nthiterator.java

java1.6众多例子参考

/*
 * 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: NthIterator.java,v 1.2.4.1 2005/09/06 09:57:04 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;

/**
 * @author Jacek Ambroziak
 * @author Morten Jorgensen
 */
public final class NthIterator extends DTMAxisIteratorBase {
    // ...[N]
    private DTMAxisIterator _source;
    private final int _position;
    private boolean _ready;

    public NthIterator(DTMAxisIterator source, int n) {
	_source = source;
	_position = n;
    }

    public void setRestartable(boolean isRestartable) {
	_isRestartable = isRestartable;
	_source.setRestartable(isRestartable);
    }
    
    public DTMAxisIterator cloneIterator() {
	try {
	    final NthIterator clone = (NthIterator) super.clone();
	    clone._source = _source.cloneIterator();	// resets source
	    clone._isRestartable = false;
	    return clone;
	}
	catch (CloneNotSupportedException e) {
	    BasisLibrary.runTimeError(BasisLibrary.ITERATOR_CLONE_ERR,
				      e.toString());
	    return null;
	}
    }

    public int next() {
	if (_ready) {
	    _ready = false;
	    return _source.getNodeByPosition(_position);
	}
	return DTMAxisIterator.END;
	/*
	if (_ready && _position > 0) {
            final int pos = _source.isReverse()
                                       ? _source.getLast() - _position + 1
                                       : _position;

	    _ready = false;
	    int node;
	    while ((node = _source.next()) != DTMAxisIterator.END) {
		if (pos == _source.getPosition()) {
		    return node;
		}
	    }
	}
	return DTMAxisIterator.END;
	*/
    }

    public DTMAxisIterator setStartNode(final int node) {
	if (_isRestartable) {
	    _source.setStartNode(node);
	    _ready = true;
	}
	return this;
    }
	
    public DTMAxisIterator reset() {
	_source.reset();
	_ready = true;
	return this;
    }
    
    public int getLast() {
	return 1;
    }
    
    public int getPosition() {
	return 1;
    }
    
    public void setMark() {
	_source.setMark();
    }
    
    public void gotoMark() {
	_source.gotoMark();
    }
}