Package net.shibboleth.shared.spring.servlet.impl

Class DelegatingServletProxy

java.lang.Object
jakarta.servlet.GenericServlet
net.shibboleth.shared.spring.servlet.impl.DelegatingServletProxy
All Implemented Interfaces:
Servlet, ServletConfig, Serializable
public class DelegatingServletProxy extends GenericServlet
Proxy for a standard Servlet, delegating to a Spring-managed bean that implements the Servlet interface. Supports a "targetBeanName" init-param in web.xml, specifying the name of the target bean in the Spring application context.

This class was originally inspired by Spring's DelegatingFilterProxy class and has the same general behavior.

See Also:

  • Field Details

    • serialVersionUID

      private static final long serialVersionUID
      For serialization.
      See Also:

    • contextAttribute

      @Nullable @NotEmpty private String contextAttribute
      The name of the ServletContext attribute which should be used to retrieve the WebApplicationContext from which to load the delegate Servlet bean.

    • webApplicationContext

      @Nullable private WebApplicationContext webApplicationContext
      The application context from which the target filter will be retrieved.

    • targetBeanName

      @Nullable @NotEmpty private String targetBeanName
      The name of the target bean in the Spring application context.

    • targetFilterLifecycle

      private boolean targetFilterLifecycle
      Whether to invoke the Servlet lifecycle methods on the target bean.

    • delegate

      @Nullable private volatile Servlet delegate
      The HttpServlet instance that this proxy will delegate to and manage the lifecycle for.

    • delegateMonitor

      @Nonnull private Object delegateMonitor
      Object used to syncrhonize access where needed.

  • Constructor Details

    • DelegatingServletProxy

      public DelegatingServletProxy()
      Constructor for traditional use in web.xml.

    • DelegatingServletProxy

      public DelegatingServletProxy(@Nonnull Servlet del)
      Constructor using the given Servlet delegate.

      Bypasses entirely the need for interacting with a Spring application context, specifying the target bean name, etc.

      For use with instance-based registration of filters.

      Parameters:
      del - the HttpServlet instance that this proxy will delegate to and manage the lifecycle for

    • DelegatingServletProxy

      public DelegatingServletProxy(@Nonnull @NotEmpty String targetBeanName)
      Constructor that will retrieve the named target bean from the Spring WebApplicationContext found in the ServletContext (either the 'root' application context or the context named by setContextAttribute(java.lang.String)).

      For use with instance-based registration of filters.

      The target bean must implement the standard Servlet interface.

      Parameters:
      targetBeanName - name of the target servlet bean to look up in the Spring application context

    • DelegatingServletProxy

      public DelegatingServletProxy(@Nonnull @NotEmpty String targetBeanName, @Nullable WebApplicationContext wac)
      Constructor that will retrieve the named target bean from the given Spring WebApplicationContext.

      For use with instance-based registration of filters.

      The target bean must implement the standard Servlet interface.

      The given WebApplicationContext may or may not be refreshed when passed in. If it has not, and if the context implements ConfigurableApplicationContext, a refresh() will be attempted before retrieving the named target bean.

      Parameters:
      targetBeanName - name of the target filter bean in the Spring application context
      wac - the application context from which the target filter will be retrieved; if null, an application context will be looked up from ServletContext as a fallback

  • Method Details

    • setContextAttribute

      public void setContextAttribute(@Nullable @NotEmpty String name)
      Set the name of the ServletContext attribute which should be used to retrieve the WebApplicationContext from which to load the delegate Servlet bean.
      Parameters:
      name - of attribute

    • getContextAttribute

      @Nullable @NotEmpty public String getContextAttribute()
      Return the name of the ServletContext attribute which should be used to retrieve the WebApplicationContext from which to load the delegate Servlet bean.
      Returns:
      name of attribute

    • setTargetBeanName

      public void setTargetBeanName(@Nullable @NotEmpty String name)
      Set the name of the target bean in the Spring application context.

      The target bean must implement the standard Servlet interface.

      By default, the servlet-name as specified for the DelegatingFilterProxy in web.xml will be used.

      Parameters:
      name - bean name

    • getTargetBeanName

      @Nullable @NotEmpty protected String getTargetBeanName()
      Return the name of the target bean in the Spring application context.
      Returns:
      bean name

    • setTargetFilterLifecycle

      public void setTargetFilterLifecycle(boolean flag)
      Set whether to invoke the Servlet.init(jakarta.servlet.ServletConfig) and Servlet.destroy() lifecycle methods on the target bean.

      Default is "false"; target beans usually rely on the Spring application context for managing their lifecycle. Setting this flag to "true" means that the servlet container will control the lifecycle of the target bean, with this proxy delegating the corresponding calls.

      Parameters:
      flag - flag to set

    • isTargetFilterLifecycle

      protected boolean isTargetFilterLifecycle()
      Return whether to invoke the Servlet lifecycle methods on the target bean.
      Returns:
      whether to invoke the Servlet lifecycle methods on the target bean

    • init

      public void init() throws ServletException
      Overrides:
      init in class GenericServlet
      Throws:
      ServletException

    • service

      public void service(ServletRequest request, ServletResponse response) throws ServletException, IOException
      Specified by:
      service in interface Servlet
      Specified by:
      service in class GenericServlet
      Throws:
      ServletException
      IOException

    • destroy

      public void destroy()
      Specified by:
      destroy in interface Servlet
      Overrides:
      destroy in class GenericServlet

    • findWebApplicationContext

      @Nullable protected WebApplicationContext findWebApplicationContext()
      Return the WebApplicationContext passed in at construction time, if available.

      Otherwise, attempt to retrieve a WebApplicationContext from the ServletContext attribute with the configured name if set. Otherwise look up a WebApplicationContext under the well-known "root" application context attribute.

      The WebApplicationContext must have already been loaded and stored in the ServletContext before this filter gets initialized (or invoked).

      Subclasses may override this method to provide a different WebApplicationContext retrieval strategy.

      Returns:
      the WebApplicationContext for this proxy, or null if not found

    • initDelegate

      @Nonnull protected Servlet initDelegate(@Nonnull WebApplicationContext wac) throws ServletException
      Initialize the Servlet delegate, defined as a bean in the given Spring application context.

      The default implementation fetches the bean from the application context and calls the standard Servlet.init method on it, passing in the ServletConfig of this Servlet proxy.

      Parameters:
      wac - the root application context
      Returns:
      the initialized delegate Filter
      Throws:
      ServletException - if thrown by the servlet or if no bean name can be found

    • invokeDelegate

      protected void invokeDelegate(@Nonnull Servlet del, @Nonnull ServletRequest request, @Nonnull ServletResponse response) throws ServletException, IOException
      Actually invoke the delegate Servlet with the given request and response.
      Parameters:
      del - the delegate Servlet
      request - the current request
      response - the current response
      Throws:
      ServletException - if thrown by the Servlet
      IOException - if thrown by the Servlet

    • destroyDelegate

      protected void destroyDelegate(@Nonnull Servlet del)
      Destroy the Servlet delegate.
      Parameters:
      del - the Servlet delegate