Database Schema with the Java Diagram Library – Part I

In this blog post we’ll build a database diagram reading the metadata of the sample MySQL database sakila.

Click here to watch the video that goes with these tutorials.

I. Configuration

For our sample to work we need to add the JDiagram.jar package to the project and a JDBC driver for MySQL. We download the JDBC driver from https://dev.mysql.com/downloads/connector/j/ and we add mysql-connector-java-5.1.40.jar to the libs folder of our project where we have placed JDiagram.jar.

The structure of the Class Diagram Java project.

The structure of the Class Diagram Java project.

II. Helper Classes

We create several helper classes that will handle the connection to the database and re-creation of the database metadata in a format which we can use to build the DB diagram.

1. We have created two classes for connecting to the sakila MySql database and reading the metadata. For the tables. In general we are interested in the names of the tables, the columns in them with column name, column data type and column data size. We also want the relationships in the database, with the primary and foreign keys. The classes that provide us with this information are DBConnection, which binds to the database and DBMetaData, which reads the database with the help of the DatabaseMetaData and ResultSet classes of the Java platform.
2. For the purpose of our project we have created two more classes. The first one represents a column in the database – DBColumn. It has just a few fields:

public class DBColumn {

    public String name;
    public String type;
    public String size;
    public boolean primaryKey;

The other class describes a relation in the database. It is equally simple:

public class DBRelation {

    public String pk_key;
    public String pk_table;

    public String fk_key;
    public String fk_table;

3. We have defined an ArrayList tables variable for the table names. We call the respective method of the DBMetaData class that reads the table names and populates the tables list.

III. UI Controls

We will use an instance of the Diagram class, a DiagramView control, a JScrollPane and a zoom control. What we want to show is a diagram pane that is scrollable both horizontally and vertically and a zoom control next to it.

We create the diagram and make sure it will resize itself when needed:

//diagram initialization
diagram = new Diagram();
diagram.setAutoResize(AutoResize.RightAndDown);

The diagram needs a diagramView to render itself onto. We create one and add it to a JScrollPane. The scroll pane provides the necessary scrollbars if the flowchart gets too big.

//initialize a diagramView that will render the diagram.
diagramView = new DiagramView(diagram);
diagramView.setVisible(true);

//use a scroll pane to host large diagrams
_scrollPane = new JScrollPane(diagramView);
_scrollPane.setVisible(true);
_scrollPane.setAutoscrolls(true);

The Java Diagram library provides a handful of auxiliary controls and in our sample we’ll use the Zoom control:

//provide a zoomer for the diagram
zoomer = new ZoomControl();
zoomer.setView(diagramView);
zoomer.setPreferredSize(new Dimension(70, 50));
zoomer.setVisible(true);

We use the setView() method to associate the zoom control with the diagramView. The BorderLayout algorithm helps us arrange the controls. First, we apply it on the JFrame ContentPane and then we align the zoom control to the right. Finally, we add the JScrollPane to the center, which lets it use all the available space left by the zoomer:

getContentPane().setLayout(new BorderLayout());
this.add(zoomer, BorderLayout.EAST);
this.add(_scrollPane, BorderLayout.CENTER);

IV. Creating the Tables

We first read the data for the DB columns and then for each table in the database we create a diagram TableNode.

ArrayList tableData = DBMetaData.getColumnsMetadata(tableName);

We use the Factory class of the diagram library:

Dimension tableSize = new Dimension(50, 30);
TableNode _table = diagram.getFactory().createTableNode(10, 10, 50, tableData.size() * 8, 4, tableData.size());
_table.setCaption("" + tableName + "");
_table.setId(tableName);

The createTableNode() method that we use takes as arguments the location of the table node, its width and height and the count of rows and columns. We use HTML formatting to make the caption of the table bold. For caption and for id of the tableNode we use the name of the table.

Since we need to use HTML styling on text in the diagram nodes we must specify:

diagram.setEnableStyledText(true);

Let’s add some more customization on the table nodes:

_table.setCaptionFormat(new TextFormat(Align.Center, Align.Center));
_table.setCaptionHeight(7f);
_table.setAllowResizeColumns(true);
_table.setShape(SimpleShape.RoundedRectangle);
_table.setBrush(new SolidBrush(new Color((int)204, (int)224, (int)255)));

The caption is aligned in the center and we increase slightly the default caption height. Then we allow users to resize table columns with the mouse and we change the table shape from rectangle to a rectangle with rounded edges. Finally, we color the table nodes with a light blue brush.

Note that once Factory creates a node it gets added to the DiagramNodes collection of the control automatically.
Now let’s populate the table with data:

int rowIndex = 0;

for(DBColumn column: tableData)
{
    _table.getCell(1, rowIndex).setText("" + column.name + "");
    _table.getCell(2, rowIndex).setText(column.type);
    _table.getCell(3, rowIndex).setText(column.size);

    //if the column is a primary key - set an image. If not, leave it empty.
    if(column.isPrimaryKey())
    {
        try {

            File pathToFile = new File("res/key.png");
            Image image = ImageIO.read(pathToFile);
            _table.getCell(0,rowIndex).setImage(image);


        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }

    rowIndex++;

}

Here we cycle through all DBColumn objects that we have created using the database metadata. In each row in the table node we write the name of the database field, the data type and the data size. Note that we start with the second column (index 1) because the first one is reserved for an image of the primary or foreign key, if applicable. So far we have gathered information only for the primary key.

Since we want the image to occupy the first column we must make some adjustments to the TableNode and its size:

//adjust the size of the tables and columns.
_table.resizeToFitText(true);
Rectangle2D.Float t_size = _table.getBounds();
_table.getColumns().get(0).setWidth(7);
_table.resize(t_size.width + 7, t_size.height);
_table.resizeToFitImage();

First we use resizeToFitText to make the table auto calculate the size it needs based on the text it holds. This, unfortunately would not include space for the image, so we must correct it manually. We resize the first column with 7 pixels to allow the image to fit and we increase the size of the table as well. Then we call resizeToFitImage() to let the TableNode update its new size.

With that we finish the first part of our tutorial. Part II will walk you through the steps to create the relationships among the nodes and arrange the database diagram using the automatic layout algorithms provided with the Java Diagram library. Here is our diagram so far:

Java Database Schema: Tables

Java Database Schema: Tables

You can download the complete sample from this link. The sample contains the sakila MySQL database with a PDF file with instructions how to install it if you haven’t already. You will need to have an installed and running MySQL server. Remember to change the login data in the DBConnection.java file to match your login credentials.

The second part of this tutorial is here.

About Diagramming for Java Swing: MindFusion.Diagramming for Java Swing provides your Java application with all necessary functionality to create and customize a diagram. The library is very easy to integrate and program. There are numerous utility methods, rich event set, more than 100 predefined shapes. The tool supports a variety of ways to render or export the diagram, advanced node types like TreeView nodes, hierarchical nodes, tables, container nodes and many more. There are 15 automatic layouts, various input / output options and fully customizable appearance. A detailed list with JDiagram’s features is uploaded here. You can check the online demo to see some of the functionality implemented.

Diagramming for Java Swing is royalty free, there are no distribution fees. Licenses depend on the count of developers using the tool – check here the prices.

Diagram Library for Java Swing, V4.3

We have released the new version of the Java Diagram library. Here is a brief summary of the new features:

Fluent API

Builder classes in com.mindfusion.diagramming.builders package add support for fluent programming style. Static with and instance init methods in DiagramItem, DiagramItemStyle and Layout -derived classes return a builder instance that can be used to set up respective new or existing objects.

DiagramLink improvements

  • The component no longer keeps a separate segmentCount field, removing a common source of errors. The SegmentCount property now calculates its value from ControlPoints elements. The updateFromPoints(updateGroups, updateSegments) overload has been removed too.
  • SegmentCount setter no longer refuses changing number of segments if auto-routing is enabled or the link is a self-loop.
  • The new Spline element of LinkShape enumeration draws links as interpolating splines that pass through all of their control points:
Java Diagram Library: Spline Links

Java Diagram Library: Spline Links

Enum types

Old-style enumeration classes with static finals have been replaced by enum types, improving type checking and auto-completion support. This change will not affect your code if only passing enum members to methods from the API. If storing them in fields on the other hand, you must change the field type from int to respective enum type.

Several bug fixes
We have fixed a setLicenseKey problem and a bug with the SvgExporter.

You can find details about the new release at the official announcement page here.

The trial version is available for download from the following link:

Download MindFusion.Diagramming for Java Swing, V4.3 Trial Version

Technical support
MindFusion puts special effort in providing high quality technical support to all its current and future clients. You can post your questions about Diagramming for Java at the forum, help desk or at support@mindfusion.eu. All support inquiries are usually answered within hours of being received.

About Diagramming for Java Swing: MindFusion.Diagramming for Java Swing provides your Java application with all necessary functionality to create and customize a diagram. The library is very easy to integrate and program. There are numerous utility methods, rich event set, more than 100 predefined shapes. The tool supports a variety of ways to render or export the diagram, advanced node types like TreeView nodes, hierarchical nodes, tables, container nodes and many more. There are 15 automatic layouts, various input / output options and fully customizable appearance. A detailed list with JDiagram’s features is uploaded here. You can check the online demo to see some of the functionality implemented.

Diagramming for Java Swing is royalty free, there are no distribution fees. Licenses depend on the count of developers using the tool – check here the prices.

Diagramming for Windows Forms, V6.4.2

We have released version 6.4.2 of FlowChart.NET. It contains several customer-requested features and improvements:

Fluent API
Extension methods in MindFusion.Diagramming.Fluent and MindFusion.Diagramming.Layout.Fluent namespaces add support for fluent programming style:

using MindFusion.Diagramming.Fluent;
using MindFusion.Diagramming.Layout.Fluent;
//...

diagram.Factory
	.CreateShapeNode(10, 10, 20, 20)
		.Brush(Color.LightGray)
		.Font("Arial", 12)
		.EnableStyledText(true)
		.Text("Task 1")
		.ToolTip("This is the task");

new TreeLayout()
	.LevelDistance(20)
	.NodeDistance(20)
	.LinkStyle(TreeLayoutLinkType.Cascading3)
	.Arrange(diagram); 

DiagramLink Improvements

  • The component no longer keeps a separate segmentCount field, removing a common source of errors. The SegmentCount property now calculates its value from ControlPoints elements. The UpdateFromPoints(updateGroups, updateSegments) overload has been removed too.
  • SegmentCount setter no longer refuses changing number of segments if auto-routing is enabled or the link is a self-loop.
  • The new Spline element of LinkShape enumeration draws links as interpolating splines that pass through all of their control points:
WinForms Diagram Control: Spline Links

WinForms Diagram Control: Spline Links

Miscellaneous

  • The ModifierKeyAction.ExtendSelection mode selects items within the lasso without deselecting old ones.
  • The Visio Stencils import API provides access to BeginArrow and EndArrow values.
  • The Visio Stencils import API provides access to Connection elements defined for a shape.
  • It is now enough to set EnableStyledText to enable styled-text mode without having to also enable PolygonalTextLayout.
  • Fixed bug where ItemAdded event wasn’t raised for interactively drawn items.
  • Miscellaneous UI control assemblies (NodeListView, LayerListView, Ruler, etc) have been merged into a single MindFusion.Diagramming.WinForms.Controls.dll.

A direct link to download the trial version follows:

Download MindFusion WinForms Diagram Component, V 6.4.2

Updated assemblies are also available as MindFusion.Diagramming NuGet package.

About MindFusion.Diagramming for WinForms: A programming component that provides any WinForms application with a full set of features for creating and customizing all types of diagrams, flowcharts, schemes, hierarchies, trees, graphs etc. The control provides numerous ways to save and load a diagram, six auxiliary controls and more than 12 automatic graph layout algorithms. Diagram elements include scrollable tables, container nodes, multi-segment arrows, custom diagram item types and many more. Further details here.

Diagramming for WinForms is a royalty-free component, clients get 12 month upgrade subscription when buying a license. The source code is also available for purchase. Visit the buy page for a list with the current license prices.

Lane diagram in JavaScript

In this post we will show how to use the JavaScript diagram library to create a lane diagram. The complete example is available here:

Lanes.zip

Create a new HTML page and add references to the jQuery library and to the MindFusion.Diagramming library:

<script src="jquery.min.js" type="text/javascript"></script>
<script src="MindFusion.Common.js" type="text/javascript"></script>
<script src="MindFusion.Diagramming.js" type="text/javascript"></script>

Create shortcuts to some classes from the diagram model:

var Events = MindFusion.Diagramming.Events;
var Diagram = MindFusion.Diagramming.Diagram;
var AnchorPattern = MindFusion.Diagramming.AnchorPattern;
var AnchorPoint = MindFusion.Diagramming.AnchorPoint;
var Alignment = MindFusion.Diagramming.Alignment;
var MarkStyle = MindFusion.Diagramming.MarkStyle;
var Style = MindFusion.Diagramming.Style;
var Theme = MindFusion.Diagramming.Theme;
var LinkShape = MindFusion.Diagramming.LinkShape;
var Shape = MindFusion.Diagramming.Shape;
var LaneGrid = MindFusion.Diagramming.Lanes.Grid;
var LaneHeader = MindFusion.Diagramming.Lanes.Header;
var LaneStyle = MindFusion.Diagramming.Lanes.Style;
var Rect = MindFusion.Drawing.Rect;
var Point = MindFusion.Drawing.Point;
var HandlesStyle = MindFusion.Diagramming.HandlesStyle;

Next, add a canvas the the page and create a diagram from it by using the Diagram.create() method:

diagram = Diagram.create($("#diagram")[0]);

You can obtain a reference to the diagram lane grid by calling the Diagram.getLaneGrid() method. You can use the returned object to add rows and columns to the grid and customize its appearance. Finally, to display the grid, call Diagram.setShowLaneGrid(). The customization is omitted here for brevity, but the full code is available in the associated sample project.

The lane grid implies some restrictions to the node and links inside of it. For example, the nodes can be moved only inside the row lanes of the grid. To enforce those restrictions, we will handle several diagram events:

diagram.addEventListener(Events.nodeCreated, onNodeCreated);
diagram.addEventListener(Events.nodeModified, onNodeModified);
diagram.addEventListener(Events.linkCreated, onLinkCreated);

In the nodeCreated event handler, get the gird cell at the top left of the node’s bounding rectangle and align the node to this cell:

function onNodeCreated(sender, e) {
    var node = e.getNode();
    node.setAnchorPattern(pattern);
    node.setHandlesStyle(HandlesStyle.HatchHandles3);

    // Place the box within the grid
    var bounds = node.getBounds();
    var topLeft = new Point(bounds.x, bounds.y);

    var cellBoundsReciever = {};
    if (!grid.getCellFromPoint(topLeft, cellBoundsReciever))
        return;
    var cellBounds = cellBoundsReciever.cellBounds;

    var pixel = 1;

    bounds.y = cellBounds.y + pixel;
    bounds.height = cellBounds.height - 2 * pixel;
    node.setBounds(bounds);
}

Similar rules can be applied to the links in the linkCreated event handler.

The following image illustrates the grid in action:

JavaScript Swimlane Diagram

For more information on MindFusion JavaScript diagram library, see its help reference and overview page.

Enjoy!

Class inheritance diagram in JavaScript

In this post we will show how to use the JavaScript diagram library to generate a class inheritance diagram. The complete example is available here:

InheritanceDiagram.zip

and a live version here:

http://mindfusion.eu/demos/jsdiagram/Inheritance.html

Let’s start by creating shortcuts to some classes from the diagram model:

var Diagram = MindFusion.Diagramming.Diagram;

var DiagramItem = MindFusion.Diagramming.DiagramItem;
var DiagramLink = MindFusion.Diagramming.DiagramLink;
var DiagramNode = MindFusion.Diagramming.DiagramNode;
var ShapeNode = MindFusion.Diagramming.ShapeNode;
var TableNode = MindFusion.Diagramming.TableNode;
var ContainerNode = MindFusion.Diagramming.ContainerNode;
var FreeFormNode = MindFusion.Diagramming.FreeFormNode;
var SvgNode = MindFusion.Diagramming.SvgNode;

var ScrollBar = MindFusion.Diagramming.ScrollBar;
var Rect = MindFusion.Drawing.Rect;
var Font = MindFusion.Drawing.Font;
var TreeLayout = MindFusion.Graphs.TreeLayout;

Next, create a function that takes a Diagram instance and a list of class names as parameters. It will create a TableNode for each class. Each property of the class prototype is listed in a TableNode cell. If the getBaseType function detects a class inherits another one from the list, we’ll create a link between their nodes. Finally, the diagram is arranged using the TreeLayout algorithm.

function createClassDiagram(diagram, classes)
{
    var classConstructors = [];

    // create a table node for each class
    for (var i = 0; i < classes.length; i++)
    {
        var className = classes[i];
        var node = diagram.getFactory().createTableNode(20, 20, 42, 42);
        node.redimTable(1, 0);
        node.setText(className);
        node.setBrush("white");
        node.setCaptionBackBrush("lightgray");
        node.setCaptionFont(
            new Font("sans-serif", 3, true /*bold*/, true /*italic*/));
        node.setScrollable(true);

        var ctor = eval(className);
        for (var property in ctor.prototype)
        {
            node.addRow();
            node.getCell(0, node.rows.length - 1).setText(property);
        }
        classConstructors.push(ctor);
        ctor.classNode = node;
    }
	
    // create a diagram link for each prototype inheritance
    classConstructors.forEach(function(ctor)
    {
        var base = getBaseType(ctor);
        if (base && base.classNode)
        {
            var link = diagram.factory.createDiagramLink(
                base.classNode,
                ctor.classNode);
            link.setHeadShape(null);
            link.setBaseShape("Triangle");
            link.setBaseShapeSize(3);
        }
    });

    // arrange as a tree
    var treeLayout = new TreeLayout();
    treeLayout.linkType = MindFusion.Graphs.TreeLayoutLinkType.Cascading;
    diagram.arrange(treeLayout);
}

The getBaseType implementation checks if a class was registered as a base for the argument using MindFusion.registerClass method or the common prototype inheritance pattern.

function getBaseType(ctor)
{
    // if class registered using MindFusion.registerClass
    if (ctor.__baseType)
        return ctor.__baseType;

    // if  prototypical inheritance with Child.prototype = new Parent()
    if (ctor.prototype && ctor.prototype.constructor != ctor)
        return ctor.prototype.constructor;
	
    return null;
}

The ready handler creates a Diagram instance binding it to a #diagram canvas element. It then calls createClassDiagram with a list of DiagramItem -derived classes as argument:

$(document).ready(function ()
{
    TableNode.prototype.useScrollBars = true;
    ScrollBar.prototype.background = "Lavender";
    ScrollBar.prototype.foreground = "DarkGray";

    // create a Diagram component that wraps the "diagram" canvas
    var diagram = Diagram.create($("#diagram")[0]);

    createClassDiagram(diagram,
    [
        "DiagramItem",
        "DiagramLink",
        "DiagramNode",
        "ShapeNode",
        "TableNode",
        "ContainerNode",
        "FreeFormNode",
        "SvgNode"
    ]);
});

If you run the sample now, you should see this nice visualization of MindFusion classes 🙂

JavaScript class inheritance diagram

For more information on MindFusion JavaScript diagram library, see its help reference and overview page.

Enjoy!