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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.cayenne.configuration.web;
import org.apache.cayenne.di.Module;
import org.apache.cayenne.util.Util;
import javax.servlet.FilterConfig;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.StringTokenizer;
/**
* A class that provides access to common Cayenne web configuration parameters retrieved
* either from a FilterConfig or a ServletConfig configuration.
*
* @since 3.1
*/
public class WebConfiguration {
static final String CONFIGURATION_LOCATION_PARAMETER = "configuration-location";
static final String EXTRA_MODULES_PARAMETER = "extra-modules";
private FilterConfig configuration;
public WebConfiguration(final ServletConfig servletConfiguration) {
this.configuration = new FilterConfig() {
public ServletContext getServletContext() {
return servletConfiguration.getServletContext();
}
@SuppressWarnings("all")
public Enumeration getInitParameterNames() {
return servletConfiguration.getInitParameterNames();
}
public String getInitParameter(String name) {
return servletConfiguration.getInitParameter(name);
}
public String getFilterName() {
return servletConfiguration.getServletName();
}
};
}
public WebConfiguration(FilterConfig filterConfiguration) {
this.configuration = filterConfiguration;
}
/**
* Returns a non-null location of an XML Cayenne configuration, extracted from the
* filter or servlet configuration parameters.
*/
public String getConfigurationLocation() {
String configurationLocation = configuration
.getInitParameter(CONFIGURATION_LOCATION_PARAMETER);
if (configurationLocation != null) {
return configurationLocation;
}
String name = configuration.getFilterName();
if (name == null) {
return null;
}
if (!name.endsWith(".xml")) {
name = name + ".xml";
}
return name;
}
/**
* Creates and returns a collection of modules made of provided standard modules and
* extra custom modules specified via an optional "extra-modules" init parameter. The
* value of the parameter is expected to be a comma or space-separated list of class
* names, with each class implementing {@link Module} interface. Each custom module
* must have a no-arg constructor. If a module of this type is already in the modules
* collection, such module is skipped.
*/
public Collection<Module> createModules(Module... standardModules)
throws ServletException {
Set<String> existingModules = new HashSet<>();
Collection<Module> modules = new ArrayList<>();
if (standardModules != null) {
for (Module module : standardModules) {
modules.add(module);
existingModules.add(module.getClass().getName());
}
}
String extraModules = configuration.getInitParameter(EXTRA_MODULES_PARAMETER);
if (extraModules != null) {
StringTokenizer toks = new StringTokenizer(extraModules, ", \n\r");
while (toks.hasMoreTokens()) {
String moduleName = toks.nextToken();
if (!existingModules.add(moduleName)) {
continue;
}
Module module;
try {
module = (Module) Util.getJavaClass(moduleName).newInstance();
}
catch (Exception e) {
String message = String
.format(
"Error instantiating custom DI module '%s' by filter '%s': %s",
moduleName,
getClass().getName(),
e.getMessage());
throw new ServletException(message, e);
}
modules.add(module);
}
}
return modules;
}
/**
* Returns a map of all init parameters from the underlying FilterConfig or
* ServletConfig object.
*/
public Map<String, String> getParameters() {
Enumeration<?> en = configuration.getInitParameterNames();
if (!en.hasMoreElements()) {
return Collections.EMPTY_MAP;
}
Map<String, String> parameters = new HashMap<>();
while (en.hasMoreElements()) {
String key = (String) en.nextElement();
parameters.put(key, configuration.getInitParameter(key));
}
return parameters;
}
/**
* Returns servlet or filter init parameters, excluding those recognized by
* WebConfiguration. Namely 'configuration-location' and 'extra-modules' parameters
* are removed from the returned map.
*/
public Map<String, String> getOtherParameters() {
Map<String, String> parameters = getParameters();
if (!parameters.isEmpty()) {
parameters.remove(CONFIGURATION_LOCATION_PARAMETER);
parameters.remove(EXTRA_MODULES_PARAMETER);
}
return parameters;
}
}