tapestry-examples/tapestry-workbench/src/org/apache/tapestry/workbench/chart/ChartPage.java

//  Copyright 2004 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.workbench.chart;

import java.awt.Color;
import java.awt.Paint;
import java.util.ArrayList;
import java.util.List;

import org.apache.tapestry.IAsset;
import org.apache.tapestry.IMarkupWriter;
import org.apache.tapestry.IRequestCycle;
import org.apache.tapestry.Tapestry;
import org.apache.tapestry.html.BasePage;
import org.apache.tapestry.valid.IValidationDelegate;
import org.jCharts.Chart;
import org.jCharts.chartData.ChartDataException;
import org.jCharts.chartData.PieChartDataSet;
import org.jCharts.nonAxisChart.PieChart2D;
import org.jCharts.properties.ChartProperties;
import org.jCharts.properties.LegendProperties;
import org.jCharts.properties.PieChart2DProperties;
import org.jCharts.test.TestDataGenerator;

/**
 *  Demonstrates more complex form handling (including loops and dynamic addition/deletion of
 *  rows) as well as dynamic image generation using JCharts.
 * 
 *  @author Howard Lewis Ship, Luis Neves
 *  @version $Id$
 *  @since 1.0.10
 * 
 **/

public class ChartPage extends BasePage implements IChartProvider
{
    private List _plotValues;
    private List _removeValues;
    private PlotValue _plotValue;

    public void initialize()
    {
        _plotValues = null;
        _removeValues = null;
        _plotValue = null;
    }

    /**
     *  Invokes {@link #getPlotValues()}, which ensures that (on the very first request cycle),
     *  the persistent values property is set <em>before</em> the page recorder is locked.
     * 
     **/

    public void beginResponse(IMarkupWriter writer, IRequestCycle cycle)
    {
        getPlotValues();
    }

    public List getPlotValues()
    {
        if (_plotValues == null)
        {
            _plotValues = new ArrayList();

            _plotValues.add(new PlotValue("Fred", 10));
            _plotValues.add(new PlotValue("Barney", 15));
            _plotValues.add(new PlotValue("Dino", 7));

            fireObservedChange("plotValues", _plotValues);
        }

        return _plotValues;
    }

    public void setPlotValues(List plotValues)
    {
        _plotValues = plotValues;

        fireObservedChange("plotValues", plotValues);
    }

    public PlotValue getPlotValue()
    {
        return _plotValue;
    }

    public void setPlotValue(PlotValue plotValue)
    {
        _plotValue = plotValue;
    }

    /**
     *  Invoked during the render; always returns false.
     * 
     **/

    public boolean isMarkedForDeletion()
    {
        return false;
    }

    /**
     *  Invoked by the deleted checkbox (for each plotValue).  If true,
     *  the the current plotValue is added to the list of plotValues to
     *  remove (though the actual removing is done inside {@link #delete(IRequestCycle)},
     *  after the loop.
     *
     **/

    public void setMarkedForDeletion(boolean value)
    {
        if (value)
        {
            if (_removeValues == null)
                _removeValues = new ArrayList();

            _removeValues.add(_plotValue);

            // Deleting things screws up the validation delegate.
            // That's because the errors are associated with the form name
            // (not the component id), and deleting elements causes
            // all the names to shift.

            IValidationDelegate delegate = (IValidationDelegate) getBeans().getBean("delegate");

            delegate.clear();
        }
    }

    /**
     *  Form listener method; does nothing since we want to stay on this page.
     * 
     **/

    public void submit(IRequestCycle cycle)
    {
    }

    /**
     *  Listener method for the add button, adds an additional (blank) plot value.
     * 
     **/

    public void add(IRequestCycle cycle)
    {
        List plotValues = getPlotValues();

        plotValues.add(new PlotValue());

        setPlotValues(plotValues);
    }

    /**
     *  Listener method for the remove button, removes any checked plot values.
     * 
     *  @see #setMarkedForDeletion(boolean)
     * 
     **/

    public void delete(IRequestCycle cycle)
    {
        if (_removeValues != null)
        {
            List plotValues = getPlotValues();

            plotValues.removeAll(_removeValues);

            setPlotValues(plotValues);
        }
    }

    private IAsset chartImageAsset;

    public IAsset getChartImageAsset()
    {
        if (chartImageAsset == null)
            chartImageAsset = new ChartAsset(getRequestCycle(), this);

        return chartImageAsset;
    }

    /**
     *  This method is invoked by the service (in a seperate request cycle from all the form handling stuff).
     *  The {@link #getChartImageAsset()} method provides an {@link IAsset} that is handled by the 
     *  {@link ChartService}, and the asset encodes the identity of this page.
     * 
     **/

    public Chart getChart()
    {
        LegendProperties legendProperties = new LegendProperties();
        legendProperties.setNumColumns(2);
        legendProperties.setPlacement(LegendProperties.RIGHT);
        ChartProperties chartProperties = new ChartProperties();
        chartProperties.setBackgroundPaint(Color.decode("#ffffcc"));

        Chart result = new PieChart2D(getData(), legendProperties, chartProperties, 400, 350);

        return result;
    }

    private PieChartDataSet getData()
    {
        List plotValues = getPlotValues();
        int count = plotValues.size();
        double[] data = new double[count];
        String[] labels = new String[count];
        PieChart2DProperties properties = new PieChart2DProperties();

        for (int i = 0; i < count; i++)
        {
            PlotValue pv = (PlotValue) plotValues.get(i);

            String name = pv.getName();

            if (Tapestry.isBlank(name))
                name = "<New>";

            data[i] = new Double(pv.getValue()).doubleValue();
            labels[i] = new String(name);
        }

        Paint[] paints = TestDataGenerator.getRandomPaints(count);
        
        try
        {
            return new PieChartDataSet("Pie Chart", data, labels, paints, properties);
        }
        catch (ChartDataException e)
        {
            return null;
        }
    }

}