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- /*
- * Copyright 2000-2016 Vaadin Ltd.
- *
- * Licensed under the Apache License, Version 2.0 (the "License"); you may not
- * use this file except in compliance with the License. You may obtain a copy of
- * the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations under
- * the 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
- * @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
- * <code>true</code> 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 <code>true</code> if the request handling should continue once
- * the session has been locked; <code>false</code> if there's no
- * need to lock the session since the request would still not be
- * handled.
- */
- protected boolean canHandleRequest(VaadinRequest request) {
- return true;
- }
-
- }
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