Library: org.gvsig.sldtools

/*******************************************************************************

 *

 *   gvSIG. Desktop Geographic Information System.

 *  

 *   Copyright (C) 2007-2013 gvSIG Association.

 *  

 *   This program is free software; you can redistribute it and/or

 *   modify it under the terms of the GNU General Public License

 *   as published by the Free Software Foundation; either version 3

 *   of the License, or (at your option) any later version.

 *  

 *   This program is distributed in the hope that it will be useful,

 *   but WITHOUT ANY WARRANTY; without even the implied warranty of

 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *   GNU General Public License for more details.

 *  

 *   You should have received a copy of the GNU General Public License

 *   along with this program; if not, write to the Free Software

 *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,

 *   MA  02110-1301, USA.

 *  

 *   For any additional information, do not hesitate to contact us

 *   at info AT gvsig.com, or visit our website www.gvsig.com.

 *   

 *******************************************************************************/

package org.gvsig.sldsupport.impl.util;

import java.util.Map;

import java.util.Stack;

/**

 * Title: XmlBuilder

 * Description: Util class to build xml

 * 

 * @author laura

 */

public class XmlBuilder {

    // Default size of the XML document to be generated. Used to set the initial

    // capacity of m_xml.

    private static final int DEF_XMLDOC_SIZE = 256;

    // Pad unit.

    private static final String PAD = "  ";

    // Number of pre-defined pad strings, one for each pad

    // level (0..NUM_PADSTRINGS-1). Should at least be set to 10 for

    // performance.

    private static final int NUM_PADSTRINGS = 20;

    // Byte representation of '\n'.

    private static final byte[] NEWLINE_BYTES = "\n".getBytes();

    // Array of pad strings, each preceded by a '\n' character.

    private static String s_padStrings[];

    // XML-encoded newline character.

    private static String s_newlineXmlEnc;

    // XML document being built.

    private StringBuffer m_xml = new StringBuffer(DEF_XMLDOC_SIZE);

    // Scratch buffer exclusively used to encode strings.

    private StringBuffer m_encodeBuf = new StringBuffer(40);

    // Current pad string.

    private String m_pad = "";

    // If set, indentation will be added to the XML document.

    private boolean m_autoPad;

    // Stack of strings. The string at the top is the tag name of the current

    // XML block. The string immediately below the top is the tag name of the

    // XML block that immediately encloses the current XML block.

    protected Stack m_openElements = new Stack();

    // Current pad level (0, 1, 2, ...).

    private int m_padLevel = 0;

    private String encoding = "UTF-8";

    /*

     * Create the pad strings.

     */

    static {

        s_padStrings = new String[NUM_PADSTRINGS];

        String pad = "";

        for (int i = 0; i < NUM_PADSTRINGS; i++) {

            s_padStrings[i] = "\n" + pad;

            pad += PAD;

        }

        StringBuffer tmp = new StringBuffer();

        for (int i = 0; i < NEWLINE_BYTES.length; i++) {

            tmp.append("&#");

            tmp.append(NEWLINE_BYTES[i]);

            tmp.append(";");

        }

        s_newlineXmlEnc = tmp.toString();

    }

    /**

     * Constructor. The XML document to be generated will automatically be

     * indented.

     */

    public XmlBuilder() {

        this(true);

    }

    /**

     * Constructor.

     * 

     * @param autoPad

     *            if set, the XML document to be generated will

     *            automatically be indented.

     */

    public XmlBuilder(boolean autoPad) {

        m_autoPad = autoPad;

        m_padLevel = 0;

        m_pad = s_padStrings[m_padLevel];

    }

    /**

     * Reset this XmlBuilder.

     */

    public void reset() {

        m_padLevel = 0;

        m_pad = s_padStrings[m_padLevel];

        m_xml.setLength(0);

    }

    /**

     * Adds raw data to the xml.

     */

    public void writeRaw(String raw) {

        m_xml.append(raw);

    }

    /**

     * Adds a comment to the xml.

     */

    public void writeComment(String comment) {

        if (m_autoPad) {

            m_xml.append(m_pad);

        }

        m_xml.append("<!-- ");

        encode(comment, m_xml);

        m_xml.append(" -->\n");

    }

    /**

     * Writes the XML document header.

     */

    public void writeHeader() {

        // XML document header.

        final String HEADER =

            "<?xml version=\"1.0\" encoding=\"" + encoding + "\"?>\n";

        m_xml.append(HEADER);

    }

    /**

     * Sets the encoding used in the XML. By default UTF-8 is used.

     * 

     * @param encoding

     */

    public void setEncoding(String encoding) {

        this.encoding = encoding;

    }

    /**

     * Adds a opening and closing tag with charcter data.

     */

    public void writeTag(String name, String data) {

        name = encode(name);

        if (m_autoPad) {

            m_xml.append(m_pad);

        }

        m_xml.append("<");

        m_xml.append(name);

        m_xml.append(">");

        encode(data, m_xml);

        m_xml.append("</");

        m_xml.append(name);

        m_xml.append(">");

    }

    /**

     * Adds a opening and closing tag with attributes.

     */

    public void writeTag(String name, Map attributes) {

        if (m_autoPad) {

            m_xml.append(m_pad);

        }

        m_xml.append("<");

        encode(name, m_xml);

        m_xml.append(" ");

        Object elems[] = attributes.keySet().toArray();

        for (int i = 0; i < elems.length; i++) {

            String nm = (String) elems[i];

            String val = (String) attributes.get(nm);

            encode(nm, m_xml);

            m_xml.append("=\"");

            encode(val, m_xml);

            m_xml.append("\" ");

        }

        m_xml.append("/>");

    }

    /**

     * Adds a opening and closing tag with an attribute and character data.

     */

    public void writeTag(String name, String attr1Name, String attr1Value,

        String attr2Name, String attr2Value) {

        if (m_autoPad) {

            m_xml.append(m_pad);

        }

        m_xml.append("<");

        encode(name, m_xml);

        m_xml.append(" ");

        encode(attr1Name, m_xml);

        m_xml.append("=\"");

        encode(attr1Value, m_xml);

        m_xml.append("\" ");

        encode(attr2Name, m_xml);

        m_xml.append("=\"");

        encode(attr2Value, m_xml);

        m_xml.append("\" ");

        m_xml.append("/>");

    }

    /**

     * Adds a opening and closing tag with an attribute and character data.

     */

    public void writeTag(String name, String data, String attrName,

        String attrValue) {

        name = encode(name);

        if (m_autoPad) {

            m_xml.append(m_pad);

        }

        m_xml.append("<");

        m_xml.append(name);

        m_xml.append(" ");

        encode(attrName, m_xml);

        m_xml.append("=\"");

        encode(attrValue, m_xml);

        m_xml.append("\" ");

        m_xml.append(">");

        encode(data, m_xml);

        m_xml.append("</");

        m_xml.append(name);

        m_xml.append(">");

    }

    /**

     * Adds a opening and closing tag with two attributes and character data.

     */

    public void writeTag(String name, String data, String attr1Name,

        String attr1Value, String attr2Name, String attr2Value) {

        name = encode(name);

        if (m_autoPad) {

            m_xml.append(m_pad);

        }

        m_xml.append("<");

        m_xml.append(name);

        m_xml.append(" ");

        encode(attr1Name, m_xml);

        m_xml.append("=\"");

        encode(attr1Value, m_xml);

        m_xml.append("\" ");

        encode(attr2Name, m_xml);

        m_xml.append("=\"");

        encode(attr2Value, m_xml);

        m_xml.append("\" ");

        m_xml.append(">");

        encode(data, m_xml);

        m_xml.append("</");

        m_xml.append(name);

        m_xml.append(">");

    }

    /**

     * Adds a opening and closing tag with attributes and character data.

     */

    public void writeTag(String name, String data, Map attributes) {

        name = encode(name);

        if (m_autoPad) {

            m_xml.append(m_pad);

        }

        m_xml.append("<");

        m_xml.append(name);

        m_xml.append(" ");

        Object elems[] = attributes.keySet().toArray();

        for (int i = 0; i < elems.length; i++) {

            String nm = (String) elems[i];

            String val = (String) attributes.get(nm);

            encode(nm, m_xml);

            m_xml.append("=\"");

            encode(val, m_xml);

            m_xml.append("\" ");

        }

        m_xml.append(">");

        encode(data, m_xml);

        m_xml.append("</");

        m_xml.append(name);

        m_xml.append(">");

    }

    /**

     * Writes an opening tag

     */

    public void openTag(String name) {

        name = encode(name);

        m_openElements.push(name); // must be encoded!

        if (m_autoPad) {

            m_xml.append(m_pad);

        }

        m_xml.append("<");

        m_xml.append(name);

        m_xml.append(">");

        if (m_autoPad) {

            m_padLevel++;

            if (m_padLevel < NUM_PADSTRINGS) {

                m_pad = s_padStrings[m_padLevel];

            } else // really deep nesting level

            {

                m_pad += PAD;

            }

        }

    }

    /**

     * Writes an opening tag with one attribute.

     */

    public void openTag(String name, String attrName, String attrValue) {

        name = encode(name);

        m_openElements.push(name); // must be encoded!

        if (m_autoPad) {

            m_xml.append(m_pad);

        }

        m_xml.append("<");

        m_xml.append(name);

        m_xml.append(" ");

        encode(attrName, m_xml);

        m_xml.append("=\"");

        encode(attrValue, m_xml);

        m_xml.append("\" ");

        m_xml.append(">");

        if (m_autoPad) {

            m_padLevel++;

            if (m_padLevel < NUM_PADSTRINGS) {

                m_pad = s_padStrings[m_padLevel];

            } else // really deep nesting level

            {

                m_pad += PAD;

            }

        }

    }

    /**

     * Writes an opening tag with two attributes.

     */

    public void openTag(String name, String attr1Name, String attr1Value,

        String attr2Name, String attr2Value) {

        name = encode(name);

        m_openElements.push(name); // must be encoded!

        if (m_autoPad) {

            m_xml.append(m_pad);

        }

        m_xml.append("<");

        m_xml.append(name);

        m_xml.append(" ");

        encode(attr1Name, m_xml);

        m_xml.append("=\"");

        encode(attr1Value, m_xml);

        m_xml.append("\" ");

        encode(attr2Name, m_xml);

        m_xml.append("=\"");

        encode(attr2Value, m_xml);

        m_xml.append("\" ");

        m_xml.append(">");

        if (m_autoPad) {

            m_padLevel++;

            if (m_padLevel < NUM_PADSTRINGS) {

                m_pad = s_padStrings[m_padLevel];

            } else // really deep nesting level

            {

                m_pad += PAD;

            }

        }

    }

    /**

     * Writes an opening tag with attributes.

     */

    public void openTag(String name, Map attributes) {

        name = encode(name);

        m_openElements.push(name); // must be encoded!

        if (m_autoPad) {

            m_xml.append(m_pad);

        }

        m_xml.append("<");

        m_xml.append(name);

        m_xml.append(" ");

        Object elems[] = attributes.keySet().toArray();

        for (int i = 0; i < elems.length; i++) {

            String nm = (String) elems[i];

            String val = (String) attributes.get(nm);

            encode(nm, m_xml);

            m_xml.append("=\"");

            encode(val, m_xml);

            m_xml.append("\" ");

        }

        m_xml.append(">");

        if (m_autoPad) {

            m_padLevel++;

            if (m_padLevel < NUM_PADSTRINGS) {

                m_pad = s_padStrings[m_padLevel];

            } else // really deep nesting level

            {

                m_pad += PAD;

            }

        }

    }

    /**

     * Closes an open tag.

     */

    public void closeTag() {

        if (m_autoPad) {

            if (m_padLevel > 0) {

                m_padLevel--;

            }

            if (m_padLevel < NUM_PADSTRINGS) {

                m_pad = s_padStrings[m_padLevel];

            } else // really deep nesting level

            {

                int len = m_pad.length() - PAD.length();

                if (len > 0) {

                    m_pad = m_pad.substring(0, len);

                }

            }

            m_xml.append(m_pad);

        }

        String name = (String) m_openElements.pop(); // already encoded

        m_xml.append("</");

        m_xml.append(name);

        m_xml.append(">");

    }

    /**

     * Get the xml.

     */

    public String getXML() {

        return m_xml.toString();

    }

/**

   * Encodes the funny characters (e.g., '&', '<', '\"') in an XML

   * string.

   *

   * @param  src  XML string to encode.

   * @return the encoded string.

   */

    private String encode(String src) {

        m_encodeBuf.setLength(0); // clear old contents

        encode(src, m_encodeBuf);

        return m_encodeBuf.toString();

    }

/**

   * Encodes the funny characters (e.g., '&', '<', '\"') in an XML

   * string.

   *

   * @param  src  XML string to encode.

   * @param  dst  string buffer to write the encoded XML string to.

   */

    private static final void encode(String src, StringBuffer dst) {

        int n = src.length();

        for (int i = 0; i < n; i++) {

            char c = src.charAt(i);

            switch (c) {

            case '&':

                dst.append("&");

                break;

            case '<':

                dst.append("<");

                break;

            case '>':

                dst.append(">");

                break;

            case '\'':

                dst.append("'");

                break;

            case '\"':

                dst.append(""");

                break;

            case '\n':

                dst.append(s_newlineXmlEnc);

                break;

            default:

                dst.append(c);

            }

        }

    }

}