/*
 * Copyright 2001 (C) MetaStuff, Ltd. All Rights Reserved.
 * 
 * This software is open source. 
 * See the bottom of this file for the licence.
 * 
 * $Id: AbstractNode.java,v 1.23 2001/09/15 14:55:14 jstrachan Exp $
 */

package org.dom4j.tree;

import java.io.IOException;
import java.io.Serializable;
import java.io.StringWriter;
import java.io.Writer;
import java.util.List;

import org.dom4j.Document;
import org.dom4j.DocumentFactory;
import org.dom4j.Element;
import org.dom4j.Node;
import org.dom4j.NodeFilter;
import org.dom4j.Visitor;
import org.dom4j.XPath;
import org.dom4j.rule.Pattern;

/** <p><code>AbstractNode</code> is an abstract base class for 
  * tree implementors to use for implementation inheritence.</p>
 *
 * @author <a href="mailto:james.strachan@metastuff.com">James Strachan</a>
 * @version $Revision: 1.23 $
 */
public abstract class AbstractNode implements Node, Cloneable, Serializable {
    
    protected static final String[] NODE_TYPE_NAMES ={
        "Node", "Element", "Attribute", "Text", "CDATA", "Entity", "Entity", "ProcessingInstruction", 
        "Comment", "Document", "DocumentType", "DocumentFragment", "Notation", "Namespace","Unknown" 
    };
    
    /** The <code>DocumentFactory</code> instance used by default */
    private static final DocumentFactory DOCUMENT_FACTORY = DocumentFactory.getInstance();
    

    public AbstractNode() {
    }

    public short getNodeType() {
        return UNKNOWN_NODE;
    }

    public String getNodeTypeName() {
        int type = getNodeType();
        if ( type < 0 || type >= NODE_TYPE_NAMES.length ) {
            return "Unknown";
        }
        return NODE_TYPE_NAMES[type];
    }
    
    public Document getDocument() {
        Element element = getParent();
        return ( element != null ) ? element.getDocument() : null;
    }
    
    public void setDocument(Document document) {
    }
    
    public Element getParent() {
        return null;
    }

    public void setParent(Element parent) {
    }
    
    public boolean supportsParent() {
        return false;
    }

    public boolean isReadOnly() {
        return true;
    }
    
    public boolean hasContent() {
        return false;
    }
    
    public String getPath() {
        return getPath(null);
    }
    
    public String getUniquePath() {
        return getUniquePath(null);
    }
    

    public Object clone() {
        if ( isReadOnly() ) {
            return this;
        }
        else {
            try {
                Node answer = (Node) super.clone();
                answer.setParent( null );
                answer.setDocument( null );
                return answer;
            }
            catch (CloneNotSupportedException e) {
                // should never happen
                throw new RuntimeException( "This should never happen. Caught: " + e );
            }
        }
    }

    public Node detach() {
        Element parent = getParent();
        if ( parent != null ) {
            parent.remove( this );
        }
        else {
            Document document = getDocument();
            if ( document != null ) {
                document.remove( this );
            }
        }
        setParent(null);
        setDocument(null);
        return this;
    }
    
    public String getName() {
        return null;
    }

    public void setName(String name) {
        throw new UnsupportedOperationException( "This node cannot be modified" );
    }

    public String getText() {
        return null;
    }
    
    public String getStringValue() {
        return getText();
    }
    
    public void setText(String text) {
        throw new UnsupportedOperationException( "This node cannot be modified" );
    }
    
    
    public void write(Writer writer) throws IOException {
        writer.write( asXML() );
    }
        

    // XPath methods
    
    public Object selectObject(String xpathExpression) {
        XPath xpath = createXPath(xpathExpression);
        return xpath.selectObject(this);
    }
    
    public List selectNodes(String xpathExpression) {
        XPath xpath = createXPath(xpathExpression);
        return xpath.selectNodes(this);
    }
    
    public List selectNodes( 
        String xpathExpression, 
        String comparisonXPathExpression 
    ) {
        return selectNodes( 
            xpathExpression,  comparisonXPathExpression, false 
        );
    }
    
    public List selectNodes(
        String xpathExpression, 
        String comparisonXPathExpression, 
        boolean removeDuplicates
    ) {
        XPath xpath = createXPath(xpathExpression);
        XPath sortBy = createXPath(comparisonXPathExpression);
        return xpath.selectNodes(this, sortBy, removeDuplicates);
    }
    
    public Node selectSingleNode(String xpathExpression) {
        XPath xpath = createXPath(xpathExpression);
        return xpath.selectSingleNode(this);
    }
    
    public String valueOf(String xpathExpression) {
        XPath xpath = createXPath(xpathExpression);
        return xpath.valueOf(this);
    }
    
    public Number numberValueOf(String xpathExpression) {
        XPath xpath = createXPath(xpathExpression);
        return xpath.numberValueOf(this);
    }
    
    public boolean matches(String patternText) {        
        NodeFilter filter = createXPathFilter(patternText);
        return filter.matches(this);
    }
    
    public XPath createXPath(String xpathExpression) {
        return getDocumentFactory().createXPath(xpathExpression);
    }
    
    public NodeFilter createXPathFilter(String patternText) {
        return getDocumentFactory().createXPathFilter(patternText);
    }
    
    public Pattern createPattern(String patternText) {
        return getDocumentFactory().createPattern(patternText);
    }
    
    
    public Node asXPathResult(Element parent) {
        if (supportsParent()) {
            return this;
        }
        return createXPathResult(parent);
    }
    
    protected DocumentFactory getDocumentFactory() {
        return DOCUMENT_FACTORY;
    }
    
    protected Node createXPathResult(Element parent) {
        throw new RuntimeException("asXPathResult() not yet implemented fully for: " + this );
    }
    
}




/*
 * Redistribution and use of this software and associated documentation
 * ("Software"), with or without modification, are permitted provided
 * that the following conditions are met:
 *
 * 1. Redistributions of source code must retain copyright
 *    statements and notices.  Redistributions must also contain a
 *    copy of this document.
 *
 * 2. 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.
 *
 * 3. The name "DOM4J" must not be used to endorse or promote
 *    products derived from this Software without prior written
 *    permission of MetaStuff, Ltd.  For written permission,
 *    please contact dom4j-info@metastuff.com.
 *
 * 4. Products derived from this Software may not be called "DOM4J"
 *    nor may "DOM4J" appear in their names without prior written
 *    permission of MetaStuff, Ltd. DOM4J is a registered
 *    trademark of MetaStuff, Ltd.
 *
 * 5. Due credit should be given to the DOM4J Project
 *    (http://dom4j.org/).
 *
 * THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESSED 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
 * METASTUFF, LTD. OR ITS 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.
 *
 * Copyright 2001 (C) MetaStuff, Ltd. All Rights Reserved.
 *
 * $Id: AbstractNode.java,v 1.23 2001/09/15 14:55:14 jstrachan Exp $
 */