001// Copyright 2004, 2005 The Apache Software Foundation
002//
003// Licensed under the Apache License, Version 2.0 (the "License");
004// you may not use this file except in compliance with the License.
005// You may obtain a copy of the License at
006//
007//     http://www.apache.org/licenses/LICENSE-2.0
008//
009// Unless required by applicable law or agreed to in writing, software
010// distributed under the License is distributed on an "AS IS" BASIS,
011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012// See the License for the specific language governing permissions and
013// limitations under the License.
014
015package org.apache.tapestry.contrib.table.components;
016
017import java.util.Iterator;
018
019import org.apache.tapestry.IAsset;
020import org.apache.tapestry.IMarkupWriter;
021import org.apache.tapestry.IRender;
022import org.apache.tapestry.IRequestCycle;
023import org.apache.tapestry.contrib.table.model.ITableColumn;
024import org.apache.tapestry.contrib.table.model.ITableColumnModel;
025
026/**
027 * A low level Table component that renders the column headers in the table. This component must be
028 * wrapped by {@link org.apache.tapestry.contrib.table.components.TableView}.
029 * <p>
030 * The component iterates over all column objects in the
031 * {@link org.apache.tapestry.contrib.table.model.ITableColumnModel}and renders a header for each
032 * one of them using the renderer provided by the getColumnRender() method in
033 * {@link org.apache.tapestry.contrib.table.model.ITableColumn}. The headers are wrapped in 'th'
034 * tags by default.
035 * <p>
036 * Please see the Component Reference for details on how to use this component. [ <a
037 * href="../../../../../../../ComponentReference/contrib.TableColumns.html">Component Reference
038 * </a>]
039 * 
040 * @author mindbridge
041 */
042public abstract class TableColumns extends AbstractTableViewComponent
043{
044    public static final String TABLE_COLUMN_ARROW_UP_ATTRIBUTE = "org.apache.tapestry.contrib.table.components.TableColumns.arrowUp";
045
046    public static final String TABLE_COLUMN_ARROW_DOWN_ATTRIBUTE = "org.apache.tapestry.contrib.table.components.TableColumns.arrowDown";
047
048    public static final String TABLE_COLUMN_CSS_CLASS_SUFFIX = "ColumnHeader";
049
050    public abstract IAsset getArrowDownAsset();
051
052    public abstract IAsset getArrowUpAsset();
053
054    public abstract void setColumn(ITableColumn column);
055
056    // Transient
057    private ITableColumn m_objTableColumn = null;
058
059    /**
060     * Returns the currently rendered table column. You can call this method to obtain the current
061     * column.
062     * 
063     * @return ITableColumn the current table column
064     */
065    public ITableColumn getTableColumn()
066    {
067        return m_objTableColumn;
068    }
069
070    /**
071     * Sets the currently rendered table column. This method is for internal use only.
072     * 
073     * @param tableColumn
074     *            The current table column
075     */
076    public void setTableColumn(ITableColumn tableColumn)
077    {
078        m_objTableColumn = tableColumn;
079
080        if (isParameterBound("column"))
081            setColumn(tableColumn);
082    }
083
084    /**
085     * Get the list of all table columns to be displayed.
086     * 
087     * @return an iterator of all table columns
088     */
089    public Iterator getTableColumnIterator()
090    {
091        ITableColumnModel objColumnModel = getTableModelSource().getTableModel().getColumnModel();
092        return objColumnModel.getColumns();
093    }
094
095    /**
096     * Returns the renderer to be used to generate the header of the current column
097     * 
098     * @return the header renderer of the current column
099     */
100    public IRender getTableColumnRenderer()
101    {
102        return getTableColumn().getColumnRenderer(
103                getPage().getRequestCycle(),
104                getTableModelSource());
105    }
106
107    public abstract String getColumnClassParameter();
108
109    /**
110     * Returns the CSS class of the generated table cell. It uses the class parameter if it has been
111     * bound, or the default value of "[column name]ColumnHeader" otherwise.
112     * 
113     * @return the CSS class of the cell
114     */
115    public String getColumnClass()
116    {
117        if (isParameterBound("class"))
118            return getColumnClassParameter();
119
120        return getTableColumn().getColumnName() + TABLE_COLUMN_CSS_CLASS_SUFFIX;
121    }
122
123    /**
124     * @see org.apache.tapestry.BaseComponent#renderComponent(IMarkupWriter, IRequestCycle)
125     */
126    protected void renderComponent(IMarkupWriter writer, IRequestCycle cycle)
127    {
128        Object oldValueUp = cycle.getAttribute(TABLE_COLUMN_ARROW_UP_ATTRIBUTE);
129        Object oldValueDown = cycle.getAttribute(TABLE_COLUMN_ARROW_DOWN_ATTRIBUTE);
130
131        try
132        {
133            cycle.setAttribute(TABLE_COLUMN_ARROW_UP_ATTRIBUTE, getArrowUpAsset());
134            cycle.setAttribute(TABLE_COLUMN_ARROW_DOWN_ATTRIBUTE, getArrowDownAsset());
135
136            super.renderComponent(writer, cycle);
137        }
138        finally
139        {
140            cycle.setAttribute(TABLE_COLUMN_ARROW_UP_ATTRIBUTE, oldValueUp);
141            cycle.setAttribute(TABLE_COLUMN_ARROW_DOWN_ATTRIBUTE, oldValueDown);
142
143            // set the current column to null when the component is not active
144            m_objTableColumn = null;
145        }
146    }
147
148}