source: main/trunk/greenstone3/src/java/org/greenstone/gsdl3/util/DisplayItemUtil.java@ 36970

/*
 *    DisplayItemUtil.java
 *    Copyright (C) 2016 New Zealand Digital Library, http://www.nzdl.org
 *
 *    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 2 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
package org.greenstone.gsdl3.util;

import org.apache.log4j.Logger;

import org.greenstone.gsdl3.util.Dictionary;
import org.greenstone.gsdl3.util.GSXML;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;


/** various methods for handling displayItems and choosing the right one for the specified language */

public class DisplayItemUtil
{

  static Logger logger = Logger.getLogger(org.greenstone.gsdl3.util.DisplayItemUtil.class.getName());

  public static Element createDisplayItem(Document doc, String name, String lang, String value) {

    Element di = doc.createElement(GSXML.DISPLAY_TEXT_ELEM);
    di.setAttribute(GSXML.NAME_ATT, name);
    di.setAttribute(GSXML.LANG_ATT, lang);
    GSXML.setNodeText(di, value);
    return di;
  }
  /** looks for displayItems from config element and stores them in displayItemList in the form
   
      <displayItem name="X">
        <displayItem name="X" lang="">value</displayItem>
        <displayItem name="X" lang="">value</displayItem>
      </displayItem>

   */
  public static boolean storeDisplayItems(Element display_item_list, Element config) {
    if (config == null) {
      logger.error("the config element is null, no displayItems to be found");
      return false;
    }
    Document doc = display_item_list.getOwnerDocument();
    NodeList displaynodes = config.getElementsByTagName(GSXML.DISPLAY_TEXT_ELEM);
    if (displaynodes.getLength() > 0) {
      
      for (int k = 0; k < displaynodes.getLength(); k++) {
    Element d = (Element) displaynodes.item(k);
    String name = d.getAttribute(GSXML.NAME_ATT);
    Element this_item = GSXML.getNamedElement(display_item_list, GSXML.DISPLAY_TEXT_ELEM, GSXML.NAME_ATT, name);
    if (this_item == null) {
      this_item = doc.createElement(GSXML.DISPLAY_TEXT_ELEM);
      this_item.setAttribute(GSXML.NAME_ATT, name);
      display_item_list.appendChild(this_item);
    }
    
    this_item.appendChild(doc.importNode(d, true));
      }
    }
    
    return true;
     
  }
  
    /** Choose the best displayItem from a list - that matches lang - and return a copy of it created by doc. */
    public static Element chooseBestMatchDisplayItem(Document doc, Element display_item_list, String lang, String default_lang, ClassLoader class_loader) {


    // is there one with the specified language?
    Element best_di = GSXML.getNamedElement(display_item_list, GSXML.DISPLAY_TEXT_ELEM, GSXML.LANG_ATT, lang);
    if (best_di != null) {
        return (Element)doc.importNode(best_di, true);
    }

    // if not, have we got one with a key?
    best_di = GSXML.getNamedElement(display_item_list, GSXML.DISPLAY_TEXT_ELEM, GSXML.KEY_ATT, null);
    if (best_di != null) {
        // look up the dictionary
          String value = Dictionary.createDictionaryAndGetString(best_di.getAttribute(GSXML.DICTIONARY_ATT), class_loader, best_di.getAttribute(GSXML.KEY_ATT), lang, null);
        if (value != null) {
        // copy the node now. Don't want to be modifying the underlying list as can lead to concurrent access problems.
        best_di = (Element)doc.importNode(best_di, true);
        GSXML.setNodeText(best_di, value);
        return best_di;
        }
    }
    // ok, key one didn't work, can we use default lang?
    if (lang != default_lang) {
      best_di = GSXML.getNamedElement(display_item_list, GSXML.DISPLAY_TEXT_ELEM, GSXML.LANG_ATT, default_lang);
      if (best_di != null) {
        return (Element)doc.importNode(best_di, true);
      }
    }
    // STILL haven't found one, lets use the first one with a lang att (so we don't just get the key one back
    best_di = (Element) GSXML.getNamedElement(display_item_list, GSXML.DISPLAY_TEXT_ELEM, GSXML.LANG_ATT, null);
    if (best_di != null) {
        return (Element)doc.importNode(best_di, true);
    }
    return null;

    }

  /** Finds the best language specific match for each displayItem in display_item_list and adds it to description */
  public static boolean addLanguageSpecificDisplayItems(Element description, Element display_item_list, String lang, String default_lang, ClassLoader class_loader) {

    Document doc = description.getOwnerDocument();
    NodeList items = display_item_list.getChildNodes();
    for (int i = 0; i < items.getLength(); i++)
      { // for each key
    Element di_list = (Element) items.item(i);
    Element new_m = chooseBestMatchDisplayItem(doc, di_list, lang, default_lang, class_loader);

    if (new_m != null) {
      description.appendChild(new_m);
    }
      } // for each key
    return true;
    
  }


}