package net.sf.saxon.evpull;
import net.sf.saxon.expr.Expression;
import net.sf.saxon.expr.XPathContext;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.evpull.EventIterator;
import net.sf.saxon.evpull.PullEvent;
/**
* Iterate over the instructions in a Block, concatenating the result of each instruction
* into a single combined sequence.
*/
public class BlockEventIterator implements EventIterator {
private Expression[] children;
private int i = 0;
private EventIterator child;
private XPathContext context;
/**
* Create an EventIterator over the results of evaluating a Block
* @param children the sequence of instructions comprising the Block
* @param context the XPath dynamic context
*/
public BlockEventIterator(Expression[] children, XPathContext context) {
this.children = children;
this.context = context;
}
/**
* Get the next item in the sequence.
*
* @return the next item, or null if there are no more items.
* @throws XPathException if an error occurs retrieving the next item
*/
public PullEvent next() throws XPathException {
while (true) {
if (child == null) {
child = children[i++].iterateEvents(context);
}
PullEvent current = child.next();
if (current != null) {
return current;
}
child = null;
if (i >= children.length) {
return null;
}
}
}
/**
* Determine whether the EventIterator returns a flat sequence of events, or whether it can return
* nested event iterators
*
* @return true if the next() method is guaranteed never to return an EventIterator
*/
public boolean isFlatSequence() {
return false;
}
}
//
// 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.
//
// Contributor(s):
//