abstractnode.java

Java的面向对象数据库系统的源代码

/*
 * 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 1.3 2003/06/10 16:18:36 per_nyfelt Exp $
 */

package org.ozoneDB.xml.dom4j.o3impl;

import org.dom4j.*;
import org.dom4j.rule.Pattern;
import org.ozoneDB.OzoneObject;

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

/** <p><code>AbstractNode</code> is an abstract base class for
 * tree implementors to use for implementation inheritence.</p>
 *
 * @author <a href="mailto:[e-mail]">James Strachan</a>
 * @version $Revision: 1.3 $
 */
public abstract class AbstractNode extends OzoneObject 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 factory instances used by default */
    private static NodeFactory NODE_FACTORY;
    private static XPathFactory XPATH_FACTORY;

    private NodeFactory nodeFactory;
    private XPathFactory xpathFactory;

    protected AbstractNode() {
    }

    public void onCreate() {
        super.onCreate();
        NODE_FACTORY = OzoneDocumentFactoryImpl.getInstance(database());
        XPATH_FACTORY = OzoneDocumentFactoryImpl.getInstance(database());
    }

    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 self();
        } 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((Node)self());
        } else {
            Document document = getDocument();
            if (document != null) {
                document.remove((Node)self());
            }
        }
        setParent(null);
        setDocument(null);
        return (Node)self();
    }

    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.evaluate(self());
    }

    public List selectNodes(String xpathExpression) {
        XPath xpath = createXPath(xpathExpression);
        return xpath.selectNodes(self());
    }

    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(self(), sortBy, removeDuplicates);
    }

    public Node selectSingleNode(String xpathExpression) {
        XPath xpath = createXPath(xpathExpression);
        return xpath.selectSingleNode(self());
    }

    public String valueOf(String xpathExpression) {
        XPath xpath = createXPath(xpathExpression);
        return xpath.valueOf(self());
    }

    public Number numberValueOf(String xpathExpression) {
        XPath xpath = createXPath(xpathExpression);
        return xpath.numberValueOf(self());
    }

    public boolean matches(String patternText) {
        NodeFilter filter = createXPathFilter(patternText);
        return filter.matches((Node)self());
    }

    public XPath createXPath(String xpathExpression) {
        return getXPathFactory().createXPath(xpathExpression);
    }

    public NodeFilter createXPathFilter(String patternText) {
        return getXPathFactory().createXPathFilter(patternText);
    }

    public Pattern createPattern(String patternText) {
        return getXPathFactory().createPattern(patternText);
    }


    public Node asXPathResult(Element parent) {
        if (supportsParent()) {
            return (Node)self();
        }
        return createXPathResult(parent);
    }

    /**
     * @deprecated      Use getNodeFactory() and getXPathFactory() instead.
     */
    public DocumentFactory getDocumentFactory() {
        return new DelegateDocumentFactory(getNodeFactory(), getXPathFactory());
    }

    /**
     * @deprecated      Use setNodeFactory() and setXPathFactory() instead.
     */
    public void setDocumentFactory(DocumentFactory factory) {
        this.nodeFactory = factory;
        this.xpathFactory = factory;
    }

    protected NodeFactory getNodeFactory() {
        return (nodeFactory == null) ? NODE_FACTORY : nodeFactory;
    }

    protected void setNodeFactory(NodeFactory nodeFactory) {
        this.nodeFactory = nodeFactory;
    }

    protected XPathFactory getXPathFactory() {
        return (xpathFactory == null) ? XPATH_FACTORY : xpathFactory;
    }

    protected void setXPathFactory(XPathFactory xpathFactory) {
        this.xpathFactory = xpathFactory;
    }

    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 [e-mail].
 *
 * 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 1.3 2003/06/10 16:18:36 per_nyfelt Exp $
 */