Java tutorial
/* * #%L * ACS AEM Commons Bundle * %% * Copyright (C) 2014 Adobe * %% * 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. * #L% */ package com.adobe.acs.commons.errorpagehandler.cache.impl; import com.adobe.acs.commons.util.ResourceDataUtil; import com.adobe.granite.jmx.annotation.AnnotatedStandardMBean; import org.apache.commons.lang.StringUtils; import org.apache.sling.api.SlingHttpServletRequest; import org.apache.sling.api.SlingHttpServletResponse; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import javax.management.NotCompliantMBeanException; import javax.management.openmbean.CompositeDataSupport; import javax.management.openmbean.CompositeType; import javax.management.openmbean.OpenDataException; import javax.management.openmbean.OpenType; import javax.management.openmbean.SimpleType; import javax.management.openmbean.TabularData; import javax.management.openmbean.TabularDataSupport; import javax.management.openmbean.TabularType; import java.util.Date; import java.util.HashMap; import java.util.Map; import java.util.concurrent.ConcurrentHashMap; import java.util.concurrent.ConcurrentMap; public final class ErrorPageCacheImpl extends AnnotatedStandardMBean implements ErrorPageCache, ErrorPageCacheMBean { private static final Logger log = LoggerFactory.getLogger(ErrorPageCacheImpl.class); private static final int KB_IN_BYTES = 1000; private final ConcurrentMap<String, CacheEntry> cache = new ConcurrentHashMap<String, CacheEntry>(); private final int ttl; private final boolean serveAuthenticatedFromCache; public ErrorPageCacheImpl(int ttl, boolean serveAuthenticatedFromCache) throws NotCompliantMBeanException { super(ErrorPageCacheMBean.class); this.ttl = ttl; this.serveAuthenticatedFromCache = serveAuthenticatedFromCache; log.info("Starting ACS AEM Commons Error Page Handler Cache"); log.info(" > TTL (in seconds): {}", ttl); log.info(" > Serve authenticated requests from cache: {}", serveAuthenticatedFromCache); } @Override public String get(final String path, final SlingHttpServletRequest request, final SlingHttpServletResponse response) { if (!serveAuthenticatedFromCache && !isAnonymousRequest(request)) { // For authenticated requests, don't return from cache return ResourceDataUtil.getIncludeAsString(path, request, response); } final long start = System.currentTimeMillis(); CacheEntry cacheEntry = cache.get(path); final boolean newEntry = cacheEntry == null; if (newEntry || cacheEntry.isExpired(new Date())) { // Cache Miss String data = ResourceDataUtil.getIncludeAsString(path, request, response); if (data == null) { log.debug("Error page representation to cache is null. Setting to empty string."); data = ""; } if (newEntry) { cacheEntry = new CacheEntry(); } cacheEntry.setData(data); cacheEntry.setExpiresIn(ttl); cacheEntry.incrementMisses(); if (newEntry) { // Add entry to cache cache.put(path, cacheEntry); } if (log.isDebugEnabled()) { final long time = System.currentTimeMillis() - start; log.debug("Served cache MISS for [ {} ] in [ {} ] ms", path, time); } return data; } else { // Cache Hit final String data = cacheEntry.getData(); cacheEntry.incrementHits(); cache.put(path, cacheEntry); if (log.isDebugEnabled()) { final long time = System.currentTimeMillis() - start; log.debug("Served cache HIT for [ {} ] in [ {} ] ms", path, time); } return data; } } private boolean isAnonymousRequest(final SlingHttpServletRequest request) { return (request.getAuthType() == null || request.getRemoteUser() == null); } /* MBean Attributes */ @Override public final int getTtlInSeconds() { return ttl; } @Override public final int getTotalHits() { int hits = 0; for (final CacheEntry entry : this.cache.values()) { hits = hits + entry.getHits(); } return hits; } @Override public final int getCacheEntriesCount() { return this.cache.size(); } @Override public final int getTotalMisses() { int misses = 0; for (final Map.Entry<String, CacheEntry> entry : this.cache.entrySet()) { misses = misses + entry.getValue().getMisses(); } return misses; } @Override public final int getTotalCacheRequests() { return this.getTotalHits() + this.getTotalMisses(); } @Override public final long getCacheSizeInKB() { long bytes = 0; for (final CacheEntry entry : this.cache.values()) { bytes = bytes + entry.getBytes(); } return bytes / KB_IN_BYTES; } @SuppressWarnings("squid:S1192") public final TabularData getCacheEntries() throws OpenDataException { final CompositeType cacheEntryType = new CompositeType("cacheEntry", "Cache Entry", new String[] { "errorPage", "hit", "miss", "hitRate", "missRate", "sizeInKB" }, new String[] { "Error Page", "Hit", "Miss", "Hit Rate", "Miss Rate", "Size in KB" }, new OpenType[] { SimpleType.STRING, SimpleType.INTEGER, SimpleType.INTEGER, SimpleType.FLOAT, SimpleType.FLOAT, SimpleType.INTEGER }); final TabularDataSupport tabularData = new TabularDataSupport( new TabularType("cacheEntries", "Cache Entries", cacheEntryType, new String[] { "errorPage" })); for (final Map.Entry<String, CacheEntry> entry : this.cache.entrySet()) { final CacheEntry cacheEntry = entry.getValue(); final Map<String, Object> data = new HashMap<String, Object>(); data.put("errorPage", entry.getKey()); data.put("hit", cacheEntry.getHits()); data.put("miss", cacheEntry.getMisses()); data.put("hitRate", cacheEntry.getHitRate()); data.put("missRate", cacheEntry.getMissRate()); data.put("sizeInKB", cacheEntry.getBytes() / KB_IN_BYTES); tabularData.put(new CompositeDataSupport(cacheEntryType, data)); } return tabularData; } /* MBean Operations */ @Override public final void clearCache() { this.cache.clear(); } @Override public final String getCacheData(final String errorPage) { final CacheEntry cacheEntry = this.cache.get(StringUtils.trim(errorPage)); if (cacheEntry == null) { return ""; } return cacheEntry.getData(); } }