/*
* [The "BSD licence"]
* Copyright (c) 2013-2014 Dandelion
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Dandelion nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.github.dandelion.core;
import java.lang.management.ManagementFactory;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.ServiceLoader;
import javax.management.JMException;
import javax.management.MBeanServer;
import javax.management.ObjectName;
import javax.servlet.FilterConfig;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.github.dandelion.core.asset.cache.AssetCacheManager;
import com.github.dandelion.core.asset.cache.impl.MemoryAssetCache;
import com.github.dandelion.core.asset.cache.spi.AssetCache;
import com.github.dandelion.core.asset.locator.Servlet2Compatible;
import com.github.dandelion.core.asset.locator.Servlet3Compatible;
import com.github.dandelion.core.asset.locator.spi.AssetLocator;
import com.github.dandelion.core.asset.processor.AssetProcessorManager;
import com.github.dandelion.core.asset.processor.spi.AssetProcessor;
import com.github.dandelion.core.bundle.loader.impl.DandelionBundleLoader;
import com.github.dandelion.core.bundle.loader.impl.VendorBundleLoader;
import com.github.dandelion.core.bundle.loader.spi.BundleLoader;
import com.github.dandelion.core.config.Configuration;
import com.github.dandelion.core.config.ConfigurationLoader;
import com.github.dandelion.core.config.StandardConfigurationLoader;
import com.github.dandelion.core.jmx.DandelionRuntime;
import com.github.dandelion.core.storage.BundleStorage;
import com.github.dandelion.core.utils.ClassUtils;
import com.github.dandelion.core.utils.StringUtils;
/**
* <p>
* This class is in charge of discovering and storing several configuration
* points, such as the configured {@link AssetCache} implementation or the
* active {@link AssetProcessor}s.
*
* <p>
* There should be only one instance of this class per JVM.
*
* @author Thibault Duchateau
* @since 0.10.0
*/
public class Context {
private static Logger LOG = LoggerFactory.getLogger(Context.class);
private AssetCache assetCache;
private Map<String, AssetProcessor> processorsMap;
private List<AssetProcessor> activeProcessors;
private List<BundleLoader> bundleLoaders;
private AssetProcessorManager assetProcessorManager;
private AssetCacheManager assetCacheManager;
private Map<String, AssetLocator> assetLocatorsMap;
private BundleStorage bundleStorage;
private Configuration configuration;
/**
* Public constructor.
*
* @param filterConfig
* The servlet filter configuration.
*/
public Context(FilterConfig filterConfig) {
init(filterConfig);
}
/**
* <p>
* Performs all the required initializations of the Dandelion context.
*
* @param filterConfig
* The servlet filter configuration.
*/
public void init(FilterConfig filterConfig) {
initConfiguration(filterConfig);
initBundleLoaders();
initAssetLocators();
initAssetCache();
initAssetProcessors();
assetProcessorManager = new AssetProcessorManager(this);
assetCacheManager = new AssetCacheManager(this);
initBundleStorage();
initMBean(filterConfig);
}
/**
* <p>
* Returns an implementation of {@link ConfigurationLoader} using the
* following strategy:
* <ol>
* <li>Check first if the <code>dandelion.confloader.class</code> system
* property is set and tries to instantiate it</li>
* <li>Otherwise, instantiate the {@link StandardConfigurationLoader} which
* reads properties files</li>
* </ol>
*
* @return an implementation of {@link ConfigurationLoader}.
*/
public void initConfiguration(FilterConfig filterConfig) {
ConfigurationLoader configurationLoader = null;
LOG.debug("Initializing the configuration loader...");
if (StringUtils.isNotBlank(System.getProperty(ConfigurationLoader.DANDELION_CONFLOADER_CLASS))) {
Class<?> clazz;
try {
clazz = ClassUtils.getClass(System.getProperty(ConfigurationLoader.DANDELION_CONFLOADER_CLASS));
configurationLoader = (ConfigurationLoader) ClassUtils.getNewInstance(clazz);
}
catch (Exception e) {
LOG.warn(
"Unable to instantiate the configured {} due to a {} exception. Falling back to the default one.",
ConfigurationLoader.DANDELION_CONFLOADER_CLASS, e.getClass().getName(), e);
}
}
if (configurationLoader == null) {
configurationLoader = new StandardConfigurationLoader();
}
Properties userProperties = new Properties();
userProperties.putAll(configurationLoader.loadUserConfiguration());
configuration = new Configuration(filterConfig, userProperties);
}
/**
* <p>
* Initializes the {@link BundleLoader}s in a particular order:
* <ol>
* <li>First, the {@link VendorBundleLoader} which loads all
* "vendor bundles"</li>
* <li>Then, all service providers of the {@link BundleLoader} SPI present
* in the classpath</li>
* <li>Finally the {@link DandelionBundleLoader} which loads all "user bundles"</li>
* </ol>
*/
public void initBundleLoaders() {
ServiceLoader<BundleLoader> blServiceLoader = ServiceLoader.load(BundleLoader.class);
VendorBundleLoader vendorLoader = new VendorBundleLoader();
vendorLoader.initLoader(this);
DandelionBundleLoader dandelionLoader = new DandelionBundleLoader();
dandelionLoader.initLoader(this);
bundleLoaders = new ArrayList<BundleLoader>();
// All vendor bundles must be loaded in first
bundleLoaders.add(vendorLoader);
// Then all bundles of the components present in the classpath
for (BundleLoader bl : blServiceLoader) {
bl.initLoader(this);
bundleLoaders.add(bl);
LOG.info("Active bundle loader found: {}", bl.getClass().getSimpleName());
}
// Finally all bundles created by users
bundleLoaders.add(dandelionLoader);
}
/**
* Initializes the service provider of {@link AssetCache} to use for
* caching.
*/
public void initAssetCache() {
ServiceLoader<AssetCache> assetCacheServiceLoader = ServiceLoader.load(AssetCache.class);
Map<String, AssetCache> caches = new HashMap<String, AssetCache>();
for (AssetCache ac : assetCacheServiceLoader) {
caches.put(ac.getCacheName().toLowerCase().trim(), ac);
LOG.info("Asset caching system found: {}", ac.getClass().getSimpleName());
}
String desiredCacheName = configuration.getCacheName();
if(StringUtils.isNotBlank(desiredCacheName)) {
if(caches.containsKey(desiredCacheName)) {
assetCache = caches.get(desiredCacheName);
}
else {
LOG.warn(
"The desired caching system ({}) hasn't been found in the classpath. Did you forget to add a dependency? The default one will be used.",
desiredCacheName);
}
}
// If no caching system is detected, it defaults to memory caching
if (assetCache == null) {
assetCache = new MemoryAssetCache();
}
assetCache.initCache(this);
LOG.info("Selected asset cache system: {} (based on {})", assetCache.getCacheName(), assetCache.getClass()
.getSimpleName());
}
/**
* Initializes all service providers of the {@link AssetLocator} SPI. The
* order doesn't matter.
*/
public void initAssetLocators() {
ServiceLoader<AssetLocator> alServiceLoader = ServiceLoader.load(AssetLocator.class);
assetLocatorsMap = new HashMap<String, AssetLocator>();
for (AssetLocator al : alServiceLoader) {
// Only register Servlet3-compatible asset locators if Servlet 3.x
// is being used
if (this.getConfiguration().isServlet3Enabled()) {
if (Servlet3Compatible.class.isAssignableFrom(al.getClass())) {
al.initLocator(this);
assetLocatorsMap.put(al.getLocationKey(), al);
LOG.info("Asset locator found: {} ({})", al.getLocationKey(), al.getClass().getSimpleName());
}
}
// Otherwise register all Servlet2-compatible asset locators
else {
if (Servlet2Compatible.class.isAssignableFrom(al.getClass())) {
al.initLocator(this);
assetLocatorsMap.put(al.getLocationKey(), al);
LOG.info("Asset locator found: {} ({})", al.getLocationKey(), al.getClass().getSimpleName());
}
}
}
}
/**
* <p>
* Initializes all service providers of the {@link AssetProcessor} SPI and
* stores them all in the {@link #processorsMap}.
*
* <p>
* If minification is enabled, the {@link #activeProcessors} is filled with
* default service providers.
*/
public void initAssetProcessors() {
ServiceLoader<AssetProcessor> apServiceLoader = ServiceLoader.load(AssetProcessor.class);
processorsMap = new HashMap<String, AssetProcessor>();
activeProcessors = new ArrayList<AssetProcessor>();
for (AssetProcessor ape : apServiceLoader) {
processorsMap.put(ape.getProcessorKey().toLowerCase(), ape);
LOG.info("Asset processor found: {}", ape.getClass().getSimpleName());
}
if (configuration.isMinificationEnabled()) {
LOG.info("Asset processors enabled.");
for (String assetProcessorKey : configuration.getAssetProcessors()) {
if (processorsMap.containsKey(assetProcessorKey)) {
activeProcessors.add(processorsMap.get(assetProcessorKey));
LOG.info("Processor enabled: {}", processorsMap.get(assetProcessorKey).getProcessorKey());
}
}
}
else {
LOG.info("Asset processors disabled. All assets will be left untouched.");
}
}
/**
* <p>
* Initializes the {@link BundleStorage} by using all configured
* {@link BundleLoader}s.
*
* <p>
* Once loader, some checks are performed on the {@link BundleStorage}.
*/
public void initBundleStorage() {
bundleStorage = new BundleStorage();
for (BundleLoader bundleLoader : getBundleLoaders()) {
bundleStorage.storeBundles(bundleLoader.loadBundles());
}
bundleStorage.checkBundleDag();
}
/**
* If JMX is enabled, initializes a MBean allowing to reload bundles and
* access cache.
*
* @param filterConfig
* The servlet filter configuration.
*/
public void initMBean(FilterConfig filterConfig) {
if (configuration.isJmxEnabled()) {
try {
MBeanServer mbeanServer = ManagementFactory.getPlatformMBeanServer();
ObjectName name = new ObjectName("com.github.dandelion", "type", DandelionRuntime.class.getSimpleName());
if (!mbeanServer.isRegistered(name)) {
mbeanServer.registerMBean(new DandelionRuntime(this, filterConfig), name);
}
}
catch (final JMException e) {
LOG.error("An exception occured while registering the DandelionRuntimeMBean", e);
}
}
}
public void destroy(){
if (configuration.isJmxEnabled()) {
try {
MBeanServer mbeanServer = ManagementFactory.getPlatformMBeanServer();
ObjectName name = new ObjectName("com.github.dandelion", "type", DandelionRuntime.class.getSimpleName());
if (mbeanServer.isRegistered(name)) {
mbeanServer.unregisterMBean(name);
}
}
catch (final JMException e) {
LOG.error("An exception occured while unregistering the DandelionRuntimeMBean", e);
}
}
}
public AssetCache getAssetCache() {
return assetCache;
}
public Map<String, AssetProcessor> getProcessorsMap() {
return processorsMap;
}
public List<BundleLoader> getBundleLoaders() {
return bundleLoaders;
}
public Map<String, AssetLocator> getAssetLocatorsMap() {
return assetLocatorsMap;
}
public List<AssetProcessor> getActiveProcessors() {
return activeProcessors;
}
public BundleStorage getBundleStorage() {
return bundleStorage;
}
public AssetProcessorManager getProcessorManager() {
return assetProcessorManager;
}
public AssetCacheManager getCacheManager() {
return assetCacheManager;
}
/**
* @return the {@link Configuration} store associated to the Dandelion
* {@link Context} .
*/
public Configuration getConfiguration() {
return configuration;
}
/**
* @return {@code true} if the {@code dandelion.mode} configuration property
* is set to "development" or any other value than "production". If
* the mode is not explicitely configured, it returns {@code true}.
*/
public boolean isDevModeEnabled() {
return "development".equalsIgnoreCase(configuration.getDandelionMode().toString());
}
}