Merge branch '4.2'

smack-im/src/main/java/org/jivesoftware/smack/roster/Roster.java

@@ -251,9 +251,10 @@ public final class Roster extends Manager {
         connection.addSyncStanzaListener(presencePacketListener, PRESENCE_PACKET_FILTER);
 
         connection.addAsyncStanzaListener(new StanzaListener() {
+            @SuppressWarnings("fallthrough")
             @Override
             public void processStanza(Stanza stanza) throws NotConnectedException,
-                            InterruptedException {
+                            InterruptedException, NotLoggedInException {
                 Presence presence = (Presence) stanza;
                 Jid from = presence.getFrom();
                 SubscribeAnswer subscribeAnswer = null;
@@ -279,13 +280,26 @@ public final class Roster extends Manager {
                     break;
                 }
 
+                if (subscribeAnswer == null) {
+                    return;
+                }
+
                 Presence response;
-                if (subscribeAnswer == SubscribeAnswer.Approve) {
+                switch (subscribeAnswer) {
+                case ApproveAndAlsoRequestIfRequired:
+                    BareJid bareFrom = from.asBareJid();
+                    RosterUtil.askForSubscriptionIfRequired(Roster.this, bareFrom);
+                    // The fall through is intended.
+                case Approve:
                     response = new Presence(Presence.Type.subscribed);
-                }
-                else {
+                    break;
+                case Deny:
                     response = new Presence(Presence.Type.unsubscribed);
+                    break;
+                default:
+                    throw new AssertionError();
                 }
+
                 response.setTo(presence.getFrom());
                 connection.sendStanza(response);
             }

smack-im/src/main/java/org/jivesoftware/smack/roster/RosterUtil.java

@@ -23,6 +23,7 @@ import java.util.concurrent.locks.Condition;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
 
+import org.jivesoftware.smack.SmackException.FeatureNotSupportedException;
 import org.jivesoftware.smack.SmackException.NotConnectedException;
 import org.jivesoftware.smack.SmackException.NotLoggedInException;
 import org.jivesoftware.smack.XMPPConnection;
@@ -86,6 +87,33 @@ public class RosterUtil {
         }
     }
 
+    /**
+     * Pre-approve the subscription if it is required and possible.
+     *
+     * @param roster The roster which should be used for the pre-approval.
+     * @param jid The XMPP address which should be pre-approved.
+     * @throws NotLoggedInException
+     * @throws NotConnectedException
+     * @throws InterruptedException
+     * @since 4.2.2
+     */
+    public static void preApproveSubscriptionIfRequiredAndPossible(Roster roster, BareJid jid)
+            throws NotLoggedInException, NotConnectedException, InterruptedException {
+        if (!roster.isSubscriptionPreApprovalSupported()) {
+            return;
+        }
+
+        RosterEntry entry = roster.getEntry(jid);
+        if (entry == null || (!entry.canSeeMyPresence() && !entry.isApproved())) {
+            try {
+                roster.preApprove(jid);
+            } catch (FeatureNotSupportedException e) {
+                // Should never happen since we checked for the feature above.
+                throw new AssertionError(e);
+            }
+        }
+    }
+
     public static void askForSubscriptionIfRequired(Roster roster, BareJid jid)
             throws NotLoggedInException, NotConnectedException, InterruptedException {
         RosterEntry entry = roster.getEntry(jid);

smack-im/src/main/java/org/jivesoftware/smack/roster/SubscribeListener.java

@@ -1,6 +1,6 @@
 /**
  *
- * Copyright 2015 Florian Schmaus
+ * Copyright 2015-2017 Florian Schmaus
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,13 +23,29 @@ import org.jxmpp.jid.Jid;
 
 
 /**
- * Handle incoming requests to subscribe to our presence.
+ * Handle incoming requests to subscribe to our presence. The
+ * {@link #processSubscribe(Jid, Presence)} method may return a subscribe
+ * answer. If no subscribe answer is returned, the next listener will be
+ * notified and asked. If no listener returns an answer, then nothing happens.
  *
  */
 public interface SubscribeListener {
 
     public enum SubscribeAnswer {
+        /**
+         * Approve the subscription request.
+         */
         Approve,
+
+        /**
+         * Approve the subscription request and also request subscription from the other party if not already subscribed.
+         * @since 4.2.2
+         */
+        ApproveAndAlsoRequestIfRequired,
+
+        /**
+         * Deny the subscription request.
+         */
         Deny,
     }