Make resolver-dnsjava, -minidns initializer

and OSGi components.

There is really no need to treat them different then
resolver-javax. This also allows the removal of the DNSUtil.init() method.

build.gradle

@@ -238,7 +238,7 @@ subprojects {
 	}
 }
 
-['smack-resolver-javax', 'smack-sasl-javax', 'smack-sasl-provided'].each { name ->
+['smack-resolver-javax', 'smack-resolver-dnsjava', 'smack-resolver-minidns', 'smack-sasl-javax', 'smack-sasl-provided'].each { name ->
 	project(":$name") {
 		jar {
 			manifest {

smack-core/src/main/java/org/jivesoftware/smack/SmackConfiguration.java

@@ -38,7 +38,6 @@ import org.jivesoftware.smack.compression.XMPPInputOutputStream;
 import org.jivesoftware.smack.initializer.SmackInitializer;
 import org.jivesoftware.smack.parsing.ExceptionThrowingCallback;
 import org.jivesoftware.smack.parsing.ParsingExceptionCallback;
-import org.jivesoftware.smack.util.DNSUtil;
 import org.jivesoftware.smack.util.FileUtils;
 import org.xmlpull.v1.XmlPullParserFactory;
 import org.xmlpull.v1.XmlPullParser;
@@ -169,9 +168,6 @@ public final class SmackConfiguration {
         catch (Exception e) {
             // Ignore.
         }
-
-        // Initialize the DNS resolvers
-        DNSUtil.init();
     }
 
     /**

smack-core/src/main/java/org/jivesoftware/smack/initializer/SmackAndOsgiInitializer.java

@@ -16,6 +16,8 @@
  */
 package org.jivesoftware.smack.initializer;
 
+import java.util.List;
+
 public abstract class SmackAndOsgiInitializer implements SmackInitializer {
 
     /**
@@ -25,4 +27,10 @@ public abstract class SmackAndOsgiInitializer implements SmackInitializer {
     public final void activate() {
         initialize();
     }
+
+    @Override
+    public List<Exception> initialize(ClassLoader classLoader) {
+        return initialize();
+    }
+
 }

smack-core/src/main/java/org/jivesoftware/smack/util/DNSUtil.java

@@ -16,8 +16,6 @@
  */
 package org.jivesoftware.smack.util;
 
-import java.lang.reflect.InvocationTargetException;
-import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.LinkedList;
@@ -41,31 +39,6 @@ public class DNSUtil {
     private static final Logger LOGGER = Logger.getLogger(DNSUtil.class.getName());
     private static DNSResolver dnsResolver = null;
 
-    /**
-     * Initializes DNSUtil. This method is automatically called by SmackConfiguration, you don't
-     * have to call it manually.
-     */
-    public static void init() {
-        final String[] RESOLVERS = new String[] { "javax.JavaxResolver", "minidns.MiniDnsResolver",
-                        "dnsjava.DNSJavaResolver" };
-        for (String resolver :RESOLVERS) {
-            DNSResolver availableResolver = null;
-            String resolverFull = "org.jivesoftware.smack.util.dns" + resolver;
-            try {
-                Class<?> resolverClass = Class.forName(resolverFull);
-                Method getInstanceMethod = resolverClass.getMethod("getInstance");
-                availableResolver = (DNSResolver) getInstanceMethod.invoke(null);
-                if (availableResolver != null) {
-                    setDNSResolver(availableResolver);
-                    break;
-                }
-            }
-            catch (ClassNotFoundException|NoSuchMethodException|SecurityException|IllegalAccessException|IllegalArgumentException|InvocationTargetException e) {
-                LOGGER.log(Level.FINE, "Exception on init", e);
-            }
-        }
-    }
-
     /**
      * Set the DNS resolver that should be used to perform DNS lookups.
      *

smack-core/src/main/resources/org.jivesoftware.smack/smack-config.xml

@@ -9,6 +9,8 @@
 
     <optionalStartupClasses>
         <className>org.jivesoftware.smack.util.dns.javax.JavaxResolver</className>
+        <className>org.jivesoftware.smack.util.dns.minidns.MiniDnsResolver</className>
+        <className>org.jivesoftware.smack.util.dns.dnsjava.DNSJavaResolver</className>
         <className>org.jivesoftware.smack.initializer.extensions.ExtensionsInitializer</className>
         <className>org.jivesoftware.smack.initializer.experimental.ExperimentalInitializer</className>
         <className>org.jivesoftware.smack.initializer.legacy.LegacyInitializer</className>

smack-resolver-dnsjava/src/main/java/org/jivesoftware/smack/util/dns/dnsjava/DNSJavaResolver.java

@@ -19,6 +19,8 @@ package org.jivesoftware.smack.util.dns.dnsjava;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.jivesoftware.smack.initializer.SmackAndOsgiInitializer;
+import org.jivesoftware.smack.util.DNSUtil;
 import org.jivesoftware.smack.util.dns.DNSResolver;
 import org.jivesoftware.smack.util.dns.SRVRecord;
 import org.xbill.DNS.Lookup;
@@ -30,13 +32,10 @@ import org.xbill.DNS.Type;
  * This implementation uses the <a href="http://www.dnsjava.org/">dnsjava</a> implementation for resolving DNS addresses.
  *
  */
-public class DNSJavaResolver implements DNSResolver {
+public class DNSJavaResolver extends SmackAndOsgiInitializer implements DNSResolver {
     
     private static DNSJavaResolver instance = new DNSJavaResolver();
-    
+
-    private DNSJavaResolver() {
-    }
-    
     public static DNSResolver getInstance() {
         return instance;
     }
@@ -65,4 +64,15 @@ public class DNSJavaResolver implements DNSResolver {
 
         return res;
     }
+
+    public static void setup() {
+        DNSUtil.setDNSResolver(getInstance());
+    }
+
+    @Override
+    public List<Exception> initialize() {
+        setup();
+        return null;
+    }
+
 }

smack-resolver-dnsjava/src/main/resources/org.jivesoftware.smack/smack-resolver-dnsjava-components.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<scr:component xmlns:scr="http://www.osgi.org/xmlns/scr/v1.2.0"
+	enabled="true" immediate="true" name="Smack Resolver JavaX API">
+	<implementation
+		class="org.jivesoftware.smack.util.dns.dnsjava.DNSJavaResolver" />
+</scr:component>

smack-resolver-javax/src/main/java/org/jivesoftware/smack/util/dns/javax/JavaxResolver.java

@@ -17,7 +17,6 @@
 package org.jivesoftware.smack.util.dns.javax;
 
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.Hashtable;
 import java.util.List;
 
@@ -56,10 +55,6 @@ public class JavaxResolver extends SmackAndOsgiInitializer implements DNSResolve
         // Try to set this DNS resolver as primary one
         setup();
     }
-    
-    public JavaxResolver() {
-        
-    }
 
     public static synchronized DNSResolver getInstance() {
         if (instance == null && isSupported()) {
@@ -102,12 +97,8 @@ public class JavaxResolver extends SmackAndOsgiInitializer implements DNSResolve
 
     @Override
     public List<Exception> initialize() {
-        return initialize(null);
+        setup();
+        return null;
     }
 
-    @Override
-    public List<Exception> initialize(ClassLoader classLoader) {
-        setup();
-        return Collections.emptyList();
-    }
 }

smack-resolver-minidns/src/main/java/org/jivesoftware/smack/util/dns/minidns/MiniDnsResolver.java

@@ -19,6 +19,8 @@ package org.jivesoftware.smack.util.dns.minidns;
 import java.util.LinkedList;
 import java.util.List;
 
+import org.jivesoftware.smack.initializer.SmackAndOsgiInitializer;
+import org.jivesoftware.smack.util.DNSUtil;
 import org.jivesoftware.smack.util.dns.DNSResolver;
 import org.jivesoftware.smack.util.dns.SRVRecord;
 import org.jxmpp.util.cache.ExpirationCache;
@@ -37,14 +39,14 @@ import de.measite.minidns.record.SRV;
  * This implementation uses the <a href="https://github.com/rtreffer/minidns/">minidns</a> implementation for
  * resolving DNS addresses.
  */
-public class MiniDnsResolver implements DNSResolver {
+public class MiniDnsResolver extends SmackAndOsgiInitializer implements DNSResolver {
 
     private static final long ONE_DAY = 24*60*60*1000;
     private static final MiniDnsResolver instance = new MiniDnsResolver();
     private static final ExpirationCache<Question, DNSMessage> cache = new ExpirationCache<Question, DNSMessage>(10, ONE_DAY);
     private final Client client; 
 
-    private MiniDnsResolver() {
+    public MiniDnsResolver() {
         client = new Client(new DNSCache() {
 
             @Override
@@ -81,4 +83,15 @@ public class MiniDnsResolver implements DNSResolver {
         }
         return res;
     }
+
+    public static void setup() {
+        DNSUtil.setDNSResolver(getInstance());
+    }
+
+    @Override
+    public List<Exception> initialize() {
+        setup();
+        return null;
+    }
+
 }

smack-resolver-minidns/src/main/resources/org.jivesoftware.smack/smack-resolver-minidns-components.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<scr:component xmlns:scr="http://www.osgi.org/xmlns/scr/v1.2.0"
+	enabled="true" immediate="true" name="Smack Resolver JavaX API">
+	<implementation
+		class="org.jivesoftware.smack.util.dns.minidns.MiniDnsResolver" />
+</scr:component>