iterate(context);
n = currentIterator.next();
}
if (n == null) {
position = -1;
} else {
position++;
}
return n;
}
public Item current() {
return currentIterator.current();
}
public int position() {
return position;
}
public void close() {
}
public SequenceIterator getAnother() throws XPathException {
return new AppendIterator(first.getAnother(), second, context);
}
/**
* Get properties of this iterator, as a bit-significant integer.
*
* @return the properties of this iterator. This will be some combination of
* properties such as {@link SequenceIterator#GROUNDED}, {@link SequenceIterator#LAST_POSITION_FINDER},
* and {@link SequenceIterator#LOOKAHEAD}. It is always
* acceptable to return the value zero, indicating that there are no known special properties.
* It is acceptable for the properties of the iterator to change depending on its state.
*/
public int getProperties() {
return 0;
}
}
//
// The contents of this file are subject to the Mozilla Public License Version 1.0 (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.mozilla.org/MPL/
//
// Software distributed under the License is distributed on an "AS IS" basis,
// WITHOUT WARRANTY OF ANY KIND, either express or implied.
// See the License for the specific language governing rights and limitations under the License.
//
// The Original Code is: all this file.
//
// The Initial Developer of the Original Code is Michael H. Kay
//
// Portions created by (your name) are Copyright (C) (your legal entity). All Rights Reserved.
//
// Contributor(s): none.
//