[core] Add XmppElementUtil.castOrThrow(ExtensionElement, Class)

This method throws an IllegalStateException if the provided extension
element is not of the expected type and hints users towards potential
causes.
listEqualsHashcode
Florian Schmaus 2 years ago
parent 99297e5a76
commit d06e9499e8
  1. 41
      smack-core/src/main/java/org/jivesoftware/smack/util/XmppElementUtil.java

@ -23,7 +23,10 @@ import java.util.logging.Logger;
import javax.xml.namespace.QName;
import org.jivesoftware.smack.packet.ExtensionElement;
import org.jivesoftware.smack.packet.FullyQualifiedElement;
import org.jivesoftware.smack.packet.StandardExtensionElement;
import org.jivesoftware.smack.provider.ProviderManager;
import org.jxmpp.util.cache.LruCache;
@ -68,21 +71,47 @@ public class XmppElementUtil {
return qname;
}
public static <E extends FullyQualifiedElement, R extends FullyQualifiedElement> List<R> getElementsFrom(
MultiMap<QName, E> elementMap, Class<R> extensionElementClass) {
public static <E extends ExtensionElement> List<E> getElementsFrom(
MultiMap<QName, ExtensionElement> elementMap, Class<E> extensionElementClass) {
QName qname = XmppElementUtil.getQNameFor(extensionElementClass);
List<E> extensionElements = elementMap.getAll(qname);
List<ExtensionElement> extensionElements = elementMap.getAll(qname);
if (extensionElements.isEmpty()) {
return Collections.emptyList();
}
List<R> res = new ArrayList<>(extensionElements.size());
for (E extensionElement : extensionElements) {
R e = extensionElementClass.cast(extensionElement);
List<E> res = new ArrayList<>(extensionElements.size());
for (ExtensionElement extensionElement : extensionElements) {
E e = castOrThrow(extensionElement, extensionElementClass);
res.add(e);
}
return res;
}
public static <E extends ExtensionElement> E castOrThrow(ExtensionElement extensionElement, Class<E> extensionElementClass) {
if (!extensionElementClass.isInstance(extensionElement)) {
final QName qname = getQNameFor(extensionElementClass);
final String detailMessage;
if (extensionElement instanceof StandardExtensionElement) {
detailMessage = "because there is no according extension element provider registered with ProviderManager for "
+ qname
+ ". WARNING: This indicates a serious problem with your Smack setup, probably causing Smack not being able to properly initialize itself.";
} else {
Object provider = ProviderManager.getExtensionProvider(qname);
detailMessage = "because there is an inconsistency with the provider registered with ProviderManager: the active provider for "
+ qname + " '" + provider.getClass()
+ "' does not return instances of type " + extensionElementClass
+ ", but instead returns instances of type " + extensionElement.getClass() + ".";
}
String message = "Extension element is not of expected class '" + extensionElementClass.getName() + "', "
+ detailMessage;
throw new IllegalStateException(message);
}
return extensionElementClass.cast(extensionElement);
}
}

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