/*
* Copyright 2002-2007 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.
* <p>Default value is <code>Integer.MAX_VALUE</code>, meaning that it's non-ordered.
* @see org.springframework.core.Ordered#getOrder()
*/
public final void setOrder(int order) {
this.order = order;
}
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.
* <p>Default is <code>null</code>, indicating no default handler.
*/
public void setDefaultHandler(Object defaultHandler) {
this.defaultHandler = defaultHandler;
}
/**
* Return the default handler for this handler mapping,
* or <code>null</code> if none.
*/
public Object getDefaultHandler() {
return this.defaultHandler;
}
/**
* Set the interceptors to apply for all handlers mapped by this handler mapping.
* <p>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</code> 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").
* <p>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.hibernate3.support.OpenSessionInViewInterceptor
*/
public void setApplyWebRequestInterceptorsToRenderPhaseOnly(boolean applyWebRequestInterceptorsToRenderPhaseOnly) {
this.applyWebRequestInterceptorsToRenderPhaseOnly = applyWebRequestInterceptorsToRenderPhaseOnly;
}
/**
* Initializes the interceptors.
* @see #extendInterceptors(java.util.List)
* @see #initInterceptors()
*/
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}).
* <p>Will be invoked before {@link #initInterceptors()} adapts the specified
* interceptors into {@link HandlerInterceptor} instances.
* <p>The default implementation is empty.
* @param interceptors the configured interceptor List (never <code>null</code>),
* 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.
* <p>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</code> 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
*/
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</code> if no
* specific one is found. This method is called by {@link #getHandler};
* a <code>null</code> return value will lead to the default handler, if one is set.
* <p>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</code> 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.
* <p>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.
* <p><b>NOTE:</b> 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.
* <p>For simply adding an interceptor, consider calling <code>super.getHandlerExecutionChain</code>
* and invoking {@link HandlerExecutionChain#addInterceptor} on the returned chain object.
* @param handler the resolved handler instance (never <code>null</code>)
* @param request current HTTP request
* @return the HandlerExecutionChain (never <code>null</code>)
* @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());
}
}
}