org.springframework.web.servlet.handler.AbstractHandlerMapping Maven / Gradle / Ivy
/*
* 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.servlet.handler;
import javax.servlet.http.HttpServletRequest;
import org.springframework.beans.BeansException;
import org.springframework.core.Ordered;
import org.springframework.web.context.request.WebRequestInterceptor;
import org.springframework.web.context.support.WebApplicationObjectSupport;
import org.springframework.web.servlet.HandlerExecutionChain;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.HandlerMapping;
/**
* Abstract base class for {@link org.springframework.web.servlet.HandlerMapping}
* implementations. Supports ordering, a default handler, and handler interceptors.
*
* Note: This base class does not support exposure of the
* {@link #PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE}. Support for this attribute
* is up to concrete subclasses, typically based on request URL mappings.
*
* @author Juergen Hoeller
* @since 07.04.2003
* @see #getHandlerInternal
* @see #setDefaultHandler
* @see #setInterceptors
* @see org.springframework.web.servlet.HandlerInterceptor
*/
public abstract class AbstractHandlerMapping extends WebApplicationObjectSupport
implements HandlerMapping, Ordered {
private int order = Integer.MAX_VALUE; // default: same as non-Ordered
private Object defaultHandler;
private Object[] interceptors;
private HandlerInterceptor[] adaptedInterceptors;
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.
*
Default is null, indicating no default handler.
*/
public void setDefaultHandler(Object defaultHandler) {
this.defaultHandler = defaultHandler;
}
/**
* Return the default handler for this handler mapping,
* or 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.
* @param interceptors array of handler interceptors, or null if none
* @see #adaptInterceptor
* @see org.springframework.web.servlet.HandlerInterceptor
* @see org.springframework.web.context.request.WebRequestInterceptor
*/
public final void setInterceptors(Object[] interceptors) {
this.interceptors = interceptors;
}
/**
* Calls the initInterceptors() method.
* @see #initInterceptors()
*/
protected void initApplicationContext() throws BeansException {
initInterceptors();
}
/**
* Initialize the specified interceptors, adapting them where necessary.
* @see #setInterceptors
* @see #adaptInterceptor
*/
protected void initInterceptors() {
if (this.interceptors != null) {
this.adaptedInterceptors = new HandlerInterceptor[this.interceptors.length];
for (int i = 0; i < this.interceptors.length; i++) {
if (this.interceptors[i] == null) {
throw new IllegalArgumentException("Entry number " + i + " in interceptors array is null");
}
this.adaptedInterceptors[i] = adaptInterceptor(this.interceptors[i]);
}
}
}
/**
* 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 org.springframework.web.servlet.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);
}
else {
throw new IllegalArgumentException("Interceptor type not supported: " + interceptor.getClass().getName());
}
}
/**
* Return the adapted interceptors as HandlerInterceptor array.
* @return the array of HandlerInterceptors, or 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 HTTP request
* @return the corresponding handler instance, or the default handler
* @see #getHandlerInternal
*/
public final HandlerExecutionChain getHandler(HttpServletRequest 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 null if no
* specific one is found. This method is called by getHandler;
* a null return value will lead to the default handler, if one is set.
* @param request current HTTP request
* @return the corresponding handler instance, or null if none found
* @throws Exception if there is an internal error
*/
protected abstract Object getHandlerInternal(HttpServletRequest 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.
* @param handler the resolved handler instance (never null)
* @param request current HTTP request
* @return the HandlerExecutionChain (never null)
* @see #getAdaptedInterceptors()
*/
protected HandlerExecutionChain getHandlerExecutionChain(Object handler, HttpServletRequest request) {
return new HandlerExecutionChain(handler, getAdaptedInterceptors());
}
}