o3documenthelper.java

Java的面向对象数据库系统的源代码

    /** <p><code>sort</code> sorts the given List of Nodes
     * using an XPath expression as a {@link java.util.Comparator}
     * and optionally removing duplicates.</p>
     *
     * @param list is the list of Nodes to sort
     * @param xpathExpression is the XPath expression used for comparison
     * @param distinct if true then duplicate values (using the sortXPath for
     *     comparisions) will be removed from the List
     */
    public static void sort(List list, String xpathExpression, boolean distinct) throws Exception {
        XPath xpath = createXPath(xpathExpression);
        xpath.sort(list, distinct);
    }

    /** <p><code>parseText</code> parses the given text as an XML document
     * and returns the newly created Document.
     *
     * @param text is the XML text to be parsed
     * @return a newly parsed Document
     * @throws org.dom4j.DocumentException if the document could not be parsed
     */
    public static Document parseText(String text) throws DocumentException {
        try {
            return getDocumentBuilder().parse(text);
        } catch (Exception e) {
            throw new DocumentException(e);
        }
    }

    public static Document parseText(String text, String objectName) throws DocumentException {
        try {
            return getDocumentBuilder().parse(text, objectName);
        } catch (Exception e) {
            throw new DocumentException(e);
        }
    }

    /**
     * Since an InputStream is not serializable we convert the content to a String
     * This might cause memory issues on big documents
     * @param in
     * @return
     * @throws DocumentException
     */
    public static Document parse(InputStream in) throws DocumentException {
        //return getDocumentBuilder().parse(in);
        return parse(new InputStreamReader(in));
    }

    /**
     * Since an InputStream is not serializable we convert the content to a String
     * This might cause memory issues on big documents
     * @param in
     * @return
     * @throws DocumentException
     */
    public static Document parse(InputStream in, String objectName) throws DocumentException {
        return parse(new InputStreamReader(in), objectName);
    }

    /**
     * Since a Reader is not serializable we convert the content to a String
     * This might cause memory issues on big documents
     * @param reader
     * @return
     * @throws DocumentException
     */
    public static Document parse(Reader reader, String objectName) throws DocumentException {
        try {
            return getDocumentBuilder().parse(convertToString(reader), objectName);
        } catch (Exception e) {
            throw new DocumentException(e);
        }
    }

    /**
     * Since a Reader is not serializable we convert the content to a String
     * This might cause memory issues on big documents
     * @param reader
     * @return
     * @throws DocumentException
     */
    public static Document parse(Reader reader) throws DocumentException {
        try {
            //return getDocumentBuilder().parse(reader);
            return getDocumentBuilder().parse(convertToString(reader));
        } catch (Exception e) {
            throw new DocumentException(e);
        }
    }

    private static String convertToString(Reader reader) throws IOException {
        LineNumberReader lineReader = new LineNumberReader(reader);
        StringBuffer buf = new StringBuffer();
        String temp;

        while ((temp = lineReader.readLine()) != null) {
            buf.append(temp);
        }
        lineReader.close();
        return buf.toString();
    }

    /**
     * This will probably not work but something to this effect needs to exist
     * in order to send the stream content through the pipe over to the server
     * @param in
     * @return
     * @throws Exception
     */
    public static Document parseRemote(InputStream in) throws Exception {
        DocumentBuilder builder = getDocumentBuilder();
        SocketAddress address = builder.prepareStreamParsing();
        Socket socket = new Socket();
        socket.connect(address);
        OutputStream out = socket.getOutputStream();
        byte[] buf = new byte[8092];

        for (int i = 0; (i = in.read(buf)) != -1;) {
            out.write(buf, 0, i);
        }
        out.flush();
        out.close();
        in.close();
        Document result = builder.getResult();
        return result;
    }

    private static DocumentBuilder getDocumentBuilder() throws Exception {
        if (builder == null) {
            builder = (DocumentBuilder) getDb().objectForName(DocumentBuilder.OBJECT_NAME);
            if (builder == null) {
                builder = DocumentBuilderImpl.create(getDb());
            }
        }
        return builder;
    }

    /**
     * Should not be used on the client side since the use will be quite slow
     * (every sax event will result in a remote call). But if we are using LocalDatabase
     * this is not the case so we might as well expose it since it gives much more flexibility
     * @return a SAXREader used for SAX based parsing
     */
    public static SAXReader getSAXReader() {
        return new O3SAXReader(getDb(), factory);
    }

    /** <p>makeElement</p> a helper method which navigates from the
     * given Document or Element node to some Element using the path
     * expression, creating any necessary elements along the way.
     * For example the path <code>a/b/c</code> would get the first
     * child &lt;a&gt; element, which would be created if it did not
     * exist, then the next child &lt;b&gt; and so on until finally a
     * &lt;c&gt; element is returned.
     *
     * @param source is the Element or Document to start navigating from
     * @param path is a simple path expression, seperated by '/' which denotes
     * the path from the source to the resulting element such as a/b/c
     *
     * @return the first Element on the given path which either already
     * existed on the path or were created by this method.
     */
    public static Element makeElement(Branch source, String path) {
        StringTokenizer enum = new StringTokenizer(path, "/");
        Element parent;
        if (source instanceof Document) {
            Document document = (Document) source;
            parent = document.getRootElement();

            // lets throw a NoSuchElementException
            // if we are given an empty path
            String name = enum.nextToken();
            if (parent == null) {
                parent = document.addElement(name);
            }
        } else {
            parent = (Element) source;
        }
        Element element = null;
        while (enum.hasMoreTokens()) {
            String name = enum.nextToken();
            if (name.indexOf(':') > 0) {
                element = parent.element(parent.getQName(name));
            } else {
                element = parent.element(name);
            }
            if (element == null) {
                element = parent.addElement(name);
            }
            parent = element;
        }
        return element;
    }
}


/*
 * 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: O3DocumentHelper.java,v 1.3 2003/11/02 18:10:02 per_nyfelt Exp $
 */