2 * Copyright 2007 ZXing authors
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 package com.google.zxing;
20 * The general exception class throw when something goes wrong during decoding of a barcode.
21 * This includes, but is not limited to, failing checksums / error correction algorithms, being
22 * unable to locate finder timing patterns, and so on.
26 public final class ReaderException extends Exception {
28 // TODO: Currently we throw up to 400 ReaderExceptions while scanning a single 240x240 image before
29 // rejecting it. This involves a lot of overhead and memory allocation, and affects both performance
30 // and latency on continuous scan clients. In the future, we should change all the decoders not to
31 // throw exceptions for routine events, like not finding a barcode on a given row. Instead, we
32 // should return error codes back to the callers, and simply delete this class. In the mean time, I
33 // have altered this class to be as lightweight as possible, by ignoring the exception string, and
34 // by disabling the generation of stack traces, which is especially time consuming. These are just
35 // temporary measures, pending the big cleanup.
37 private static final ReaderException instance = new ReaderException();
39 private ReaderException() {
43 public static ReaderException getInstance() {
47 // Prevent stack traces from being taken
48 public Throwable fillInStackTrace() {