/*
   Copyright (C) 2005-2012, by the President and Fellows of Harvard College.

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

         http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

   Dataverse Network - A web application to share, preserve and analyze research data.
   Developed at the Institute for Quantitative Social Science, Harvard University.
   Version 3.0.
*/
package edu.harvard.iq.dvn.core.web;


/**
 * The SortableList class is a utility class used by the  data table
 * paginator example.
 *
 */
public abstract class SortableList {

    protected String sortColumnName;
    protected boolean ascending;

    // we only want to resort if the order or column has changed.
    protected String oldSort;
    protected boolean oldAscending;


    protected SortableList() {
        //
    }
    protected SortableList(String defaultSortColumn) {
        sortColumnName = defaultSortColumn;
        ascending = isDefaultAscending(defaultSortColumn);
        oldSort = sortColumnName;
        // make sure sortColumnName on first render
        oldAscending = !ascending;
 
    }
    
    protected void checkSort() {
        // we only want to sortColumnName if the column or ordering has changed.
            if (!oldSort.equals(sortColumnName) ||
                oldAscending != ascending){
                sort();
                oldSort = sortColumnName;
                oldAscending = ascending;
            }
       
        }

    /**
     * Sort the list.
     */
    protected abstract void sort();

    /**
     * Is the default sortColumnName direction for the given column "ascending" ?
     */
    protected abstract boolean isDefaultAscending(String sortColumn);

    /**
     * Gets the sortColumnName column.
     *
     * @return column to sortColumnName
     */
    public String getSortColumnName() {
        return sortColumnName;
    }

    /**
     * Sets the sortColumnName column
     *
     * @param sortColumnName column to sortColumnName
     */
    public void setSortColumnName(String sortColumnName) {
        oldSort = this.sortColumnName;
        this.sortColumnName = sortColumnName;

    }

    /**
     * Is the sortColumnName ascending.
     *
     * @return true if the ascending sortColumnName otherwise false.
     */   public boolean isAscending() {
        return ascending;
    }

    /**
     * Set sortColumnName type.
     *
     * @param ascending true for ascending sortColumnName, false for desending sortColumnName.
     */
    public void setAscending(boolean ascending) {
        oldAscending = this.ascending;
        this.ascending = ascending;
    }
    
    //regular bean stuff
    
}