TableItemSortStringSetActionListener.java

/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * 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.
 */
package com.motorola.studio.android.wizards.elements.sorting;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.widgets.Table;
import org.eclipse.swt.widgets.TableColumn;
import org.eclipse.swt.widgets.TableItem;

import com.motorola.studio.android.wizards.elements.sorting.TableItemStringComparator.SortDirection;

/**
 * This selection listener sorts the columns of a {@link Table}. It assumes
 * the columns being sorted are {@link String}s.
 */
public class TableItemSortStringSetActionListener implements SelectionListener
{

    /* (non-Javadoc)
     * @see org.eclipse.swt.events.SelectionListener#widgetDefaultSelected(org.eclipse.swt.events.SelectionEvent)
     */
    public void widgetDefaultSelected(SelectionEvent e)
    {
        // sort the table
        sortTable(e);
    }

    /* (non-Javadoc)
     * @see org.eclipse.swt.events.SelectionListener#widgetSelected(org.eclipse.swt.events.SelectionEvent)
     */
    public void widgetSelected(SelectionEvent e)
    {
        // sort the table
        sortTable(e);
    }

    /**
     * Execute the {@link Table} sorting.
     * 
     * @param e Event object of the sort.
     */
    private void sortTable(SelectionEvent e)
    {
        // get column to be sorted
        TableColumn column = (TableColumn) e.widget;
        // get table belonging to to sorted column
        Table table = column.getParent();

        // get selected items because the sort messes with them, so they will be restored later
        TableItem[] selectedItems = table.getSelection();
        // create a list of new selected items - items which will be selected after the sorting
        List<TableItem> selectedItemsAfterSorting = new ArrayList<TableItem>();

        // get the sort direction from the table
        int sortDirection = table.getSortDirection();
        // determine the new sorting direction according to the old one
        sortDirection = sortDirection == SWT.UP ? SWT.DOWN : SWT.UP;

        // get Table items
        TableItem[] items = table.getItems();
        if ((items != null) && (items.length > 0))
        {
            // sort the items - assume you always sort them by String
            Arrays.sort(items, new TableItemStringComparator(table.indexOf(column),
                    sortDirection == SWT.UP ? SortDirection.ASCENDING : SortDirection.DESCENDING));

            // rearrange the table according to the sorted items - the iteration is in the new sorted order
            TableItem newItem = null;
            TableItem item = null;
            for (int rowIndex = 0; rowIndex < items.length; rowIndex++)
            {
                // get current item - to be removed
                item = items[rowIndex];
                // create a new table item to be inserted in the table
                newItem = new TableItem(table, SWT.NONE, rowIndex);
                // set the text for this new item based on the item in the order
                newItem.setText(getTableItemData(item));
                // in case the current item is a selected one, put the new one in the selection list
                if (isElementInArray(item, selectedItems))
                {
                    selectedItemsAfterSorting.add(newItem);
                }
                // remove the current item
                item.dispose();
            }
        }
        // set the new selection items
        TableItem[] selectedItemsAfterSortingArray =
                new TableItem[selectedItemsAfterSorting.size()];
        for (int rowIndex = 0; rowIndex < selectedItemsAfterSortingArray.length; rowIndex++)
        {
            selectedItemsAfterSortingArray[rowIndex] = selectedItemsAfterSorting.get(rowIndex);
        }
        table.setSelection(selectedItemsAfterSortingArray);

        // set the new sorting direction and sorted column
        table.setSortDirection(sortDirection);
        table.setSortColumn((column));
        table.setRedraw(true);
    }

    /**
     * Verify whether an element belongs to an array.
     * 
     * @param <E> Any type of object or primitive
     * @param element Element to be verified whether it is in a certain array.
     * @param array Array which the element will be verified to be within.
     * 
     * @return Returns <code>true</code> in case the element is in the array, <code>false</code>
     * otherwise.
     */
    private <E> boolean isElementInArray(E element, E[] array)
    {
        boolean hasElement = false;

        // first all items must not be null and the list not empty
        if ((element != null) && (array != null) && (array.length > 0))
        {
            // verify whether the element is in the array
            for (E arrayItem : array)
            {
                // the element was found, set the flag and quit the loop
                if (arrayItem.equals(element))
                {
                    hasElement = true;
                    break;
                }
            }
        }

        return hasElement;
    }

    /**
     * Get an array of string holding the data of a {@link TableItem}.
     * 
     * @param tableItem Table item in which data will be retrieved.
     * 
     * @return Array of data from the Table Item.
     */
    private String[] getTableItemData(TableItem tableItem)
    {
        String[] itemArray = new String[0];
        // get the related table
        Table table = tableItem.getParent();
        if (table != null)
        {
            // get the number of columns in the table
            int columnCount = table.getColumnCount();
            if (columnCount > 0)
            {
                // set a string of data to be returned, based on the number of columns
                itemArray = new String[columnCount];
                // for each column item put in the array to be returned
                for (int columnIndex = 0; columnIndex < columnCount; columnIndex++)
                {
                    itemArray[columnIndex] = tableItem.getText(columnIndex);
                }
            }
        }
        return itemArray;
    }
}