com.sun.faces.application.resource.ResourceCache Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of jakarta.faces Show documentation
EE4J Compatible Implementation for Jakarta Faces API
There is a newer version: 4.1.2
/*
 * Copyright (c) 1997, 2020 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package com.sun.faces.application.resource;

import static com.sun.faces.util.Util.notNull;
import static java.util.logging.Level.FINE;

import java.util.ArrayList;
import java.util.List;
import java.util.logging.Logger;

import com.sun.faces.config.WebConfiguration;
import com.sun.faces.config.WebConfiguration.WebContextInitParameter;
import com.sun.faces.util.FacesLogger;
import com.sun.faces.util.MultiKeyConcurrentHashMap;

import jakarta.servlet.ServletContext;

/**
 * 
 * This is the caching mechanism for caching ResourceInfo instances to offset the cost of looking up the resource.
 * 
 *
 * 
 * This cache uses a background thread to check for modifications to the underlying webapp or JAR files containing
 * resources. This check is periodic, configurable via context init param
 * com.sun.faces.resourceUpdateCheckPeriod. Through this config option, the cache can also be made static
 * or completely disabled. If the value of of this option is 0, then no check will be made making the cache
 * static. If value of this option is less than 0, then no caching will be perfomed. Otherwise, the value
 * of the option will be the number of minutes between modification checks.
 * 
 */
public class ResourceCache {

    private static final Logger LOGGER = FacesLogger.RESOURCE.getLogger();

    /**
     * The ResourceInfo cache.
     */
    private MultiKeyConcurrentHashMap resourceCache;

    /**
     * Resource check period in minutes.
     */
    private long checkPeriod;

    // ------------------------------------------------------------ Constructors

    /**
     * Constructs a new ResourceCache.
     */
    public ResourceCache() {
        this(WebConfiguration.getInstance());
    }

    private ResourceCache(WebConfiguration config) {
        this(getCheckPeriod(config));

        if (LOGGER.isLoggable(FINE)) {
            ServletContext sc = config.getServletContext();
            LOGGER.log(FINE, "ResourceCache constructed for {0}.  Check period is {1} minutes.",
                    new Object[] { getServletContextIdentifier(sc), checkPeriod });
        }
    }

    // this one is for unit tests
    ResourceCache(long period) {
        checkPeriod = period != -1 ? period * 1000L * 60L : -1;
        resourceCache = new MultiKeyConcurrentHashMap<>(30);
    }

    // ---------------------------------------------------------- Public Methods

    /**
     * Add the {@link ResourceInfo} to the internal cache.
     *
     * @param info resource metadata
     *
     * @param contracts the contracts
     * @return previous value associated with specified key, or null if there was no mapping for key
     */
    public ResourceInfo add(ResourceInfo info, List contracts) {
        notNull("info", info);

        if (LOGGER.isLoggable(FINE)) {
            LOGGER.log(FINE, "Caching ResourceInfo: {0}", info.toString());
        }
        ResourceInfoCheckPeriodProxy proxy = resourceCache.putIfAbsent(info.name, info.libraryName, info.localePrefix, new ArrayList(contracts),
                new ResourceInfoCheckPeriodProxy(info, checkPeriod));
        return proxy != null ? proxy.getResourceInfo() : null;

    }

    /**
     * @param name the resource name
     * @param libraryName the library name
     * @param localePrefix the locale prefix
     * @param contracts the contracts
     * @return the {@link ResourceInfo} associated with key if any.
     */
    public ResourceInfo get(String name, String libraryName, String localePrefix, List contracts) {
        notNull("name", name);

        ResourceInfoCheckPeriodProxy proxy = resourceCache.get(name, libraryName, localePrefix, contracts);
        if (proxy != null && proxy.needsRefreshed()) {
            resourceCache.remove(name, libraryName, localePrefix, contracts);
            return null;
        }
        
        return proxy != null ? proxy.getResourceInfo() : null;
    }

    /**
     * 
     * Empty the cache.
     * 
     */
    public void clear() {
        resourceCache.clear();
        LOGGER.log(FINE, "Cache Cleared");
    }

    // --------------------------------------------------------- Private Methods

    private static Long getCheckPeriod(WebConfiguration webConfig) {
        String val = webConfig.getOptionValue(WebContextInitParameter.ResourceUpdateCheckPeriod);
        try {
            return Long.parseLong(val);
        } catch (NumberFormatException nfe) {
            return Long.parseLong(WebContextInitParameter.ResourceUpdateCheckPeriod.getDefaultValue());
        }
    }

    private static String getServletContextIdentifier(ServletContext context) {
        return context.getContextPath();
    }

    // ---------------------------------------------------------- Nested Classes

    private static final class ResourceInfoCheckPeriodProxy {

        private final ResourceInfo resourceInfo;
        private Long checkTime;

        // -------------------------------------------------------- Constructors

        public ResourceInfoCheckPeriodProxy(ResourceInfo resourceInfo, long checkPeriod) {

            this.resourceInfo = resourceInfo;
            if (checkPeriod != -1L && !(resourceInfo.getHelper() instanceof ClasspathResourceHelper)) {
                checkTime = System.currentTimeMillis() + checkPeriod;
            }
        }

        private boolean needsRefreshed() {
            return checkTime != null && checkTime < System.currentTimeMillis();
        }

        private ResourceInfo getResourceInfo() {
            return resourceInfo;
        }

    } // END ResourceInfoCheckPeriodProxy

}