resource-change-monitor

This is a simple event-driven library for monitoring file changes.

Maven

This library is available as a Maven artifact from Maven Central, so you don't need to add any additional repositories.

Usage

In order to use the ResourceChangeMonitor, you will need to implement the ResourceChangeListener as illustrated below:

private class Observer implements ResourceChangeListener
{

    @Override
    public void handleEvent(ResourceChangeEvent event)
    {
        try
        {
            if (event.getEventType() == ResourceChangeEvent.EVENT_RESOURCE_CONTENTS_CHANGED)
            {
                System.out.println(event.getResourceFile().getCanonicalPath() + ": contents have changed.");
            }

            if (event.getEventType() == ResourceChangeEvent.EVENT_RESOURCE_SIZE_CHANGED)
            {
                System.out.println(event.getResourceFile().getCanonicalPath() + ": size has changed.");
            }

            if (event.getEventType() == ResourceChangeEvent.EVENT_RESOURCE_DELETED)
            {
                System.out.println(event.getResourceFile().getCanonicalPath() + ": has been deleted.");
            }
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
    }
}

Then, in order to observe files for changes:

File file1 = new File(DIR_TEST_RESOURCES, "file1"); // size changed

Observer observer = new Observer();

ResourceChangeMonitor monitor = new ResourceChangeMonitor();
monitor.setInterval(1000); // Check for changes every second
monitor.addResource(new Resource(file1, getHashFor(file1), 10 * 1024));
monitor.addListener(observer);
monitor.start();

For more details and an example implementation, check src/test/java/org/carlspring/resource/ChangeMonitorTest.java.