/*
* Copyright 2002-2010 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.Set;
import javax.portlet.PortletRequest;
import javax.portlet.WindowState;
import javax.portlet.RenderRequest;
import javax.portlet.RenderResponse;
import javax.portlet.ResourceRequest;
import javax.portlet.ResourceResponse;
import javax.portlet.MimeResponse;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.web.portlet.HandlerExceptionResolver;
import org.springframework.web.portlet.ModelAndView;
import org.springframework.core.Ordered;
/**
* Abstract base class for {@link HandlerExceptionResolver} implementations.
*
* <p>Provides a set of mapped handlers that the resolver should map to,
* and the {@link Ordered} implementation.
*
* @author Arjen Poutsma
* @since 3.0
*/
public abstract class AbstractHandlerExceptionResolver implements HandlerExceptionResolver, Ordered {
/** Logger available to subclasses */
protected final Log logger = LogFactory.getLog(getClass());
private int order = Ordered.LOWEST_PRECEDENCE;
private Set mappedHandlers;
private Class[] mappedHandlerClasses;
private Log warnLogger;
private boolean renderWhenMinimized = false;
public void setOrder(int order) {
this.order = order;
}
public int getOrder() {
return this.order;
}
/**
* Specify the set of handlers that this exception resolver should map.
* The exception mappings and the default error view will only apply
* to the specified handlers.
* <p>If no handlers set, both the exception mappings and the default error
* view will apply to all handlers. This means that a specified default
* error view will be used as fallback for all exceptions; any further
* HandlerExceptionResolvers in the chain will be ignored in this case.
*/
public void setMappedHandlers(Set mappedHandlers) {
this.mappedHandlers = mappedHandlers;
}
/**
* Specify the set of classes that this exception resolver should apply to.
* The exception mappings and the default error view will only apply
* to handlers of the specified type; the specified types may be interfaces
* and superclasses of handlers as well.
* <p>If no handlers and handler classes are set, the exception mappings
* and the default error view will apply to all handlers. This means that
* a specified default error view will be used as fallback for all exceptions;
* any further HandlerExceptionResolvers in the chain will be ignored in
* this case.
*/
public void setMappedHandlerClasses(Class[] mappedHandlerClasses) {
this.mappedHandlerClasses = mappedHandlerClasses;
}
/**
* Set the log category for warn logging. The name will be passed to the
* underlying logger implementation through Commons Logging, getting
* interpreted as log category according to the logger's configuration.
* <p>Default is no warn logging. Specify this setting to activate
* warn logging into a specific category. Alternatively, override
* the {@link #logException} method for custom logging.
* @see org.apache.commons.logging.LogFactory#getLog(String)
* @see org.apache.log4j.Logger#getLogger(String)
* @see java.util.logging.Logger#getLogger(String)
*/
public void setWarnLogCategory(String loggerName) {
this.warnLogger = LogFactory.getLog(loggerName);
}
/**
* Set if the resolver should render a view when the portlet is in
* a minimized window. The default is "false".
* @see javax.portlet.RenderRequest#getWindowState()
* @see javax.portlet.WindowState#MINIMIZED
*/
public void setRenderWhenMinimized(boolean renderWhenMinimized) {
this.renderWhenMinimized = renderWhenMinimized;
}
/**
* Checks whether this resolver is supposed to apply (i.e. the handler
* matches in case of "mappedHandlers" having been specified), then
* delegates to the {@link #doResolveException} template method.
*/
public ModelAndView resolveException(RenderRequest request, RenderResponse response, Object handler, Exception ex) {
if (shouldApplyTo(request, handler)) {
return doResolveException(request, response, handler, ex);
}
else {
return null;
}
}
public ModelAndView resolveException(ResourceRequest request, ResourceResponse response, Object handler, Exception ex) {
if (shouldApplyTo(request, handler)) {
return doResolveException(request, response, handler, ex);
}
else {
return null;
}
}
/**
* Check whether this resolver is supposed to apply to the given handler.
* <p>The default implementation checks against the specified mapped handlers
* and handler classes, if any, and alspo checks the window state (according
* to the "renderWhenMinimize" property).
* @param request current portlet request
* @param handler the executed handler, or <code>null</code> if none chosen at the
* time of the exception (for example, if multipart resolution failed)
* @return whether this resolved should proceed with resolving the exception
* for the given request and handler
* @see #setMappedHandlers
* @see #setMappedHandlerClasses
*/
protected boolean shouldApplyTo(PortletRequest request, Object handler) {
// If the portlet is minimized and we don't want to render then return null.
if (WindowState.MINIMIZED.equals(request.getWindowState()) && !this.renderWhenMinimized) {
return false;
}
// Check mapped handlers...
if (handler != null) {
if (this.mappedHandlers != null && this.mappedHandlers.contains(handler)) {
return true;
}
if (this.mappedHandlerClasses != null) {
for (Class mappedClass : this.mappedHandlerClasses) {
if (mappedClass.isInstance(handler)) {
return true;
}
}
}
}
// Else only apply if there are no explicit handler mappings.
return (this.mappedHandlers == null && this.mappedHandlerClasses == null);
}
/**
* Log the given exception at warn level, provided that warn logging has been
* activated through the {@link #setWarnLogCategory "warnLogCategory"} property.
* <p>Calls {@link #buildLogMessage} in order to determine the concrete message
* to log. Always passes the full exception to the logger.
* @param ex the exception that got thrown during handler execution
* @param request current portlet request (useful for obtaining metadata)
* @see #setWarnLogCategory
* @see #buildLogMessage
* @see org.apache.commons.logging.Log#warn(Object, Throwable)
*/
protected void logException(Exception ex, PortletRequest request) {
if (this.warnLogger != null && this.warnLogger.isWarnEnabled()) {
this.warnLogger.warn(buildLogMessage(ex, request), ex);
}
}
/**
* Build a log message for the given exception, occured during processing
* the given request.
* @param ex the exception that got thrown during handler execution
* @param request current portlet request (useful for obtaining metadata)
* @return the log message to use
*/
protected String buildLogMessage(Exception ex, PortletRequest request) {
return "Handler execution resulted in exception";
}
/**
* Actually resolve the given exception that got thrown during on handler execution,
* returning a ModelAndView that represents a specific error page if appropriate.
* <p>Must be overridden in subclasses, in order to apply specific exception checks.
* Note that this template method will be invoked <i>after</i> checking whether this
* resolved applies ("mappedHandlers" etc), so an implementation may simply proceed
* with its actual exception handling.
* @param request current portlet request
* @param response current portlet response
* @param handler the executed handler, or null if none chosen at the time of
* the exception (for example, if multipart resolution failed)
* @param ex the exception that got thrown during handler execution
* @return a corresponding ModelAndView to forward to, or null for default processing
*/
protected abstract ModelAndView doResolveException(PortletRequest request, MimeResponse response,
Object handler, Exception ex);
}
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