/**
* Add a Thumbnailer-Class to the list of available Thumbnailers Note that the order you add
* Thumbnailers may make a difference: First added Thumbnailers are tried first, if one fails, the
* next (that claims to be able to treat such a document) is tried. (Thumbnailers that claim to
* treat all MIME Types are tried last, though.)
*
* @param thumbnailer Thumbnailer to add.
*/
public void registerThumbnailer(Thumbnailer thumbnailer) {
String[] acceptMIME = thumbnailer.getAcceptedMIMETypes();
if (acceptMIME == null) thumbnailers.put(ALL_MIME_WILDCARD, thumbnailer);
else {
for (String mime : acceptMIME) thumbnailers.put(mime, thumbnailer);
}
allThumbnailers.add(thumbnailer);
thumbnailer.setImageSize(thumbWidth, thumbHeight, thumbOptions);
}
/**
* Set the image size of all following thumbnails.
*
* <p>ThumbnailManager delegates this to all his containing Thumbailers.
*/
public void setImageSize(int width, int height, int imageResizeOptions) {
thumbHeight = height;
thumbWidth = width;
thumbOptions = imageResizeOptions;
if (thumbWidth < 0) thumbWidth = 0;
if (thumbHeight < 0) thumbHeight = 0;
for (Thumbnailer thumbnailer : allThumbnailers)
thumbnailer.setImageSize(thumbWidth, thumbHeight, thumbOptions);
}
/**
* Instead of a deconstructor: De-initialize ThumbnailManager and its thumbnailers.
*
* <p>This functions should be called before termination of the program, and Thumbnails can't be
* generated after calling this function.
*/
public void close() {
if (allThumbnailers == null) return; // Already closed
for (Thumbnailer thumbnailer : allThumbnailers) {
try {
thumbnailer.close();
} catch (IOException e) {
mLog.error("Error during close of Thumbnailer:", e);
}
}
thumbnailers = null;
allThumbnailers = null;
}
/**
* Helper function for Thumbnail generation: execute all thumbnailers of a given MimeType.
*
* @param useMimeType Which MIME Type the thumbnailers should be taken from
* @param input Input File that should be processed
* @param output Output file where the image shall be written.
* @param detectedMimeType MIME Type that was returned by automatic MIME Detection
* @return True on success (1 thumbnailer could generate the output file).
* @throws IOException Input file cannot be read, or output file cannot be written, or necessary
* temporary files could not be created.
*/
private boolean executeThumbnailers(
String useMimeType, File input, File output, String detectedMimeType) throws IOException {
for (Thumbnailer thumbnailer : thumbnailers.getIterable(useMimeType)) {
try {
thumbnailer.generateThumbnail(input, output, detectedMimeType);
return true;
} catch (ThumbnailerException e) {
// This Thumbnailer apparently wasn't suitable, so try next
mLog.warn(
"Warning: "
+ thumbnailer.getClass().getName()
+ " could not handle the file "
+ input.getName()
+ " (trying next)",
e);
}
}
return false;
}