/*
* Copyright 2011 <a href="mailto:lincolnbaxter@gmail.com">Lincoln Baxter, III</a>
*
* 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.ocpsoft.rewrite.servlet.impl;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.ocpsoft.common.pattern.WeightedComparator;
import org.ocpsoft.common.services.NonEnriching;
import org.ocpsoft.common.services.ServiceLoader;
import org.ocpsoft.common.util.Iterators;
import org.ocpsoft.rewrite.servlet.DispatcherType;
import org.ocpsoft.rewrite.servlet.http.HttpRequestCycleWrapper;
import org.ocpsoft.rewrite.servlet.spi.DispatcherTypeProvider;
import org.ocpsoft.rewrite.servlet.spi.RequestParameterProvider;
/**
* @author <a href="mailto:lincolnbaxter@gmail.com">Lincoln Baxter, III</a>
*
*/
public class HttpRewriteRequestCycleWrapper extends HttpRequestCycleWrapper implements NonEnriching
{
private volatile List<RequestParameterProvider> providers;
private final List<DispatcherTypeProvider> dispatcherProviders;
@SuppressWarnings("unchecked")
public HttpRewriteRequestCycleWrapper()
{
if (providers == null)
synchronized (this) {
if (providers == null)
providers = Iterators.asList(ServiceLoader.load(RequestParameterProvider.class));
}
dispatcherProviders = Iterators.asList(
ServiceLoader.loadTypesafe(DispatcherTypeProvider.class).iterator());
Collections.sort(dispatcherProviders, new WeightedComparator());
}
@Override
public HttpServletRequest wrapRequest(final HttpServletRequest request, final HttpServletResponse response,
final ServletContext servletContext)
{
HttpServletRequest result = request;
if (HttpRewriteWrappedRequest.getCurrentInstance(request) == null) {
Map<String, String[]> additionalParams = new LinkedHashMap<String, String[]>();
for (RequestParameterProvider provider : providers) {
Map<String, String[]> m = provider.getAdditionalParameters(request, response);
if (m != null)
{
additionalParams.putAll(m);
}
}
result = new HttpRewriteWrappedRequest(request, additionalParams);
}
return result;
}
@Override
public HttpServletResponse wrapResponse(final HttpServletRequest request, final HttpServletResponse response,
final ServletContext servletContext)
{
HttpServletResponse result = response;
/*
* The Servlet spec requires that the unwrapped response is used in case of dispatch type ERROR.
* Therefore we must ALWAYS wrap the response for the ERROR dispatch type.
*/
if (HttpRewriteWrappedResponse.getCurrentInstance(request) == null ||
getDispatcherType(request, servletContext) == DispatcherType.ERROR)
result = new HttpRewriteWrappedResponse(request, response, servletContext);
return result;
}
/**
* Determines the {@link DispatcherType} of the current request using the {@link DispatcherTypeProvider} SPI.
*/
private DispatcherType getDispatcherType(HttpServletRequest request, ServletContext context)
{
for (DispatcherTypeProvider provider : dispatcherProviders) {
DispatcherType dispatcherType = provider.getDispatcherType(request, context);
if (dispatcherType != null) {
return dispatcherType;
}
}
throw new IllegalStateException("Unable to determine dispatcher type of current request");
}
@Override
public int priority()
{
return 0;
}
}