/*
    * Copyright (C) 2007 ETH Zurich
    *
    * This file is part of Fosstrak (www.fosstrak.org).
    *
    * Fosstrak is free software; you can redistribute it and/or
    * modify it under the terms of the GNU Lesser General Public
    * License version 2.1, as published by the Free Software Foundation.
    *
   * Fosstrak 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
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with Fosstrak; if not, write to the Free
   * Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
   * Boston, MA  02110-1301  USA
   */
  
  package org.fosstrak.epcis.captureclient;
  
  import java.net.URL;
  import java.text.DecimalFormat;
  import java.util.ArrayList;
  import java.util.Calendar;
  import java.util.GregorianCalendar;
  import java.util.List;
  import java.util.Map;
  import java.util.StringTokenizer;
  import java.util.TimeZone;
  import java.util.Map.Entry;
  
  import javax.swing.ImageIcon;
  
  import org.w3c.dom.Document;
  import org.w3c.dom.Element;
  
  /**
   * This is a helper class which encapsulates common functionality used within
   * the capture client classes.
   * 
   * @author Marco Steybe
   */
  public class CaptureClientHelper {
  
      /**
       * Miscellaneous numeric formats used in formatting.
       */
      public static final DecimalFormat XX_FORMAT = new DecimalFormat("00");
      public static final DecimalFormat XXX_FORMAT = new DecimalFormat("000");
      public static final DecimalFormat XXXX_FORMAT = new DecimalFormat("0000");
  
      /**
       * The various tooltips.
       */
      public static final String toolTipDate = "Format is ISO 8601, i.e. YYYY-MM-DDThh:mm:ss.SSSZ";
      public static final String toolTipUri = "URI";
      public static final String toolTipUris = "One or multiple URIs, separated by spaces";
      public static final String toolTipInteger = "Integer number";
      public static final String toolTipOptional = ". This field is optional";
      public static final String toolTipBizTransType = "Business Transaction Type";
      public static final String toolTipBizTransID = "Business Transactio ID";
  
      /**
       * The possible values for the "actions" parameter.
       */
      public static final String[] ACTIONS = { "ADD", "OBSERVE", "DELETE" };
  
      /**
       * The four possible event types, in human readable form.
       */
      public static final String[] EPCIS_EVENT_NAMES = {
              "Object event", "Aggregation event", "Quantity event", "Transaction event" };
  
      public enum EpcisEventType {
  
          ObjectEvent(0, "Object event"), AggregationEvent(1, "Aggregation event"), QuantityEvent(2, "Quantity event"),
          TransactionEvent(3, "Transaction event");
  
          private int guiIndex;
          private String guiName;
  
          private EpcisEventType(int guiIndex, String guiName) {
              this.guiIndex = guiIndex;
              this.guiName = guiName;
          }
  
          public static EpcisEventType fromGuiIndex(int index) {
              for (EpcisEventType eventType : values()) {
                  if (eventType.guiIndex == index) {
                      return eventType;
                  }
              }
              return null;
          }
  
          public static String[] guiNames() {
              String[] guiNames = new String[values().length];
             for (int i = 0; i < values().length; i++) {
                 guiNames[i] = values()[i].getGuiName();
             }
             return guiNames;
         }
 
         public String getGuiName() {
             return guiName;
         }
     }
 
     /**
      * Returns the time zone designator in a ISO6601-compliant format from the
      * given <code>Calendar</code> value.
      * 
      * @param cal
      *            The Calendar to be formatted.
      * @return The time zone designator from the given Calendar.
      */
     public static String getTimeZone(final Calendar cal) {
         StringBuilder buf = new StringBuilder();
         TimeZone tz = cal.getTimeZone();
         // determine offset of timezone from UTC (incl. daylight saving)
         int offset = tz.getOffset(cal.getTimeInMillis());
         int hours = Math.abs((offset / (60 * 1000)) / 60);
         int minutes = Math.abs((offset / (60 * 1000)) % 60);
         buf.append(offset < 0 ? '-' : '+');
         buf.append(XX_FORMAT.format(hours));
         buf.append(':');
         buf.append(XX_FORMAT.format(minutes));
         return buf.toString();
     }
 
     /**
      * Formats a <code>Calendar</code> value into an ISO8601-compliant date/time
      * string.
      * 
      * @param cal
      *            The time value to be formatted into a date/time string.
      * @return The formatted date/time string.
      */
     public static String format(final Calendar cal) {
         if (cal == null) {
             throw new IllegalArgumentException("argument can not be null");
         }
 
         // determine era and adjust year if necessary
         int year = cal.get(Calendar.YEAR);
         if (cal.isSet(Calendar.ERA) && cal.get(Calendar.ERA) == GregorianCalendar.BC) {
             /**
              * calculate year using astronomical system: year n BCE =>
              * astronomical year -n + 1
              */
             year = 0 - year + 1;
         }
 
         /**
          * the format of the date/time string is: YYYY-MM-DDThh:mm:ss.SSSTZD
          * note that we cannot use java.text.SimpleDateFormat for formatting
          * because it can't handle years <= 0 and TZD's
          */
         StringBuilder buf = new StringBuilder();
         // year ([-]YYYY)
         buf.append(XXXX_FORMAT.format(year));
         buf.append('-');
         // month (MM)
         buf.append(XX_FORMAT.format(cal.get(Calendar.MONTH) + 1));
         buf.append('-');
         // day (DD)
         buf.append(XX_FORMAT.format(cal.get(Calendar.DAY_OF_MONTH)));
         buf.append('T');
         // hour (hh)
         buf.append(XX_FORMAT.format(cal.get(Calendar.HOUR_OF_DAY)));
         buf.append(':');
         // minute (mm)
         buf.append(XX_FORMAT.format(cal.get(Calendar.MINUTE)));
         buf.append(':');
         // second (ss)
         buf.append(XX_FORMAT.format(cal.get(Calendar.SECOND)));
         buf.append('.');
         // millisecond (SSS)
         buf.append(XXX_FORMAT.format(cal.get(Calendar.MILLISECOND)));
         // time zone designator (+/-hh:mm)
         buf.append(getTimeZone(cal));
         return buf.toString();
     }
 
     /**
      * Implements a class that holds examples for the EPCIS Capture Interface
      * Client.
      * 
      * @author David Gubler
      */
     public static final class ExampleEvents {
  
         private static List<CaptureEvent> examples = null;
 
         /**
          * Sets up the examples. Add examples here if you wish.
          */
         private static void initEvents() {
             examples = new ArrayList<CaptureEvent>();
             CaptureEvent ex = new CaptureEvent();
             ex.setDescription("DEMO 1: Item is assigned a new EPC");
             ex.setType(0);
             ex.setEventTime("2006-09-20T06:36:17Z");
             ex.setEventTimeZoneOffset("+00:00");
             ex.setAction(0);
             ex.setBizStep("urn:epcglobal:cbv:bizstep:commissioning");
             ex.setDisposition("urn:epcglobal:cbv:bizstep:active");
             ex.setBizLocation("urn:epc:id:sgln:0614141.00729.loc5");
             ex.setReadPoint("urn:epc:id:sgln:0614141.00729.rp97");
             ex.setEpcList("urn:epc:id:sgtin:0057000.123780.7788");
             examples.add(ex);
 
             ex = new CaptureEvent();
             ex.setDescription("DEMO 2: Item is inspected for QA");
             ex.setType(0);
             ex.setEventTime("2006-09-20T07:33:31.116Z");
             ex.setEventTimeZoneOffset("+00:00");
             ex.setAction(1);
             ex.setBizStep("urn:epcglobal:cbv:bizstep:inspecting");
             ex.setDisposition("urn:epcglobal:cbv:bizstep:active");
             ex.setBizLocation("urn:epc:id:sgln:0614141.00729.loc5");
             ex.setReadPoint("urn:epc:id:sgln:0614141.00729.handheld8");
             ex.setEpcList("urn:epc:id:sgtin:0057000.123780.7788");
             examples.add(ex);
 
             ex = new CaptureEvent();
             ex.setDescription("DEMO 3: Item is aggregated onto a pallet");
             ex.setType(1);
             ex.setAction(0);
             ex.setEventTime("2006-09-20T08:55:04Z");
             ex.setEventTimeZoneOffset("+00:00");
             ex.setBizStep("urn:epcglobal:cbv:bizstep:packing");
             ex.setDisposition("urn:epcglobal:cbv:disp:in_progress");
             ex.setBizLocation("urn:epc:id:sgln:0614141.00729.loc450");
             ex.setReadPoint("urn:epc:id:sgln:0614141.00729.rp104");
             ex.setBizTransaction("urn:epcglobal:cbv:btt:po", "http://transaction.fosstrak.org/po/12345678");
             ex.setParentID("urn:epc:id:sscc:0614141.1234567890");
             ex.setChildEPCs("urn:epc:id:sgtin:0057000.123780.7788 urn:epc:id:sgtin:0057000.123430.2027 "
                     + "urn:epc:id:sgtin:0057000.123430.2028 urn:epc:id:sgtin:0057000.123430.2029");
             examples.add(ex);
 
             ex = new CaptureEvent();
             ex.setDescription("DEMO 4: Pallet arrives at port of Kaohsiung");
             ex.setType(0);
             ex.setEventTime("2006-09-20T10:33:31.116Z");
             ex.setEventTimeZoneOffset("+00:00");
             ex.setAction(1);
             ex.setBizStep("urn:epcglobal:cbv:bizstep:arriving");
             ex.setDisposition("urn:epcglobal:cbv:disp:in_progress");
             ex.setBizLocation("http://epcis.fosstrak.org/demo/loc/china/kaohsiung");
             ex.setReadPoint("http://epcis.fosstrak.org/demo/loc/china/kaohsiung/e62");
             ex.setEpcList("urn:epc:id:sscc:0614141.1234567890");
             examples.add(ex);
 
             ex = new CaptureEvent();
             ex.setDescription("DEMO 5: Pallet departs from port of Kaohsiung");
             ex.setType(0);
             ex.setEventTime("2006-09-21T13:27:08.155Z");
             ex.setEventTimeZoneOffset("+00:00");
             ex.setAction(1);
             ex.setBizStep("urn:epcglobal:cbv:bizstep:departing");
             ex.setDisposition("urn:epcglobal:cbv:disp:in_transit");
             ex.setBizLocation("http://epcis.fosstrak.org/demo/loc/china/kaohsiung");
             ex.setReadPoint("http://epcis.fosstrak.org/demo/loc/china/kaohsiung/b18");
             ex.setEpcList("urn:epc:id:sscc:0614141.1234567890");
             examples.add(ex);
 
             ex = new CaptureEvent();
             ex.setDescription("Item passes a reader during manufacturing process");
             ex.setType(0);
             ex.setEventTime("2006-04-03T20:33:31.116Z");
             ex.setEventTimeZoneOffset("+00:00");
             ex.setAction(1);
             ex.setBizStep("http://epcis.fosstrak.org/bizstep/production");
             ex.setBizLocation("urn:epc:id:sgln:0614141.00101.loc210");
             ex.setReadPoint("urn:epc:id:sgln:0614141.00101.rp210");
             ex.setEpcList("urn:epc:id:sgtin:0057000.123780.3167");
             examples.add(ex);
 
             ex = new CaptureEvent();
             ex.setDescription("Two pallets are loaded onto a truck");
             ex.setType(0);
             ex.setEventTime("2006-05-09T21:01:44Z");
             ex.setEventTimeZoneOffset("+00:00");
             ex.setAction(1);
             ex.setBizStep("urn:epcglobal:cbv:bizstep:loading");
             ex.setDisposition("urn:epcglobal:cbv:disp:in_transit");
             ex.setBizLocation("urn:epc:id:sgln:0614141.00101.loc209");
             ex.setReadPoint("urn:epc:id:sgln:0614141.00101.rp53");
             ex.setEpcList("urn:epc:id:sscc:0614141.2644895423 urn:epc:id:sscc:0614141.2644895424");
             ex.setBizTransaction("urn:epcglobal:cbv:fmcg:btt:po", "http://transaction.example.com/po/12345678");
             examples.add(ex);
 
             ex = new CaptureEvent();
             ex.setDescription("Item arrives for repair");
             ex.setType(0);
             ex.setEventTime("2006-05-10T04:50:35Z");
             ex.setEventTimeZoneOffset("+00:00");
             ex.setAction(1);
             ex.setBizStep("urn:epcglobal:cbv:bizstep:receiving");
             ex.setDisposition("http://epcis.fosstrak.org/disp/in_repair");
             ex.setBizLocation("urn:epc:id:sgln:0614141.00101.repair-center");
             ex.setReadPoint("urn:epc:id:sgln:0614141.00101.rp77");
             ex.setEpcList("urn:epc:id:sgtin:0034000.987650.2686");
             examples.add(ex);
 
             ex = new CaptureEvent();
             ex.setDescription("Three items are aggregated onto a barcode-labeled pallet");
             ex.setType(1);
             ex.setAction(0);
             ex.setEventTime("2006-06-01T15:55:04Z");
             ex.setEventTimeZoneOffset("+00:00");
             ex.setBizStep("urn:epcglobal:cbv:bizstep:packing");
             ex.setDisposition("urn:epcglobal:cbv:disp:in_progress");
             ex.setBizLocation("urn:epc:id:sgln:0614141.00101.loc208");
             ex.setReadPoint("urn:epc:id:sgln:0614141.00101.rp98");
             ex.setBizTransaction("urn:epcglobal:cbv:fmcg:btt:po", "http://transaction.example.com/po/12345678");
             ex.setBizTransaction("urn:epcglobal:cbv:btt:asn", "http://transaction.example.com/asn/1152");
             ex.setParentID("urn:epc:id:sscc:0614141.2644895423");
             ex.setChildEPCs("urn:epc:id:sgtin:0057000.123430.2025 urn:epc:id:sgtin:0057000.123430.2027 "
                     + "urn:epc:id:sgtin:0057000.123430.2028");
             examples.add(ex);
 
             ex = new CaptureEvent();
             ex.setDescription("Aggregation ends at customer site");
             ex.setType(1);
             ex.setAction(2);
             ex.setEventTime("2006-06-05T09:26:06Z");
             ex.setEventTimeZoneOffset("+00:00");
             ex.setBizLocation("urn:epc:id:sgln:0614141.82863.loc3");
             ex.setReadPoint("urn:epc:id:sgln:0614141.82863.reader10");
             ex.setBizTransaction("urn:epcglobal:cbv:fmcg:btt:po", "http://po.example.org/E58J3Q");
             ex.setBizTransaction("urn:epcglobal:cbv:btt:asn", "http://transaction.example.com/asn/1152");
             ex.setParentID("urn:epc:id:sscc:0614141.2644895423");
             examples.add(ex);
 
             ex = new CaptureEvent();
             ex.setDescription("Physical inventory count: 67 items");
             ex.setType(2);
             ex.setEventTime("2006-01-15T16:15:31Z");
             ex.setEventTimeZoneOffset("+00:00");
             ex.setBizStep("urn:epcglobal:cbv:bizstep:storing");
             ex.setDisposition("urn:epcglobal:cbv:disp:active");
             ex.setBizLocation("urn:epc:id:sgln:0614141.82863.loc6");
             ex.setReadPoint("urn:epc:id:sgln:0614141.82863.loc6-virt");
             ex.setEpcClass("urn:epc:id:sgtin:0069000.957110");
             ex.setQuantity(67);
             examples.add(ex);
 
             ex = new CaptureEvent();
             ex.setDescription("Order changed by customer - two more objects added to transaction");
             ex.setType(3);
             ex.setEventTime("2006-08-18T11:53:01Z");
             ex.setEventTimeZoneOffset("+00:00");
             ex.setAction(0);
             ex.setBizTransaction("urn:epcglobal:cbv:fmcg:btt:po", "http://transaction.example.com/po/6677150");
             ex.setEpcList("urn:epc:id:sgtin:0057000.678930.5003 urn:epc:id:sgtin:0057000.678930.5004");
             examples.add(ex);
 
             ex = new CaptureEvent();
             ex.setDescription("Transaction is finished");
             ex.setType(3);
             ex.setEventTime("2006-08-20T07:03:51Z");
             ex.setEventTimeZoneOffset("+00:00");
             ex.setAction(2);
             ex.setBizTransaction("urn:epcglobal:cbv:fmcg:btt:po", "http://transaction.example.com/po/6677150");
             ex.setEpcList("urn:epc:id:sgtin:0057000.678930.5003 urn:epc:id:sgtin:0057000.678930.5004");
             examples.add(ex);
         }
         
         public static List<CaptureEvent> getExamples() {
             if (examples == null) {
                 initEvents();
             }
             return examples;
         }
     }
 
     /**
      * Loads ImageIcon from either JAR or filesystem.
      * 
      * @param filename
      *            The name of the file holding the image icon.
      * @return The ImageIcon.
      */
     public static ImageIcon getImageIcon(final String filename) {
         // try loading image from JAR (Web Start environment)
         ClassLoader classLoader = CaptureClientHelper.class.getClassLoader();
         URL url = classLoader.getResource("gui/" + filename);
         if (url != null) {
             return new ImageIcon(url);
         } else {
             // try loading image from filesystem - hack as we
             // can be called in either Eclipse or shell environment
             ImageIcon ii;
             ii = new ImageIcon("./tools/capturingGUI/media/" + filename);
             if (ii.getImageLoadStatus() != java.awt.MediaTracker.COMPLETE) {
                 ii = new ImageIcon("./gui/" + filename);
             }
             return ii;
         }
     }
 
     /**
      * Adds the given quantity value as {@code <quantity>} element to the XML
      * document.
      * 
      * @param document
      *            The Document to generate the {@code <quantity>} element from.
      * @param root
      *            The root Element under which the {@code <quantity>} element
      *            should be generated.
      * @param quantity
      *            The value for the {@code <quantity>} element.
      * @return <true> if the {@code <quantity>} element was successfully
      *         created, <code>false</code> otherwise.
      */
     public static boolean addQuantity(final Document document, final Element root, final String quantity) {
         Integer n = null;
         try {
             n = new Integer(quantity);
         } catch (NumberFormatException e) {
             return false;
         }
         return addElement(document, root, n.toString(), "quantity");
     }
 
     /**
      * Adds the given epcClass value as {@code <epcClass>} element to the XML
      * document.
      * 
      * @param document
      *            The Document to generate the {@code <epcClass>} element from.
      * @param root
      *            The root Element under which the {@code <epcClass>} element
      *            should be generated.
      * @param epcClass
      *            The value for the {@code <epcClass>} element.
      * @return <true> if the {@code <epcClass>} element was successfully
      *         created, <code>false</code> otherwise.
      */
     public static boolean addEpcClass(final Document document, final Element root, final String epcClass) {
         return addElement(document, root, epcClass, "epcClass");
     }
 
     /**
      * Adds the EPCs from the given list of childEPCs as {@code <epc>} elements
      * inside an {@code <childEPCs>} element to the XML document.
      * 
      * @param document
      *            The Document to generate the {@code <epc>} and {@code
      *            <childEPCs>} element from.
      * @param root
      *            The root Element under which the {@code <childEPCs>} element
      *            should be generated.
      * @param childEPCs
      *            A space-separated list of EPCs.
      * @return <true> if the {@code <childEPCs>} element was successfully
      *         created, <code>false</code> otherwise.
      */
     public static boolean addChildEpcList(final Document document, final Element root, final String childEPCs) {
         if (isEmpty(childEPCs)) {
             return false;
         }
         Element element = document.createElement("childEPCs");
         StringTokenizer st = new StringTokenizer(childEPCs);
         while (st.hasMoreTokens()) {
             addElement(document, element, st.nextToken(), "epc");
         }
         root.appendChild(element);
         return true;
     }
 
     /**
      * Adds the given mapping of business transactions ([business transaction
      * IDs] -> [business transaction types]) as part of a {@code
      * <bizTransactionList>} element to the XML document.
      * 
      * @param document
      *            The Document to generate the {@code <bizTransactionList>}
      *            element from.
      * @param root
      *            The root Element under which the {@code <bizTransactionList>}
      *            element should be generated.
      * @param bizTransactions
      *            A mapping of business transaction IDs to business transaction
      *            types.
      * @return <true> if the {@code <bizTransactionList>} element was
      *         successfully created, <code>false</code> otherwise.
      */
     public static boolean addBizTransactions(final Document document, final Element root,
             final Map<String, String> bizTransactions) {
         if (bizTransactions == null || bizTransactions.isEmpty() || bizTransactions.keySet().size() < 1) {
             return false;
         }
         Element element = document.createElement("bizTransactionList");
         for (Entry<String, String> bizTransEntry : bizTransactions.entrySet()) {
             if (!isEmpty(bizTransEntry.getKey()) && !isEmpty(bizTransEntry.getValue())) {
                 Element bizNode = document.createElement("bizTransaction");
                 bizNode.appendChild(document.createTextNode(bizTransEntry.getKey()));
                 bizNode.setAttribute("type", bizTransEntry.getValue());
                 element.appendChild(bizNode);
             }
         }
         root.appendChild(element);
         return true;
     }
 
     /**
      * Adds the given bizLocation as {@code <id>} element inside a {@code
      * <bizLocation>} element to the XML document.
      * 
      * @param document
      *            The Document to generate the {@code <id>} and {@code
      *            <bizLocation>} elements from.
      * @param root
      *            The root Element under which the {@code <bizLocation>} element
      *            should be generated.
      * @param bizLocation
      *            The value for the {@code <id>} element.
      * @return <true> if the {@code <bizLocation>} element was successfully
      *         created, <code>false</code> otherwise.
      */
     public static boolean addBizLocation(final Document document, final Element root, final String bizLocation) {
         if (isEmpty(bizLocation)) {
             return false;
         }
         Element element = document.createElement("bizLocation");
         addElement(document, element, bizLocation, "id");
         root.appendChild(element);
         return true;
     }
 
     /**
      * Adds the given readPoint as {@code <id>} element inside a {@code
      * <readPoint>} element to the XML document.
      * 
      * @param document
      *            The Document to generate the {@code <id>} and {@code
      *            <readPoint>} elements from.
      * @param root
      *            The root Element under which the {@code <readPoint>} element
      *            should be generated.
      * @param readPoint
      *            The value for the {@code <id>} element.
      * @return <true> if the {@code <readPoint>} element was successfully
      *         created, <code>false</code> otherwise.
      */
     public static boolean addReadPoint(final Document document, final Element root, final String readPoint) {
         if (isEmpty(readPoint)) {
             return false;
         }
         Element element = document.createElement("readPoint");
         addElement(document, element, readPoint, "id");
         root.appendChild(element);
         return true;
     }
 
     /**
      * Adds the given disposition value as {@code <disposition>} element to the
      * XML document.
      * 
      * @param document
      *            The Document to generate the {@code <disposition>} element
      *            from.
      * @param root
      *            The root Element under which the {@code <disposition>} element
      *            should be generated.
      * @param disposition
      *            The value for the {@code <disposition>} element.
      * @return <true> if the {@code <disposition>} element was successfully
      *         created, <code>false</code> otherwise.
      */
     public static boolean addDisposition(final Document document, final Element root, String disposition) {
         return addElement(document, root, disposition, "disposition");
     }
 
     /**
      * Adds the given bizStep value as {@code <bizStep>} element to the XML
      * document.
      * 
      * @param document
      *            The Document to generate the {@code <bizStep>} element from.
      * @param root
      *            The root Element under which the {@code <bizStep>} element
      *            should be generated.
      * @param bizStep
      *            The value for the {@code <bizStep>} element.
      * @return <true> if the {@code <bizStep>} element was successfully created,
      *         <code>false</code> otherwise.
      */
     public static boolean addBizStep(final Document document, final Element root, final String bizStep) {
         return addElement(document, root, bizStep, "bizStep");
     }
 
     /**
      * Adds the given action value as {@code <action>} element to the XML
      * document.
      * 
      * @param document
      *            The Document to generate the {@code <action>} element from.
      * @param root
      *            The root Element under which the {@code <action>} element
      *            should be generated.
      * @param action
      *            The value for the {@code <action>} element.
      * @return <true> if the {@code <action>} element was successfully created,
      *         <code>false</code> otherwise.
      */
     public static boolean addAction(final Document document, final Element root, String action) {
         return addElement(document, root, action, "action");
     }
 
     /**
      * Adds the EPCs from the given epcList as {@code <epc>} elements inside an
      * {@code <epcList>} element to the XML document.
      * 
      * @param document
      *            The Document to generate the {@code <epc>} and {@code
      *            <epcList>} element from.
      * @param root
      *            The root Element under which the {@code <childEPCs>} element
      *            should be generated.
      * @param epcList
      *            A space-separated list of EPCs.
      * @return <true> if the {@code <epcList>} element was successfully created,
      *         <code>false</code> otherwise.
      */
     public static boolean addEpcList(final Document document, final Element root, final String epcList) {
         if (isEmpty(epcList)) {
             return false;
         }
         Element element = document.createElement("epcList");
         StringTokenizer st = new StringTokenizer(epcList);
         while (st.hasMoreTokens()) {
             addElement(document, element, st.nextToken(), "epc");
         }
         root.appendChild(element);
         return true;
     }
 
     /**
      * Adds the given parentID value as {@code <parentID>} element to the XML
      * document.
      * 
      * @param document
      *            The Document to generate the {@code <parentID>} element from.
      * @param root
      *            The root Element under which the {@code <parentID>} element
      *            should be generated.
      * @param parentID
      *            The value for the {@code <parentID>} element.
      * @return <true> if the {@code <parentID>} element was successfully
      *         created, <code>false</code> otherwise.
      */
     public static boolean addParentId(final Document document, final Element root, String parentID) {
         return addElement(document, root, parentID, "parentID");
     }
 
     /**
      * Adds the given eventTime value as {@code <eventTime>} element to the XML
      * document.
      * 
      * @param document
      *            The Document to generate the {@code <eventTime>} element from.
      * @param root
      *            The root Element under which the {@code <eventTime>} element
      *            should be generated.
      * @param eventTime
      *            The value for the {@code <eventTime>} element.
      * @return <true> if the {@code <eventTime>} element was successfully
      *         created, <code>false</code> otherwise.
      */
     public static boolean addEventTime(final Document document, final Element root, final String eventTime) {
         return addElement(document, root, eventTime, "eventTime");
     }
 
     /**
      * Adds the given eventTimeZoneOffset value as {@code <eventTimeZoneOffset>}
      * element to the XML document.
      * 
      * @param document
      *            The Document to generate the {@code <eventTimeZoneOffset>}
      *            element from.
      * @param root
      *            The root Element under which the {@code <eventTimeZoneOffset>}
      *            element should be generated.
      * @param eventTimeZoneOffset
      *            The value for the {@code <eventTimeZoneOffset>} element.
      * @return <true> if the {@code <eventTimeZoneOffset>} element was
      *         successfully created, <code>false</code> otherwise.
      */
     public static boolean addEventTimeZoneOffset(final Document document, final Element root,
             final String eventTimeZoneOffset) {
         return addElement(document, root, eventTimeZoneOffset, "eventTimeZoneOffset");
     }
 
     private static boolean addElement(final Document document, final Element root, final String elementValue,
             final String elementName) {
         if (isEmpty(elementValue)) {
             return false;
         }
         Element element = document.createElement(elementName);
         element.appendChild(document.createTextNode(elementValue));
         root.appendChild(element);
         return true;
     }
 
     private static boolean isEmpty(String s) {
         return s == null || s.trim().equals("");
     }
 }