+ checkNotNull(image, "image must not be null");
+ checkNotNull(image.getSone(), "image must have an owner");
+ checkArgument(image.getSone().equals(sone), "image must belong to the same Sone as this album");
+ imageIds.remove(image.getId());
+ images.remove(image.getId());
+ if (image.getId().equals(albumImage)) {
+ if (images.isEmpty()) {
+ albumImage = null;
+ } else {
+ albumImage = images.values().iterator().next().getId();
+ }
+ }
+ }
+
+ /**
+ * Moves the given image up in this album’s images. If the image is already
+ * the first image, nothing happens.
+ *
+ * @param image
+ * The image to move up
+ * @return The image that the given image swapped the place with, or
+ * <code>null</code> if the image did not change its place
+ */
+ public Image moveImageUp(Image image) {
+ checkNotNull(image, "image must not be null");
+ checkNotNull(image.getSone(), "image must have an owner");
+ checkArgument(image.getSone().equals(sone), "image must belong to the same Sone as this album");
+ checkArgument(image.getAlbum().equals(this), "image must belong to this album");
+ int oldIndex = imageIds.indexOf(image.getId());
+ if (oldIndex <= 0) {
+ return null;
+ }
+ imageIds.remove(image.getId());
+ imageIds.add(oldIndex - 1, image.getId());
+ return images.get(imageIds.get(oldIndex));
+ }
+
+ /**
+ * Moves the given image down in this album’s images. If the image is
+ * already the last image, nothing happens.
+ *
+ * @param image
+ * The image to move down
+ * @return The image that the given image swapped the place with, or
+ * <code>null</code> if the image did not change its place
+ */
+ public Image moveImageDown(Image image) {
+ checkNotNull(image, "image must not be null");
+ checkNotNull(image.getSone(), "image must have an owner");
+ checkArgument(image.getSone().equals(sone), "image must belong to the same Sone as this album");
+ checkArgument(image.getAlbum().equals(this), "image must belong to this album");
+ int oldIndex = imageIds.indexOf(image.getId());
+ if ((oldIndex == -1) || (oldIndex >= (imageIds.size() - 1))) {
+ return null;
+ }
+ imageIds.remove(image.getId());
+ imageIds.add(oldIndex + 1, image.getId());
+ return images.get(imageIds.get(oldIndex));