package net.sf.saxon.tree;
import net.sf.saxon.om.AxisIterator;
import net.sf.saxon.om.Item;
import net.sf.saxon.om.LookaheadIterator;
import net.sf.saxon.pattern.NodeTest;
abstract class TreeEnumeration implements AxisIterator, LookaheadIterator {
protected NodeImpl start;
protected NodeImpl next;
protected NodeTest nodeTest;
protected NodeImpl current = null;
protected int position = 0;
//protected int last = -1;
/**
* Create an axis enumeration for a given type and name of node, from a given
* origin node
* @param origin the node from which the axis originates
* @param nodeTest test to be satisfied by the returned nodes, or null if all nodes
* are to be returned.
*/
public TreeEnumeration(NodeImpl origin, NodeTest nodeTest) {
next = origin;
start = origin;
this.nodeTest = nodeTest;
}
/**
* Test whether a node conforms to the node type and name constraints.
* Note that this returns true if the supplied node is null, this is a way of
* terminating a loop.
*/
protected boolean conforms(NodeImpl node) {
if (node==null || nodeTest==null) {
return true;
}
return nodeTest.matches(node);
}
/**
* Advance along the axis until a node is found that matches the required criteria
*/
protected final void advance() {
do {
step();
} while (!conforms(next));
}
/**
* Advance one step along the axis: the resulting node might not meet the required
* criteria for inclusion
*/
protected abstract void step();
/**
* 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.
*
* @return true if there are more items in the sequence
*/
public boolean hasNext() {
return next != null;
}
/**
* Return the next node in the enumeration
*/
public final Item next() {
if (next==null) {
current = null;
position = -1;
return null;
} else {
current = next;
position++;
advance();
return current;
}
}
/**
* Return the current Item
*/
public final Item current() {
return current;
}
/**
* Return the current position
*/
public final int position() {
return position;
}
/**
* 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 GROUNDED}, {@link LAST_POSITION_FINDER},
* and {@link 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 LOOKAHEAD;
}
/**
* Indicate that any nodes returned in the sequence will be atomized. This
* means that if it wishes to do so, the implementation can return the typed
* values of the nodes rather than the nodes themselves. The implementation
* is free to ignore this hint.
* @param atomizing true if the caller of this iterator will atomize any
* nodes that are returned, and is therefore willing to accept the typed
* value of the nodes instead of the nodes themselves.
*/
//public void setIsAtomizing(boolean atomizing) {}
}
//
// 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.
//
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