com.liferay.portletmvc4spring.HandlerMapping Maven / Gradle / Ivy
/**
* Copyright (c) 2000-2020 the original author or authors.
*
* 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.liferay.portletmvc4spring;
import javax.portlet.PortletRequest;
/**
* Interface to be implemented by objects that define a mapping between requests and handler objects.
*
* This class can be implemented by application developers, although this is not necessary, as {@link
* com.liferay.portletmvc4spring.handler.PortletModeHandlerMapping}, {@link
* com.liferay.portletmvc4spring.handler.ParameterHandlerMapping} and {@link
* com.liferay.portletmvc4spring.handler.PortletModeParameterHandlerMapping} are included in the framework. The first is
* the default if no HandlerMapping bean is registered in the portlet application context.
*
*
HandlerMapping implementations can support mapped interceptors but do not have to. A handler will always be
* wrapped in a {@link HandlerExecutionChain} instance, optionally accompanied by some {@link HandlerInterceptor}
* instances. The DispatcherPortlet will first call each HandlerInterceptor's {@code preHandle} method in the given
* order, finally invoking the handler itself if all {@code preHandle} methods have returned {@code true}.
*
*
The ability to parameterize this mapping is a powerful and unusual capability of the PortletMVC4Spring framework.
* For example, it is possible to write a custom mapping based on session state, cookie state or many other variables.
* No other MVC framework seems to be equally flexible.
*
*
Note: Implementations can implement the {@link org.springframework.core.Ordered} interface to be able to specify a
* sorting order and thus a priority for getting applied by DispatcherPortlet. Non-Ordered instances get treated as
* lowest priority.
*
* @author John A. Lewis
* @author Juergen Hoeller
* @see org.springframework.core.Ordered
* @see com.liferay.portletmvc4spring.handler.AbstractHandlerMapping
* @see com.liferay.portletmvc4spring.handler.PortletModeHandlerMapping
* @see com.liferay.portletmvc4spring.handler.ParameterHandlerMapping
* @see com.liferay.portletmvc4spring.handler.PortletModeParameterHandlerMapping
*/
public interface HandlerMapping {
/**
* Return a handler and any interceptors for this request. The choice may be made on portlet mode, session state, or
* any factor the implementing class chooses.
*
*
The returned HandlerExecutionChain contains a handler Object, rather than even a tag interface, so that
* handlers are not constrained in any way. For example, a HandlerAdapter could be written to allow another
* framework's handler objects to be used.
*
*
Returns {@code null} if no match was found. This is not an error. The DispatcherPortlet will query all
* registered HandlerMapping beans to find a match, and only decide there is an error if none can find a handler.
*
* @param request current portlet request
*
* @return a HandlerExecutionChain instance containing handler object and any interceptors, or null if no mapping
* found
*
* @throws Exception if there is an internal error
*/
HandlerExecutionChain getHandler(PortletRequest request) throws Exception;
}