/**
This program demonstrates how to use a custom tree
model. It displays the fields of an object.
*/
public class ObjectInspectorTest
{
public static void main(String[] args)
{
JFrame frame = new ObjectInspectorFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.show();
}
}
/**
This frame holds the object tree.
*/
class ObjectInspectorFrame extends JFrame
{
public ObjectInspectorFrame()
{
setTitle("ObjectInspectorTest");
setSize(WIDTH, HEIGHT);
// we inspect this frame object
Variable v = new Variable(getClass(), "this", this);
ObjectTreeModel model = new ObjectTreeModel();
model.setRoot(v);
// construct and show tree
tree = new JTree(model);
getContentPane().add(new JScrollPane(tree),
BorderLayout.CENTER);
}
private JTree tree;
private static final int WIDTH = 400;
private static final int HEIGHT = 300;
}
/**
This tree model describes the tree structure of a Java
object. Children are the objects that are stored in instance
variables.
*/
class ObjectTreeModel implements TreeModel
{
/**
Constructs an empty tree.
*/
public ObjectTreeModel()
{
root = null;
}
/**
Sets the root to a given variable.
@param v the variable that is being described by this tree
*/
public void setRoot(Variable v)
{
Variable oldRoot = v;
root = v;
fireTreeStructureChanged(oldRoot);
}
public Object getRoot()
{
return root;
}
public int getChildCount(Object parent)
{
return ((Variable)parent).getFields().size();
}
public Object getChild(Object parent, int index)
{
ArrayList fields = ((Variable)parent).getFields();
Field f = (Field)fields.get(index);
Object parentValue = ((Variable)parent).getValue();
try
{
return new Variable(f.getType(), f.getName(),
f.get(parentValue));
}
catch(IllegalAccessException e)
{
return null;
}
}
public int getIndexOfChild(Object parent, Object child)
{
int n = getChildCount(parent);
for (int i = 0; i < n; i++)
if (getChild(parent, i).equals(child))
return i;
return -1;
}
public boolean isLeaf(Object node)
{
return getChildCount(node) == 0;
}
public void valueForPathChanged(TreePath path,
Object newValue)
{}
public void addTreeModelListener(TreeModelListener l)
{
listenerList.add(TreeModelListener.class, l);
}
public void removeTreeModelListener(TreeModelListener l)
{
listenerList.remove(TreeModelListener.class, l);
}
protected void fireTreeStructureChanged(Object oldRoot)
{
TreeModelEvent event
= new TreeModelEvent(this, new Object[] {oldRoot});
EventListener[] listeners = listenerList.getListeners(
TreeModelListener.class);
for (int i = 0; i < listeners.length; i++)
((TreeModelListener)listeners).treeStructureChanged(
event);
}
private Variable root;
private EventListenerList listenerList
= new EventListenerList();
}
/**
A variable with a type, name, and value.
*/
class Variable
{
/**
Construct a variable
@param aType the type
@param aName the name
@param aValue the value
*/
public Variable(Class aType, String aName, Object aValue)
{
type = aType;
name = aName;
value = aValue;
fields = new ArrayList();
/*
find all fields if we have a class type
except we don't expand strings and null values
*/
if (!type.isPrimitive() && !type.isArray() &&
!type.equals(String.class) && value != null)
{
// get fields from the class and all superclasses
for (Class c = value.getClass(); c != null;
c = c.getSuperclass())
{
Field[] f = c.getDeclaredFields();
AccessibleObject.setAccessible(f, true);
// get all nonstatic fields
for (int i = 0; i < f.length; i++)
if ((f.getModifiers() & Modifier.STATIC) == 0)
fields.add(f);
}
}
}
/**
Gets the value of this variable.
@return the value
*/
public Object getValue()
{
return value;
}
/**
Gets all nonstatic fields of this variable.
@return an array list of variables describing the fields
*/
public ArrayList getFields()
{
return fields;
}
public String toString()
{
String r = type + " " + name;
if (type.isPrimitive())
r += "=" + value;
else if (type.equals(String.class))
r += "=" + value;
else if (value == null)
r += "=null";
return r;
}