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/*
* Copyright 2007 ZXing authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.zxing;
/**
* The general exception class throw when something goes wrong during decoding of a barcode.
* This includes, but is not limited to, failing checksums / error correction algorithms, being
* unable to locate finder timing patterns, and so on.
*
* @author Sean Owen
*/
public abstract class ReaderException extends Exception {
// TODO: Currently we throw up to 400 ReaderExceptions while scanning a single 240x240 image before
// rejecting it. This involves a lot of overhead and memory allocation, and affects both performance
// and latency on continuous scan clients. In the future, we should change all the decoders not to
// throw exceptions for routine events, like not finding a barcode on a given row. Instead, we
// should return error codes back to the callers, and simply delete this class. In the mean time, I
// have altered this class to be as lightweight as possible, by ignoring the exception string, and
// by disabling the generation of stack traces, which is especially time consuming. These are just
// temporary measures, pending the big cleanup.
//private static final ReaderException instance = new ReaderException();
// EXCEPTION TRACKING SUPPORT
// Identifies who is throwing exceptions and how often. To use:
//
// 1. Uncomment these lines and the code below which uses them.
// 2. Uncomment the two corresponding lines in j2se/CommandLineRunner.decode()
// 3. Change core to build as Java 1.5 temporarily
// private static int exceptionCount = 0;
// private static Map<String,Integer> throwers = new HashMap<String,Integer>(32);
ReaderException() {
// do nothing
}
//public static ReaderException getInstance() {
// Exception e = new Exception();
// // Take the stack frame before this one.
// StackTraceElement stack = e.getStackTrace()[1];
// String key = stack.getClassName() + "." + stack.getMethodName() + "(), line " +
// stack.getLineNumber();
// if (throwers.containsKey(key)) {
// Integer value = throwers.get(key);
// value++;
// throwers.put(key, value);
// } else {
// throwers.put(key, 1);
// }
// exceptionCount++;
//return instance;
//}
// public static int getExceptionCountAndReset() {
// int temp = exceptionCount;
// exceptionCount = 0;
// return temp;
// }
//
// public static String getThrowersAndReset() {
// StringBuilder builder = new StringBuilder(1024);
// Object[] keys = throwers.keySet().toArray();
// for (int x = 0; x < keys.length; x++) {
// String key = (String) keys[x];
// Integer value = throwers.get(key);
// builder.append(key);
// builder.append(": ");
// builder.append(value);
// builder.append("\n");
// }
// throwers.clear();
// return builder.toString();
// }
// Prevent stack traces from being taken
// srowen says: huh, my IDE is saying this is not an override. native methods can't be overridden?
// This, at least, does not hurt. Because we use a singleton pattern here, it doesn't matter anyhow.
public final Throwable fillInStackTrace() {
return null;
}
}
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