An example class for testing a method of setting conditional breakpoints based off of the hash of the current stack trace.

TestDebugStackTrace.java

import java.awt.BorderLayout;

/**
 * An example class for testing a method of setting conditional breakpoints
 * based off of the hash of the current stack trace.
 * 
 * Eventually, I'd like to edit the Java breakpoint condition editor:
 * org.eclipse.jdt.debug.ui.breakpoints.JavaBreakpointConditionEditor.java
 * to allow keeping track of the stack trace history for a given breakpoint, and
 * only break on certain hashes.  It would also be nice to keep a count of each
 * occurrence.
 */
public class TestDebugStackTrace {

	private JFrame frame;
	private ClickListener clickListener;
	private int actionNum = 0;
	private JTextArea textArea;

	/**
	 * Launch the application.
	 */
	public static void main(String[] args) {
		EventQueue.invokeLater(new Runnable() {
			public void run() {
				try {
					TestDebugStackTrace window = new TestDebugStackTrace();
					window.frame.setVisible(true);
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
		});
	}

	/**
	 * Create the application.
	 */
	public TestDebugStackTrace() {
		initialize();
	}

	/**
	 * Initialize the contents of the frame.
	 */
	private void initialize() {
		clickListener = new ClickListener();
		frame = new JFrame();
		frame.setTitle("Test Breakpoints by hasing stack trace");
		frame.setBounds(100, 100, 450, 300);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);		

		// HASH1: ActionListener = clickListener
		JButton btnOne = new JButton("Button 1 - HASH 1");
		btnOne.addActionListener(clickListener);
		frame.getContentPane().add(btnOne, BorderLayout.WEST);

		// HASH1: ActionListener = clickListener
		JButton btnTwo = new JButton("Button 2 - HASH 1");
		btnTwo.addActionListener(clickListener);
		frame.getContentPane().add(btnTwo, BorderLayout.EAST);
		
		// HASH2: ActionListener = new ActionListener
		JButton btnThree = new JButton("Button 3 - HASH 2");
		btnThree.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				performAction(e);
			}
		});
		frame.getContentPane().add(btnThree, BorderLayout.SOUTH);

		// A place to show debug info (instead of writing to console)
		JScrollPane scrollPane = new JScrollPane();
		frame.getContentPane().add(scrollPane, BorderLayout.CENTER);
		textArea = new JTextArea();
		scrollPane.setViewportView(textArea);
	}

	/**
	 * This will call our private function {@link TestDebugStackTrace#performAction(ActionEvent)}
	 */
	private class ClickListener implements ActionListener {
		public void actionPerformed(ActionEvent e) {
			performAction(e);
		}
	}

	/**
	 * Will increment the internal counter "actionNum", and write some
	 * debug info to our scrollable textArea.
	 * @param e A pass-through for the current ActionEvent
	 */
	private void performAction(ActionEvent e) {
		actionNum++;
		textArea.append("(" + actionNum + ") " + getStackTraceInfo() + "\n");		
	}

	/**
	 * @return A debug string containing the stack trace as one line, prefixed
	 * by the hashCode of that string.
	 */
	private String getStackTraceInfo() {
		// Get stack trace as one line string (easier to compare differences in console)
		String stackTrace = Arrays.toString(new Throwable().getStackTrace());
		// Store the hash of the stack trace
		int hash = stackTrace.hashCode();
		// Get a pretty string for the console
		String debugString = "" + hash + " ==> " + stackTrace;
		return debugString;
	}
}