package org.pdf4j.saxon.expr;
import org.pdf4j.saxon.om.Item;
import org.pdf4j.saxon.om.SequenceIterator;
import org.pdf4j.saxon.trans.XPathException;
/**
* ContextMappingIterator merges a sequence of sequences into a single flat
* sequence. It takes as inputs an iteration, and a mapping function to be
* applied to each Item returned by that iteration. The mapping function itself
* returns another iteration. The result is an iteration of the concatenation of all
* the iterations returned by the mapping function.<p>
*
* This is a specialization of the MappingIterator class: it differs in that it
* sets each item being processed as the context item
*/
public final class ContextMappingIterator implements SequenceIterator {
private SequenceIterator base;
private ContextMappingFunction action;
private XPathContext context;
private SequenceIterator stepIterator = null;
private Item current = null;
private int position = 0;
/**
* Construct a ContextMappingIterator that will apply a specified ContextMappingFunction to
* each Item returned by the base iterator.
* @param action the mapping function to be applied
* @param context the processing context. The mapping function is applied to each item returned
* by context.getCurrentIterator() in turn.
*/
public ContextMappingIterator(ContextMappingFunction action, XPathContext context) {
base = context.getCurrentIterator();
this.action = action;
this.context = context;
}
public Item next() throws XPathException {
Item nextItem;
while (true) {
if (stepIterator != null) {
nextItem = stepIterator.next();
if (nextItem != null) {
break;
} else {
stepIterator = null;
}
}
if (base.next() != null) {
// Call the supplied mapping function
stepIterator = action.map(context);
nextItem = stepIterator.next();
if (nextItem == null) {
stepIterator = null;
} else {
break;
}
} else {
stepIterator = null;
current = null;
position = -1;
return null;
}
}
current = nextItem;
position++;
return nextItem;
}
public Item current() {
return current;
}
public int position() {
return position;
}
public void close() {
base.close();
}
public SequenceIterator getAnother() throws XPathException {
SequenceIterator newBase = base.getAnother();
XPathContext c2 = context;
if (c2!=null) {
c2 = c2.newMinorContext();
c2.setCurrentIterator(newBase);
c2.setOrigin(context.getOrigin());
}
return new ContextMappingIterator(action, c2);
}
/**
* 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 org.pdf4j.saxon.om.SequenceIterator#GROUNDED}, {@link org.pdf4j.saxon.om.SequenceIterator#LAST_POSITION_FINDER},
* and {@link org.pdf4j.saxon.om.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;
}
/**
* 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.atomizing = 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.
//