ModuleOptionsPropertySourceInitializer.java

/*
 * Copyright 2015 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
 *
 *      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.springframework.bus.xd.bootstrap;

import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.condition.ConditionalOnExpression;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.bus.runner.config.MessageBusProperties;
import org.springframework.context.ApplicationContextInitializer;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.core.env.Environment;
import org.springframework.core.env.MapPropertySource;
import org.springframework.xd.dirt.plugins.job.JobPluginMetadataResolver;
import org.springframework.xd.dirt.plugins.stream.ModuleTypeConversionPluginMetadataResolver;
import org.springframework.xd.module.ModuleDefinition;
import org.springframework.xd.module.ModuleDefinitions;
import org.springframework.xd.module.ModuleType;
import org.springframework.xd.module.options.DefaultModuleOptionsMetadataResolver;
import org.springframework.xd.module.options.DelegatingModuleOptionsMetadataResolver;
import org.springframework.xd.module.options.EnvironmentAwareModuleOptionsMetadataResolver;
import org.springframework.xd.module.options.ModuleOption;
import org.springframework.xd.module.options.ModuleOptionsMetadata;
import org.springframework.xd.module.options.ModuleOptionsMetadataResolver;

/**
 * Initialize the application context with default values for the module options.
 *
 * @author Dave Syer
 *
 */
@Configuration
@EnableConfigurationProperties(MessageBusProperties.class)
@Order(Ordered.HIGHEST_PRECEDENCE + 10)
public class ModuleOptionsPropertySourceInitializer implements
		ApplicationContextInitializer<ConfigurableApplicationContext> {

	@Autowired
	private MessageBusProperties module = new MessageBusProperties();

	@Autowired(required=false)
	private EnvironmentAwareModuleOptionsMetadataResolver wrapper;

	@Override
	public void initialize(ConfigurableApplicationContext applicationContext) {
		ConfigurableEnvironment environment = applicationContext.getEnvironment();
		ModuleOptionsMetadataResolver resolver = moduleOptionsMetadataResolver(environment);
		ModuleOptionsMetadata resolved = resolver.resolve(getModuleDefinition(applicationContext));
		Map<String, Object> map = new LinkedHashMap<String, Object>();
		for (ModuleOption option : resolved) {
			if (option.getDefaultValue() != null) {
				map.put(option.getName(), option.getDefaultValue());
			}
		}
		insert(environment, new MapPropertySource("moduleDefaults", map));
	}

	private ModuleDefinition getModuleDefinition(ConfigurableApplicationContext applicationContext) {
		String location = "file:.";
		ClassLoader classLoader = applicationContext.getClassLoader();
		if (classLoader instanceof URLClassLoader) {
			URL[] urls = ((URLClassLoader) classLoader).getURLs();
			String firstUrl = urls[0].toString();
			if (firstUrl.startsWith("jar:") && firstUrl.endsWith("!/")) {
				location = firstUrl.substring(4, firstUrl.length() - 2);
			}
		}
		return ModuleDefinitions.simple(module.getName(),
				ModuleType.valueOf(module.getType()), location);
	}

	private void insert(ConfigurableEnvironment environment, MapPropertySource source) {
		environment.getPropertySources().addLast(source);
	}

	private ModuleOptionsMetadataResolver moduleOptionsMetadataResolver(Environment environment) {
		List<ModuleOptionsMetadataResolver> delegates = new ArrayList<ModuleOptionsMetadataResolver>();
		delegates.add(defaultResolver());
		delegates.add(new ModuleTypeConversionPluginMetadataResolver());
		delegates.add(new JobPluginMetadataResolver());
		DelegatingModuleOptionsMetadataResolver delegatingResolver = new DelegatingModuleOptionsMetadataResolver();
		delegatingResolver.setDelegates(delegates);
		ModuleOptionsMetadataResolver resolver = delegatingResolver;
		if (wrapper!=null) {
			wrapper.setDelegate(delegatingResolver);
			resolver = wrapper;
		}
		return resolver;
	}

	@Bean
	// TODO: allow override of this
	public DefaultModuleOptionsMetadataResolver defaultResolver() {
		DefaultModuleOptionsMetadataResolver defaultResolver = new DefaultModuleOptionsMetadataResolver();
		defaultResolver.setShouldCreateModuleClassLoader(false);
		return defaultResolver;
	}

	@ConditionalOnExpression("'${xd.module.config.location:${xd.config.home:}}'!=''")
	protected static class EnvironmentAwareModuleOptionsMetadataResolverConfiguration {
		@Bean
		public EnvironmentAwareModuleOptionsMetadataResolver environmentAwareModuleOptionsMetadataResolver() {
			return new EnvironmentAwareModuleOptionsMetadataResolver();
		}
	}

}