net.sf.saxon.expr.AppendIterator Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of saxon9 Show documentation

Provides a basic XSLT 2.0 and XQuery 1.0 processor (W3C Recommendations, January 2007). Command line interfaces and implementations of several Java APIs (DOM, XPath, s9api) are also included.

The newest version!

package net.sf.saxon.expr;

import net.sf.saxon.om.SequenceIterator;
import net.sf.saxon.om.Item;
import net.sf.saxon.trans.XPathException;

/**
* Iterator that concatenates the results of two supplied iterators
*/

public class AppendIterator implements SequenceIterator {

    private SequenceIterator first;
    private SequenceIterable second;
    private XPathContext context;
    private SequenceIterator currentIterator;
    private int position = 0;

    /**
     * This form of constructor is designed to delay getting an iterator for the second
     * expression until it is actually needed. This gives savings in cases where the
     * iteration is aborted prematurely.
     * @param first Iterator over the first operand
     * @param second The second operand
     * @param context The dynamic context for evaluation of the second operand
     */

    public AppendIterator(SequenceIterator first, SequenceIterable second, XPathContext context) {
        this.first = first;
        this.second = second;
        this.context = context;
        this.currentIterator = first;
    }

    public Item next() throws XPathException {
        Item n = currentIterator.next();
        if (n == null && currentIterator==first) {
            currentIterator = second.iterate(context);
            n = currentIterator.next();
        }
        if (n == null) {
            position = -1;
        } else {
            position++;
        }
        return n;
    }

    public Item current() {
        return currentIterator.current();
    }

    public int position() {
        return position;
    }

    public SequenceIterator getAnother() throws XPathException {
        return new AppendIterator(first.getAnother(), second, context);
    }

    /**
     * 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 SequenceIterator#GROUNDED}, {@link SequenceIterator#LAST_POSITION_FINDER},
     *         and {@link 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;
    }
}

//
// 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.
//