/*
 Copyright (c) 2009, The Cytoscape Consortium (www.cytoscape.org)

 The Cytoscape Consortium is:
 - Institute for Systems Biology
 - University of California San Diego
 - Memorial Sloan-Kettering Cancer Center
 - Institut Pasteur
 - Agilent Technologies

 This library 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 2.1 of the License, or
 any later version.

 This library 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.  The software and
 documentation provided hereunder is on an "as is" basis, and the
 Institute for Systems Biology and the Whitehead Institute
 have no obligations to provide maintenance, support,
 updates, enhancements or modifications.  In no event shall the
 Institute for Systems Biology and the Whitehead Institute
 be liable to any party for direct, indirect, special,
 incidental or consequential damages, including lost profits, arising
 out of the use of this software and its documentation, even if the
 Institute for Systems Biology and the Whitehead Institute
 have been advised of the possibility of such damage.  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 this library; if not, write to the Free Software Foundation,
 Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*/

package cytoscape.util.swing;

import java.util.Vector;
import javax.swing.DefaultComboBoxModel;

/**
 * @author Noel Ruddock
 * This ComboBoxModel tracks the widest string
 * getLabel(Object anObject) should be overridden to derive the String from
 * an Object in the model when getString() doesn't provide what will be
 * displayed.
 */
public class WidestStringComboBoxModel extends DefaultComboBoxModel implements WidestStringProvider {
    private String widest = null;
    private boolean widestValid = false;

    /**
     * Class Constructor.
     */
    public WidestStringComboBoxModel() {
        super();
    }

    /**
     * Class Constructor specifying an array of Objects to form the model.
     *
     * @param items
     */
    public WidestStringComboBoxModel(Object[] items) {
        super(items);
    }

    /**
     * Class Constructor specifying a vector of Objects to form the model.
     *
     * @param v
     */
    public WidestStringComboBoxModel(Vector<?> v) {
        super(v);
    }

    /**
     * Adds the given object to the model.
     * Additionally updates cached longest String.
     *
     * @param anObject the object to be added to the model
     */
    @Override
    public void addElement(Object anObject) {
        updateWidest(anObject, true);
        super.addElement(anObject);
    }

    /**
     * Inserts an object into the model at the given index.
     * Additionally updates cached longest String.
     *
     * @param anObject the object to be added to the model
     * @param index the index at which the given object is to be added
     */
    @Override
    public void insertElementAt(Object anObject, int index) {
        updateWidest(anObject, true);
        super.insertElementAt(anObject, index);
    }

    /**
     * Removes all objects from the model.
     * Additionally updates cached longest String.
     */
    @Override
    public void removeAllElements() {
        resetWidest();
        super.removeAllElements();
    }

    /**
     * Removes the given object from the model.
     * Additionally updates cached longest String.
     *
     * @param anObject the object to be removed from the model
     */
    @Override
    public void removeElement(Object anObject) {
        updateWidest(anObject, false);
        super.removeElement(anObject);
    }

    /**
     * Removes the object at the specified index from the model.
     * Additionally updates cached longest String.
     */
    @Override
    public void removeElementAt(int index) {
        updateWidest(getElementAt(index), false);
        super.removeElementAt(index);
    }

    /**
     * Invalidates the cached longest String.
     */
    public void resetWidest() {
        widest = null;
        widestValid = false;
    }

    /**
     * Returns the longest display String for the objects in this model.
     * If the cached longest String is not valid, the longest String is
     * determined and cached.
     * @return the longest display String for the objects in this model
     */
    public String getWidest() {
        if (!widestValid) {
            findWidest();
        }

        return widest;
    }

    /**
     * Update the cached longest String if required when a new object is added
     * to the model, or invalidate it when removing.
     *
     * @param anObject the Object being added or removed
     * @param adding true if the anObject is being added to the model, false if
     * it is being removed
     */
    private void updateWidest(Object anObject, boolean adding) {
        String label;

        label = getLabel(anObject);
        if (widestValid) {
            if (adding) {
                if (label.length() > widest.length()) {
                    widest = label;
                }
            }
            else {
                if (widest.equals(label)) {
                    resetWidest();
                }
            }
        }
        else {
            if (adding) {
                widest = label;
                widestValid = true;
            }
        }
    }

    /**
     * Find which display string for the objects in the model is the longest.
     */
    private void findWidest() {
        int size;

        size = getSize();
        widest = "";
        for (int i = 0; i < size; i++) {
            String label;

            label = getLabel(getElementAt(i));
            if (label.length() > widest.length()) {
                widest = label;
            }
        }
        widestValid = true;
    }

    /**
     * Returns the String corresponding to the parameter object for use in
     * calculating the width of popup required.
     * This method should be overridden when the toString method of whatever
     * objects are stored in the model, doesn't return a suitable String.
     * Should return an empty string when anObject == null.
     *
     * @param anObject
     * @return the string that will be displayed for anObject. "" is returned
     * when the passed object is null
     */
    protected String getLabel(Object anObject) {
        return (anObject != null) ? anObject.toString() : "";
    }
}