src/main/java/org/apache/sling/servlets/resolver/internal/resolution/ResolutionCache.java - sling-org-apache-sling-servlets-resolver - Git at Google

 /*
  * 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.sling.servlets.resolver.internal.resolution;

 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Dictionary;
 import java.util.Hashtable;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;

 import javax.management.NotCompliantMBeanException;
 import javax.management.StandardMBean;
 import javax.script.ScriptEngineFactory;
 import javax.script.ScriptEngineManager;
 import javax.servlet.Servlet;

 import org.apache.sling.api.resource.LoginException;
 import org.apache.sling.api.resource.observation.ExternalResourceChangeListener;
 import org.apache.sling.api.resource.observation.ResourceChange;
 import org.apache.sling.api.resource.observation.ResourceChangeListener;
 import org.apache.sling.api.resource.path.Path;
 import org.apache.sling.servlets.resolver.internal.ResolverConfig;
 import org.apache.sling.servlets.resolver.internal.helper.AbstractResourceCollector;
 import org.apache.sling.servlets.resolver.jmx.SlingServletResolverCacheMBean;
 import org.osgi.framework.BundleContext;
 import org.osgi.framework.Constants;
 import org.osgi.framework.ServiceRegistration;
 import org.osgi.service.component.annotations.Activate;
 import org.osgi.service.component.annotations.Component;
 import org.osgi.service.component.annotations.Deactivate;
 import org.osgi.service.component.annotations.Modified;
 import org.osgi.service.component.annotations.Reference;
 import org.osgi.service.event.Event;
 import org.osgi.service.event.EventConstants;
 import org.osgi.service.event.EventHandler;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

 /**
  * Cache for script resolution
  *
  */
 @Component(configurationPid = ResolverConfig.PID,
            service = {ResolutionCache.class})
 public class ResolutionCache
     implements EventHandler, ResourceChangeListener, ExternalResourceChangeListener {

     private final Logger logger = LoggerFactory.getLogger(this.getClass());

     @Reference
     private ScriptEngineManager scriptEngineManager;

     private volatile List<String> scriptEnginesExtensions = Collections.emptyList();

     /** The script resolution cache. */
     private volatile Map<AbstractResourceCollector, Servlet> cache;

     /** The cache size. */
     private volatile int cacheSize;

     /** Flag to log warning if cache size exceed only once. */
     private volatile boolean logCacheSizeWarning;

     /** Registration as event handler. */
     private volatile ServiceRegistration<EventHandler> eventHandlerRegistration;

     private volatile ServiceRegistration<ResourceChangeListener> resourceListenerRegistration;

     private volatile ServiceRegistration<SlingServletResolverCacheMBean> mbeanRegistration;

     /**
      * Activate this component.
      */
     @Activate
     protected void activate(final BundleContext context,
             final ResolverConfig config) throws LoginException {
         // create cache - if a cache size is configured
         this.cacheSize = config.servletresolver_cacheSize();
         if (this.cacheSize > 5) {
             this.cache = new ConcurrentHashMap<>(cacheSize);
             this.logCacheSizeWarning = true;

             // register MBean
             try {
                 Dictionary<String, String> mbeanProps = new Hashtable<>();
                 mbeanProps.put("jmx.objectname", "org.apache.sling:type=servletResolver,service=SlingServletResolverCache");

                 ServletResolverCacheMBeanImpl mbean = new ServletResolverCacheMBeanImpl();
                 mbeanRegistration = context.registerService(SlingServletResolverCacheMBean.class, mbean, mbeanProps);
             } catch (final Throwable t) {
                 logger.warn("Unable to register servlets resolver cache MBean", t);
             }
         }

         // and finally register as event listener
         // to invalidate cache and script extensions
         final Dictionary<String, Object> props = new Hashtable<>();
         props.put(Constants.SERVICE_DESCRIPTION, "Apache Sling Servlet Resolver Event Handler");
         props.put(Constants.SERVICE_VENDOR,"The Apache Software Foundation");

         // the event listener is for updating the script engine extensions
         props.put(EventConstants.EVENT_TOPIC, new String[] {
                 "javax/script/ScriptEngineFactory/*",
                 "org/apache/sling/api/adapter/AdapterFactory/*",
                 "org/apache/sling/scripting/core/BindingsValuesProvider/*" });

         this.eventHandlerRegistration = context.registerService(EventHandler.class, this, props);

         // we need a resource change listener to invalidate the cache
         if ( this.cache != null ) {
             final String[] listenerPaths = new String[config.servletresolver_paths().length];
             for(int i=0; i<config.servletresolver_paths().length; i++) {
                 final Path p = new Path(config.servletresolver_paths()[i]);
                 listenerPaths[i] = p.getPath();
             }

             final Dictionary<String, Object> listenerProps = new Hashtable<>();
             listenerProps.put(Constants.SERVICE_DESCRIPTION, "Apache Sling Servlet Resolver Resource Listener");
             listenerProps.put(Constants.SERVICE_VENDOR,"The Apache Software Foundation");
             listenerProps.put(ResourceChangeListener.PATHS, listenerPaths);
             this.resourceListenerRegistration = context.registerService(ResourceChangeListener.class, this, listenerProps);
         }

         updateScriptEngineExtensions();
     }

     @Modified
     protected void modified(final BundleContext context,
             final ResolverConfig config) throws LoginException {
         this.deactivate();
         this.activate(context, config);
     }

     /**
      * Deactivate this component.
      */
     @Deactivate
     protected void deactivate() {
         this.cache = null;

         // unregister mbean
         if ( this.mbeanRegistration != null ) {
             this.mbeanRegistration.unregister();
             this.mbeanRegistration = null;
         }

         // unregister event handler
         if (this.eventHandlerRegistration != null) {
             this.eventHandlerRegistration.unregister();
             this.eventHandlerRegistration = null;
         }

         // unregister event handler
         if (this.resourceListenerRegistration != null) {
             this.resourceListenerRegistration.unregister();
             this.resourceListenerRegistration = null;
         }
     }

     /**
      * Get the list of script engine extensions
      * @return The list of script engine extensions
      */
     public List<String> getScriptEngineExtensions() {
         return this.scriptEnginesExtensions;
     }

     private void updateScriptEngineExtensions() {
         final ScriptEngineManager localScriptEngineManager = scriptEngineManager;
         // use local variable to avoid racing with deactivate
         if ( localScriptEngineManager != null ) {
             final List<String> scriptEnginesExtensions = new ArrayList<>();
             for (ScriptEngineFactory factory : localScriptEngineManager.getEngineFactories()) {
                 scriptEnginesExtensions.addAll(factory.getExtensions());
             }
             this.scriptEnginesExtensions = Collections.unmodifiableList(scriptEnginesExtensions);
         }
     }

     /**
      * @see org.osgi.service.event.EventHandler#handleEvent(org.osgi.service.event.Event)
      */
     @Override
     public void handleEvent(final Event event) {
         // return immediately if already deactivated
         if ( this.eventHandlerRegistration == null ) {
             return;
         }
         flushCache();
         updateScriptEngineExtensions();
     }

     public void flushCache() {
         // use local variable to avoid racing with deactivate
         final Map<AbstractResourceCollector, Servlet> localCache = this.cache;
         if ( localCache != null ) {
             localCache.clear();
             this.logCacheSizeWarning = true;
         }
     }

     @Override
 	public void onChange(final List<ResourceChange> changes) {
         // return immediately if already deactivated
         if ( resourceListenerRegistration == null || changes.isEmpty() ) {
             return;
         }
         // we invalidate the cache once, regardless of the number of changes
         flushCache();
     }

     class ServletResolverCacheMBeanImpl extends StandardMBean implements SlingServletResolverCacheMBean {

         ServletResolverCacheMBeanImpl() throws NotCompliantMBeanException {
             super(SlingServletResolverCacheMBean.class);
         }

         @Override
         public int getCacheSize() {
             // use local variable to avoid racing with deactivate
             final Map<AbstractResourceCollector, Servlet> localCache = cache;
             return localCache != null ? localCache.size() : 0;
         }

         @Override
         public void flushCache() {
             ResolutionCache.this.flushCache();
         }

         @Override
         public int getMaximumCacheSize() {
             return cacheSize;
         }

     }

     public Servlet get(final AbstractResourceCollector context) {
         final Map<AbstractResourceCollector, Servlet> localCache = this.cache;
         if ( localCache != null ) {
             return localCache.get(context);
         }
         return null;
     }

     public void put(final AbstractResourceCollector context, final Servlet candidate) {
         final Map<AbstractResourceCollector, Servlet> localCache = this.cache;
         if ( localCache != null ) {
             if ( localCache.size() < this.cacheSize ) {
                 localCache.put(context, candidate);
             } else if ( this.logCacheSizeWarning ) {
                 this.logCacheSizeWarning = false;
                 logger.warn("Script cache has reached its limit of {}. You might want to increase the cache size for the servlet resolver.",
                     this.cacheSize);
             }
         }
     }
 }
	/*
	* 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.sling.servlets.resolver.internal.resolution;

	import java.util.ArrayList;
	import java.util.Collections;
	import java.util.Dictionary;
	import java.util.Hashtable;
	import java.util.List;
	import java.util.Map;
	import java.util.concurrent.ConcurrentHashMap;

	import javax.management.NotCompliantMBeanException;
	import javax.management.StandardMBean;
	import javax.script.ScriptEngineFactory;
	import javax.script.ScriptEngineManager;
	import javax.servlet.Servlet;

	import org.apache.sling.api.resource.LoginException;
	import org.apache.sling.api.resource.observation.ExternalResourceChangeListener;
	import org.apache.sling.api.resource.observation.ResourceChange;
	import org.apache.sling.api.resource.observation.ResourceChangeListener;
	import org.apache.sling.api.resource.path.Path;
	import org.apache.sling.servlets.resolver.internal.ResolverConfig;
	import org.apache.sling.servlets.resolver.internal.helper.AbstractResourceCollector;
	import org.apache.sling.servlets.resolver.jmx.SlingServletResolverCacheMBean;
	import org.osgi.framework.BundleContext;
	import org.osgi.framework.Constants;
	import org.osgi.framework.ServiceRegistration;
	import org.osgi.service.component.annotations.Activate;
	import org.osgi.service.component.annotations.Component;
	import org.osgi.service.component.annotations.Deactivate;
	import org.osgi.service.component.annotations.Modified;
	import org.osgi.service.component.annotations.Reference;
	import org.osgi.service.event.Event;
	import org.osgi.service.event.EventConstants;
	import org.osgi.service.event.EventHandler;
	import org.slf4j.Logger;
	import org.slf4j.LoggerFactory;

	/**
	* Cache for script resolution
	*
	*/
	@Component(configurationPid = ResolverConfig.PID,
	service = {ResolutionCache.class})
	public class ResolutionCache
	implements EventHandler, ResourceChangeListener, ExternalResourceChangeListener {

	private final Logger logger = LoggerFactory.getLogger(this.getClass());

	@Reference
	private ScriptEngineManager scriptEngineManager;

	private volatile List<String> scriptEnginesExtensions = Collections.emptyList();

	/** The script resolution cache. */
	private volatile Map<AbstractResourceCollector, Servlet> cache;

	/** The cache size. */
	private volatile int cacheSize;

	/** Flag to log warning if cache size exceed only once. */
	private volatile boolean logCacheSizeWarning;

	/** Registration as event handler. */
	private volatile ServiceRegistration<EventHandler> eventHandlerRegistration;

	private volatile ServiceRegistration<ResourceChangeListener> resourceListenerRegistration;

	private volatile ServiceRegistration<SlingServletResolverCacheMBean> mbeanRegistration;

	/**
	* Activate this component.
	*/
	@Activate
	protected void activate(final BundleContext context,
	final ResolverConfig config) throws LoginException {
	// create cache - if a cache size is configured
	this.cacheSize = config.servletresolver_cacheSize();
	if (this.cacheSize > 5) {
	this.cache = new ConcurrentHashMap<>(cacheSize);
	this.logCacheSizeWarning = true;

	// register MBean
	try {
	Dictionary<String, String> mbeanProps = new Hashtable<>();
	mbeanProps.put("jmx.objectname", "org.apache.sling:type=servletResolver,service=SlingServletResolverCache");

	ServletResolverCacheMBeanImpl mbean = new ServletResolverCacheMBeanImpl();
	mbeanRegistration = context.registerService(SlingServletResolverCacheMBean.class, mbean, mbeanProps);
	} catch (final Throwable t) {
	logger.warn("Unable to register servlets resolver cache MBean", t);
	}
	}

	// and finally register as event listener
	// to invalidate cache and script extensions
	final Dictionary<String, Object> props = new Hashtable<>();
	props.put(Constants.SERVICE_DESCRIPTION, "Apache Sling Servlet Resolver Event Handler");
	props.put(Constants.SERVICE_VENDOR,"The Apache Software Foundation");

	// the event listener is for updating the script engine extensions
	props.put(EventConstants.EVENT_TOPIC, new String[] {
	"javax/script/ScriptEngineFactory/*",
	"org/apache/sling/api/adapter/AdapterFactory/*",
	"org/apache/sling/scripting/core/BindingsValuesProvider/*" });

	this.eventHandlerRegistration = context.registerService(EventHandler.class, this, props);

	// we need a resource change listener to invalidate the cache
	if ( this.cache != null ) {
	final String[] listenerPaths = new String[config.servletresolver_paths().length];
	for(int i=0; i<config.servletresolver_paths().length; i++) {
	final Path p = new Path(config.servletresolver_paths()[i]);
	listenerPaths[i] = p.getPath();
	}

	final Dictionary<String, Object> listenerProps = new Hashtable<>();
	listenerProps.put(Constants.SERVICE_DESCRIPTION, "Apache Sling Servlet Resolver Resource Listener");
	listenerProps.put(Constants.SERVICE_VENDOR,"The Apache Software Foundation");
	listenerProps.put(ResourceChangeListener.PATHS, listenerPaths);
	this.resourceListenerRegistration = context.registerService(ResourceChangeListener.class, this, listenerProps);
	}

	updateScriptEngineExtensions();
	}

	@Modified
	protected void modified(final BundleContext context,
	final ResolverConfig config) throws LoginException {
	this.deactivate();
	this.activate(context, config);
	}

	/**
	* Deactivate this component.
	*/
	@Deactivate
	protected void deactivate() {
	this.cache = null;

	// unregister mbean
	if ( this.mbeanRegistration != null ) {
	this.mbeanRegistration.unregister();
	this.mbeanRegistration = null;
	}

	// unregister event handler
	if (this.eventHandlerRegistration != null) {
	this.eventHandlerRegistration.unregister();
	this.eventHandlerRegistration = null;
	}

	// unregister event handler
	if (this.resourceListenerRegistration != null) {
	this.resourceListenerRegistration.unregister();
	this.resourceListenerRegistration = null;
	}
	}

	/**
	* Get the list of script engine extensions
	* @return The list of script engine extensions
	*/
	public List<String> getScriptEngineExtensions() {
	return this.scriptEnginesExtensions;
	}

	private void updateScriptEngineExtensions() {
	final ScriptEngineManager localScriptEngineManager = scriptEngineManager;
	// use local variable to avoid racing with deactivate
	if ( localScriptEngineManager != null ) {
	final List<String> scriptEnginesExtensions = new ArrayList<>();
	for (ScriptEngineFactory factory : localScriptEngineManager.getEngineFactories()) {
	scriptEnginesExtensions.addAll(factory.getExtensions());
	}
	this.scriptEnginesExtensions = Collections.unmodifiableList(scriptEnginesExtensions);
	}
	}

	/**
	* @see org.osgi.service.event.EventHandler#handleEvent(org.osgi.service.event.Event)
	*/
	@Override
	public void handleEvent(final Event event) {
	// return immediately if already deactivated
	if ( this.eventHandlerRegistration == null ) {
	return;
	}
	flushCache();
	updateScriptEngineExtensions();
	}

	public void flushCache() {
	// use local variable to avoid racing with deactivate
	final Map<AbstractResourceCollector, Servlet> localCache = this.cache;
	if ( localCache != null ) {
	localCache.clear();
	this.logCacheSizeWarning = true;
	}
	}

	@Override
	public void onChange(final List<ResourceChange> changes) {
	// return immediately if already deactivated
	if ( resourceListenerRegistration == null \|\| changes.isEmpty() ) {
	return;
	}
	// we invalidate the cache once, regardless of the number of changes
	flushCache();
	}

	class ServletResolverCacheMBeanImpl extends StandardMBean implements SlingServletResolverCacheMBean {

	ServletResolverCacheMBeanImpl() throws NotCompliantMBeanException {
	super(SlingServletResolverCacheMBean.class);
	}

	@Override
	public int getCacheSize() {
	// use local variable to avoid racing with deactivate
	final Map<AbstractResourceCollector, Servlet> localCache = cache;
	return localCache != null ? localCache.size() : 0;
	}

	@Override
	public void flushCache() {
	ResolutionCache.this.flushCache();
	}

	@Override
	public int getMaximumCacheSize() {
	return cacheSize;
	}

	}

	public Servlet get(final AbstractResourceCollector context) {
	final Map<AbstractResourceCollector, Servlet> localCache = this.cache;
	if ( localCache != null ) {
	return localCache.get(context);
	}
	return null;
	}

	public void put(final AbstractResourceCollector context, final Servlet candidate) {
	final Map<AbstractResourceCollector, Servlet> localCache = this.cache;
	if ( localCache != null ) {
	if ( localCache.size() < this.cacheSize ) {
	localCache.put(context, candidate);
	} else if ( this.logCacheSizeWarning ) {
	this.logCacheSizeWarning = false;
	logger.warn("Script cache has reached its limit of {}. You might want to increase the cache size for the servlet resolver.",
	this.cacheSize);
	}
	}
	}
	}