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/*
 * Copyright 2002-2014 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 org.springframework.web.portlet.handler;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javax.portlet.PortletRequest;

import org.springframework.beans.BeansException;
import org.springframework.context.support.ApplicationObjectSupport;
import org.springframework.core.Ordered;
import org.springframework.web.context.request.WebRequestInterceptor;
import org.springframework.web.portlet.HandlerExecutionChain;
import org.springframework.web.portlet.HandlerInterceptor;
import org.springframework.web.portlet.HandlerMapping;

/**
 * Abstract base class for {@link org.springframework.web.portlet.HandlerMapping}
 * implementations. Supports ordering, a default handler, and handler interceptors.
 *
 * @author Juergen Hoeller
 * @author John A. Lewis
 * @since 2.0
 * @see #getHandlerInternal
 * @see #setDefaultHandler
 * @see #setInterceptors
 * @see org.springframework.web.portlet.HandlerInterceptor
 */
public abstract class AbstractHandlerMapping extends ApplicationObjectSupport implements HandlerMapping, Ordered {

	private int order = Integer.MAX_VALUE;  // default: same as non-Ordered

	private Object defaultHandler;

	private final List interceptors = new ArrayList();

	private boolean applyWebRequestInterceptorsToRenderPhaseOnly = true;

	private HandlerInterceptor[] adaptedInterceptors;


	/**
	 * Specify the order value for this HandlerMapping bean.
	 * 

Default value is {@code Integer.MAX_VALUE}, meaning that it's non-ordered. * @see org.springframework.core.Ordered#getOrder() */ public final void setOrder(int order) { this.order = order; } @Override public final int getOrder() { return this.order; } /** * Set the default handler for this handler mapping. * This handler will be returned if no specific mapping was found. *

Default is {@code null}, indicating no default handler. */ public void setDefaultHandler(Object defaultHandler) { this.defaultHandler = defaultHandler; } /** * Return the default handler for this handler mapping, * or {@code null} if none. */ public Object getDefaultHandler() { return this.defaultHandler; } /** * Set the interceptors to apply for all handlers mapped by this handler mapping. *

Supported interceptor types are HandlerInterceptor and WebRequestInterceptor. * Each given WebRequestInterceptor will be wrapped in a WebRequestHandlerInterceptorAdapter. * @param interceptors array of handler interceptors, or {@code null} if none * @see #adaptInterceptor * @see org.springframework.web.portlet.HandlerInterceptor * @see org.springframework.web.context.request.WebRequestInterceptor */ public void setInterceptors(Object[] interceptors) { this.interceptors.addAll(Arrays.asList(interceptors)); } /** * Specify whether to apply WebRequestInterceptors to the Portlet render phase * only ("true", or whether to apply them to the Portlet action phase as well * ("false"). *

Default is "true", since WebRequestInterceptors are usually built for * MVC-style handler execution plus rendering process (which is, for example, * the primary target scenario for "Open Session in View" interceptors, * offering lazy loading of persistent objects during view rendering). * Set this to "false" to have WebRequestInterceptors apply to the action * phase as well (for example, in case of an "Open Session in View" interceptor, * to allow for lazy loading outside of a transaction during the action phase). * @see #setInterceptors * @see org.springframework.web.context.request.WebRequestInterceptor * @see WebRequestHandlerInterceptorAdapter#WebRequestHandlerInterceptorAdapter(WebRequestInterceptor, boolean) * @see org.springframework.orm.jpa.support.OpenEntityManagerInViewInterceptor */ public void setApplyWebRequestInterceptorsToRenderPhaseOnly(boolean applyWebRequestInterceptorsToRenderPhaseOnly) { this.applyWebRequestInterceptorsToRenderPhaseOnly = applyWebRequestInterceptorsToRenderPhaseOnly; } /** * Initializes the interceptors. * @see #extendInterceptors(java.util.List) * @see #initInterceptors() */ @Override protected void initApplicationContext() throws BeansException { extendInterceptors(this.interceptors); initInterceptors(); } /** * Extension hook that subclasses can override to register additional interceptors, * given the configured interceptors (see {@link #setInterceptors}). *

Will be invoked before {@link #initInterceptors()} adapts the specified * interceptors into {@link HandlerInterceptor} instances. *

The default implementation is empty. * @param interceptors the configured interceptor List (never {@code null}), * allowing to add further interceptors before as well as after the existing * interceptors */ protected void extendInterceptors(List interceptors) { } /** * Initialize the specified interceptors, adapting them where necessary. * @see #setInterceptors * @see #adaptInterceptor */ protected void initInterceptors() { if (!this.interceptors.isEmpty()) { this.adaptedInterceptors = new HandlerInterceptor[this.interceptors.size()]; for (int i = 0; i < this.interceptors.size(); i++) { Object interceptor = this.interceptors.get(i); if (interceptor == null) { throw new IllegalArgumentException("Entry number " + i + " in interceptors array is null"); } this.adaptedInterceptors[i] = adaptInterceptor(interceptor); } } } /** * Adapt the given interceptor object to the HandlerInterceptor interface. *

Supported interceptor types are HandlerInterceptor and WebRequestInterceptor. * Each given WebRequestInterceptor will be wrapped in a WebRequestHandlerInterceptorAdapter. * Can be overridden in subclasses. * @param interceptor the specified interceptor object * @return the interceptor wrapped as HandlerInterceptor * @see #setApplyWebRequestInterceptorsToRenderPhaseOnly * @see org.springframework.web.portlet.HandlerInterceptor * @see org.springframework.web.context.request.WebRequestInterceptor * @see WebRequestHandlerInterceptorAdapter */ protected HandlerInterceptor adaptInterceptor(Object interceptor) { if (interceptor instanceof HandlerInterceptor) { return (HandlerInterceptor) interceptor; } else if (interceptor instanceof WebRequestInterceptor) { return new WebRequestHandlerInterceptorAdapter( (WebRequestInterceptor) interceptor, this.applyWebRequestInterceptorsToRenderPhaseOnly); } else { throw new IllegalArgumentException("Interceptor type not supported: " + interceptor.getClass().getName()); } } /** * Return the adapted interceptors as HandlerInterceptor array. * @return the array of HandlerInterceptors, or {@code null} if none */ protected final HandlerInterceptor[] getAdaptedInterceptors() { return this.adaptedInterceptors; } /** * Look up a handler for the given request, falling back to the default * handler if no specific one is found. * @param request current portlet request * @return the corresponding handler instance, or the default handler * @see #getHandlerInternal */ @Override public final HandlerExecutionChain getHandler(PortletRequest request) throws Exception { Object handler = getHandlerInternal(request); if (handler == null) { handler = getDefaultHandler(); } if (handler == null) { return null; } // Bean name or resolved handler? if (handler instanceof String) { String handlerName = (String) handler; handler = getApplicationContext().getBean(handlerName); } return getHandlerExecutionChain(handler, request); } /** * Look up a handler for the given request, returning {@code null} if no * specific one is found. This method is called by {@link #getHandler}; * a {@code null} return value will lead to the default handler, if one is set. *

Note: This method may also return a pre-built {@link HandlerExecutionChain}, * combining a handler object with dynamically determined interceptors. * Statically specified interceptors will get merged into such an existing chain. * @param request current portlet request * @return the corresponding handler instance, or {@code null} if none found * @throws Exception if there is an internal error * @see #getHandler */ protected abstract Object getHandlerInternal(PortletRequest request) throws Exception; /** * Build a HandlerExecutionChain for the given handler, including applicable interceptors. *

The default implementation simply builds a standard HandlerExecutionChain with * the given handler and this handler mapping's common interceptors. Subclasses may * override this in order to extend/rearrange the list of interceptors. *

NOTE: The passed-in handler object may be a raw handler or a pre-built * HandlerExecutionChain. This method should handle those two cases explicitly, * either building a new HandlerExecutionChain or extending the existing chain. *

For simply adding an interceptor, consider calling {@code super.getHandlerExecutionChain} * and invoking {@link HandlerExecutionChain#addInterceptor} on the returned chain object. * @param handler the resolved handler instance (never {@code null}) * @param request current portlet request * @return the HandlerExecutionChain (never {@code null}) * @see #getAdaptedInterceptors() */ protected HandlerExecutionChain getHandlerExecutionChain(Object handler, PortletRequest request) { if (handler instanceof HandlerExecutionChain) { HandlerExecutionChain chain = (HandlerExecutionChain) handler; chain.addInterceptors(getAdaptedInterceptors()); return chain; } else { return new HandlerExecutionChain(handler, getAdaptedInterceptors()); } } }