| /* |
| * Copyright (C) 2008 Google Inc. |
| * |
| * 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 com.google.inject.servlet; |
| |
| import com.google.common.collect.Iterators; |
| import com.google.inject.Injector; |
| import com.google.inject.Key; |
| import com.google.inject.Scopes; |
| import com.google.inject.spi.BindingTargetVisitor; |
| import com.google.inject.spi.ProviderInstanceBinding; |
| import com.google.inject.spi.ProviderWithExtensionVisitor; |
| import java.util.Collections; |
| import java.util.Enumeration; |
| import java.util.HashMap; |
| import java.util.Map; |
| import java.util.Set; |
| import java.util.concurrent.atomic.AtomicReference; |
| import javax.servlet.Filter; |
| import javax.servlet.FilterConfig; |
| import javax.servlet.ServletContext; |
| import javax.servlet.ServletException; |
| import javax.servlet.http.HttpServletRequest; |
| |
| /** |
| * An internal representation of a filter definition against a particular URI pattern. |
| * |
| * @author dhanji@gmail.com (Dhanji R. Prasanna) |
| */ |
| class FilterDefinition implements ProviderWithExtensionVisitor<FilterDefinition> { |
| private final Key<? extends Filter> filterKey; |
| private final UriPatternMatcher patternMatcher; |
| private final Map<String, String> initParams; |
| // set only if this was bound to an instance of a Filter. |
| private final Filter filterInstance; |
| |
| // always set after init is called. |
| private final AtomicReference<Filter> filter = new AtomicReference<>(); |
| |
| public FilterDefinition( |
| Key<? extends Filter> filterKey, |
| UriPatternMatcher patternMatcher, |
| Map<String, String> initParams, |
| Filter filterInstance) { |
| this.filterKey = filterKey; |
| this.patternMatcher = patternMatcher; |
| this.initParams = Collections.unmodifiableMap(new HashMap<String, String>(initParams)); |
| this.filterInstance = filterInstance; |
| } |
| |
| @Override |
| public FilterDefinition get() { |
| return this; |
| } |
| |
| @Override |
| public <B, V> V acceptExtensionVisitor( |
| BindingTargetVisitor<B, V> visitor, ProviderInstanceBinding<? extends B> binding) { |
| if (visitor instanceof ServletModuleTargetVisitor) { |
| if (filterInstance != null) { |
| return ((ServletModuleTargetVisitor<B, V>) visitor) |
| .visit(new InstanceFilterBindingImpl(initParams, filterInstance, patternMatcher)); |
| } else { |
| return ((ServletModuleTargetVisitor<B, V>) visitor) |
| .visit(new LinkedFilterBindingImpl(initParams, filterKey, patternMatcher)); |
| } |
| } else { |
| return visitor.visit(binding); |
| } |
| } |
| |
| private boolean shouldFilter(String uri) { |
| return uri != null && patternMatcher.matches(uri); |
| } |
| |
| public void init( |
| final ServletContext servletContext, Injector injector, Set<Filter> initializedSoFar) |
| throws ServletException { |
| |
| // This absolutely must be a singleton, and so is only initialized once. |
| if (!Scopes.isSingleton(injector.getBinding(filterKey))) { |
| throw new ServletException( |
| "Filters must be bound as singletons. " |
| + filterKey |
| + " was not bound in singleton scope."); |
| } |
| |
| Filter filter = injector.getInstance(filterKey); |
| this.filter.set(filter); |
| |
| // Only fire init() if this Singleton filter has not already appeared earlier |
| // in the filter chain. |
| if (initializedSoFar.contains(filter)) { |
| return; |
| } |
| |
| //initialize our filter with the configured context params and servlet context |
| filter.init( |
| new FilterConfig() { |
| @Override |
| public String getFilterName() { |
| return filterKey.toString(); |
| } |
| |
| @Override |
| public ServletContext getServletContext() { |
| return servletContext; |
| } |
| |
| @Override |
| public String getInitParameter(String s) { |
| return initParams.get(s); |
| } |
| |
| @Override |
| public Enumeration getInitParameterNames() { |
| return Iterators.asEnumeration(initParams.keySet().iterator()); |
| } |
| }); |
| |
| initializedSoFar.add(filter); |
| } |
| |
| public void destroy(Set<Filter> destroyedSoFar) { |
| // filters are always singletons |
| Filter reference = filter.get(); |
| |
| // Do nothing if this Filter was invalid (usually due to not being scoped |
| // properly), or was already destroyed. According to Servlet Spec: it is |
| // "out of service", and does not need to be destroyed. |
| // Also prevent duplicate destroys to the same singleton that may appear |
| // more than once on the filter chain. |
| if (null == reference || destroyedSoFar.contains(reference)) { |
| return; |
| } |
| |
| try { |
| reference.destroy(); |
| } finally { |
| destroyedSoFar.add(reference); |
| } |
| } |
| |
| public Filter getFilterIfMatching(HttpServletRequest request) { |
| |
| final String path = ServletUtils.getContextRelativePath(request); |
| if (shouldFilter(path)) { |
| return filter.get(); |
| } else { |
| return null; |
| } |
| } |
| |
| //VisibleForTesting |
| Filter getFilter() { |
| return filter.get(); |
| } |
| } |