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/*
 * The contents of this file are subject to the terms
 * of the Common Development and Distribution License
 * (the "License").  You may not use this file except
 * in compliance with the License.
 *
 * You can obtain a copy of the license at
 * glassfish/bootstrap/legal/CDDLv1.0.txt or
 * https://glassfish.dev.java.net/public/CDDLv1.0.html.
 * See the License for the specific language governing
 * permissions and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL
 * HEADER in each file and include the License file at
 * glassfish/bootstrap/legal/CDDLv1.0.txt.  If applicable,
 * add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your
 * own identifying information: Portions Copyright [yyyy]
 * [name of copyright owner]
 *
 * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
 *
 * Portions Copyright Apache Software Foundation.
 */

package javax.servlet.jsp;

import javax.el.ELResolver;
import javax.el.ExpressionFactory;
import javax.el.ELContextListener;

/**
 * Stores application-scoped information relevant to JSP containers.
 *
 * 

The JSP container must create a single instance of * JspApplicationContext for each * ServletContext instance.

* *

An instance of JspApplicationContext is obtained by * invoking the static {@link JspFactory#getJspApplicationContext} method, * passing the ServletContext of the corresponding web * application.

* *

The JspApplicationContext provides the following services * to JSP applications: *

    *
  • Allows registration of ELResolvers, which are used to * resolve variables in EL expressions contained in JSP pages and * tag files.
  • *
  • Provides an instance of ExpressionFactory for those * applications or frameworks that need to perform programmatic * evaluation of EL expressions instead of allowing the JSP * container to do it for them.
  • *
  • Allows the attachment of ELContextListener instances * for notification whenever a new ELContext is created. * This is necessary when an application wishes to make custom * context objects available to their pluggable * ELResolvers.
  • *
*

* * @see javax.servlet.ServletContext * @see JspFactory * @see javax.el.ELResolver * @see javax.el.ExpressionFactory * @see javax.el.ELContextListener * @since JSP 2.1 */ public interface JspApplicationContext { /** * Adds an ELResolver to affect the way EL variables * and properties are resolved for EL expressions appearing in JSP pages * and tag files. * *

For example, in the EL expression ${employee.lastName}, an * ELResolver determines what object "employee" * references and how to find its "lastName" property.

* *

When evaluating an expression, the JSP container will consult a * set of standard resolvers as well as any resolvers registered via * this method. The set of resolvers are consulted in the following * order: *

    *
  • {@link javax.servlet.jsp.el.ImplicitObjectELResolver}
  • *
  • ELResolvers registered via this method, in the * order in which they are registered.
  • *
  • {@link javax.el.MapELResolver}
  • *
  • {@link javax.el.ListELResolver}
  • *
  • {@link javax.el.ArrayELResolver}
  • *
  • {@link javax.el.BeanELResolver}
  • *
  • {@link javax.servlet.jsp.el.ScopedAttributeELResolver}
  • *

* *

It is illegal to register an ELResolver after the * application has received any request from the client. If an * attempt is made to register an ELResolver after that time, * an IllegalStateException is thrown.

* This restriction is * in place to allow the JSP container to optimize for the common * case where no additional ELResolvers are in the chain, * aside from the standard ones. It is permissible to add * ELResolvers before or after initialization to * a CompositeELResolver that is already in the chain.

* *

It is not possible to remove an ELResolver registered * with this method, once it has been registered.

* * @param resolver The new ELResolver * @throws IllegalStateException if an attempt is made to * call this method after all ServletContextListeners * have had their contextInitialized methods invoked. */ public void addELResolver(ELResolver resolver); /** * Returns a factory used to create ValueExpressions and * MethodExpressions so that EL expressions can be * parsed and evaluated. * * @return A concrete implementation of the * an ExpressionFactory. */ public ExpressionFactory getExpressionFactory(); /** * Registers a ELContextListeners so that context objects * can be added whenever a new ELContext is created. * *

At a minimum, the ELContext objects created will * contain a reference to the JspContext for this request, * which is added by the JSP container. * This is sufficient for all the * default ELResolvers listed in {@link #addELResolver}. * Note that JspContext.class is used as the key to ELContext.putContext() * for the JspContext object reference.

* *

This method is generally used by frameworks and applications that * register their own ELResolver that needs context other * than JspContext. The listener will typically add the * necessary context to the ELContext provided in the * event object. Registering a listener that adds context allows the * ELResolvers in the stack to access the context they * need when they do a resolution.

* * @param listener The listener to be notified when a new * ELContext is created. */ public void addELContextListener(ELContextListener listener); }




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