Java 7: Dolphin

Sun is releasing weekly early access snapshots of the complete source, binaries and documentation for JDK 7. These raw snapshot releases let you review and contribute to the Java SE platform as it is being developed.

Some possible language changes being considered for Dolphin include:

• property support (for getFoo()/setFoo() pattern)
• method references (a quick way to write an event notification pattern)
• block closures (collection of statements within a statement)
• native XML support

For more information:
Latest JDK 7 binary snapshots
Latest JDK 7 source snapshots
Latest JDK 7 Java Docs
Summary of changes in JDK 7

Source: https://jdk7.dev.java.net/

Advertisements

Creating BarCharts with custom colours using JFreeChart

This can be achieved by extending the BarRenderer. BarRenderer is responsible for all kind of UI related things like setting the font, setting the colors, setting the alignment etc etc. Rather we can say everything. The same can be achieved by extending corresponding renderer.

Here the getItemPaint(row, col) has been overridden to achieve the custom colors.

CustomRenderer:

import org.jfree.chart.renderer.category.BarRenderer; 
import java.awt.Color; 
import java.awt.Paint;

class CustomRenderer extends BarRenderer 
{ 
 private Paint[] colors;

 public CustomRenderer() 
 { 
    this.colors = new Paint[] {Color.red, Color.blue, Color.green, 
      Color.yellow, Color.orange, Color.cyan, 
      Color.magenta, Color.blue}; 
 }

 public Paint getItemPaint(final int row, final int column) 
 { 
    // returns color for each column 
    return (this.colors[column % this.colors.length]); 
 } 
}

Using custom renderer with the CategoryPlot:

final JFreeChart chart = ChartFactory.createBarChart( 
   "chart title", 
   "x axis label", 
   "y axis label ", 
   dataset, 
   PlotOrientation.VERTICAL, 
   false,                 
   true, 
   false 
);

chart.setBackgroundPaint(Color.lightGray);

// get a reference to the plot for further customisation... 
final CategoryPlot plot = chart.getCategoryPlot(); 
CategoryItemRenderer renderer = new CustomRenderer(); 
plot.setRenderer(renderer);

Other useful links:
Creating a 3D BarChart using JFreeChart
Creating Time Series charts using JFreeChart
Creating Pie Chart using JFreeChart (Using plot)
Creating Pie Chart using JFreeChart

Creating a 3D BarChart using JFreeChart

The given code snippet can create a 3D Bar Chart. The given Bar Chart compares 2 aspects of each customer. The generated chart will have two bars for each customer for both Profit1 and Profit 2 (see the dataset).

Profit 1 can can be total annual profit and Profit 2 can be profit for a particular period like monthly or weekly profit. Please find the sample image created using this code.

DefaultCategoryDataset dataset = new DefaultCategoryDataset(); 
dataset.setValue(6, "Profit1", "Jane"); 
dataset.setValue(3, "Profit2", "Jane"); 
dataset.setValue(7, "Profit1", "Tom"); 
dataset.setValue(10, "Profit2", "Tom"); 
dataset.setValue(8, "Profit1", "Jill"); 
dataset.setValue(8, "Profit2", "Jill"); 
dataset.setValue(5, "Profit1", "John"); 
dataset.setValue(6, "Profit2", "John"); 
dataset.setValue(12, "Profit1", "Fred"); 
dataset.setValue(5, "Profit2", "Fred");

// Profit1, Profit2 represent the row keys 
// Jane, Tom, Jill, etc. represent the column keys

JFreeChart chart = ChartFactory.createBarChart3D( 
   "Comparison between Salesman",  // Chart name 
   "Salesman",                     // X axis label 
   "Value ($)",                    // Y axis value 
   dataset,                        // data set 
   PlotOrientation.VERTICAL, 
   true, true, false);

// Creating a JPEG image 
try 
{ 
   ChartUtilities.saveChartAsJPEG(new File("myChart.jpg"), chart, 500, 300); 
} 
catch (IOException e) 
{ 
   System.err.println("Problem occurred creating chart."); 
} 

Image generated:

Other useful links:
Creating Time Series charts using JFreeChart
Creating Pie Chart using JFreeChart (Using plot)
Creating Pie Chart using JFreeChart