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Java example source code file (ForwardPositionIterator.java)

This example Java source code file (ForwardPositionIterator.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

clonenotsupportedexception, dtmaxisiterator, dtmaxisiteratorbase, forwardpositioniterator

The ForwardPositionIterator.java Java example source code

/*
 * reserved comment block
 * DO NOT REMOVE OR ALTER!
 */
/*
 * Copyright 2001-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: ForwardPositionIterator.java,v 1.2.4.1 2005/09/06 06:22:05 pvedula Exp $
 */

package com.sun.org.apache.xalan.internal.xsltc.dom;

import com.sun.org.apache.xalan.internal.xsltc.runtime.BasisLibrary;
import com.sun.org.apache.xml.internal.dtm.DTMAxisIterator;
import com.sun.org.apache.xml.internal.dtm.ref.DTMAxisIteratorBase;

/**
 * This iterator is a wrapper that always returns the position of
 * a node in document order. It is needed for the case where
 * a call to position() occurs in the context of an XSLT element
 * such as xsl:for-each, xsl:apply-templates, etc.
 *
 * The getPosition() methods in DTMAxisIterators defined
 * in DTMDefaultBaseIterators always return the position
 * in document order, which is backwards for XPath in the
 * case of the ancestor, ancestor-or-self, previous and
 * previous-sibling.
 *
 * XSLTC implements position() with the
 * BasisLibrary.positionF() method, and uses the
 * DTMAxisIterator.isReverse() method to determine
 * whether the result of getPosition() should be
 * interpreted as being equal to position().
 * But when the expression appears in apply-templates of
 * for-each, the position() function operates in document
 * order.
 *
 * The only effect of the ForwardPositionIterator is to force
 * the result of isReverse() to false, so that
 * BasisLibrary.positionF() calculates position() in a way
 * that's consistent with the context in which the
 * iterator is being used."
 *
 * (Apparently the correction of isReverse() occurs
 * implicitly, by inheritance. This class also appears
 * to maintain its own position counter, which seems
 * redundant.)
 *
 * @deprecated This class exists only for backwards compatibility with old
 *             translets.  New code should not reference it.
 */
public final class ForwardPositionIterator extends DTMAxisIteratorBase {

    private DTMAxisIterator _source;

    public ForwardPositionIterator(DTMAxisIterator source) {
        _source = source;
    }

    public DTMAxisIterator cloneIterator() {
        try {
            final ForwardPositionIterator clone =
                (ForwardPositionIterator) super.clone();
            clone._source = _source.cloneIterator();
            clone._isRestartable = false;
            return clone.reset();
        }
        catch (CloneNotSupportedException e) {
            BasisLibrary.runTimeError(BasisLibrary.ITERATOR_CLONE_ERR,
                                      e.toString());
            return null;
        }
    }

    public int next() {
        return returnNode(_source.next());
    }

    public DTMAxisIterator setStartNode(int node) {
        _source.setStartNode(node);
        return this;
    }

    public DTMAxisIterator reset() {
        _source.reset();
        return resetPosition();
    }

    public void setMark() {
        _source.setMark();
    }

    public void gotoMark() {
        _source.gotoMark();
    }
}

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