ColumnInfo

/*
 * $Source$
 * $Revision$
 *
 * 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();
  }
}