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jtstand-common is a library derived from jcommon, used by jtstand-chart, which is derived from jfreechart
There is a newer version: 1.5.9
/*
 * Copyright (c) 2009 Albert Kurucz. 
 *
 * This file, KeyedComboBoxModel.java is part of JTStand.
 *
 * JTStand is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * JTStand 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 GTStand.  If not, see .
 */
package org.jfree.ui;

import java.util.ArrayList;
import javax.swing.ComboBoxModel;
import javax.swing.event.ListDataEvent;
import javax.swing.event.ListDataListener;

/**
 * The KeyedComboBox model allows to define an internal key (the data element)
 * for every entry in the model.
 * 
 * This class is usefull in all cases, where the public text differs from the
 * internal view on the data. A separation between presentation data and
 * processing data is a prequesite for localizing combobox entries. This model
 * does not allow selected elements, which are not in the list of valid
 * elements.
 *
 * @author Thomas Morgner
 */
public class KeyedComboBoxModel implements ComboBoxModel
{

  /**
   * The internal data carrier to map keys to values and vice versa.
   */
  private static class ComboBoxItemPair
  {
    /**
     * The key.
     */
    private Object key;
    /**
     * The value for the key.
     */
    private Object value;

    /**
     * Creates a new item pair for the given key and value. The value can be
     * changed later, if needed.
     *
     * @param key   the key
     * @param value the value
     */
    public ComboBoxItemPair(final Object key, final Object value)
    {
      this.key = key;
      this.value = value;
    }

    /**
     * Returns the key.
     *
     * @return the key.
     */
    public Object getKey()
    {
      return this.key;
    }

    /**
     * Returns the value.
     *
     * @return the value for this key.
     */
    public Object getValue()
    {
      return this.value;
    }

    /**
     * Redefines the value stored for that key.
     *
     * @param value the new value.
     */
    public void setValue(final Object value)
    {
      this.value = value;
    }
  }

  /**
   * The index of the selected item.
   */
  private int selectedItemIndex;
  private Object selectedItemValue;
  /**
   * The data (contains ComboBoxItemPairs).
   */
  private ArrayList data;
  /**
   * The listeners.
   */
  private ArrayList listdatalistener;
  /**
   * The cached listeners as array.
   */
  private transient ListDataListener[] tempListeners;
  private boolean allowOtherValue;

  /**
   * Creates a new keyed combobox model.
   */
  public KeyedComboBoxModel()
  {
    this.data = new ArrayList();
    this.listdatalistener = new ArrayList();
  }

  /**
   * Creates a new keyed combobox model for the given keys and values. Keys
   * and values must have the same number of items.
   *
   * @param keys   the keys
   * @param values the values
   */
  public KeyedComboBoxModel(final Object[] keys, final Object[] values)
  {
    this();
    setData(keys, values);
  }

  /**
   * Replaces the data in this combobox model. The number of keys must be
   * equals to the number of values.
   *
   * @param keys   the keys
   * @param values the values
   */
  public void setData(final Object[] keys, final Object[] values)
  {
    if (values.length != keys.length)
    {
      throw new IllegalArgumentException("Values and text must have the same length.");
    }

    this.data.clear();
    this.data.ensureCapacity(keys.length);

    for (int i = 0; i < values.length; i++)
    {
      add(keys[i], values[i]);
    }

    this.selectedItemIndex = -1;
    final ListDataEvent evt = new ListDataEvent
        (this, ListDataEvent.CONTENTS_CHANGED, 0, this.data.size() - 1);
    fireListDataEvent(evt);
  }

  /**
   * Notifies all registered list data listener of the given event.
   *
   * @param evt the event.
   */
  protected synchronized void fireListDataEvent(final ListDataEvent evt)
  {
    if (this.tempListeners == null)
    {
        this.tempListeners = (ListDataListener[]) this.listdatalistener.toArray
          (new ListDataListener[this.listdatalistener.size()]);
    }

    final ListDataListener[] listeners = this.tempListeners;
    for (int i = 0; i < listeners.length; i++)
    {
      final ListDataListener l = listeners[i];
      l.contentsChanged(evt);
    }
  }

  /**
   * Returns the selected item.
   *
   * @return The selected item or null if there is no selection
   */
  public Object getSelectedItem()
  {
    return this.selectedItemValue;
  }

  /**
   * Defines the selected key. If the object is not in the list of values, no
   * item gets selected.
   *
   * @param anItem the new selected item.
   */
  public void setSelectedKey(final Object anItem)
  {
    if (anItem == null)
    {
        this.selectedItemIndex = -1;
        this.selectedItemValue = null;
    }
    else
    {
      final int newSelectedItem = findDataElementIndex(anItem);
      if (newSelectedItem == -1)
      {
          this.selectedItemIndex = -1;
          this.selectedItemValue = null;
      }
      else
      {
          this.selectedItemIndex = newSelectedItem;
          this.selectedItemValue = getElementAt(this.selectedItemIndex);
      }
    }
    fireListDataEvent(new ListDataEvent(this, ListDataEvent.CONTENTS_CHANGED, -1, -1));
  }

  /**
   * Set the selected item. The implementation of this  method should notify
   * all registered ListDataListeners that the contents have
   * changed.
   *
   * @param anItem the list object to select or null to clear the
   *               selection
   */
  public void setSelectedItem(final Object anItem)
  {
    if (anItem == null)
    {
        this.selectedItemIndex = -1;
        this.selectedItemValue = null;
    }
    else
    {
      final int newSelectedItem = findElementIndex(anItem);
      if (newSelectedItem == -1)
      {
        if (isAllowOtherValue())
        {
            this.selectedItemIndex = -1;
            this.selectedItemValue = anItem;
        }
        else
        {
            this.selectedItemIndex = -1;
          this.selectedItemValue = null;
        }
      }
      else
      {
          this.selectedItemIndex = newSelectedItem;
          this.selectedItemValue = getElementAt(this.selectedItemIndex);
      }
    }
    fireListDataEvent(new ListDataEvent(this, ListDataEvent.CONTENTS_CHANGED, -1, -1));
  }

  private boolean isAllowOtherValue()
  {
    return this.allowOtherValue;
  }

  /**
   * @param allowOtherValue
   */
  public void setAllowOtherValue(final boolean allowOtherValue)
  {
    this.allowOtherValue = allowOtherValue;
  }

  /**
   * Adds a listener to the list that's notified each time a change to the data
   * model occurs.
   *
   * @param l the ListDataListener to be added
   */
  public synchronized void addListDataListener(final ListDataListener l)
  {
    if (l == null)
    {
      throw new NullPointerException();
    }
    this.listdatalistener.add(l);
    this.tempListeners = null;
  }

  /**
   * Returns the value at the specified index.
   *
   * @param index the requested index
   * @return the value at index
   */
  public Object getElementAt(final int index)
  {
    if (index >= this.data.size())
    {
      return null;
    }

    final ComboBoxItemPair datacon = (ComboBoxItemPair) this.data.get(index);
    if (datacon == null)
    {
      return null;
    }
    return datacon.getValue();
  }

  /**
   * Returns the key from the given index.
   *
   * @param index the index of the key.
   * @return the the key at the specified index.
   */
  public Object getKeyAt(final int index)
  {
    if (index >= this.data.size())
    {
      return null;
    }

    if (index < 0)
    {
      return null;
    }

    final ComboBoxItemPair datacon = (ComboBoxItemPair) this.data.get(index);
    if (datacon == null)
    {
      return null;
    }
    return datacon.getKey();
  }

  /**
   * Returns the selected data element or null if none is set.
   *
   * @return the selected data element.
   */
  public Object getSelectedKey()
  {
    return getKeyAt(this.selectedItemIndex);
  }

  /**
   * Returns the length of the list.
   *
   * @return the length of the list
   */
  public int getSize()
  {
    return this.data.size();
  }

  /**
   * Removes a listener from the list that's notified each time a change to
   * the data model occurs.
   *
   * @param l the ListDataListener to be removed
   */
  public void removeListDataListener(final ListDataListener l)
  {
      this.listdatalistener.remove(l);
      this.tempListeners = null;
  }

  /**
   * Searches an element by its data value. This method is called by the
   * setSelectedItem method and returns the first occurence of the element.
   *
   * @param anItem the item
   * @return the index of the item or -1 if not found.
   */
  private int findDataElementIndex(final Object anItem)
  {
    if (anItem == null)
    {
      throw new NullPointerException("Item to find must not be null");
    }

    for (int i = 0; i < this.data.size(); i++)
    {
      final ComboBoxItemPair datacon = (ComboBoxItemPair) this.data.get(i);
      if (anItem.equals(datacon.getKey()))
      {
        return i;
      }
    }
    return -1;
  }

  /**
   * Tries to find the index of element with the given key. The key must not
   * be null.
   *
   * @param key the key for the element to be searched.
   * @return the index of the key, or -1 if not found.
   */
  public int findElementIndex(final Object key)
  {
    if (key == null)
    {
      throw new NullPointerException("Item to find must not be null");
    }

    for (int i = 0; i < this.data.size(); i++)
    {
      final ComboBoxItemPair datacon = (ComboBoxItemPair) this.data.get(i);
      if (key.equals(datacon.getValue()))
      {
        return i;
      }
    }
    return -1;
  }

  /**
   * Removes an entry from the model.
   *
   * @param key the key
   */
  public void removeDataElement(final Object key)
  {
    final int idx = findDataElementIndex(key);
    if (idx == -1)
    {
      return;
    }

    this.data.remove(idx);
    final ListDataEvent evt = new ListDataEvent
        (this, ListDataEvent.INTERVAL_REMOVED, idx, idx);
    fireListDataEvent(evt);
  }

  /**
   * Adds a new entry to the model.
   *
   * @param key    the key
   * @param cbitem the display value.
   */
  public void add(final Object key, final Object cbitem)
  {
    final ComboBoxItemPair con = new ComboBoxItemPair(key, cbitem);
    this.data.add(con);
    final ListDataEvent evt = new ListDataEvent
        (this, ListDataEvent.INTERVAL_ADDED, this.data.size() - 2, this.data.size() - 2);
    fireListDataEvent(evt);
  }

  /**
   * Removes all entries from the model.
   */
  public void clear()
  {
    final int size = getSize();
    this.data.clear();
    final ListDataEvent evt = new ListDataEvent(this, ListDataEvent.INTERVAL_REMOVED, 0, size - 1);
    fireListDataEvent(evt);
  }

}