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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2018-2022 Saxonica Limited
// This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
// If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
// This Source Code Form is "Incompatible With Secondary Licenses", as defined by the Mozilla Public License, v. 2.0.
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
package net.sf.saxon.tree.iter;
import net.sf.saxon.om.SequenceIterator;
/**
* A SequenceIterator is used to iterate over a sequence. A LookaheadIterator
* is one that supports a hasNext() method to determine if there are more nodes
* after the current node.
*/
public interface LookaheadIterator extends SequenceIterator {
/**
* Ask whether the hasNext() method can be called. This method must
* be called before calling hasNext(), because some iterators
* implement this interface, but only support look-ahead under particular
* circumstances (this is usually because they delegate to another
* iterator)
* @return true if the {@link #hasNext()} method is available
*/
boolean supportsHasNext();
/**
* Determine whether there are more items to come. Note that this operation
* is stateless and it is not necessary (or usual) to call it before calling
* next(). It is used only when there is an explicit need to tell if we
* are at the last element.
* This method must not be called unless the result of {@link #supportsHasNext()}
* is true.
*
* @return true if there are more items in the sequence
*/
boolean hasNext();
}