org.fife.rsta.ui.RComboBoxModel Maven / Gradle / Ivy
/*
* 01/15/2004
*
* RComboBoxModel.java - A combo box model that limits the number of items
* the combo box wil remember. It also won't add an item to the combo box
* if it is already there.
* This library is distributed under a modified BSD license. See the included
* RSTAUI.License.txt file for details.
*/
package org.fife.rsta.ui;
import java.util.Vector;
import javax.swing.DefaultComboBoxModel;
/**
* A combo box model that limits the number of items the combo box will
* "remember." You can use it like so:
*
* RComboBoxModel model = new RComboBoxModel();
* model.setMaxNumElements(10);
* JComboBox comboBox = new JComboBox(model);
* It also won't let you add an item to the combo box twice (i.e., no
* duplicates), and it adds new items to the beginning of the list, not
* the end (as JComboBox's do by default).
* It defaults to 8 elements remembered.
*
* @param The type of item in the combo box.
* @author Robert Futrell
* @version 0.8
*/
public class RComboBoxModel extends DefaultComboBoxModel {
private static final long serialVersionUID = 1L;
/**
* The number of items the combo box will remember.
*/
private int maxNumElements;
/**
* Creates a new combo box model with a maximum element count of
* 8.
*/
public RComboBoxModel() {
setMaxNumElements(8);
}
/**
* Creates a new combo box model with a maximum element count of
* 8.
*
* @param items The initial items to use to populate the combo box.
*/
public RComboBoxModel(E[] items) {
super(items);
setMaxNumElements(8);
}
/**
* Creates a new combo box model with a maximum element count of
* 8.
*
* @param v The initial items to use to populate the combo box.
*/
public RComboBoxModel(Vector v) {
super(v);
setMaxNumElements(8);
}
/**
* Adds the object (if it's not already in the list) to the front of
* the list. If it's already in the list, move it to the top.
*
* @param anObject The object to add.
*/
@Override
public void addElement(E anObject) {
insertElementAt(anObject, 0);
}
/**
* Ensures the number if items remembered by this combo box is valid.
*/
private void ensureValidItemCount() {
while (getSize()>maxNumElements) {
removeElementAt(getSize() - 1);
}
}
/**
* Returns the maximum number of items this combo box can hold.
*
* @return The maximum number of items this combo box can hold.
*/
public int getMaxNumElements() {
return maxNumElements;
}
/**
* Adds an item at a specified index. The implementation of this method
* should notify all registered ListDataListeners that the
* item has been added.
*
* @param anObject The Object to be added.
* @param index Location to add the object.
*/
@Override
public void insertElementAt(E anObject, int index) {
int oldPos = getIndexOf(anObject);
if (oldPos==index) { // Already at the desired location.
return;
}
if (oldPos>-1) { // Remove it first if it's somewhere else.
removeElement(anObject);
}
super.insertElementAt(anObject, index);
ensureValidItemCount();
}
/**
* Sets the maximum number of items this combo box can hold.
*
* @param numElements The maximum number of items this combo box can hold.
* If numElements <= 0, then the capacity
* of this combo box is set to 4.
*/
public void setMaxNumElements(int numElements) {
maxNumElements = numElements<=0 ? 4 : numElements;
ensureValidItemCount();
}
}