move to singleton ReaderException for a bit more performance

git-svn-id: https://zxing.googlecode.com/svn/trunk@714 59b500cc-1b3d-0410-9834-0bbf25fbcc57

bug/src/com/google/zxing/client/bug/AWTImageMonochromeBitmapSource.java

@@ -47,7 +47,7 @@ public final class AWTImageMonochromeBitmapSource extends BaseMonochromeBitmapSo
     try {
       grabber.grabPixels();
     } catch (InterruptedException ie) {
-      throw new ReaderException("Interrupted while reading pixels");
+      throw ReaderException.getInstance();
     }
   }
 

core/src/com/google/zxing/ReaderException.java

@@ -23,19 +23,25 @@ package com.google.zxing;
  *
  * @author Sean Owen
  */
+public final class ReaderException extends Exception {
 
-// TODO: Currently we throw up to 400 ReaderExceptions while scanning a single 240x240 image before
+  // 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
+  // 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
+  // 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
+  // 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
+  // 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
+  // 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
+  // by disabling the generation of stack traces, which is especially time consuming. These are just
-// temporary measures, pending the big cleanup.
+  // temporary measures, pending the big cleanup.
-public final class ReaderException extends java.lang.Throwable {
 
-  public ReaderException(String message) {
+  private static final ReaderException instance = new ReaderException();
-    // Do not pass message to Throwable, let it get optimized out
+
+  private ReaderException() {
+    // do nothing
+  }
+
+  public static ReaderException getInstance() {
+    return instance;
   }
 
   // Prevent stack traces from being taken

core/src/com/google/zxing/common/BlackPointEstimator.java

@@ -88,7 +88,7 @@ public final class BlackPointEstimator {
     // for 1D formats, which are relatively lenient.
     // We arbitrarily say "close" is "<= 1/16 of the total histogram buckets apart"
     if (secondPeak - firstPeak <= numBuckets >> 4) {
-      throw new ReaderException("Too little dynamic range in luminance");
+      throw ReaderException.getInstance();
     }
 
     // Find a valley between them that is low and closer to the white peak

core/src/com/google/zxing/common/DefaultGridSampler.java

@@ -67,7 +67,7 @@ public final class DefaultGridSampler extends GridSampler {
         // This results in an ugly runtime exception despite our clever checks above -- can't have that.
         // We could check each point's coordinates but that feels duplicative. We settle for
         // catching and wrapping ArrayIndexOutOfBoundsException.
-        throw new ReaderException(aioobe.toString());
+        throw ReaderException.getInstance();
       }
     }
     return bits;

core/src/com/google/zxing/common/GridSampler.java

@@ -122,7 +122,7 @@ public abstract class GridSampler {
       int x = (int) points[offset];
       int y = (int) points[offset + 1];
       if (x < -1 || x > width || y < -1 || y > height) {
-        throw new ReaderException("Transformed point out of bounds at " + x + ',' + y);
+        throw ReaderException.getInstance();
       }
       nudged = false;
       if (x == -1) {
@@ -146,7 +146,7 @@ public abstract class GridSampler {
       int x = (int) points[offset];
       int y = (int) points[offset + 1];
       if (x < -1 || x > width || y < -1 || y > height) {
-        throw new ReaderException("Transformed point out of bounds at " + x + ',' + y);
+        throw ReaderException.getInstance();
       }
       nudged = false;
       if (x == -1) {

core/src/com/google/zxing/datamatrix/DataMatrixReader.java

@@ -92,7 +92,7 @@ public final class DataMatrixReader implements Reader {
       borderWidth++;
     }
     if (borderWidth == minDimension) {
-      throw new ReaderException("No black pixels found along diagonal");
+      throw ReaderException.getInstance();
     }
 
     // And then keep tracking across the top-left black module to determine module size
@@ -101,7 +101,7 @@ public final class DataMatrixReader implements Reader {
       moduleEnd++;
     }
     if (moduleEnd == width) {
-      throw new ReaderException("No end to black pixels found along row");
+      throw ReaderException.getInstance();
     }
 
     int moduleSize = moduleEnd - borderWidth;
@@ -112,14 +112,13 @@ public final class DataMatrixReader implements Reader {
     	columnEndOfSymbol--;
     }
     if (columnEndOfSymbol < 0) {
-      throw new ReaderException("Can't find end of bottommost black module");
+      throw ReaderException.getInstance();
     }
     columnEndOfSymbol++;
 
     // Make sure width of barcode is a multiple of module size
     if ((columnEndOfSymbol - borderWidth) % moduleSize != 0) {
-      throw new ReaderException("Bad module size / width: " + moduleSize +
+      throw ReaderException.getInstance();
-          " / " + (columnEndOfSymbol - borderWidth));
     }
     int dimension = (columnEndOfSymbol - borderWidth) / moduleSize;
 
@@ -130,7 +129,7 @@ public final class DataMatrixReader implements Reader {
 
     int sampleDimension = borderWidth + (dimension - 1) * moduleSize;
     if (sampleDimension >= width || sampleDimension >= height) {
-      throw new ReaderException("Estimated pure image size is beyond image boundaries");
+      throw ReaderException.getInstance();
     }
 
     // Now just read off the bits

core/src/com/google/zxing/datamatrix/decoder/BitMatrixParser.java

@@ -35,7 +35,7 @@ final class BitMatrixParser {
   BitMatrixParser(BitMatrix bitMatrix) throws ReaderException {
     int dimension = bitMatrix.getDimension();
     if (dimension < 10 || dimension > 144 || (dimension & 0x01) != 0) {
-      throw new ReaderException("Invalid dimension (" + dimension + ")  Must be 0 mod 2 and >= 10 and <= 144");
+      throw ReaderException.getInstance();
     }
     
     version = readVersion(bitMatrix);
@@ -141,7 +141,7 @@ final class BitMatrixParser {
     } while ((row < numRows) || (column < numColumns));
 
     if (resultOffset != version.getTotalCodewords()) {
-      throw new ReaderException("Did not read all codewords");
+      throw ReaderException.getInstance();
     }
     return result;
   }

core/src/com/google/zxing/datamatrix/decoder/DecodedBitStreamParser.java

@@ -102,7 +102,7 @@ final class DecodedBitStreamParser {
             decodeBase256Segment(bits, result, byteSegments);
             break;
           default:
-            throw new ReaderException("Unsupported mode indicator");
+            throw ReaderException.getInstance();
         }
         mode = ASCII_ENCODE;
       }
@@ -122,7 +122,7 @@ final class DecodedBitStreamParser {
     do {
       int oneByte = bits.readBits(8);
       if (oneByte == 0) {
-	    	throw new ReaderException("0 is an invalid ASCII codeword");
+	    	throw ReaderException.getInstance();
 	    } else if (oneByte <= 128) {  // ASCII data (ASCII value + 1)
 	    	oneByte = upperShift ? (oneByte + 128) : oneByte;
 	    	upperShift = false;
@@ -141,11 +141,11 @@ final class DecodedBitStreamParser {
 	    } else if (oneByte == 231) {  // Latch to Base 256 encodation
 	    	return BASE256_ENCODE;
 	    } else if (oneByte == 232) {  // FNC1
-	    	throw new ReaderException("Currently not supporting FNC1");
+	    	throw ReaderException.getInstance();
 	    } else if (oneByte == 233) {  // Structured Append
-	    	throw new ReaderException("Currently not supporting Structured Append");
+	    	throw ReaderException.getInstance();
 	    } else if (oneByte == 234) {  // Reader Programming
-	    	throw new ReaderException("Currently not supporting Reader Programming");
+	    	throw ReaderException.getInstance();
 	    } else if (oneByte == 235) {  // Upper Shift (shift to Extended ASCII)
 	    	upperShift = true;
 	    } else if (oneByte == 236) {  // 05 Macro
@@ -162,9 +162,9 @@ final class DecodedBitStreamParser {
 	    	return EDIFACT_ENCODE;
 	    } else if (oneByte == 241) {  // ECI Character
 	    	// TODO(bbrown): I think we need to support ECI
-	    	throw new ReaderException("Currently not supporting ECI Character");
+	    	throw ReaderException.getInstance();
 	    } else if (oneByte >= 242) {  // Not to be used in ASCII encodation
-	    	throw new ReaderException(oneByte + " should not be used in ASCII encodation");
+	    	throw ReaderException.getInstance();
 	    }
     } while (bits.available() > 0);
     return ASCII_ENCODE;
@@ -226,11 +226,11 @@ final class DecodedBitStreamParser {
                 result.append(C40_SHIFT2_SET_CHARS[cValue]);
               }
             } else if (cValue == 27) {  // FNC1
-              throw new ReaderException("Currently not supporting FNC1");
+              throw ReaderException.getInstance();
             } else if (cValue == 30) {  // Upper Shift
               upperShift = true;
             } else {
-              throw new ReaderException(cValue + " is not valid in the C40 Shift 2 set");
+              throw ReaderException.getInstance();
             }
             shift = 0;
             break;
@@ -244,7 +244,7 @@ final class DecodedBitStreamParser {
             shift = 0;
             break;
           default:
-            throw new ReaderException("Invalid shift value");
+            throw ReaderException.getInstance();
         }
       }
     } while (bits.available() > 0);
@@ -307,11 +307,11 @@ final class DecodedBitStreamParser {
                 result.append(C40_SHIFT2_SET_CHARS[cValue]);
               }
             } else if (cValue == 27) {  // FNC1
-              throw new ReaderException("Currently not supporting FNC1");
+              throw ReaderException.getInstance();
             } else if (cValue == 30) {  // Upper Shift
               upperShift = true;
             } else {
-              throw new ReaderException(cValue + " is not valid in the C40 Shift 2 set");
+              throw ReaderException.getInstance();
             }
             shift = 0;
             break;
@@ -325,7 +325,7 @@ final class DecodedBitStreamParser {
             shift = 0;
             break;
           default:
-            throw new ReaderException("Invalid shift value");
+            throw ReaderException.getInstance();
         }
       }
     } while (bits.available() > 0);
@@ -366,7 +366,7 @@ final class DecodedBitStreamParser {
         } else if (cValue < 40) {  // A - Z
           result.append((char) (cValue + 51));
         } else {
-          throw new ReaderException(cValue + " is not valid in the ANSI X12 set");
+          throw ReaderException.getInstance();
         }
       }
     } while (bits.available() > 0);

core/src/com/google/zxing/datamatrix/decoder/Decoder.java

@@ -119,7 +119,7 @@ public final class Decoder {
     try {
       rsDecoder.decode(codewordsInts, numECCodewords);
     } catch (ReedSolomonException rse) {
-      throw new ReaderException(rse.toString());
+      throw ReaderException.getInstance();
     }
     // Copy back into array of bytes -- only need to worry about the bytes that were data
     // We don't care about errors in the error-correction codewords

core/src/com/google/zxing/datamatrix/decoder/Version.java

@@ -98,7 +98,7 @@ public final class Version {
    */
   public static Version getVersionForDimensions(int numRows, int numColumns) throws ReaderException {
     if ((numRows & 0x01) != 0 || (numColumns & 0x01) != 0) {
-      throw new ReaderException("Dimension must be 0 mod 2");
+      throw ReaderException.getInstance();
     }
     
     // TODO(bbrown): This is doing a linear search through the array of versions.
@@ -112,7 +112,7 @@ public final class Version {
       }
     }
     
-    throw new ReaderException("Dimensions do not correspond to a valid Data Matrix Version.");
+    throw ReaderException.getInstance();
   }
 
   /**

core/src/com/google/zxing/datamatrix/detector/Detector.java

@@ -130,7 +130,7 @@ public final class Detector {
     }
 
     if (maybeTopLeft == null || bottomLeft == null || maybeBottomRight == null) {
-      throw new ReaderException("Could not find three corners");
+      throw ReaderException.getInstance();
     }
 
     // Bottom left is correct but top left and bottom right might be switched
@@ -212,7 +212,7 @@ public final class Detector {
       }
       if (range == null) {
         if (lastRange == null) {
-          throw new ReaderException("Center of image not within barcode");
+          throw ReaderException.getInstance();
         }
         // lastRange was found
         if (dj == 0) {
@@ -240,7 +240,7 @@ public final class Detector {
       }
       lastRange = range;
     }
-    throw new ReaderException("Couldn't find an end to barcode");
+    throw ReaderException.getInstance();
   }
 
   /**

core/src/com/google/zxing/oned/AbstractOneDReader.java

@@ -140,7 +140,7 @@ public abstract class AbstractOneDReader implements OneDReader {
       }
     }
 
-    throw new ReaderException("No barcode found");
+    throw ReaderException.getInstance();
   }
 
   /**
@@ -162,7 +162,7 @@ public abstract class AbstractOneDReader implements OneDReader {
     }
     int end = row.getSize();
     if (start >= end) {
-      throw new ReaderException("Couldn't fully read a pattern");
+      throw ReaderException.getInstance();
     }
     boolean isWhite = !row.get(start);
     int counterPosition = 0;
@@ -185,7 +185,7 @@ public abstract class AbstractOneDReader implements OneDReader {
     // If we read fully the last section of pixels and filled up our counters -- or filled
     // the last counter but ran off the side of the image, OK. Otherwise, a problem.
     if (!(counterPosition == numCounters || (counterPosition == numCounters - 1 && i == end))) {
-      throw new ReaderException("Couldn't fully read a pattern");
+      throw ReaderException.getInstance();
     }
   }
 

core/src/com/google/zxing/oned/AbstractUPCEANReader.java

@@ -124,12 +124,12 @@ public abstract class AbstractUPCEANReader extends AbstractOneDReader implements
     int end = endRange[1];
     int quietEnd = end + (end - endRange[0]);
     if (quietEnd >= row.getSize() || !row.isRange(end, quietEnd, false)) {
-      throw new ReaderException("Pattern not followed by whitespace");
+      throw ReaderException.getInstance();
     }
 
     String resultString = result.toString();
     if (!checkChecksum(resultString)) {
-      throw new ReaderException("Checksum failed");
+      throw ReaderException.getInstance();
     }
 
     float left = (float) (startGuardRange[1] + startGuardRange[0]) / 2.0f;
@@ -162,7 +162,7 @@ public abstract class AbstractUPCEANReader extends AbstractOneDReader implements
     for (int i = length - 2; i >= 0; i -= 2) {
       int digit = (int) s.charAt(i) - (int) '0';
       if (digit < 0 || digit > 9) {
-        throw new ReaderException("Illegal character during checksum");
+        throw ReaderException.getInstance();
       }
       sum += digit;
     }
@@ -170,7 +170,7 @@ public abstract class AbstractUPCEANReader extends AbstractOneDReader implements
     for (int i = length - 1; i >= 0; i -= 2) {
       int digit = (int) s.charAt(i) - (int) '0';
       if (digit < 0 || digit > 9) {
-        throw new ReaderException("Illegal character during checksum");
+        throw ReaderException.getInstance();
       }
       sum += digit;
     }
@@ -242,7 +242,7 @@ public abstract class AbstractUPCEANReader extends AbstractOneDReader implements
         isWhite = !isWhite;
       }
     }
-    throw new ReaderException("Can't find pattern");
+    throw ReaderException.getInstance();
   }
 
   /**
@@ -274,7 +274,7 @@ public abstract class AbstractUPCEANReader extends AbstractOneDReader implements
     if (bestMatch >= 0) {
       return bestMatch;
     } else {
-      throw new ReaderException("Could not match any digit in pattern");
+      throw ReaderException.getInstance();
     }
   }
 

core/src/com/google/zxing/oned/Code128Reader.java

@@ -213,7 +213,7 @@ public final class Code128Reader extends AbstractOneDReader {
         isWhite = !isWhite;
       }
     }
-    throw new ReaderException("Can't find pattern");
+    throw ReaderException.getInstance();
   }
 
   private static int decodeCode(BitArray row, int[] counters, int rowOffset) throws ReaderException {
@@ -232,7 +232,7 @@ public final class Code128Reader extends AbstractOneDReader {
     if (bestMatch >= 0) {
       return bestMatch;
     } else {
-      throw new ReaderException("Could not match any code pattern");
+      throw ReaderException.getInstance();
     }
   }
 
@@ -252,7 +252,7 @@ public final class Code128Reader extends AbstractOneDReader {
         codeSet = CODE_CODE_C;
         break;
       default:
-        throw new ReaderException("Illegal start code");
+        throw ReaderException.getInstance();
     }
 
     boolean done = false;
@@ -302,7 +302,7 @@ public final class Code128Reader extends AbstractOneDReader {
         case CODE_START_A:
         case CODE_START_B:
         case CODE_START_C:
-          throw new ReaderException("Unexpected start code");
+          throw ReaderException.getInstance();
       }
 
       switch (codeSet) {
@@ -423,14 +423,14 @@ public final class Code128Reader extends AbstractOneDReader {
       nextStart++;
     }
     if (!row.isRange(nextStart, Math.min(row.getSize(), nextStart + (nextStart - lastStart) / 2), false)) {
-      throw new ReaderException("Pattern not followed by whitespace");
+      throw ReaderException.getInstance();
     }
 
     // Pull out from sum the value of the penultimate check code
     checksumTotal -= multiplier * lastCode;
     // lastCode is the checksum then:
     if (checksumTotal % 103 != lastCode) {
-      throw new ReaderException("Checksum failed");
+      throw ReaderException.getInstance();
     }
 
     // Need to pull out the check digits from string
@@ -449,7 +449,7 @@ public final class Code128Reader extends AbstractOneDReader {
 
     if (resultString.length() == 0) {
       // Almost surely a false positive
-      throw new ReaderException("Empty barcode found; assuming a false positive");
+      throw ReaderException.getInstance();
     }
 
     float left = (float) (startPatternInfo[1] + startPatternInfo[0]) / 2.0f;

core/src/com/google/zxing/oned/Code39Reader.java

@@ -129,7 +129,7 @@ public final class Code39Reader extends AbstractOneDReader {
     // If 50% of last pattern size, following last pattern, is not whitespace, fail
     // (but if it's whitespace to the very end of the image, that's OK)
     if (nextStart != end && whiteSpaceAfterEnd / 2 < lastPatternSize) {
-      throw new ReaderException("Pattern not followed by whitespace");
+      throw ReaderException.getInstance();
     }
 
     if (usingCheckDigit) {
@@ -139,7 +139,7 @@ public final class Code39Reader extends AbstractOneDReader {
         total += ALPHABET_STRING.indexOf(result.charAt(i));
       }
       if (total % 43 != ALPHABET_STRING.indexOf(result.charAt(max))) {
-        throw new ReaderException("Checksum failed");
+        throw ReaderException.getInstance();
       }
       result.deleteCharAt(max);
     }
@@ -151,7 +151,7 @@ public final class Code39Reader extends AbstractOneDReader {
 
     if (resultString.length() == 0) {
       // Almost surely a false positive
-      throw new ReaderException("Empty barcode found; assuming a false positive");
+      throw ReaderException.getInstance();
     }
 
     float left = (float) (start[1] + start[0]) / 2.0f;
@@ -212,7 +212,7 @@ public final class Code39Reader extends AbstractOneDReader {
         isWhite = !isWhite;
       }
     }
-    throw new ReaderException("Can't find pattern");
+    throw ReaderException.getInstance();
   }
 
   private static int toNarrowWidePattern(int[] counters) throws ReaderException {
@@ -249,14 +249,14 @@ public final class Code39Reader extends AbstractOneDReader {
             wideCounters--;
             // totalWideCountersWidth = 3 * average, so this checks if counter >= 3/2 * average
             if ((counter << 1) >= totalWideCountersWidth) {
-              throw new ReaderException("Wide bars vary too much in width, rejecting");
+              throw ReaderException.getInstance();
             }
           }
         }
         return pattern;
       }
     } while (wideCounters > 3);
-    throw new ReaderException("Can't find 3 wide bars/spaces out of 9");
+    throw ReaderException.getInstance();
   }
 
   private static char patternToChar(int pattern) throws ReaderException {
@@ -265,7 +265,7 @@ public final class Code39Reader extends AbstractOneDReader {
         return ALPHABET[i];
       }
     }
-    throw new ReaderException("Pattern did not match character encoding");
+    throw ReaderException.getInstance();
   }
 
   private static String decodeExtended(String encoded) throws ReaderException {
@@ -282,7 +282,7 @@ public final class Code39Reader extends AbstractOneDReader {
             if (next >= 'A' && next <= 'Z') {
               decodedChar = (char) (next + 32);
             } else {
-              throw new ReaderException("Invalid extended code 39 sequence: " + c + next);
+              throw ReaderException.getInstance();
             }
             break;
           case '$':
@@ -290,7 +290,7 @@ public final class Code39Reader extends AbstractOneDReader {
             if (next >= 'A' && next <= 'Z') {
               decodedChar = (char) (next - 64);
             } else {
-              throw new ReaderException("Invalid extended code 39 sequence: " + c + next);
+              throw ReaderException.getInstance();
             }
             break;
           case '%':
@@ -300,7 +300,7 @@ public final class Code39Reader extends AbstractOneDReader {
             } else if (next >= 'F' && next <= 'W') {
               decodedChar = (char) (next - 11);
             } else {
-              throw new ReaderException("Invalid extended code 39 sequence: " + c + next);
+              throw ReaderException.getInstance();
             }
             break;
           case '/':
@@ -310,7 +310,7 @@ public final class Code39Reader extends AbstractOneDReader {
             } else if (next == 'Z') {
               decodedChar = ':';
             } else {
-              throw new ReaderException("Invalid extended sequence: " + c + next);
+              throw ReaderException.getInstance();
             }
             break;
         }

core/src/com/google/zxing/oned/EAN13Reader.java

@@ -126,7 +126,7 @@ public final class EAN13Reader extends AbstractUPCEANReader {
         return;
       }
     }
-    throw new ReaderException("Unable to determine first digit");
+    throw ReaderException.getInstance();
   }
 
 }

core/src/com/google/zxing/oned/MultiFormatOneDReader.java

@@ -68,7 +68,7 @@ public final class MultiFormatOneDReader extends AbstractOneDReader {
       }
     }
 
-    throw new ReaderException("No barcode was detected in this image.");
+    throw ReaderException.getInstance();
   }
 
 }

core/src/com/google/zxing/oned/MultiFormatUPCEANReader.java

@@ -88,7 +88,7 @@ public final class MultiFormatUPCEANReader extends AbstractOneDReader {
       return result;
     }
 
-    throw new ReaderException("No barcode was detected in this image.");
+    throw ReaderException.getInstance();
   }
 
 }

core/src/com/google/zxing/oned/UPCAReader.java

@@ -55,7 +55,7 @@ public final class UPCAReader implements UPCEANReader {
     if (text.charAt(0) == '0') {
       return new Result(text.substring(1), null, result.getResultPoints(), BarcodeFormat.UPC_A);
     } else {
-      throw new ReaderException("Found EAN-13 code but was not a UPC-A code");
+      throw ReaderException.getInstance();
     }
   }
 

core/src/com/google/zxing/oned/UPCEReader.java

@@ -99,7 +99,7 @@ public final class UPCEReader extends AbstractUPCEANReader {
         }
       }
     }
-    throw new ReaderException("Unable to determine number system and check digit");
+    throw ReaderException.getInstance();
   }
 
   BarcodeFormat getBarcodeFormat() {

core/src/com/google/zxing/qrcode/QRCodeReader.java

@@ -93,7 +93,7 @@ public final class QRCodeReader implements Reader {
       borderWidth++;
     }
     if (borderWidth == minDimension) {
-      throw new ReaderException("No black pixels found along diagonal");
+      throw ReaderException.getInstance();
     }
 
     // And then keep tracking across the top-left black module to determine module size
@@ -102,7 +102,7 @@ public final class QRCodeReader implements Reader {
       moduleEnd++;
     }
     if (moduleEnd == minDimension) {
-      throw new ReaderException("No end to black pixels found along diagonal");
+      throw ReaderException.getInstance();
     }
 
     int moduleSize = moduleEnd - borderWidth;
@@ -113,14 +113,13 @@ public final class QRCodeReader implements Reader {
       rowEndOfSymbol--;
     }
     if (rowEndOfSymbol < 0) {
-      throw new ReaderException("Can't find end of rightmost black module");
+      throw ReaderException.getInstance();
     }
     rowEndOfSymbol++;
 
     // Make sure width of barcode is a multiple of module size
     if ((rowEndOfSymbol - borderWidth) % moduleSize != 0) {
-      throw new ReaderException("Bad module size / width: " + moduleSize +
+      throw ReaderException.getInstance();
-          " / " + (rowEndOfSymbol - borderWidth));
     }
     int dimension = (rowEndOfSymbol - borderWidth) / moduleSize;
 
@@ -131,7 +130,7 @@ public final class QRCodeReader implements Reader {
 
     int sampleDimension = borderWidth + (dimension - 1) * moduleSize;
     if (sampleDimension >= width || sampleDimension >= height) {
-      throw new ReaderException("Estimated pure image size is beyond image boundaries");
+      throw ReaderException.getInstance();
     }
 
     // Now just read off the bits

core/src/com/google/zxing/qrcode/decoder/BitMatrixParser.java

@@ -35,7 +35,7 @@ final class BitMatrixParser {
   BitMatrixParser(BitMatrix bitMatrix) throws ReaderException {
     int dimension = bitMatrix.getDimension();
     if (dimension < 21 || (dimension & 0x03) != 1) {
-      throw new ReaderException("Dimension must be 1 mod 4 and >= 21");
+      throw ReaderException.getInstance();
     }
     this.bitMatrix = bitMatrix;
   }
@@ -87,7 +87,7 @@ final class BitMatrixParser {
     if (parsedFormatInfo != null) {
       return parsedFormatInfo;
     }
-    throw new ReaderException("Could not decode format information");
+    throw ReaderException.getInstance();
   }
 
   /**
@@ -137,7 +137,7 @@ final class BitMatrixParser {
     if (parsedVersion != null) {
       return parsedVersion;
     }
-    throw new ReaderException("Could not decode version");
+    throw ReaderException.getInstance();
   }
 
   private int copyBit(int i, int j, int versionBits) {
@@ -201,7 +201,7 @@ final class BitMatrixParser {
       readingUp = !readingUp; // switch directions
     }
     if (resultOffset != version.getTotalCodewords()) {
-      throw new ReaderException("Did not read all codewords");
+      throw ReaderException.getInstance();
     }
     return result;
   }

core/src/com/google/zxing/qrcode/decoder/DecodedBitStreamParser.java

@@ -96,7 +96,7 @@ final class DecodedBitStreamParser {
           } else if (mode.equals(Mode.KANJI)) {
             decodeKanjiSegment(bits, result, count);
           } else {
-            throw new ReaderException("Unsupported mode indicator");
+            throw ReaderException.getInstance();
           }
         }
       }
@@ -132,7 +132,7 @@ final class DecodedBitStreamParser {
     try {
       result.append(new String(buffer, SHIFT_JIS));
     } catch (UnsupportedEncodingException uee) {
-      throw new ReaderException(SHIFT_JIS + " encoding is not supported on this device");
+      throw ReaderException.getInstance();
     }
   }
 
@@ -143,7 +143,7 @@ final class DecodedBitStreamParser {
                                         Vector byteSegments) throws ReaderException {
     byte[] readBytes = new byte[count];
     if (count << 3 > bits.available()) {
-      throw new ReaderException("Count too large: " + count);
+      throw ReaderException.getInstance();
     }
     for (int i = 0; i < count; i++) {
       readBytes[i] = (byte) bits.readBits(8);
@@ -162,7 +162,7 @@ final class DecodedBitStreamParser {
     try {
       result.append(new String(readBytes, encoding));
     } catch (UnsupportedEncodingException uce) {
-      throw new ReaderException(uce.toString());
+      throw ReaderException.getInstance();
     }
     byteSegments.addElement(readBytes);
   }
@@ -208,7 +208,7 @@ final class DecodedBitStreamParser {
       // Each 10 bits encodes three digits
       int threeDigitsBits = bits.readBits(10);
       if (threeDigitsBits >= 1000) {
-        throw new ReaderException("Illegal value for 3-digit unit: " + threeDigitsBits);
+        throw ReaderException.getInstance();
       }
       result.append(ALPHANUMERIC_CHARS[threeDigitsBits / 100]);
       result.append(ALPHANUMERIC_CHARS[(threeDigitsBits / 10) % 10]);
@@ -219,7 +219,7 @@ final class DecodedBitStreamParser {
       // Two digits left over to read, encoded in 7 bits
       int twoDigitsBits = bits.readBits(7);
       if (twoDigitsBits >= 100) {
-        throw new ReaderException("Illegal value for 2-digit unit: " + twoDigitsBits);
+        throw ReaderException.getInstance();
       }
       result.append(ALPHANUMERIC_CHARS[twoDigitsBits / 10]);
       result.append(ALPHANUMERIC_CHARS[twoDigitsBits % 10]);
@@ -227,7 +227,7 @@ final class DecodedBitStreamParser {
       // One digit left over to read
       int digitBits = bits.readBits(4);
       if (digitBits >= 10) {
-        throw new ReaderException("Illegal value for digit unit: " + digitBits);
+        throw ReaderException.getInstance();
       }
       result.append(ALPHANUMERIC_CHARS[digitBits]);
     }

core/src/com/google/zxing/qrcode/decoder/Decoder.java

@@ -119,7 +119,7 @@ public final class Decoder {
     try {
       rsDecoder.decode(codewordsInts, numECCodewords);
     } catch (ReedSolomonException rse) {
-      throw new ReaderException(rse.toString());
+      throw ReaderException.getInstance();
     }
     // Copy back into array of bytes -- only need to worry about the bytes that were data
     // We don't care about errors in the error-correction codewords

core/src/com/google/zxing/qrcode/decoder/ErrorCorrectionLevel.java

@@ -63,7 +63,7 @@ final class ErrorCorrectionLevel {
    */
   static ErrorCorrectionLevel forBits(int bits) throws ReaderException {
     if (bits < 0 || bits >= FOR_BITS.length) {
-      throw new ReaderException("Illegal error correction level bits" + bits);
+      throw ReaderException.getInstance();
     }
     return FOR_BITS[bits];
   }

core/src/com/google/zxing/qrcode/decoder/Mode.java

@@ -67,7 +67,7 @@ final class Mode {
       case 0x9:
         return FNC1_SECOND_POSITION;
       default:
-        throw new ReaderException("Unsupported mode bits: " + bits);
+        throw ReaderException.getInstance();
     }
   }
 

core/src/com/google/zxing/qrcode/decoder/Version.java

@@ -95,14 +95,14 @@ public final class Version {
    */
   public static Version getProvisionalVersionForDimension(int dimension) throws ReaderException {
     if (dimension % 4 != 1) {
-      throw new ReaderException("Dimension must be 1 mod 4");
+      throw ReaderException.getInstance();
     }
     return getVersionForNumber((dimension - 17) >> 2);
   }
 
   public static Version getVersionForNumber(int versionNumber) throws ReaderException {
     if (versionNumber < 1 || versionNumber > 40) {
-      throw new ReaderException("versionNumber must be between 1 and 40");
+      throw ReaderException.getInstance();
     }
     return VERSIONS[versionNumber - 1];
   }

core/src/com/google/zxing/qrcode/detector/AlignmentPatternFinder.java

@@ -148,7 +148,7 @@ final class AlignmentPatternFinder {
       return (AlignmentPattern) possibleCenters.elementAt(0);
     }
 
-    throw new ReaderException("Could not find alignment pattern");
+    throw ReaderException.getInstance();
   }
 
   /**

core/src/com/google/zxing/qrcode/detector/Detector.java

@@ -75,7 +75,7 @@ public final class Detector {
 
     float moduleSize = calculateModuleSize(topLeft, topRight, bottomLeft);
     if (moduleSize < 1.0f) {
-      throw new ReaderException("Module size too small");
+      throw ReaderException.getInstance();
     }
     int dimension = computeDimension(topLeft, topRight, bottomLeft, moduleSize);
     Version provisionalVersion = Version.getProvisionalVersionForDimension(dimension);
@@ -108,7 +108,7 @@ public final class Detector {
         }
       }
       if (alignmentPattern == null) {
-        throw new ReaderException("Could not find alignment pattern");
+        throw ReaderException.getInstance();
       }
 
     }
@@ -188,7 +188,7 @@ public final class Detector {
         dimension--;
         break;
       case 3:
-        throw new ReaderException("Bad dimension: " + dimension);
+        throw ReaderException.getInstance();
     }
     return dimension;
   }
@@ -335,7 +335,7 @@ public final class Detector {
     int alignmentAreaLeftX = Math.max(0, estAlignmentX - allowance);
     int alignmentAreaRightX = Math.min(image.getWidth() - 1, estAlignmentX + allowance);
     if (alignmentAreaRightX - alignmentAreaLeftX < overallEstModuleSize * 3) {
-      throw new ReaderException("Alignment pattern is too small to search");
+      throw ReaderException.getInstance();
     }
 
     int alignmentAreaTopY = Math.max(0, estAlignmentY - allowance);

core/src/com/google/zxing/qrcode/detector/FinderPatternFinder.java

@@ -484,7 +484,7 @@ final class FinderPatternFinder {
 
     if (size < 3) {
       // Couldn't find enough finder patterns
-      throw new ReaderException("Could not find three finder patterns");
+      throw ReaderException.getInstance();
     }
 
     if (size > 3) {