001/** 002 * 003 * Copyright 2018-2020 Florian Schmaus 004 * 005 * Licensed under the Apache License, Version 2.0 (the "License"); 006 * you may not use this file except in compliance with the License. 007 * You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.jivesoftware.smack.util; 018 019import java.util.ArrayList; 020import java.util.Collections; 021import java.util.List; 022import java.util.logging.Logger; 023 024import javax.xml.namespace.QName; 025 026import org.jivesoftware.smack.packet.ExtensionElement; 027import org.jivesoftware.smack.packet.FullyQualifiedElement; 028import org.jivesoftware.smack.packet.StandardExtensionElement; 029import org.jivesoftware.smack.provider.ProviderManager; 030 031import org.jxmpp.util.cache.LruCache; 032 033public class XmppElementUtil { 034 035 private static final LruCache<Class<? extends FullyQualifiedElement>, QName> CLASS_TO_QNAME_CACHE = new LruCache<>(512); 036 037 public static final Logger LOGGER = Logger.getLogger(XmppElementUtil.class.getName()); 038 039 public static QName getQNameFor(Class<? extends FullyQualifiedElement> fullyQualifiedElement) { 040 QName qname = CLASS_TO_QNAME_CACHE.get(fullyQualifiedElement); 041 if (qname != null) { 042 return qname; 043 } 044 045 try { 046 Object qnameObject = fullyQualifiedElement.getField("QNAME").get(null); 047 if (QName.class.isAssignableFrom(qnameObject.getClass())) { 048 qname = (QName) qnameObject; 049 CLASS_TO_QNAME_CACHE.put(fullyQualifiedElement, qname); 050 return qname; 051 } 052 LOGGER.warning("The QNAME field of " + fullyQualifiedElement + " is not of type QNAME."); 053 } catch (NoSuchFieldException e) { 054 LOGGER.finer("The " + fullyQualifiedElement + " has no static QNAME field. Consider adding one."); 055 // Proceed to fallback strategy. 056 } catch (IllegalArgumentException | IllegalAccessException | SecurityException e) { 057 throw new IllegalArgumentException(e); 058 } 059 060 String element, namespace; 061 try { 062 element = (String) fullyQualifiedElement.getField("ELEMENT").get(null); 063 namespace = (String) fullyQualifiedElement.getField("NAMESPACE").get(null); 064 } 065 catch (IllegalArgumentException | IllegalAccessException | NoSuchFieldException | SecurityException e) { 066 throw new IllegalArgumentException("The " + fullyQualifiedElement + " has no ELEMENT, NAMESPACE or QNAME member. Consider adding QNAME", e); 067 } 068 069 qname = new QName(namespace, element); 070 CLASS_TO_QNAME_CACHE.put(fullyQualifiedElement, qname); 071 return qname; 072 } 073 074 public static <E extends ExtensionElement> List<E> getElementsFrom( 075 MultiMap<QName, ExtensionElement> elementMap, Class<E> extensionElementClass) { 076 QName qname = XmppElementUtil.getQNameFor(extensionElementClass); 077 078 List<ExtensionElement> extensionElements = elementMap.getAll(qname); 079 080 if (extensionElements.isEmpty()) { 081 return Collections.emptyList(); 082 } 083 084 List<E> res = new ArrayList<>(extensionElements.size()); 085 for (ExtensionElement extensionElement : extensionElements) { 086 E e = castOrThrow(extensionElement, extensionElementClass); 087 res.add(e); 088 } 089 return res; 090 } 091 092 public static <E extends ExtensionElement> E castOrThrow(ExtensionElement extensionElement, Class<E> extensionElementClass) { 093 if (!extensionElementClass.isInstance(extensionElement)) { 094 final QName qname = getQNameFor(extensionElementClass); 095 096 final String detailMessage; 097 if (extensionElement instanceof StandardExtensionElement) { 098 detailMessage = "because there is no according extension element provider registered with ProviderManager for " 099 + qname 100 + ". WARNING: This indicates a serious problem with your Smack setup, probably causing Smack not being able to properly initialize itself."; 101 } else { 102 Object provider = ProviderManager.getExtensionProvider(qname); 103 detailMessage = "because there is an inconsistency with the provider registered with ProviderManager: the active provider for " 104 + qname + " '" + provider.getClass() 105 + "' does not return instances of type " + extensionElementClass 106 + ", but instead returns instances of type " + extensionElement.getClass() + "."; 107 } 108 109 String message = "Extension element is not of expected class '" + extensionElementClass.getName() + "', " 110 + detailMessage; 111 throw new IllegalStateException(message); 112 } 113 114 return extensionElementClass.cast(extensionElement); 115 } 116 117}