Andrew E. Bruno

When creating a chart that has rather long labels for the x-axis it is sometimes desirable to rotate them a bit so they fit on the plot. The method to use is setCategoryLabelPositions(..) on the CategoryAxis class. Here’s a quick example:

And the code..

import java.io.File;
import java.io.IOException;

import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartUtilities;
import org.jfree.chart.ChartColor;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.CategoryPlot;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.axis.CategoryLabelPositions;
import org.jfree.chart.axis.CategoryAxis;
import org.jfree.data.category.DefaultCategoryDataset;

public class RotateLabels {
    public static void main(String[] args) {
        DefaultCategoryDataset dataSet = new DefaultCategoryDataset();
        dataSet.addValue(51, "series", "Colonel Forbin");
        dataSet.addValue(92, "series", "The Lizards");
        dataSet.addValue(33, "series", "Wilson");
        dataSet.addValue(77, "series", "Rutherford the Brave");
        dataSet.addValue(37, "series", "The Unit Monster");
        dataSet.addValue(97, "series", "The Famous Mockingbird");
        dataSet.addValue(67, "series", "Poster Nutbag");

        JFreeChart chart = ChartFactory.createBarChart(
            "Gamehendge",
            null,
            null,
            dataSet,
            PlotOrientation.VERTICAL,
            false,
            false,
            false
        );

        CategoryPlot plot = (CategoryPlot)chart.getPlot();
        CategoryAxis xAxis = (CategoryAxis)plot.getDomainAxis();
        xAxis.setCategoryLabelPositions(CategoryLabelPositions.UP_45);

        chart.setBackgroundPaint(ChartColor.WHITE);
        try {
            ChartUtilities.saveChartAsPNG(new File("chart.png"), chart, 400, 300);
        } catch(IOException e) {
            e.printStackTrace();
        }
    }
}

One nuance I recently ran into while using iBATIS was inserting data into MySQL bigint unsigned columns. iBATIS doesn’t seem to have a way to handle BigInteger data types and throws an exception when attempting to do an insert. Fetching data out seemed to work OK because if iBATIS doesn’t know how to handle a certain type it just returns a java.lang.Object. The way to go about inserting BigInteger types is to set up a type handler. Here’s an example type handler for BigInteger types:

package org.qnot.util;

import java.math.BigDecimal;
import java.math.BigInteger;
import java.sql.SQLException;
import java.sql.Types;

import com.ibatis.sqlmap.client.extensions.ParameterSetter;
import com.ibatis.sqlmap.client.extensions.ResultGetter;
import com.ibatis.sqlmap.client.extensions.TypeHandlerCallback;

public class BigIntegerTypeHandler implements TypeHandlerCallback {

    public Object getResult(ResultGetter getter) throws SQLException {
        if(getter.wasNull()) {
            return null;
        }

        Object o = getter.getObject();
        if(o instanceof BigDecimal) {
            BigDecimal bd = (BigDecimal)o;
            return bd.toBigInteger();
        } else if(o instanceof BigInteger) {
            return (BigInteger)o;
        } else {
            return o;
        }
    }

    public void setParameter(ParameterSetter setter, Object parameter)
            throws SQLException {
        if (parameter == null) {
            setter.setNull(Types.BIGINT);
        } else {
            BigInteger i = (BigInteger) parameter;
            setter.setBigDecimal(new BigDecimal(i));
        }
    }

    public Object valueOf(String s) {
        return s;
    }
}