Implement retrieveThreadMember (#1919)

Co-authored-by: Florian Spieß <business@minn.dev>

src/main/java/net/dv8tion/jda/api/entities/ThreadChannel.java

@@ -101,6 +101,88 @@ default ThreadMember getThreadMemberById(String id)
     @Nullable
     ThreadMember getThreadMemberById(long id);
 
+    /**
+     * Load the thread-member for the specified user.
+     * <br>If the thread-member is already loaded it, will be retrieved from {@link #getThreadMemberById(long)}
+     * and immediately provided if the thread-member information is consistent. If the bot hasn't joined the thread,
+     * {@link net.dv8tion.jda.api.requests.GatewayIntent#GUILD_MEMBERS GatewayIntent.GUILD_MEMBERS} is required to keep the cache updated.
+     *
+     * @param  member
+     *         The member to load the thread-member from
+     *
+     * @throws IllegalArgumentException
+     *         If provided with null
+     *
+     * @return {@link RestAction} - Type: {@link ThreadMember}
+     */
+    @Nonnull
+    @CheckReturnValue
+    default RestAction<ThreadMember> retrieveThreadMember(@Nonnull Member member)
+    {
+        Checks.notNull(member, "Member");
+        return retrieveThreadMemberById(member.getIdLong());
+    }
+
+    /**
+     * Load the thread-member for the specified user.
+     * <br>If the thread-member is already loaded, it will be retrieved from {@link #getThreadMemberById(long)}
+     * and immediately provided if the thread-member information is consistent. If the bot hasn't joined the thread,
+     * {@link net.dv8tion.jda.api.requests.GatewayIntent#GUILD_MEMBERS GatewayIntent.GUILD_MEMBERS} is required to keep the cache updated.
+     *
+     * @param  user
+     *         The user to load the thread-member from
+     *
+     * @throws IllegalArgumentException
+     *         If provided with null
+     *
+     * @return {@link RestAction} - Type: {@link ThreadMember}
+     */
+    @Nonnull
+    @CheckReturnValue
+    default RestAction<ThreadMember> retrieveThreadMember(@Nonnull User user)
+    {
+        Checks.notNull(user, "User");
+        return retrieveThreadMemberById(user.getIdLong());
+    }
+
+    /**
+     * Load the thread-member for the user with the specified id.
+     * <br>If the thread-member is already loaded, it will be retrieved from {@link #getThreadMemberById(long)}
+     * and immediately provided if the thread-member information is consistent. If the bot hasn't joined the thread,
+     * {@link net.dv8tion.jda.api.requests.GatewayIntent#GUILD_MEMBERS GatewayIntent.GUILD_MEMBERS} is required to keep the cache updated.
+     *
+     * @param  id
+     *         The user id to load the thread-member from
+     *
+     * @throws IllegalArgumentException
+     *         If the provided id is empty or null
+     * @throws NumberFormatException
+     *         If the provided id is not a snowflake
+     *
+     * @return {@link RestAction} - Type: {@link ThreadMember}
+     */
+    @Nonnull
+    @CheckReturnValue
+    default RestAction<ThreadMember> retrieveThreadMemberById(@Nonnull String id)
+    {
+        return retrieveThreadMemberById(MiscUtil.parseSnowflake(id));
+    }
+
+    /**
+     * Load the thread-member for the user with the specified id.
+     * <br>If the thread-member is already loaded, it will be retrieved from {@link #getThreadMemberById(long)}
+     * and immediately provided if the thread-member information is consistent. If the bot hasn't joined the thread,
+     * {@link net.dv8tion.jda.api.requests.GatewayIntent#GUILD_MEMBERS GatewayIntent.GUILD_MEMBERS} is required to keep the cache updated.
+     *
+     * @param  id
+     *         The user id to load the thread-member from
+     *
+     * @return {@link RestAction} - Type: {@link ThreadMember}
+     */
+    @Nonnull
+    @CheckReturnValue
+    RestAction<ThreadMember> retrieveThreadMemberById(long id);
+
     @CheckReturnValue
     RestAction<List<ThreadMember>> retrieveThreadMembers();
 

src/main/java/net/dv8tion/jda/internal/entities/ThreadChannelImpl.java

@@ -23,22 +23,24 @@
 import net.dv8tion.jda.api.utils.cache.CacheView;
 import net.dv8tion.jda.api.utils.data.DataArray;
 import net.dv8tion.jda.api.utils.data.DataObject;
+import net.dv8tion.jda.internal.JDAImpl;
 import net.dv8tion.jda.internal.entities.mixin.channel.middleman.GuildMessageChannelMixin;
 import net.dv8tion.jda.internal.managers.channel.concrete.ThreadChannelManagerImpl;
+import net.dv8tion.jda.internal.requests.DeferredRestAction;
 import net.dv8tion.jda.internal.requests.RestActionImpl;
 import net.dv8tion.jda.internal.requests.Route;
 import net.dv8tion.jda.internal.utils.Checks;
 import net.dv8tion.jda.internal.utils.Helpers;
-import org.jetbrains.annotations.Nullable;
 
 import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
 import java.time.OffsetDateTime;
 import java.util.Collections;
 import java.util.LinkedList;
 import java.util.List;
 
-public class ThreadChannelImpl extends AbstractGuildChannelImpl<ThreadChannelImpl> implements 
-        ThreadChannel, 
+public class ThreadChannelImpl extends AbstractGuildChannelImpl<ThreadChannelImpl> implements
+        ThreadChannel,
         GuildMessageChannelMixin<ThreadChannelImpl>
 {
     private final ChannelType type;
@@ -135,6 +137,21 @@ public ThreadMember getThreadMemberById(long id)
         return threadMembers.get(id);
     }
 
+    @Nonnull
+    @Override
+    public RestAction<ThreadMember> retrieveThreadMemberById(long id)
+    {
+        JDAImpl jda = (JDAImpl) getJDA();
+        return new DeferredRestAction<>(jda, ThreadMember.class,
+                () -> getThreadMemberById(id),
+                () -> {
+                    Route.CompiledRoute route = Route.Channels.GET_THREAD_MEMBER.compile(getId(), Long.toUnsignedString(id));
+                    return new RestActionImpl<>(jda, route, (resp, req) -> {
+                        return jda.getEntityBuilder().createThreadMember(getGuild(), this, resp.getObject());
+                    });
+                });
+    }
+
     @Override
     public RestAction<List<ThreadMember>> retrieveThreadMembers()
     {