Application: gvSIG desktop

package org.gvsig.expressionevaluator.impl.function.programming;

import java.awt.Dimension;

import java.awt.Graphics2D;

import java.awt.Image;

import java.awt.image.BufferedImage;

import javax.json.JsonArray;

import javax.json.JsonObject;

import javax.json.JsonValue;

import org.apache.commons.lang3.Range;

import org.apache.commons.lang3.StringUtils;

import org.gvsig.expressionevaluator.Function;

import org.gvsig.expressionevaluator.Interpreter;

import org.gvsig.expressionevaluator.spi.AbstractFunction;

import org.gvsig.expressionevaluator.spi.JsonUtils;

import org.gvsig.tools.swing.api.SimpleImage;

import org.gvsig.tools.swing.api.ToolsSwingLocator;

import org.jfree.chart.ChartFactory;

import org.jfree.chart.ChartPanel;

import org.jfree.chart.JFreeChart;

import org.jfree.chart.plot.PlotOrientation;

import org.jfree.data.category.DefaultCategoryDataset;

public class CreateChartFunction extends AbstractFunction {

    public CreateChartFunction() {

        super(

            Function.GROUP_PROGRAMMING, 

            "CREATE_CHART", 

            Range.is(1),

            "",

            "CREATE_CHART"+"({{string}})",

            null,

            "SimpleImage",

            false

        );

    }

    @Override

    public boolean allowConstantFolding() {

        return false;

    }    

    @Override

    public Object call(Interpreter interpreter, final Object[] args) throws Exception {

        Object obj = getObject(args, 0);

        if( obj == null ) {

            return null;

            //throw new ExpressionRuntimeException("Null is not valid in "+FUNCTION_GETITEM+" function.");

        }

        if( !(obj instanceof JsonObject )) {

            obj = JsonUtils.toJsonObject(obj);

        }

        JsonObject jsonobj = ((JsonObject)obj);

        SimpleImage graph = ToolsSwingLocator.getToolsSwingManager().createSimpleImage(createGraph(jsonobj));

        return graph;

    }

    public Image createGraph(JsonObject json) {

        String chartType = json.getString("chartType").toLowerCase();

        switch(chartType){

            case "barchart": {

                JsonArray datasetJson = json.getJsonArray("dataset");

                DefaultCategoryDataset ds = new DefaultCategoryDataset();

                for (JsonValue jsonValue : datasetJson) {

                    JsonArray element = (JsonArray) jsonValue;

                    double value = element.getJsonNumber(0).doubleValue();

                    String field1 = element.getString(1, null);

                    String field2 = element.getString(2, null);

                    ds.addValue(value, field1, field2);

                }

                JFreeChart barChart = ChartFactory.createBarChart(

                            json.getString("title", ""),

                            json.getString("categoryAxisLabel",""),

                            json.getString("valueAxisLabel",""),

                            ds,

                            StringUtils.equalsIgnoreCase(json.getString("orientation",null),"HORIZONTAL")? PlotOrientation.HORIZONTAL:PlotOrientation.VERTICAL,

                            json.getBoolean("legend", true),

                            false,

                            false);

                ChartPanel chartPanel = new ChartPanel(barChart);

                chartPanel.setPreferredSize(new Dimension( json.getInt("witdh",360) , json.getInt("height",200) ));

                Dimension d = chartPanel.getSize();

                BufferedImage image = new BufferedImage(d.width, d.height, BufferedImage.TYPE_INT_RGB);

                Graphics2D g2d = image.createGraphics();

                chartPanel.print( g2d );

                g2d.dispose();

                return image;

            }

            default: 

                throw new IllegalArgumentException("Unknown chart type:" + chartType);

        }

    }

}