001/*
002 * Copyright 2002-2018 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.web.context.support;
018
019import javax.servlet.ServletConfig;
020import javax.servlet.ServletContext;
021
022import org.springframework.core.env.Environment;
023import org.springframework.core.env.MutablePropertySources;
024import org.springframework.core.env.PropertySource;
025import org.springframework.core.env.PropertySource.StubPropertySource;
026import org.springframework.core.env.StandardEnvironment;
027import org.springframework.jndi.JndiLocatorDelegate;
028import org.springframework.jndi.JndiPropertySource;
029import org.springframework.lang.Nullable;
030import org.springframework.web.context.ConfigurableWebEnvironment;
031
032/**
033 * {@link Environment} implementation to be used by {@code Servlet}-based web
034 * applications. All web-related (servlet-based) {@code ApplicationContext} classes
035 * initialize an instance by default.
036 *
037 * <p>Contributes {@code ServletConfig}, {@code ServletContext}, and JNDI-based
038 * {@link PropertySource} instances. See {@link #customizePropertySources} method
039 * documentation for details.
040 *
041 * @author Chris Beams
042 * @since 3.1
043 * @see StandardEnvironment
044 */
045public class StandardServletEnvironment extends StandardEnvironment implements ConfigurableWebEnvironment {
046
047        /** Servlet context init parameters property source name: {@value}. */
048        public static final String SERVLET_CONTEXT_PROPERTY_SOURCE_NAME = "servletContextInitParams";
049
050        /** Servlet config init parameters property source name: {@value}. */
051        public static final String SERVLET_CONFIG_PROPERTY_SOURCE_NAME = "servletConfigInitParams";
052
053        /** JNDI property source name: {@value}. */
054        public static final String JNDI_PROPERTY_SOURCE_NAME = "jndiProperties";
055
056
057        /**
058         * Customize the set of property sources with those contributed by superclasses as
059         * well as those appropriate for standard servlet-based environments:
060         * <ul>
061         * <li>{@value #SERVLET_CONFIG_PROPERTY_SOURCE_NAME}
062         * <li>{@value #SERVLET_CONTEXT_PROPERTY_SOURCE_NAME}
063         * <li>{@value #JNDI_PROPERTY_SOURCE_NAME}
064         * </ul>
065         * <p>Properties present in {@value #SERVLET_CONFIG_PROPERTY_SOURCE_NAME} will
066         * take precedence over those in {@value #SERVLET_CONTEXT_PROPERTY_SOURCE_NAME}, and
067         * properties found in either of the above take precedence over those found in
068         * {@value #JNDI_PROPERTY_SOURCE_NAME}.
069         * <p>Properties in any of the above will take precedence over system properties and
070         * environment variables contributed by the {@link StandardEnvironment} superclass.
071         * <p>The {@code Servlet}-related property sources are added as
072         * {@link StubPropertySource stubs} at this stage, and will be
073         * {@linkplain #initPropertySources(ServletContext, ServletConfig) fully initialized}
074         * once the actual {@link ServletContext} object becomes available.
075         * @see StandardEnvironment#customizePropertySources
076         * @see org.springframework.core.env.AbstractEnvironment#customizePropertySources
077         * @see ServletConfigPropertySource
078         * @see ServletContextPropertySource
079         * @see org.springframework.jndi.JndiPropertySource
080         * @see org.springframework.context.support.AbstractApplicationContext#initPropertySources
081         * @see #initPropertySources(ServletContext, ServletConfig)
082         */
083        @Override
084        protected void customizePropertySources(MutablePropertySources propertySources) {
085                propertySources.addLast(new StubPropertySource(SERVLET_CONFIG_PROPERTY_SOURCE_NAME));
086                propertySources.addLast(new StubPropertySource(SERVLET_CONTEXT_PROPERTY_SOURCE_NAME));
087                if (JndiLocatorDelegate.isDefaultJndiEnvironmentAvailable()) {
088                        propertySources.addLast(new JndiPropertySource(JNDI_PROPERTY_SOURCE_NAME));
089                }
090                super.customizePropertySources(propertySources);
091        }
092
093        @Override
094        public void initPropertySources(@Nullable ServletContext servletContext, @Nullable ServletConfig servletConfig) {
095                WebApplicationContextUtils.initServletPropertySources(getPropertySources(), servletContext, servletConfig);
096        }
097
098}