com.vaadin.server.SynchronizedRequestHandler Maven / Gradle / Ivy
/*
* Vaadin Framework 7
*
* Copyright (C) 2000-2024 Vaadin Ltd
*
* This program is available under Vaadin Commercial License and Service Terms.
*
* See for the full
* license.
*/
package com.vaadin.server;
import java.io.IOException;
/**
* RequestHandler which takes care of locking and unlocking of the VaadinSession
* automatically. The session is locked before
* {@link #synchronizedHandleRequest(VaadinSession, VaadinRequest, VaadinResponse)}
* is called and unlocked after it has completed.
*
* @author Vaadin Ltd
* @version @VERSION@
* @since 7.1
*/
public abstract class SynchronizedRequestHandler implements RequestHandler {
@Override
public boolean handleRequest(VaadinSession session, VaadinRequest request,
VaadinResponse response) throws IOException {
if (!canHandleRequest(request)) {
return false;
}
session.lock();
try {
return synchronizedHandleRequest(session, request, response);
} finally {
session.unlock();
}
}
/**
* Identical to
* {@link #handleRequest(VaadinSession, VaadinRequest, VaadinResponse)}
* except the {@link VaadinSession} is locked before this is called and
* unlocked after this has completed.
*
* @see #handleRequest(VaadinSession, VaadinRequest, VaadinResponse)
* @param session
* The session for the request
* @param request
* The request to handle
* @param response
* The response object to which a response can be written.
* @return true if a response has been written and no further request
* handlers should be called, otherwise false
*
* @throws IOException
* If an IO error occurred
*/
public abstract boolean synchronizedHandleRequest(VaadinSession session,
VaadinRequest request, VaadinResponse response) throws IOException;
/**
* Check whether a request may be handled by this handler. This can be used
* as an optimization to avoid locking the session just to investigate some
* method property. The default implementation just returns
* true which means that all requests will be handled by
* calling
* {@link #synchronizedHandleRequest(VaadinSession, VaadinRequest, VaadinResponse)}
* with the session locked.
*
* @since 7.2
* @param request
* the request to handle
* @return true if the request handling should continue once
* the session has been locked; false if there's no
* need to lock the session since the request would still not be
* handled.
*/
protected boolean canHandleRequest(VaadinRequest request) {
return true;
}
}