/*

  * $Source$

  * $Revision$

  *

  * Copyright (C) 2000 William Chesters

  *

  * Part of Melati (http://melati.org), a framework for the rapid

  * development of clean, maintainable web applications.

  *

  * Melati is free software; Permission is granted to copy, distribute

  * and/or modify this software under the terms either:

  *

  * a) 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,

  *

  *    or

  *

  * b) any version of the Melati Software License, as published

  *    at http://melati.org

  *

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

  * the Melati Software License along with this program;

  * if not, write to the Free Software Foundation, Inc.,

  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA to obtain the

  * GNU General Public License and visit http://melati.org to obtain the

  * Melati Software License.

  *

  * Feel free to contact the Developers of Melati (http://melati.org),

  * if you would like to work out a different arrangement than the options

  * outlined here.  It is our intention to allow Melati to be used by as

  * wide an audience as possible.

  *

  * 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.

  *

  * Contact details for copyright holder:

  *

  *     William Chesters <williamc At paneris.org>

  *     http://paneris.org/~williamc

  *     Obrechtstraat 114, 2517VX Den Haag, The Netherlands

  */

 package org.melati.poem;

 import java.util.Vector;

 import java.util.Enumeration;

 import org.melati.poem.generated.ColumnInfoBase;

 /**

  * All the data defining a {@link Column}; actually a {@link Persistent} 

  * from the {@link ColumnInfoTable}.

  * 

  * Melati POEM generated, programmer modifiable stub 

  * for a <code>Persistent</code> <code>ColumnInfo</code> object.

  * 

  * <p> 

  * Description: 

  *   Configuration information about a column in the database. 

  * </p>

  * 

  * <table> 

  * <caption>

  * Field summary for SQL table <code>ColumnInfo</code>

  * </caption>

  * <tr><th>Name</th><th>Type</th><th>Description</th></tr>

  * <tr><td> id </td><td> Integer </td><td> &nbsp; </td></tr> 

  * <tr><td> tableinfo </td><td> TableInfo </td><td> The table to which the 

  * field belongs </td></tr> 

  * <tr><td> name </td><td> String </td><td> A code-name for the field 

  * </td></tr> 

  * <tr><td> displayorder </td><td> Integer </td><td> A rank determining where 

  * the field appears in lists </td></tr> 

  * <tr><td> usercreateable </td><td> Boolean </td><td> Whether it makes sense 

  * for the user to initialise the field's value </td></tr> 

  * <tr><td> displaylevel </td><td> DisplayLevel </td><td> A category 

  * determining what granularity of report the field appears in </td></tr> 

  * <tr><td> searchability </td><td> Searchability </td><td> A category 

  * determining what level of searching this field supports </td></tr> 

  * <tr><td> displayorderpriority </td><td> Integer </td><td> If present, the 

  * level at which lists of records are sorted by the field </td></tr> 

  * <tr><td> sortdescending </td><td> Boolean </td><td> Whether when sorting 

  * by this column, the sort order should be reversed </td></tr> 

  * <tr><td> indexed </td><td> Boolean </td><td> Whether the field is indexed 

  * (ignored if the field is marked `unique') </td></tr> 

  * <tr><td> unique </td><td> Boolean </td><td> Whether the field is unique 

  * (implies that it's `indexed') </td></tr> 

  * <tr><td> integrityfix </td><td> StandardIntegrityFix </td><td> How 

  * referential integrity is maintained, what to do when the object referred 

  * to is deleted </td></tr> 

  * </table> 

  * 

  * See org.melati.poem.prepro.TableDef#generateMainJava 

  */

 public class ColumnInfo extends ColumnInfoBase {

   /**

    * Allow reading by not throwing an exception.

    * {@inheritDoc}

    * @see org.melati.poem.Persistent#assertCanRead(org.melati.poem.AccessToken)

    */

   public void assertCanRead(AccessToken token) {

   }

   private Column<?> _column = null;

   /**

    * @return the column

    */

   Column<?> column() {

     // I have not fathomed how this circumstance arrives, but 

     // it can.

     if (_column == null && troid() != null)

       _column = getDatabase().columnWithColumnInfoID(troid().intValue());

     return _column;

   }

   void setColumn(Column<?> column) {

     _column = column;

   }

  /**

   * Set the name if it is not set.

   * 

   * @param name the name to set

   */

   public void setName(String name) {

     String current = getName();

     if (current != null && !current.equals(name))

       throw new ColumnRenamePoemException(name);

     super.setName(name);

   }

  /**

   * Set the TableInfo reference.

   * 

   * @param raw the troid value to set

   */

   public void setTableinfoTroid(Integer raw) throws AccessPoemException {

     Integer ti = super.getTableinfoTroid();

     if (ti != null && !ti.equals(raw))

       throw new IllegalArgumentException();

     super.setTableinfoTroid(raw);

   }

  /**

   * Set the DisplaylevelIndex value.

   * 

   * @param index the DisplaylevelIndex value to set

   */

   public void setDisplaylevelIndex(Integer index) {

     super.setDisplaylevelIndex(index);

     Column<?> column = column();

     if (column != null) {

       Table<?> table = column.getTable();

       Column<?> previous = table.displayColumn();

       if (previous != null && previous != column) {

         if (index.equals(DisplayLevel.primary.getIndex())) {

           previous.setDisplayLevel(DisplayLevel.summary);

           table.setDisplayColumn(column);

         } else { 

           table.clearColumnInfoCaches();

         }

       }

     }

   }

   /**

    * Only those fields which are relevant to this column 

    * and legal as a field qualifier in the DSD.

    * Used in org.melati.admin.DSD.wm.

    * 

    * @return an Enumeration of {@link Field}s 

    */

   public Enumeration<Field<?>> getDsdQualifiers() {

     Vector<Field<?>> v = new Vector<Field<?>>();

     Enumeration<Field<?>> allFields = getFields();

     while (allFields.hasMoreElements()) {

       Field<?> f = allFields.nextElement();

       String n = f.getName();

       if (!(f.getType() instanceof TroidPoemType)  // The id of this columnInfo record, not the target 

           && !n.equals("name")  // Name is not a qualifier

           && !n.equals("typefactory")   

           && !n.equals("tableinfo") // The tableInfo of this columnInfo, not the target

           && !(n.equals("size") && !(column().getType() instanceof SizedAtomPoemType))

           && !(n.equals("integrityfix") && !(column().getType() instanceof PersistentReferencePoemType)) 

           && !(n.equals("precision")    && !(column().getType() instanceof FixedPointAtomPoemType))

           && !(n.equals("scale")        && !(column().getType() instanceof FixedPointAtomPoemType)))

         v.addElement(f);

     }

     return v.elements();

   }

 }