/*
* $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/DefaultNavigator.java,v 1.19 2006/02/05 21:47:41 elharo Exp $
* $Revision: 1.19 $
* $Date: 2006/02/05 21:47:41 $
*
* ====================================================================
*
* Copyright 2000-2002 bob mcwhirter & James Strachan.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* * Neither the name of the Jaxen Project nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
* OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* ====================================================================
* This software consists of voluntary contributions made by many
* individuals on behalf of the Jaxen Project and was originally
* created by bob mcwhirter <bob@werken.com> and
* James Strachan <jstrachan@apache.org>. For more information on the
* Jaxen Project, please see <http://www.jaxen.org/>.
*
* $Id: DefaultNavigator.java,v 1.19 2006/02/05 21:47:41 elharo Exp $
*/
package org.orbeon.jaxen;
import org.orbeon.jaxen.pattern.Pattern;
import org.orbeon.jaxen.util.*;
import java.util.Iterator;
/** Default implementation of {@link Navigator}.
*
* <p>
* This implementation is an abstract class, since
* some required operations cannot be implemented without
* additional knowledge of the object model.
* </p>
*
* <p>
* When possible, default method implementations build
* upon each other, to reduce the number of methods required
* to be implemented for each object model. All methods,
* of course, may be overridden, to provide more-efficient
* implementations.
* </p>
*
* @author bob mcwhirter (bob@werken.com)
* @author Erwin Bolwidt (ejb@klomp.org)
*/
public abstract class DefaultNavigator implements Navigator
{
/** Throws <code>UnsupportedAxisException</code>
*
* @param contextNode
* @return never returns
* @throws UnsupportedAxisException always
*/
public Iterator getChildAxisIterator(Object contextNode) throws UnsupportedAxisException
{
throw new UnsupportedAxisException("child");
}
/* (non-Javadoc)
* @see org.orbeon.jaxen.Navigator#getDescendantAxisIterator(java.lang.Object)
*/
public Iterator getDescendantAxisIterator(Object contextNode) throws UnsupportedAxisException
{
return new DescendantAxisIterator( contextNode,
this );
}
/** Throws <code>UnsupportedAxisException</code>
*
* @param contextNode
* @return never returns
* @throws UnsupportedAxisException
*/
public Iterator getParentAxisIterator(Object contextNode) throws UnsupportedAxisException
{
throw new UnsupportedAxisException("parent");
}
public Iterator getAncestorAxisIterator(Object contextNode) throws UnsupportedAxisException
{
return new AncestorAxisIterator( contextNode,
this );
}
public Iterator getFollowingSiblingAxisIterator(Object contextNode) throws UnsupportedAxisException
{
return new FollowingSiblingAxisIterator( contextNode,
this );
}
public Iterator getPrecedingSiblingAxisIterator(Object contextNode) throws UnsupportedAxisException
{
return new PrecedingSiblingAxisIterator( contextNode,
this );
}
public Iterator getFollowingAxisIterator(Object contextNode) throws UnsupportedAxisException
{
return new FollowingAxisIterator( contextNode,
this );
// throw new UnsupportedAxisException("following");
}
public Iterator getPrecedingAxisIterator(Object contextNode) throws UnsupportedAxisException
{
return new PrecedingAxisIterator( contextNode,
this );
// throw new UnsupportedAxisException("preceding");
}
/** Throws <code>UnsupportedAxisException</code>. Subclasses that
* support the attribute axis must override this method.
*
* @param contextNode
* @return never returns
* @throws UnsupportedAxisException
*/
public Iterator getAttributeAxisIterator(Object contextNode) throws UnsupportedAxisException
{
throw new UnsupportedAxisException("attribute");
}
/** Throws <code>UnsupportedAxisException</code>. Subclasses that
* support the namespace axis must override this method.
*
* @param contextNode
* @return never returns
* @throws UnsupportedAxisException
*/
public Iterator getNamespaceAxisIterator(Object contextNode) throws UnsupportedAxisException
{
throw new UnsupportedAxisException("namespace");
}
public Iterator getSelfAxisIterator(Object contextNode) throws UnsupportedAxisException
{
return new SelfAxisIterator( contextNode );
}
public Iterator getDescendantOrSelfAxisIterator(Object contextNode) throws UnsupportedAxisException
{
return new DescendantOrSelfAxisIterator( contextNode,
this );
}
public Iterator getAncestorOrSelfAxisIterator(Object contextNode) throws UnsupportedAxisException
{
return new AncestorOrSelfAxisIterator( contextNode,
this );
}
public Object getDocumentNode(Object contextNode)
{
return null;
}
public String translateNamespacePrefixToUri(String prefix, Object element)
{
return null;
}
public String getProcessingInstructionTarget(Object obj)
{
return null;
}
public String getProcessingInstructionData(Object obj)
{
return null;
}
public short getNodeType(Object node)
{
if ( isElement(node) )
{
return Pattern.ELEMENT_NODE;
}
else if ( isAttribute(node) )
{
return Pattern.ATTRIBUTE_NODE;
}
else if ( isText(node) )
{
return Pattern.TEXT_NODE;
}
else if ( isComment(node) )
{
return Pattern.COMMENT_NODE;
}
else if ( isDocument(node) )
{
return Pattern.DOCUMENT_NODE;
}
else if ( isProcessingInstruction(node) )
{
return Pattern.PROCESSING_INSTRUCTION_NODE;
}
else if ( isNamespace(node) )
{
return Pattern.NAMESPACE_NODE;
}
else {
return Pattern.UNKNOWN_NODE;
}
}
/**
* Default inefficient implementation. Subclasses
* should override this method.
*
* @param contextNode the node whose parent to return
* @return the parent node
* @throws UnsupportedAxisException if the parent axis is not supported
*/
public Object getParentNode(Object contextNode) throws UnsupportedAxisException
{
Iterator iter = getParentAxisIterator( contextNode );
if ( iter != null && iter.hasNext() )
{
return iter.next();
}
return null;
}
/**
* Default implementation that always returns null. Override in subclass
* if the subclass can load documents.
*
* @param url the URL of the document to load
*
* @return null
* @throws FunctionCallException if an error occurs while loading the
* URL; e.g. an I/O error or the document is malformed
*/
public Object getDocument(String url) throws FunctionCallException
{
return null;
}
/**
* Default implementation that cannot find elements. Override in subclass
* if subclass does know about attribute types.
*
* @param contextNode a node from the document in which to look for the
* id
* @param elementId id to look for
*
* @return null
*/
public Object getElementById(Object contextNode, String elementId)
{
return null;
}
}