/**
 * Licensed under the Artistic License; you may not use this file
 * except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://displaytag.sourceforge.net/license.html
 *
 * THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */
package org.displaytag.model;

import java.util.Iterator;
import java.util.List;


/**
 * Iterator on columns.
 * @author Fabrizio Giustina
 * @version $Revision$ ($Author$)
 */
public class ColumnIterator
{

    /**
     * current row.
     */
    private Row parentRow;

    /**
     * Internal iterator on header cells.
     */
    private Iterator<HeaderCell> headerIterator;

    /**
     * Internal iterator on cells.
     */
    private Iterator<Cell> cellIterator;

    /**
     * Creates a new ColumnIterator given a list of column and a row.
     * @param columns List containing column objects
     * @param row current Row
     */
    public ColumnIterator(List<HeaderCell> columns, Row row)
    {
        this.headerIterator = columns.iterator();
        this.cellIterator = row.getCellList().iterator();
        this.parentRow = row;
    }

    /**
     * Are there more columns?
     * @return boolean <code>true</code> if there are more columns
     */
    public boolean hasNext()
    {
        return this.headerIterator.hasNext();
    }

    /**
     * Returns the next column.
     * @return Column next column
     */
    public Column nextColumn()
    {
        HeaderCell header = this.headerIterator.next();

        Cell cell = Cell.EMPTY_CELL;

        // if cells is not present simply return an empty cell.
        // this is needed for automatic properties discovery
        if (this.cellIterator.hasNext())
        {
            cell = this.cellIterator.next();
        }

        // create a new column using the next value in the header and cell iterators and returns it
        return new Column(header, cell, this.parentRow);
    }

}