org.springframework.web.servlet.handler.AbstractDetectingUrlHandlerMapping Maven / Gradle / Ivy
/*
* Copyright 2002-2012 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
*
* https://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 org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactoryUtils;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextException;
import org.springframework.util.ObjectUtils;
/**
* Abstract implementation of the {@link org.springframework.web.servlet.HandlerMapping}
* interface, detecting URL mappings for handler beans through introspection of all
* defined beans in the application context.
*
* @author Juergen Hoeller
* @since 2.5
* @see #determineUrlsForHandler
*/
public abstract class AbstractDetectingUrlHandlerMapping extends AbstractUrlHandlerMapping {
private boolean detectHandlersInAncestorContexts = false;
/**
* Set whether to detect handler beans in ancestor ApplicationContexts.
* Default is "false": Only handler beans in the current ApplicationContext
* will be detected, i.e. only in the context that this HandlerMapping itself
* is defined in (typically the current DispatcherServlet's context).
*
Switch this flag on to detect handler beans in ancestor contexts
* (typically the Spring root WebApplicationContext) as well.
*/
public void setDetectHandlersInAncestorContexts(boolean detectHandlersInAncestorContexts) {
this.detectHandlersInAncestorContexts = detectHandlersInAncestorContexts;
}
/**
* Calls the {@link #detectHandlers()} method in addition to the
* superclass's initialization.
*/
@Override
public void initApplicationContext() throws ApplicationContextException {
super.initApplicationContext();
detectHandlers();
}
/**
* Register all handlers found in the current ApplicationContext.
*
The actual URL determination for a handler is up to the concrete
* {@link #determineUrlsForHandler(String)} implementation. A bean for
* which no such URLs could be determined is simply not considered a handler.
* @throws org.springframework.beans.BeansException if the handler couldn't be registered
* @see #determineUrlsForHandler(String)
*/
protected void detectHandlers() throws BeansException {
ApplicationContext applicationContext = obtainApplicationContext();
String[] beanNames = (this.detectHandlersInAncestorContexts ?
BeanFactoryUtils.beanNamesForTypeIncludingAncestors(applicationContext, Object.class) :
applicationContext.getBeanNamesForType(Object.class));
// Take any bean name that we can determine URLs for.
for (String beanName : beanNames) {
String[] urls = determineUrlsForHandler(beanName);
if (!ObjectUtils.isEmpty(urls)) {
// URL paths found: Let's consider it a handler.
registerHandler(urls, beanName);
}
}
if ((logger.isDebugEnabled() && !getHandlerMap().isEmpty()) || logger.isTraceEnabled()) {
logger.debug("Detected " + getHandlerMap().size() + " mappings in " + formatMappingName());
}
}
/**
* Determine the URLs for the given handler bean.
* @param beanName the name of the candidate bean
* @return the URLs determined for the bean, or an empty array if none
*/
protected abstract String[] determineUrlsForHandler(String beanName);
}