Add FileUpload class

src/main/java/net/dv8tion/jda/api/utils/AttachedFile.java

@@ -182,7 +182,7 @@ static FileUpload fromData(@Nonnull Path path, @Nonnull String name, @Nonnull Op
     @Nonnull
     static FileUpload fromData(@Nonnull Path path, @Nonnull OpenOption... options)
     {
-        return FileUpload.fromData(path, path.getFileName().toString(), options);
+        return FileUpload.fromData(path, options);
     }
 
     /**
@@ -241,7 +241,7 @@ static AttachmentUpdate fromAttachment(@Nonnull Message.Attachment attachment)
      * @throws IllegalStateException
      *         If this attachment has already been used
      */
-    default void claim() {}
+    void claim();
 
     /**
      * Whether this attached file has already been used.
@@ -251,20 +251,19 @@ default void claim() {}
      *
      * @return True if this attachment has already been used
      */
-    default boolean isClaimed()
-    {
-        return false;
-    }
+    boolean isClaimed();
 
     /**
      * Used internally to build the multipart request.
      *
+     * <p>The index can be used as a unique identifier for the multipart name, which is required to be unique by Discord.
+     *
      * @param builder
      *        The {@link MultipartBody.Builder} used for the request body
      * @param index
      *        The index of the attachment, ignored for {@link AttachmentUpdate}
      */
-    default void addPart(MultipartBody.Builder builder, int index) {}
+    void addPart(@Nonnull MultipartBody.Builder builder, int index);
 
     /**
      * Used internally to build attachment descriptions for requests.

src/main/java/net/dv8tion/jda/api/utils/AttachmentUpdate.java

@@ -20,6 +20,8 @@
 import net.dv8tion.jda.api.entities.Message;
 import net.dv8tion.jda.api.utils.data.DataObject;
 import net.dv8tion.jda.internal.utils.Checks;
+import okhttp3.MultipartBody;
+import org.jetbrains.annotations.NotNull;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -105,6 +107,18 @@ public long getIdLong()
         return id;
     }
 
+    @Override
+    public void claim() {}
+
+    @Override
+    public boolean isClaimed()
+    {
+        return false;
+    }
+
+    @Override
+    public void addPart(@NotNull MultipartBody.Builder builder, int index) {}
+
     @Nonnull
     @Override
     public DataObject toAttachmentData(int index)
@@ -121,6 +135,6 @@ public void close() {}
     @Override
     public String toString()
     {
-        return "AttachedFile[Attachment]:" + name + '(' + id + ')';
+        return "AttachedFile[Attachment]" + (name == null ? "" : ":" + name) + '(' + id + ')';
     }
 }

src/main/java/net/dv8tion/jda/api/utils/FileUpload.java

@@ -70,7 +70,7 @@ protected FileUpload(InputStream resource, String name)
     public static FileUpload fromData(@Nonnull InputStream data, @Nonnull String name)
     {
         Checks.notNull(data, "Data");
-        Checks.notNull(name, "Name");
+        Checks.notBlank(name, "Name");
         return new FileUpload(data, name);
     }
 
@@ -191,13 +191,14 @@ public static FileUpload fromData(@Nonnull Path path, @Nonnull String name, @Non
     {
         Checks.notNull(path, "Path");
         Checks.noneNull(options, "Options");
+        Checks.check(Files.isReadable(path), "File for specified path cannot be read. Path: %s", path);
         try
         {
             return fromData(Files.newInputStream(path, options), name);
         }
         catch (IOException e)
         {
-            throw new UncheckedIOException(e);
+            throw new UncheckedIOException("Could not open file for specified path. Path: " + path, e);
         }
     }
 
@@ -224,7 +225,10 @@ public static FileUpload fromData(@Nonnull Path path, @Nonnull String name, @Non
     @Nonnull
     public static FileUpload fromData(@Nonnull Path path, @Nonnull OpenOption... options)
     {
-        return fromData(path, path.getFileName().toString(), options);
+        Checks.notNull(path, "Path");
+        Path fileName = path.getFileName();
+        Checks.check(fileName != null, "Path does not have a file name. Path: %s", path);
+        return fromData(path, fileName.toString(), options);
     }
 
     /**
@@ -264,7 +268,7 @@ public synchronized boolean isClaimed()
     }
 
     @Override
-    public void addPart(MultipartBody.Builder builder, int index)
+    public void addPart(@Nonnull MultipartBody.Builder builder, int index)
     {
         builder.addFormDataPart("files[" + index + "]", name, IOUtil.createRequestBody(Requester.MEDIA_TYPE_OCTET, resource));
     }