| gvSIG desktop 1

package org.gvsig.fmap.mapcontext.rendering.legend;

import java.util.HashMap;

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, HashMap 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, HashMap 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, HashMap 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); 

      }

    }

  }

}