Java tutorial
/* * JasperReports - Free Java Reporting Library. * Copyright (C) 2001 - 2019 TIBCO Software Inc. All rights reserved. * http://www.jaspersoft.com * * Unless you have purchased a commercial license agreement from Jaspersoft, * the following license terms apply: * * This program is part of JasperReports. * * JasperReports is free software: you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * JasperReports is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with JasperReports. If not, see <http://www.gnu.org/licenses/>. */ package net.sf.jasperreports.extensions; import java.net.URL; import java.util.ArrayList; import java.util.Collections; import java.util.HashMap; import java.util.IdentityHashMap; import java.util.Iterator; import java.util.LinkedHashMap; import java.util.List; import java.util.Map; import java.util.Map.Entry; import org.apache.commons.collections4.map.ReferenceMap; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import net.sf.jasperreports.annotations.properties.Property; import net.sf.jasperreports.annotations.properties.PropertyScope; import net.sf.jasperreports.engine.JRPropertiesMap; import net.sf.jasperreports.engine.JRPropertiesUtil; import net.sf.jasperreports.engine.JRPropertiesUtil.PropertySuffix; import net.sf.jasperreports.engine.util.ClassLoaderResource; import net.sf.jasperreports.engine.util.ClassUtils; import net.sf.jasperreports.engine.util.JRLoader; import net.sf.jasperreports.engine.util.ObjectUtils; import net.sf.jasperreports.properties.PropertyConstants; /** * The default {@link ExtensionsRegistry extension registry} implementation. * * <p> * The implementation builds an extension registry by scanning the context * classloader for resources named <code>jasperreports_extension.properties</code>. * * <p> * Each such resource is loaded as a properties file, and properties that start * with {@link #PROPERTY_REGISTRY_FACTORY_PREFIX net.sf.jasperreports.extension.registry.factory.} are identified. * * <p> * Each such property should have as value the name of a * {@link ExtensionsRegistryFactory} implementation. The registry factory class is * instantiated, and * {@link ExtensionsRegistryFactory#createRegistry(String, JRPropertiesMap)} * is called on it, using the propery suffix as registry ID and passing the * properties map. The registry factory can collect properties that apply to the * specific registry by using a property prefix obtain by appending the registry ID * to "{@link #PROPERTY_REGISTRY_PREFIX net.sf.jasperreports.extension.}". * * <p> * If instantiating an extension registry results in an exception, the registry * is skipped and an error message is logged. * * @author Lucian Chirita (lucianc@users.sourceforge.net) */ public class DefaultExtensionsRegistry implements ExtensionsRegistry { private final Log log = LogFactory.getLog(DefaultExtensionsRegistry.class); /** * The name of property file resources that are used to load JasperReports * extensions. */ public final static String EXTENSION_RESOURCE_NAME = "jasperreports_extension.properties"; /** * The property prefix of extension registry factories. */ @Property(name = "net.sf.jasperreports.extension.registry.factory.{arbitrary_name}", category = PropertyConstants.CATEGORY_EXTENSIONS, scopes = { PropertyScope.EXTENSION }, sinceVersion = PropertyConstants.VERSION_3_1_0) public final static String PROPERTY_REGISTRY_FACTORY_PREFIX = JRPropertiesUtil.PROPERTY_PREFIX + "extension.registry.factory."; /** * A prefix that can be used to provide registry-specific properties, * by appending the registry ID and a fixed property suffix to it. */ @Property(name = "net.sf.jasperreports.extension.{registry_id}.{property_suffix}", category = PropertyConstants.CATEGORY_EXTENSIONS, scopes = { PropertyScope.EXTENSION }, sinceVersion = PropertyConstants.VERSION_3_1_0) public static final String PROPERTY_REGISTRY_PREFIX = JRPropertiesUtil.PROPERTY_PREFIX + "extension."; private final ReferenceMap<Object, List<ExtensionsRegistry>> registrySetCache = new ReferenceMap<Object, List<ExtensionsRegistry>>( ReferenceMap.ReferenceStrength.WEAK, ReferenceMap.ReferenceStrength.HARD); private final ReferenceMap<ClassLoader, Map<URL, URLRegistries>> registryCache = new ReferenceMap<ClassLoader, Map<URL, URLRegistries>>( ReferenceMap.ReferenceStrength.WEAK, ReferenceMap.ReferenceStrength.HARD); @Override public <T> List<T> getExtensions(Class<T> extensionType) { List<ExtensionsRegistry> registries = getRegistries(); List<T> extensions = new ArrayList<T>(registries.size()); for (Iterator<ExtensionsRegistry> it = registries.iterator(); it.hasNext();) { ExtensionsRegistry registry = it.next(); List<T> registryExtensions = registry.getExtensions(extensionType); if (registryExtensions != null && !registryExtensions.isEmpty()) { extensions.addAll(registryExtensions); } } return extensions; } protected List<ExtensionsRegistry> getRegistries() { List<ExtensionsRegistry> registries; Object cacheKey = ExtensionsEnvironment.getExtensionsCacheKey(); synchronized (registrySetCache) { registries = registrySetCache.get(cacheKey); if (registries == null) { if (log.isDebugEnabled()) { log.debug("Loading registries for cache key " + cacheKey); } registries = loadRegistries(); registrySetCache.put(cacheKey, registries); } } return registries; } protected List<ExtensionsRegistry> loadRegistries() { //there is no identity linked hash map/set, using separate map and list IdentityHashMap<ExtensionsRegistry, Object> registrySet = new IdentityHashMap<>(); List<ExtensionsRegistry> allRegistries = new ArrayList<ExtensionsRegistry>(); List<ClassLoaderResource> extensionResources = loadExtensionPropertyResources(); for (ClassLoaderResource extensionResource : extensionResources) { ClassLoader classLoader = extensionResource.getClassLoader(); Map<URL, URLRegistries> classLoaderRegistries = getClassLoaderRegistries(classLoader); URL url = extensionResource.getUrl(); List<ExtensionsRegistry> registries; Map<String, Exception> registryExceptions = new LinkedHashMap<String, Exception>(); synchronized (classLoaderRegistries) { URLRegistries urlRegistries = classLoaderRegistries.get(url); if (urlRegistries == null) { if (log.isDebugEnabled()) { log.debug("Loading JasperReports extension properties resource " + url); } JRPropertiesMap properties = JRPropertiesMap.loadProperties(url); URL duplicateURL = detectDuplicate(properties, classLoaderRegistries);//search across classloaders? if (duplicateURL == null) { registries = loadRegistries(properties, registryExceptions); } else { log.warn("Extension resource " + url + " was found to be a duplicate of " + duplicateURL + " in classloader " + classLoader); registries = Collections.emptyList(); } classLoaderRegistries.put(url, new URLRegistries(properties, registries)); } else { registries = urlRegistries.registries; } } for (Map.Entry<String, Exception> entry : registryExceptions.entrySet()) { log.error("Error instantiating extensions registry for " + entry.getKey() + " from " + url, entry.getValue()); } for (ExtensionsRegistry extensionsRegistry : registries) { //detecting identity duplicates boolean added = registrySet.put(extensionsRegistry, Boolean.FALSE) == null; if (added) { allRegistries.add(extensionsRegistry); } else if (log.isDebugEnabled()) { log.debug("Found duplicate extension registry " + extensionsRegistry); } } } return allRegistries; } protected List<ClassLoaderResource> loadExtensionPropertyResources() { return JRLoader.getClassLoaderResources(EXTENSION_RESOURCE_NAME); } protected Map<URL, URLRegistries> getClassLoaderRegistries(ClassLoader classLoader) { synchronized (registryCache) { Map<URL, URLRegistries> registries = registryCache.get(classLoader); if (registries == null) { registries = new HashMap<URL, URLRegistries>(); registryCache.put(classLoader, registries); } return registries; } } protected List<ExtensionsRegistry> loadRegistries(JRPropertiesMap properties, Map<String, Exception> registryExceptions) { List<ExtensionsRegistry> registries = new ArrayList<ExtensionsRegistry>(); List<PropertySuffix> factoryProps = JRPropertiesUtil.getProperties(properties, PROPERTY_REGISTRY_FACTORY_PREFIX); for (Iterator<PropertySuffix> it = factoryProps.iterator(); it.hasNext();) { PropertySuffix factoryProp = it.next(); String registryId = factoryProp.getSuffix(); String factoryClass = factoryProp.getValue(); if (log.isDebugEnabled()) { log.debug( "Instantiating registry of type " + factoryClass + " for property " + factoryProp.getKey()); } try { ExtensionsRegistry registry = instantiateRegistry(properties, registryId, factoryClass); registries.add(registry); } catch (Exception e) { //skip this registry //error logging is deferred after the registries are cached to avoid a loop from JRRuntimeException.resolveMessage registryExceptions.put(registryId, e); } } return registries; } protected ExtensionsRegistry instantiateRegistry(JRPropertiesMap props, String registryId, String factoryClass) { if (log.isDebugEnabled()) { log.debug( "Instantiating extensions registry for " + registryId + " using factory class " + factoryClass); } ExtensionsRegistryFactory factory = (ExtensionsRegistryFactory) ClassUtils.instantiateClass(factoryClass, ExtensionsRegistryFactory.class); return factory.createRegistry(registryId, props); } protected URL detectDuplicate(JRPropertiesMap properties, Map<URL, URLRegistries> registries) { URL duplicateURL = null; for (Entry<URL, URLRegistries> registryEntry : registries.entrySet()) { JRPropertiesMap entryProperties = registryEntry.getValue().properties; if (ObjectUtils.equals(properties, entryProperties)) { duplicateURL = registryEntry.getKey(); break; } } return duplicateURL; } protected static class URLRegistries { JRPropertiesMap properties; List<ExtensionsRegistry> registries; public URLRegistries(JRPropertiesMap properties, List<ExtensionsRegistry> registries) { this.properties = properties; this.registries = registries; } } }