/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
*
* Portions Copyright Apache Software Foundation.
*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common Development
* and Distribution License("CDDL") (collectively, the "License"). You
* may not use this file except in compliance with the License. You can obtain
* a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
* or glassfish/bootstrap/legal/LICENSE.txt. See the License for the specific
* language governing permissions and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
* Sun designates this particular file as subject to the "Classpath" exception
* as provided by Sun in the GPL Version 2 section of the License file that
* accompanied this code. If applicable, add the following below the License
* Header, with the fields enclosed by brackets [] replaced by your own
* identifying information: "Portions Copyrighted [year]
* [name of copyright owner]"
*
* Contributor(s):
*
* If you wish your version of this file to be governed by only the CDDL or
* only the GPL Version 2, indicate your decision by adding "[Contributor]
* elects to include this software in this distribution under the [CDDL or GPL
* Version 2] license." If you don't indicate a single choice of license, a
* recipient has the option to distribute your version of this file under
* either the CDDL, the GPL Version 2 or to extend the choice of license to
* its licensees as provided above. However, if you add GPL Version 2 code
* and therefore, elected the GPL Version 2 license, then the option applies
* only if the new code is made subject to such option by the copyright
* holder.
*/
package javax.servlet.jsp;
import javax.el.ELResolver;
import javax.el.ExpressionFactory;
import javax.el.ELContextListener;
/**
* Stores application-scoped information relevant to JSP containers.
*
* <p>The JSP container must create a single instance of
* <code>JspApplicationContext</code> for each
* <code>ServletContext</code> instance.</p>
*
* <p>An instance of <code>JspApplicationContext</code> is obtained by
* invoking the static {@link JspFactory#getJspApplicationContext} method,
* passing the <code>ServletContext</code> of the corresponding web
* application.</p>
*
* <p>The <code>JspApplicationContext</code> provides the following services
* to JSP applications:
* <ul>
* <li>Allows registration of <code>ELResolver</code>s, which are used to
* resolve variables in EL expressions contained in JSP pages and
* tag files.</li>
* <li>Provides an instance of <code>ExpressionFactory</code> 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.</li>
* <li>Allows the attachment of <code>ELContextListener</code> instances
* for notification whenever a new <code>ELContext</code> is created.
* This is necessary when an application wishes to make custom
* context objects available to their pluggable
* <code>ELResolver</code>s.</li>
* </ul>
* </p>
*
* @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 <code>ELResolver</code> to affect the way EL variables
* and properties are resolved for EL expressions appearing in JSP pages
* and tag files.
*
* <p>For example, in the EL expression ${employee.lastName}, an
* <code>ELResolver</code> determines what object "employee"
* references and how to find its "lastName" property.</p>
*
* <p>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:
* <ul>
* <li>{@link javax.servlet.jsp.el.ImplicitObjectELResolver}</li>
* <li><code>ELResolver</code>s registered via this method, in the
* order in which they are registered.</li>
* <li>{@link javax.el.MapELResolver}</li>
* <li>{@link javax.el.ListELResolver}</li>
* <li>{@link javax.el.ArrayELResolver}</li>
* <li>{@link javax.el.BeanELResolver}</li>
* <li>{@link javax.servlet.jsp.el.ScopedAttributeELResolver}</li>
* </ul></p>
*
* <p>It is illegal to register an <code>ELResolver</code> after the
* application has received any request from the client. If an
* attempt is made to register an <code>ELResolver</code> after that time,
* an <code>IllegalStateException</code> is thrown.</p>
* This restriction is
* in place to allow the JSP container to optimize for the common
* case where no additional <code>ELResolver</code>s are in the chain,
* aside from the standard ones. It is permissible to add
* <code>ELResolver</code>s before or after initialization to
* a <code>CompositeELResolver</code> that is already in the chain.</p>
*
* <p>It is not possible to remove an <code>ELResolver</code> registered
* with this method, once it has been registered.</p>
*
* @param resolver The new <code>ELResolver</code>
* @throws IllegalStateException if an attempt is made to
* call this method after all <code>ServletContextListener</code>s
* have had their <code>contextInitialized</code> methods invoked.
*/
public void addELResolver(ELResolver resolver);
/**
* Returns a factory used to create <code>ValueExpression</code>s and
* <code>MethodExpression</code>s so that EL expressions can be
* parsed and evaluated.
*
* @return A concrete implementation of the
* an <code>ExpressionFactory</code>.
*/
public ExpressionFactory getExpressionFactory();
/**
* Registers a <code>ELContextListener</code>s so that context objects
* can be added whenever a new <code>ELContext</code> is created.
*
* <p>At a minimum, the <code>ELContext</code> objects created will
* contain a reference to the <code>JspContext</code> for this request,
* which is added by the JSP container.
* This is sufficient for all the
* default <code>ELResolver</code>s listed in {@link #addELResolver}.
* Note that <code>JspContext.class</code> is used as the key to ELContext.putContext()
* for the <code>JspContext</code> object reference.</p>
*
* <p>This method is generally used by frameworks and applications that
* register their own <code>ELResolver</code> that needs context other
* than <code>JspContext</code>. The listener will typically add the
* necessary context to the <code>ELContext</code> provided in the
* event object. Registering a listener that adds context allows the
* <code>ELResolver</code>s in the stack to access the context they
* need when they do a resolution.</p>
*
* @param listener The listener to be notified when a new
* <code>ELContext</code> is created.
*/
public void addELContextListener(ELContextListener listener);
}
|
