/*
 * Copyright 2002-2019 the original author or authors.
 *
 * 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
 *
 *      https://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.springframework.web.context.support;

import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;

import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.context.support.GenericApplicationContext;
import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.lang.Nullable;
import org.springframework.ui.context.Theme;
import org.springframework.ui.context.ThemeSource;
import org.springframework.ui.context.support.UiApplicationContextUtils;
import org.springframework.util.Assert;
import org.springframework.util.ObjectUtils;
import org.springframework.util.StringUtils;
import org.springframework.web.context.ConfigurableWebApplicationContext;
import org.springframework.web.context.ConfigurableWebEnvironment;
import org.springframework.web.context.ServletContextAware;

Subclass of GenericApplicationContext, suitable for web environments. 
Implements ConfigurableWebApplicationContext, but is not intended for declarative setup in web.xml. Instead, it is designed for programmatic setup, for example for building nested contexts or for use within WebApplicationInitializers. 
If you intend to implement a WebApplicationContext that reads bean definitions from configuration files, consider deriving from AbstractRefreshableWebApplicationContext, reading the bean definitions in an implementation of the loadBeanDefinitions method.
Interprets resource paths as servlet context resources, i.e. as paths beneath
the web application root. Absolute paths, e.g. for files outside the web app root,
can be accessed via "file:" URLs, as implemented by AbstractApplicationContext.
In addition to the special beans detected by AbstractApplicationContext, this class detects a ThemeSource bean in the context, with the name "themeSource". 
Author:
Juergen Hoeller, Chris Beams
Since:
1.2/**
 * Subclass of {@link GenericApplicationContext}, suitable for web environments.
 *
 * <p>Implements {@link org.springframework.web.context.ConfigurableWebApplicationContext},
 * but is not intended for declarative setup in {@code web.xml}. Instead, it is designed
 * for programmatic setup, for example for building nested contexts or for use within
 * {@link org.springframework.web.WebApplicationInitializer WebApplicationInitializers}.
 *
 * <p><b>If you intend to implement a WebApplicationContext that reads bean definitions
 * from configuration files, consider deriving from AbstractRefreshableWebApplicationContext,
 * reading the bean definitions in an implementation of the {@code loadBeanDefinitions}
 * method.</b>
 *
 * <p>Interprets resource paths as servlet context resources, i.e. as paths beneath
 * the web application root. Absolute paths, e.g. for files outside the web app root,
 * can be accessed via "file:" URLs, as implemented by AbstractApplicationContext.
 *
 * <p>In addition to the special beans detected by
 * {@link org.springframework.context.support.AbstractApplicationContext},
 * this class detects a ThemeSource bean in the context, with the name "themeSource".
 *
 * @author Juergen Hoeller
 * @author Chris Beams
 * @since 1.2
 */
public class GenericWebApplicationContext extends GenericApplicationContext
		implements ConfigurableWebApplicationContext, ThemeSource {

	@Nullable
	private ServletContext servletContext;

	@Nullable
	private ThemeSource themeSource;


	
Create a new GenericWebApplicationContext.
See Also:
setServletContext
registerBeanDefinition
refresh/**
	 * Create a new GenericWebApplicationContext.
	 * @see #setServletContext
	 * @see #registerBeanDefinition
	 * @see #refresh
	 */
	public GenericWebApplicationContext() {
		super();
	}

	
Create a new GenericWebApplicationContext for the given ServletContext.
Params:
servletContext – the ServletContext to run in
See Also:
registerBeanDefinition
refresh/**
	 * Create a new GenericWebApplicationContext for the given ServletContext.
	 * @param servletContext the ServletContext to run in
	 * @see #registerBeanDefinition
	 * @see #refresh
	 */
	public GenericWebApplicationContext(ServletContext servletContext) {
		this.servletContext = servletContext;
	}

	
Create a new GenericWebApplicationContext with the given DefaultListableBeanFactory.
Params:
beanFactory – the DefaultListableBeanFactory instance to use for this context
See Also:
setServletContext
registerBeanDefinition
refresh/**
	 * Create a new GenericWebApplicationContext with the given DefaultListableBeanFactory.
	 * @param beanFactory the DefaultListableBeanFactory instance to use for this context
	 * @see #setServletContext
	 * @see #registerBeanDefinition
	 * @see #refresh
	 */
	public GenericWebApplicationContext(DefaultListableBeanFactory beanFactory) {
		super(beanFactory);
	}

	
Create a new GenericWebApplicationContext with the given DefaultListableBeanFactory.
Params:
beanFactory – the DefaultListableBeanFactory instance to use for this context
servletContext – the ServletContext to run in
See Also:
registerBeanDefinition
refresh/**
	 * Create a new GenericWebApplicationContext with the given DefaultListableBeanFactory.
	 * @param beanFactory the DefaultListableBeanFactory instance to use for this context
	 * @param servletContext the ServletContext to run in
	 * @see #registerBeanDefinition
	 * @see #refresh
	 */
	public GenericWebApplicationContext(DefaultListableBeanFactory beanFactory, ServletContext servletContext) {
		super(beanFactory);
		this.servletContext = servletContext;
	}


	
Set the ServletContext that this WebApplicationContext runs in.
/**
	 * Set the ServletContext that this WebApplicationContext runs in.
	 */
	@Override
	public void setServletContext(@Nullable ServletContext servletContext) {
		this.servletContext = servletContext;
	}

	@Override
	@Nullable
	public ServletContext getServletContext() {
		return this.servletContext;
	}

	@Override
	public String getApplicationName() {
		return (this.servletContext != null ? this.servletContext.getContextPath() : "");
	}

	
Create and return a new StandardServletEnvironment. /**
	 * Create and return a new {@link StandardServletEnvironment}.
	 */
	@Override
	protected ConfigurableEnvironment createEnvironment() {
		return new StandardServletEnvironment();
	}

	
Register ServletContextAwareProcessor.
See Also:
ServletContextAwareProcessor/**
	 * Register ServletContextAwareProcessor.
	 * @see ServletContextAwareProcessor
	 */
	@Override
	protected void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) {
		if (this.servletContext != null) {
			beanFactory.addBeanPostProcessor(new ServletContextAwareProcessor(this.servletContext));
			beanFactory.ignoreDependencyInterface(ServletContextAware.class);
		}
		WebApplicationContextUtils.registerWebApplicationScopes(beanFactory, this.servletContext);
		WebApplicationContextUtils.registerEnvironmentBeans(beanFactory, this.servletContext);
	}

	
This implementation supports file paths beneath the root of the ServletContext.
See Also:
ServletContextResource/**
	 * This implementation supports file paths beneath the root of the ServletContext.
	 * @see ServletContextResource
	 */
	@Override
	protected Resource getResourceByPath(String path) {
		Assert.state(this.servletContext != null, "No ServletContext available");
		return new ServletContextResource(this.servletContext, path);
	}

	
This implementation supports pattern matching in unexpanded WARs too.
See Also:
ServletContextResourcePatternResolver/**
	 * This implementation supports pattern matching in unexpanded WARs too.
	 * @see ServletContextResourcePatternResolver
	 */
	@Override
	protected ResourcePatternResolver getResourcePatternResolver() {
		return new ServletContextResourcePatternResolver(this);
	}

	
Initialize the theme capability.
/**
	 * Initialize the theme capability.
	 */
	@Override
	protected void onRefresh() {
		this.themeSource = UiApplicationContextUtils.initThemeSource(this);
	}

	
{@inheritDoc}
Replace Servlet-related property sources. /**
	 * {@inheritDoc}
	 * <p>Replace {@code Servlet}-related property sources.
	 */
	@Override
	protected void initPropertySources() {
		ConfigurableEnvironment env = getEnvironment();
		if (env instanceof ConfigurableWebEnvironment) {
			((ConfigurableWebEnvironment) env).initPropertySources(this.servletContext, null);
		}
	}

	@Override
	@Nullable
	public Theme getTheme(String themeName) {
		Assert.state(this.themeSource != null, "No ThemeSource available");
		return this.themeSource.getTheme(themeName);
	}


	// ---------------------------------------------------------------------
	// Pseudo-implementation of ConfigurableWebApplicationContext
	// ---------------------------------------------------------------------

	@Override
	public void setServletConfig(@Nullable ServletConfig servletConfig) {
		// no-op
	}

	@Override
	@Nullable
	public ServletConfig getServletConfig() {
		throw new UnsupportedOperationException(
				"GenericWebApplicationContext does not support getServletConfig()");
	}

	@Override
	public void setNamespace(@Nullable String namespace) {
		// no-op
	}

	@Override
	@Nullable
	public String getNamespace() {
		throw new UnsupportedOperationException(
				"GenericWebApplicationContext does not support getNamespace()");
	}

	@Override
	public void setConfigLocation(String configLocation) {
		if (StringUtils.hasText(configLocation)) {
			throw new UnsupportedOperationException(
					"GenericWebApplicationContext does not support setConfigLocation(). " +
					"Do you still have an 'contextConfigLocations' init-param set?");
		}
	}

	@Override
	public void setConfigLocations(String... configLocations) {
		if (!ObjectUtils.isEmpty(configLocations)) {
			throw new UnsupportedOperationException(
					"GenericWebApplicationContext does not support setConfigLocations(). " +
					"Do you still have an 'contextConfigLocations' init-param set?");
		}
	}

	@Override
	public String[] getConfigLocations() {
		throw new UnsupportedOperationException(
				"GenericWebApplicationContext does not support getConfigLocations()");
	}

}