tapestry/tapestry-contrib/src/java/org/apache/tapestry/contrib/table/model/ITableColumn.java

// Copyright 2004, 2005 The Apache Software Foundation
//
// 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 org.apache.tapestry.contrib.table.model;

import java.util.Comparator;

import org.apache.tapestry.IRender;
import org.apache.tapestry.IRequestCycle;

/**
 * The interface defining a table column. A column is responsible for presenting
 * a particular part of the data from the objects in the table. This is done via
 * the getValueRender() method. A column may be sortable, in which case it
 * defines the way in which the objects in the table must be sorted by providing
 * a Comparator.
 * 
 * @author mindbridge
 */
public interface ITableColumn
{

    /**
     * Method getColumnName provides the name of the column. The column name
     * must be unique and is generally used for the identification of the
     * column. It does not have to be the same as the display name via which the
     * column is identified to the user (see the getColumnRender() method).
     * 
     * @return String the name of the column
     */
    String getColumnName();

    /**
     * Method getSortable declares whether the column allows sorting. If the
     * column allows sorting, it must also return a valid Comparator via the
     * getComparator() method.
     * 
     * @return boolean whether the column is sortable or not
     */
    boolean getSortable();

    /**
     * Method getComparator returns the Comparator to be used to sort the data
     * in the table according to this column. The Comparator must accept two
     * different rows, compare them according to this column, and return the
     * appropriate value.
     * 
     * @return Comparator the Comparator used to sort the table data
     */
    Comparator getComparator();

    /**
     * Method getColumnRenderer provides a renderer that takes care of rendering
     * the column in the table header. If the column is sortable, the renderer
     * may provide a mechanism to sort the table in an ascending or descending
     * manner.
     * 
     * @param objCycle
     *            the current request cycle
     * @param objSource
     *            a component that can provide the table model (typically
     *            TableView)
     * @return IRender the renderer to present the column header
     */
    IRender getColumnRenderer(IRequestCycle objCycle,
            ITableModelSource objSource);

    /**
     * Method getValueRenderer provides a renderer for presenting the value of a
     * particular row in the current column.
     * 
     * @param objCycle
     *            the current request cycle
     * @param objSource
     *            a component that can provide the table model (typically
     *            TableView)
     * @param objRow
     *            the row data
     * @return IRender the renderer to present the value of the row in this
     *         column
     */
    IRender getValueRenderer(IRequestCycle objCycle,
            ITableModelSource objSource, Object objRow);
}