Bug 323816

Description Dennis Hendriks 2010-08-27 08:58:37 EDT

Build Identifier: Build id: 20100617-1415 (Helios)

I have a plug-in that contributes an action. Executing the action clears the console, and prints some
output. This repeated multiple times. After the last clear, output is also written. However, the console is empty after executing the action. Invoking the action a second or third time does give me output on the console after the action. It feels like a race condition between writing and clearing, kind of like described in this old and long time ago fixed bug: https://bugs.eclipse.org/bugs/show_bug.cgi?id=202564

Reproducible: Always

Steps to Reproduce:
1. Create a Hello World Command plugin project. Call the handler "TestHandler"
and set the package to "testplugin.handlers".
2. Replace the handler code with the code below.
3. Run the plugin.
4. Select the "Sample Command" from the "Sample Menu" (or use ctrl+6 shortcut).
5. Observe that output is written and the console is emptied (you have to be careful here, as it is done very fast!). The most important thing is that the console is empty after the command finishes execution.
6. Run the command again. There should be output this time.

NOTE: if it is a race condition, I can't guarantee this is reproducible on other systems. However, on my system, it happens every time I restart the Eclipse Application and execute the action for the first time...

Code:

package testplugin.handlers;

import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;

import org.eclipse.ui.console.ConsolePlugin;
import org.eclipse.ui.console.IConsole;
import org.eclipse.ui.console.IConsoleManager;
import org.eclipse.ui.console.MessageConsole;
import org.eclipse.ui.console.MessageConsoleStream;

public class TestHandler extends AbstractHandler {

    private static final String PLUGIN_CONSOLE_NAME = "Test";

    public Object execute(ExecutionEvent event) throws ExecutionException {
        MessageConsole console = getConsole();
        MessageConsoleStream out = console.newMessageStream();
        for (int i = 0;i<20;i++){
            console.clearConsole();
            for (int j = 0; j<20;j++)
            {
                out.println("Plugin command output...");
            }
        }
        return null;
    }

    public static MessageConsole findConsole(String name) {
        ConsolePlugin plugin = ConsolePlugin.getDefault();
        IConsoleManager conMan = plugin.getConsoleManager();
        IConsole[] existing = conMan.getConsoles();
        for (int i = 0; i < existing.length; i++)
            if (name.equals(existing[i].getName()))
                return (MessageConsole) existing[i];
        // no console found, so create a new one
        MessageConsole myConsole = new MessageConsole(name, null);
        conMan.addConsoles(new IConsole[] { myConsole });
        return myConsole;
    }

    public static MessageConsole getConsole() {
        MessageConsole myConsole = findConsole(PLUGIN_CONSOLE_NAME);
        myConsole.activate();
        return myConsole;
    }
}