Add support for forum channels

src/main/java/net/dv8tion/jda/api/requests/restaction/AbstractThreadCreateAction.java

@@ -21,7 +21,6 @@
 import net.dv8tion.jda.api.entities.channel.ChannelType;
 import net.dv8tion.jda.api.entities.channel.concrete.ThreadChannel;
 import net.dv8tion.jda.api.entities.channel.middleman.GuildChannel;
-import net.dv8tion.jda.api.requests.FluentRestAction;
 import net.dv8tion.jda.api.requests.RestAction;
 
 import javax.annotation.CheckReturnValue;
@@ -36,7 +35,7 @@
  * @param <R>
  *        The common return type of setters, allowing for fluid interface design
  */
-public interface AbstractThreadCreateAction<T, R extends AbstractThreadCreateAction<T, R>> extends FluentRestAction<T, R>
+public interface AbstractThreadCreateAction<T, R extends AbstractThreadCreateAction<T, R>> extends RestAction<T>
 {
     /**
      * The guild to create this {@link GuildChannel} for.

src/main/java/net/dv8tion/jda/api/requests/restaction/AuditableRestAction.java

@@ -80,12 +80,18 @@ public interface AuditableRestAction<T> extends RestAction<T>
      */
     @Nonnull
     @Override
-    AuditableRestAction<T> timeout(long timeout, @Nonnull TimeUnit unit);
+    default AuditableRestAction<T> timeout(long timeout, @Nonnull TimeUnit unit)
+    {
+        return (AuditableRestAction<T>) RestAction.super.timeout(timeout, unit);
+    }
 
     /**
      * {@inheritDoc}
      */
     @Nonnull
     @Override
-    AuditableRestAction<T> deadline(long timestamp);
+    default AuditableRestAction<T> deadline(long timestamp)
+    {
+        return (AuditableRestAction<T>) RestAction.super.deadline(timestamp);
+    }
 }

src/main/java/net/dv8tion/jda/api/requests/restaction/FluentAuditableRestAction.java

@@ -0,0 +1,64 @@
+/*
+ * Copyright 2015 Austin Keener, Michael Ritter, Florian Spieß, and the JDA contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.dv8tion.jda.api.requests.restaction;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import java.util.concurrent.TimeUnit;
+import java.util.function.BooleanSupplier;
+
+/**
+ * Interface used to mixin the customization parameters for {@link AuditableRestAction AuditableRestActions}.
+ * <br>This simply fixes the return types to be the concrete implementation instead of the base interface.
+ *
+ * @param <T>
+ *        The result type of the AuditableRestAction
+ * @param <R>
+ *        The concrete AuditableRestAction type used for chaining (fluent interface)
+ */
+@SuppressWarnings("unchecked")
+public interface FluentAuditableRestAction<T, R extends FluentAuditableRestAction<T, R>> extends AuditableRestAction<T>
+{
+    @Nonnull
+    @Override
+    R reason(@Nullable String reason);
+
+    @Nonnull
+    @Override
+    R setCheck(@Nullable BooleanSupplier checks);
+
+    @Nonnull
+    @Override
+    default R addCheck(@Nonnull BooleanSupplier checks)
+    {
+        return (R) AuditableRestAction.super.addCheck(checks);
+    }
+
+    @Nonnull
+    @Override
+    default R timeout(long timeout, @Nonnull TimeUnit unit)
+    {
+        return (R) AuditableRestAction.super.timeout(timeout, unit);
+    }
+
+    @Nonnull
+    @Override
+    default R deadline(long timestamp)
+    {
+        return (R) AuditableRestAction.super.deadline(timestamp);
+    }
+}

src/main/java/net/dv8tion/jda/api/requests/restaction/ForumPostAction.java

@@ -19,6 +19,7 @@
 import net.dv8tion.jda.api.entities.channel.concrete.ForumChannel;
 import net.dv8tion.jda.api.entities.channel.forums.ForumPost;
 import net.dv8tion.jda.api.entities.channel.forums.ForumTagSnowflake;
+import net.dv8tion.jda.api.requests.FluentRestAction;
 import net.dv8tion.jda.api.utils.messages.MessageCreateData;
 import net.dv8tion.jda.api.utils.messages.MessageCreateRequest;
 import net.dv8tion.jda.internal.utils.Checks;
@@ -36,7 +37,7 @@
  *
  * @see net.dv8tion.jda.api.entities.channel.concrete.ForumChannel#createForumPost(String, MessageCreateData)
  */
-public interface ForumPostAction extends AbstractThreadCreateAction<ForumPost, ForumPostAction>, MessageCreateRequest<ForumPostAction>
+public interface ForumPostAction extends AbstractThreadCreateAction<ForumPost, ForumPostAction>, MessageCreateRequest<ForumPostAction>, FluentRestAction<ForumPost, ForumPostAction>
 {
     /**
      * The {@link ForumChannel} to create the post in

src/main/java/net/dv8tion/jda/api/requests/restaction/ThreadChannelAction.java

@@ -21,9 +21,6 @@
 
 import javax.annotation.CheckReturnValue;
 import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
-import java.util.concurrent.TimeUnit;
-import java.util.function.BooleanSupplier;
 
 /**
  * Extension of {@link net.dv8tion.jda.api.requests.RestAction RestAction} specifically
@@ -36,20 +33,8 @@
  * @see    net.dv8tion.jda.api.entities.channel.attribute.IThreadContainer#createThreadChannel(String, long)
  * @see    net.dv8tion.jda.api.entities.channel.attribute.IThreadContainer#createThreadChannel(String, String)
  */
-public interface ThreadChannelAction extends AbstractThreadCreateAction<ThreadChannel, ThreadChannelAction>, AuditableRestAction<ThreadChannel>
+public interface ThreadChannelAction extends AbstractThreadCreateAction<ThreadChannel, ThreadChannelAction>, FluentAuditableRestAction<ThreadChannel, ThreadChannelAction>
 {
-    @Nonnull
-    @Override
-    ThreadChannelAction setCheck(@Nullable BooleanSupplier checks);
-
-    @Nonnull
-    @Override
-    ThreadChannelAction timeout(long timeout, @Nonnull TimeUnit unit);
-
-    @Nonnull
-    @Override
-    ThreadChannelAction deadline(long timestamp);
-
     //TODO-v5: Docs
     @Nonnull
     @CheckReturnValue

src/main/java/net/dv8tion/jda/internal/requests/restaction/ThreadChannelActionImpl.java

@@ -63,6 +63,13 @@ public ThreadChannelActionImpl(GuildChannel channel, String name, String parentM
         this.name = name;
     }
 
+    @Nonnull
+    @Override
+    public ThreadChannelActionImpl reason(String reason)
+    {
+        return (ThreadChannelActionImpl) super.reason(reason);
+    }
+
     @Nonnull
     @Override
     public ThreadChannelActionImpl setCheck(BooleanSupplier checks)