/*
* Copyright 2012 OmniFaces.
*
* 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.omnifaces.component.output.cache;
import static java.util.Collections.list;
import static org.omnifaces.util.Platform.getFacesServletRegistration;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.FilterRegistration;
import javax.servlet.ServletContext;
import javax.servlet.ServletRegistration;
import org.omnifaces.ApplicationListener;
import org.omnifaces.filter.OnDemandResponseBufferFilter;
/**
* Optional initializer for the {@link Cache} used by the Omnifaces Cache component.
* <p>
* It takes a configuration from web.xml context parameters and used that to set a cache provider and/or configure the
* caching provider. If no initialization is done defaults are used.
*
* @since 1.1
* @author Arjan Tijms
* @see ApplicationListener
*/
public class CacheInitializer {
// Web context parameter to set the cache provider implementation
public static final String CACHE_PROVIDER_INIT_PARAM_NAME = "org.omnifaces.CACHE_PROVIDER";
public static final String CACHE_INSTALL_BUFFER_FILTER = "org.omnifaces.CACHE_INSTALL_BUFFER_FILTER";
public static final String CACHE_PROVIDER_SETTING_INIT_PARAM_PREFIX = "org.omnifaces.CACHE_SETTING_";
public static void loadProviderAndRegisterFilter(ServletContext context) {
// Check for a user configured custom cache provider, or get default one
CacheProvider cacheProvider = getCacheProvider(context);
// Build a map of settings for either the custom- or the default cache provider and set them.
cacheProvider.setParameters(getCacheSetting(context));
// Installs a filter that on demands buffers the response from the Faces Servlet, in order to grab child content
// from the buffer.
if (Boolean.TRUE.equals(Boolean.valueOf(context.getInitParameter(CACHE_INSTALL_BUFFER_FILTER)))) {
ServletRegistration facesServletRegistration = getFacesServletRegistration(context);
FilterRegistration bufferFilterRegistration = context.addFilter(OnDemandResponseBufferFilter.class.getName(), OnDemandResponseBufferFilter.class);
bufferFilterRegistration.addMappingForServletNames(null, true, facesServletRegistration.getName());
}
}
private static CacheProvider getCacheProvider(ServletContext context) {
CacheProvider cacheProvider = null;
String cacheProviderName = context.getInitParameter(CACHE_PROVIDER_INIT_PARAM_NAME);
if (cacheProviderName != null) {
cacheProvider = createInstance(cacheProviderName);
CacheFactory.setCacheProvider(cacheProvider, context);
} else {
cacheProvider = CacheFactory.getDefaultCacheProvider();
}
return cacheProvider;
}
private static CacheProvider createInstance(String cacheProviderName) {
try {
return (CacheProvider) Class.forName(cacheProviderName).newInstance();
}
catch (InstantiationException | IllegalAccessException | ClassNotFoundException e) {
throw new IllegalArgumentException(e);
}
}
private static Map<String, String> getCacheSetting(ServletContext context) {
Map<String, String> settings = new HashMap<>();
for (String initParameterName : list(context.getInitParameterNames())) {
if (initParameterName.startsWith(CACHE_PROVIDER_SETTING_INIT_PARAM_PREFIX)) {
settings.put(
initParameterName.substring(CACHE_PROVIDER_SETTING_INIT_PARAM_PREFIX.length()),
context.getInitParameter(initParameterName)
);
}
}
return settings;
}
}