org.apache.cayenne.configuration.web.SessionContextRequestHandler Maven / Gradle / Ivy
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package org.apache.cayenne.configuration.web;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import org.apache.cayenne.BaseContext;
import org.apache.cayenne.ObjectContext;
import org.apache.cayenne.configuration.CayenneRuntime;
import org.apache.cayenne.configuration.ObjectContextFactory;
import org.apache.cayenne.di.Inject;
import org.apache.cayenne.di.Injector;
/**
* Default implementation of the {@link RequestHandler} that stores per-user
* {@link ObjectContext} in a web session and binds it to request thread. Note that using
* this handler would force {@link HttpSession} creation, that may not be desirable in
* many cases. Also session-bound context may result in a race condition with two user
* requests updating the same persistent objects in parallel.
*
* User applications in most cases should provide a custom RequestHandler that implements
* a smarter app-specific strategy for providing ObjectContext.
*
* For stateless (per request) context creation use {@link StatelessContextRequestHandler}.
*
* @since 3.1
*/
public class SessionContextRequestHandler implements RequestHandler {
static final String SESSION_CONTEXT_KEY = SessionContextRequestHandler.class
.getName()
+ ".SESSION_CONTEXT";
// using injector to lookup services instead of injecting them directly for lazy
// startup and "late binding"
@Inject
private Injector injector;
public void requestStart(ServletRequest request, ServletResponse response) {
CayenneRuntime.bindThreadInjector(injector);
if (request instanceof HttpServletRequest) {
// this forces session creation if it does not exist yet
HttpSession session = ((HttpServletRequest) request).getSession();
ObjectContext context;
synchronized (session) {
context = (ObjectContext) session.getAttribute(SESSION_CONTEXT_KEY);
if (context == null) {
context = injector
.getInstance(ObjectContextFactory.class)
.createContext();
session.setAttribute(SESSION_CONTEXT_KEY, context);
}
}
BaseContext.bindThreadObjectContext(context);
}
}
public void requestEnd(ServletRequest request, ServletResponse response) {
CayenneRuntime.bindThreadInjector(null);
BaseContext.bindThreadObjectContext(null);
}
}