/*
    * Copyright (c) 2001 - 2005 ivata limited.
    * All rights reserved.
    * -----------------------------------------------------------------------------
    * ivata masks may be redistributed under the GNU General Public
    * License as published by the Free Software Foundation;
    * version 2 of the License.
    *
    * These programs are free software; you can redistribute them and/or
   * modify them under the terms of the GNU General Public License
   * as published by the Free Software Foundation; version 2 of the License.
   *
   * These programs are distributed in the hope that they 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 in the file LICENSE.txt for more
   * details.
   *
   * If you would like a copy of the GNU General Public License write to
   *
   * Free Software Foundation, Inc.
   * 59 Temple Place - Suite 330
   * Boston, MA 02111-1307, USA.
   *
   *
   * To arrange commercial support and licensing, contact ivata at
   *                  http://www.ivata.com/contact.jsp
   * -----------------------------------------------------------------------------
   * $Log: FieldTag.java,v $
   * Revision 1.7.2.1  2005/10/08 10:54:51  colinmacleod
   * Added temporary workarounds for bugs in ivata groupware v0.11.x
   *
   * Revision 1.7  2005/04/09 18:04:19  colinmacleod
   * Changed copyright text to GPL v2 explicitly.
   *
   * Revision 1.6  2005/01/19 13:14:04  colinmacleod
   * Renamed CausedByException to SystemException.
   *
   * Revision 1.5  2005/01/06 23:10:02  colinmacleod
   * Moved up a version number.
   * Changed copyright notices to 2005.
   * Updated the documentation:
   *   - started working on multiproject:site docu.
   *   - changed the logo.
   * Added checkstyle and fixed LOADS of style issues.
   * Added separate thirdparty subproject.
   * Added struts (in web), util and webgui (in webtheme) from ivata op.
   *
   * Revision 1.4  2004/12/23 21:28:32  colinmacleod
   * Modifications to add ivata op compatibility.
   *
   * Revision 1.3  2004/11/12 15:10:42  colinmacleod
   * Moved persistence classes from ivata op as a replacement for
   * ValueObjectLocator.
   *
   * Revision 1.2  2004/11/11 13:48:40  colinmacleod
   * Added subField.
   *
   * Revision 1.1.1.1  2004/05/16 20:40:33  colinmacleod
   * Ready for 0.1 release
   * -----------------------------------------------------------------------------
   */
  package com.ivata.mask.web.tag;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.jsp.JspException;
  import javax.servlet.jsp.PageContext;
  import javax.servlet.jsp.tagext.TagSupport;
  import org.apache.struts.taglib.TagUtils;
  import com.ivata.mask.Mask;
  import com.ivata.mask.field.Field;
  import com.ivata.mask.util.SystemException;
  import com.ivata.mask.valueobject.ValueObject;
  import com.ivata.mask.web.field.FieldWriter;
  import com.ivata.mask.web.field.FieldWriterFactory;
  import com.ivata.mask.web.struts.InputMaskForm;
  import com.ivata.mask.web.struts.ListForm;
  import com.ivata.mask.web.struts.MaskForm;
  /***
   * <p>
   * Creates an input field, or displays the value for a field.
   * </p>
   *
   * <p>
   * <b>Note: </b> you must set a session attribute
   *
   * @since ivata masks 0.1 (2004-05-11)
   * @author Colin MacLeod
   * <a href='mailto:colin.macleod@ivata.com'>colin.macleod@ivata.com</a>
   * @version $Revision: 1.7.2.1 $
   */
  public class FieldTag extends TagSupport {
      /***
       * <p>
       * Set this to the field writer factory we'll be using to create field
       * writers.
       * </p>
       */
      private static FieldWriterFactory fieldWriterFactory = null;
     /***
      * <p>
      * Get the field writer factory we'll be using to create field writers.
      * </p>
      *
      * @param pageContext current tag page context, used to lookup the factory
      * attribute.
      * @return field writer factory, used to create field writers.
      * @throws JspException
      *             if the field writer factory has not been set to an
      *             application scope attribute called {@link
      *             FieldWriterFactory#APPLICATION_ATTRIBUTE
      *             FieldWriterFactory.APPLICATION_ATTRIBUTE}.
      */
     public static synchronized FieldWriterFactory getFieldWriterFactory(
             final PageContext pageContext) throws JspException {
         if (fieldWriterFactory == null) {
             fieldWriterFactory = (FieldWriterFactory) TagUtils.getInstance()
                     .lookup(pageContext,
                             FieldWriterFactory.APPLICATION_ATTRIBUTE,
                             "application");
             if (fieldWriterFactory == null) {
                 throw new JspException("ERROR: you must specify a valid field "
                         + "writer factory in application scope, called '"
                         + FieldWriterFactory.APPLICATION_ATTRIBUTE + "'");
             }
         }
         return fieldWriterFactory;
     }
     /***
      * <p>
      * If <code>true</code>, the field will not allow user entry.
      * </p>
      */
     private boolean disabled = false;
     /***
      * <p>
      * Field to be displayed.
      * </p>
      */
     private Field field;
     /***
      * <p>
      * If <code>true</code>, overrides the hidden value of the field definition,
      * to make this a hidden field.
      * </p>
      * @see Field#isHidden
      */
     private boolean hidden = false;
     /***
      * <p>
      * Sub-field within the field to be displayed.
      * </p>
      */
     private Field subField;
     /***
      * <p>
      * Value object to display/edit.
      * </p>
      */
     private ValueObject valueObject;
     /***
      * <p>
      * Called when the tag is first encountered. Simply diplays the field for
      * now.
      * </p>
      *
      * @see javax.servlet.jsp.tagext.Tag#doStartTag()
      */
     public int doStartTag() throws JspException {
         // make sure we have a field writer factory
         getFieldWriterFactory(pageContext);
         HttpServletRequest request = (HttpServletRequest) pageContext
                 .getRequest();
         Mask mask = null;
         ListForm listForm = (ListForm) request
                 .getAttribute(ListForm.REQUEST_ATTRIBUTE);
         MaskForm form;
         boolean displayOnly;
         if (listForm == null) {
             InputMaskForm maskForm = (InputMaskForm) request
                     .getAttribute(InputMaskForm.REQUEST_ATTRIBUTE);
             // TODO: temporary workaround for ivata groupware
             if (maskForm == null) {
                 maskForm = (InputMaskForm) request.getSession()
                     .getAttribute(InputMaskForm.REQUEST_ATTRIBUTE);
             }
             if (maskForm == null) {
                 throw new NullPointerException("Either ListForm or MaskForm "
                         + "must be specified in request scope.");
             }
             mask = maskForm.getMask();
             displayOnly = maskForm.isDisplayOnly();
             form = maskForm;
         } else {
             mask = listForm.getMask();
             displayOnly = mask.isDisplayOnly();
             form = listForm;
         }
         FieldWriter fieldWriter;
         try {
             fieldWriter = fieldWriterFactory.getFieldWriter(valueObject, field,
                     subField, hidden);
         } catch (SystemException e) {
             throw new JspException(e);
         }
         if (disabled) {
             fieldWriter.setAttribute("disabled", "true");
         } else {
             fieldWriter.removeAttribute("disabled");
         }
         String value = fieldWriter.write(pageContext, valueObject, displayOnly);
         TagUtils.getInstance().write(pageContext, value);
         return super.doStartTag();
     }
     /***
      * <p>
      * Field to be displayed.
      * </p>
      *
      * @return field to be displayed.
      */
     public Field getField() {
         return field;
     }
     /***
      * <p>
      * Sub-field within the field to be displayed.
      * </p>
      *
      * @return Sub-field within the field to be displayed.
      */
     public Field getSubField() {
         return subField;
     }
     /***
      * <p>
      * Value object to display/edit.
      * </p>
      *
      * @return value object to display/edit.
      */
     public ValueObject getValueObject() {
         return valueObject;
     }
     /***
      * <p>
      * If <code>true</code>, the field will not allow user entry.
      * </p>
      *
      * @return Returns whether or not the field is disabled.
      */
     public boolean isDisabled() {
         return disabled;
     }
     /***
      * <p>
      * If <code>true</code>, overrides the hidden value of the field definition,
      * to make this a hidden field.
      * </p>
      * @return Returns whether or not the field definition is overridden as
      *  hidden.
      * @see Field#isHidden
      */
     public boolean isHidden() {
         return hidden;
     }
     /***
      * <p>
      * If <code>true</code>, the field will not allow user entry.
      * </p>
      *
      * @param disabledParam Set whether or not the field is disabled.
      */
     public void setDisabled(final boolean disabledParam) {
         this.disabled = disabledParam;
     }
     /***
      * <p>
      * Stores the identifier of the field within this group to be displayed.
      * </p>
      *
      * @param fieldParam definition of the field which this tag is going to
      * display/edit.
      */
     public final void setField(final Field fieldParam) {
         this.field = fieldParam;
     }
     /***
      * <p>
      * If <code>true</code>, overrides the hidden value of the field definition,
      * to make this a hidden field.
      * </p>
      * @param hiddenParam Set to <code>true</code> to hide the field, overriding
      * any setting in the field definition.
      * @see Field#isHidden
      */
     public void setHidden(final boolean hiddenParam) {
         this.hidden = hiddenParam;
     }
     /***
      * <p>
      * Sub-field within the field to be displayed.
      * </p>
      *
      * @param fieldParam
      *            Sub-field within the field to be displayed.
      */
     public void setSubField(final Field fieldParam) {
         subField = fieldParam;
     }
     /***
      * <p>
      * Value object to display/edit.
      * </p>
      *
      * @param object
      *            value object to display/edit.
      */
     public void setValueObject(final ValueObject object) {
         valueObject = object;
     }
 }