Added "data too long" exception class, changed code to make use of it, updated Javadoc comments.

src/io/nayuki/fastqrcodegen/DataTooLongException.java

@@ -0,0 +1,57 @@
+/* 
+ * Fast QR Code generator library
+ * 
+ * Copyright (c) Project Nayuki. (MIT License)
+ * https://www.nayuki.io/page/fast-qr-code-generator-library
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ * - The above copyright notice and this permission notice shall be included in
+ *   all copies or substantial portions of the Software.
+ * - The Software is provided "as is", without warranty of any kind, express or
+ *   implied, including but not limited to the warranties of merchantability,
+ *   fitness for a particular purpose and noninfringement. In no event shall the
+ *   authors or copyright holders be liable for any claim, damages or other
+ *   liability, whether in an action of contract, tort or otherwise, arising from,
+ *   out of or in connection with the Software or the use or other dealings in the
+ *   Software.
+ */
+
+package io.nayuki.fastqrcodegen;
+
+
+/**
+ * Thrown when the supplied data does not fit any QR Code version. Ways to handle this exception include:
+ * <ul>
+ *   <li><p>Decrease the error correction level if it was greater than {@code Ecc.LOW}.</p></li>
+ *   <li><p>If the advanced {@code encodeSegments()} function with 6 arguments or the
+ *     {@code makeSegmentsOptimally()} function was called, then increase the maxVersion argument
+ *     if it was less than {@link QrCode#MAX_VERSION}. (This advice does not apply to the other
+ *     factory functions because they search all versions up to {@code QrCode.MAX_VERSION}.)</p></li>
+ *   <li><p>Split the text data into better or optimal segments in order to reduce the number of
+ *     bits required. (See {@link QrSegmentAdvanced#makeSegmentsOptimally(String,QrCode.Ecc,int,int)
+ *     QrSegmentAdvanced.makeSegmentsOptimally()}.)</p></li>
+ *   <li><p>Change the text or binary data to be shorter.</p></li>
+ *   <li><p>Change the text to fit the character set of a particular segment mode (e.g. alphanumeric).</p></li>
+ *   <li><p>Propagate the error upward to the caller/user.</p></li>
+ * </ul>
+ * @see QrCode#encodeText(String, QrCode.Ecc)
+ * @see QrCode#encodeBinary(byte[], QrCode.Ecc)
+ * @see QrCode#encodeSegments(java.util.List, QrCode.Ecc)
+ * @see QrCode#encodeSegments(java.util.List, QrCode.Ecc, int, int, int, boolean)
+ * @see QrSegmentAdvanced#makeSegmentsOptimally(String, QrCode.Ecc, int, int)
+ */
+public class DataTooLongException extends IllegalArgumentException {
+	
+	public DataTooLongException() {}
+	
+	
+	public DataTooLongException(String msg) {
+		super(msg);
+	}
+	
+}

src/io/nayuki/fastqrcodegen/QrCode.java

@@ -64,7 +64,7 @@ public final class QrCode {
 	 * @param ecl the error correction level to use (not {@code null}) (boostable)
 	 * @return a QR Code (not {@code null}) representing the text
 	 * @throws NullPointerException if the text or error correction level is {@code null}
-	 * @throws IllegalArgumentException if the text fails to fit in the
+	 * @throws DataTooLongException if the text fails to fit in the
 	 * largest version QR Code at the ECL, which means it is too long
 	 */
 	public static QrCode encodeText(String text, Ecc ecl) {
@@ -84,7 +84,7 @@ public final class QrCode {
 	 * @param ecl the error correction level to use (not {@code null}) (boostable)
 	 * @return a QR Code (not {@code null}) representing the data
 	 * @throws NullPointerException if the data or error correction level is {@code null}
-	 * @throws IllegalArgumentException if the data fails to fit in the
+	 * @throws DataTooLongException if the data fails to fit in the
 	 * largest version QR Code at the ECL, which means it is too long
 	 */
 	public static QrCode encodeBinary(byte[] data, Ecc ecl) {
@@ -109,7 +109,7 @@ public final class QrCode {
 	 * @param ecl the error correction level to use (not {@code null}) (boostable)
 	 * @return a QR Code (not {@code null}) representing the segments
 	 * @throws NullPointerException if the list of segments, any segment, or the error correction level is {@code null}
-	 * @throws IllegalArgumentException if the segments fail to fit in the
+	 * @throws DataTooLongException if the segments fail to fit in the
 	 * largest version QR Code at the ECL, which means they are too long
 	 */
 	public static QrCode encodeSegments(List<QrSegment> segs, Ecc ecl) {
@@ -137,8 +137,9 @@ public final class QrCode {
 	 * @return a QR Code (not {@code null}) representing the segments
 	 * @throws NullPointerException if the list of segments, any segment, or the error correction level is {@code null}
 	 * @throws IllegalArgumentException if 1 &#x2264; minVersion &#x2264; maxVersion &#x2264; 40
-	 * or &#x2212;1 &#x2264; mask &#x2264; 7 is violated; or if the segments fail to
-	 * fit in the maxVersion QR Code at the ECL, which means they are too long
+	 * or &#x2212;1 &#x2264; mask &#x2264; 7 is violated
+	 * @throws DataTooLongException if the segments fail to fit in
+	 * the maxVersion QR Code at the ECL, which means they are too long
 	 */
 	public static QrCode encodeSegments(List<QrSegment> segs, Ecc ecl, int minVersion, int maxVersion, int mask, boolean boostEcl) {
 		Objects.requireNonNull(segs);
@@ -153,8 +154,12 @@ public final class QrCode {
 			dataUsedBits = QrSegment.getTotalBits(segs, version);
 			if (dataUsedBits != -1 && dataUsedBits <= dataCapacityBits)
 				break;  // This version number is found to be suitable
-			if (version >= maxVersion)  // All versions in the range could not fit the given data
-				throw new IllegalArgumentException("Data too long");
+			if (version >= maxVersion) {  // All versions in the range could not fit the given data
+				String msg = "Segment too long";
+				if (dataUsedBits != -1)
+					msg = String.format("Data length = %d bits, Max capacity = %d bits", dataUsedBits, dataCapacityBits);
+				throw new DataTooLongException(msg);
+			}
 		}
 		assert dataUsedBits != -1;
 		

src/io/nayuki/fastqrcodegen/QrCodeGeneratorWorker.java

@@ -91,9 +91,7 @@ public final class QrCodeGeneratorWorker {
 					System.out.println(qr.getModule(x, y) ? 1 : 0);
 			}
 			
-		} catch (IllegalArgumentException e) {
-			if (!e.getMessage().equals("Data too long"))
-				throw e;
+		} catch (DataTooLongException e) {
 			System.out.println(-1);
 		}
 		System.out.flush();

src/io/nayuki/fastqrcodegen/QrSegmentAdvanced.java

@@ -57,8 +57,8 @@ public final class QrSegmentAdvanced {
 	 * @return a new mutable list (not {@code null}) of segments (not {@code null})
 	 * containing the text, minimizing the bit length with respect to the constraints
 	 * @throws NullPointerException if the text or error correction level is {@code null}
-	 * @throws IllegalArgumentException if 1 ≤ minVersion ≤ maxVersion ≤ 40
-	 * is violated, or if the data is too long to fit in a QR Code at maxVersion at ECL
+	 * @throws IllegalArgumentException if 1 ≤ minVersion ≤ maxVersion ≤ 40 is violated
+	 * @throws DataTooLongException if the text fails to fit in the maxVersion QR Code at the ECL
 	 */
 	public static List<QrSegment> makeSegmentsOptimally(String text, QrCode.Ecc ecl, int minVersion, int maxVersion) {
 		// Check arguments
@@ -70,7 +70,7 @@ public final class QrSegmentAdvanced {
 		// Iterate through version numbers, and make tentative segments
 		List<QrSegment> segs = null;
 		int[] codePoints = toCodePoints(text);
-		for (int version = minVersion; version <= maxVersion; version++) {
+		for (int version = minVersion; ; version++) {
 			if (version == minVersion || version == 10 || version == 27)
 				segs = makeSegmentsOptimally(codePoints, version);
 			assert segs != null;
@@ -79,9 +79,14 @@ public final class QrSegmentAdvanced {
 			int dataCapacityBits = QrCode.getNumDataCodewords(version, ecl) * 8;
 			int dataUsedBits = QrSegment.getTotalBits(segs, version);
 			if (dataUsedBits != -1 && dataUsedBits <= dataCapacityBits)
-				return segs;
+				return segs;  // This version number is found to be suitable
+			if (version >= maxVersion) {  // All versions in the range could not fit the given text
+				String msg = "Segment too long";
+				if (dataUsedBits != -1)
+					msg = String.format("Data length = %d bits, Max capacity = %d bits", dataUsedBits, dataCapacityBits);
+				throw new DataTooLongException(msg);
+			}
 		}
-		throw new IllegalArgumentException("Data too long");
 	}