package client.net.sf.saxon.ce.tree.linked;
import client.net.sf.saxon.ce.tree.iter.AxisIterator;
import client.net.sf.saxon.ce.om.Item;
import client.net.sf.saxon.ce.pattern.NodeTest;
import client.net.sf.saxon.ce.value.Value;
import client.net.sf.saxon.ce.trans.XPathException;
abstract class TreeEnumeration implements AxisIterator {
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();
/**
* Move to the next node, without returning it. Returns true if there is
* a next node, false if the end of the sequence has been reached. After
* calling this method, the current node may be retrieved using the
* current() function.
*/
public boolean moveNext() {
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;
}
/**
* Return an iterator over an axis, starting at the current node.
*
* @param axis the axis to iterate over, using a constant such as
* {@link client.net.sf.saxon.ce.om.Axis#CHILD}
* @param test a predicate to apply to the nodes before returning them.
* @throws NullPointerException if there is no current node
*/
public AxisIterator iterateAxis(byte axis, NodeTest test) {
return current.iterateAxis(axis, test);
}
/**
* Return the atomized value of the current node.
*
* @return the atomized value.
* @throws NullPointerException if there is no current node
*/
public Value atomize() throws XPathException {
return current.getTypedValue();
}
/**
* Return the string value of the current node.
*
* @return the string value, as an instance of CharSequence.
* @throws NullPointerException if there is no current node
*/
public CharSequence getStringValue() {
return current.getStringValueCS();
}
/**
* 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},. 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;
}
/**
* 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) {}
}
// 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.