adding support for collecting blank lines of comments

src/main/java/com/univocity/parsers/common/AbstractParser.java

@@ -66,6 +66,7 @@ public abstract class AbstractParser<T extends CommonParserSettings<?>> {
 	protected final Map<Long, String> comments;
 	protected String lastComment;
 	private final boolean collectComments;
+	private final boolean collectEmptyComments;
 	private final int errorContentLength;
 	private boolean extractingHeaders = false;
 	private final boolean extractHeaders;
@@ -95,6 +96,7 @@ public AbstractParser(T settings) {
 		this.errorHandler = settings.getProcessorErrorHandler();
 		this.rowsToSkip = settings.getNumberOfRowsToSkip();
 		this.collectComments = settings.isCommentCollectionEnabled();
+		this.collectEmptyComments = settings.isBlankCommentCollectionEnabled();
 		this.comments = collectComments ? new TreeMap<Long, String>() : Collections.<Long, String>emptyMap();
 		this.extractHeaders = settings.isHeaderExtractionEnabled();
 		this.whitespaceRangeStart = settings.getWhitespaceRangeStart();
@@ -105,7 +107,7 @@ protected void processComment() {
 		if (collectComments) {
 			long line = input.lineCount();
 			String comment = input.readComment();
-			if (comment != null) {
+			if (comment != null || collectEmptyComments) {
 				lastComment = comment;
 				comments.put(line, lastComment);
 			}

src/main/java/com/univocity/parsers/common/CommonParserSettings.java

@@ -64,6 +64,7 @@ public abstract class CommonParserSettings<F extends Format> extends CommonSetti
 	private boolean lineSeparatorDetectionEnabled = false;
 	private long numberOfRowsToSkip = 0L;
 	private boolean commentCollectionEnabled = false;
+	private boolean blankCommentCollectionEnabled = false;
 	private boolean autoClosingEnabled = true;
 	private boolean commentProcessingEnabled = true;
 	private List<InputAnalysisProcess> inputAnalysisProcesses = new ArrayList<InputAnalysisProcess>();
@@ -411,6 +412,30 @@ public void setCommentCollectionEnabled(boolean commentCollectionEnabled) {
 		this.commentCollectionEnabled = commentCollectionEnabled;
 	}
 
+	/**
+	 * Enables collection of comments found in the input (disabled by default). If enabled, comment lines will be
+	 * stored by the parser and made available via {@code AbstractParser.getContext().comments()} and {@code AbstractParser.getContext().lastComment()}
+	 *
+	 * @param commentCollectionEnabled flag indicating whether or not to enable collection of comments.
+	 * @param includeBlank             flag indicating whether or not to collect blank lines in comments (these will come as {@code null})
+	 */
+	public void setCommentCollectionEnabled(boolean commentCollectionEnabled, boolean includeBlank) {
+		setCommentCollectionEnabled(commentCollectionEnabled);
+		this.blankCommentCollectionEnabled = commentCollectionEnabled && includeBlank;
+	}
+
+	/**
+	 * Indicates that blank comments found in the input must be collected (disabled by default). If enabled, comment lines will be
+	 * stored by the parser and made available via {@code AbstractParser.getContext().comments()} and {@code AbstractParser.getContext().lastComment()}
+	 *
+	 * Blank comments will come as {@code null}.
+	 *
+	 * @return a flag indicating whether or not to enable collection of blank comments.
+	 */
+	public boolean isBlankCommentCollectionEnabled() {
+		return blankCommentCollectionEnabled;
+	}
+
 	@Override
 	final void runAutomaticConfiguration() {
 		Class<?> beanClass = null;

src/test/java/com/univocity/parsers/issues/github/Github_447.java

@@ -0,0 +1,39 @@
+package com.univocity.parsers.issues.github;
+
+import com.univocity.parsers.fixed.*;
+import org.testng.annotations.*;
+
+import java.io.*;
+
+import static org.testng.Assert.*;
+
+
+/**
+ * From: https://github.com/univocity/univocity-parsers/issues/447
+ *
+ * @author Univocity Software Pty Ltd - <a href="mailto:[email protected]">[email protected]</a>
+ */
+public class Github_447 {
+
+	@Test
+	public void parseCSV() {
+		String input = "" +
+				"#\n" +
+				"# underscores are used as the padding character, so leading/trailing whitespace can be considered part of the value\n" +
+				"#\n" +
+				"#4    5     40      40      8";
+
+		final FixedWidthParserSettings settings = new FixedWidthParserSettings(new FixedWidthFields(4, 5, 40, 40, 8));
+		settings.setCommentCollectionEnabled(true, true);
+		settings.getFormat().setComment('#');
+		settings.getFormat().setNormalizedNewline('\n');
+		settings.getFormat().setLineSeparator("\n");
+		settings.setHeaderExtractionEnabled(true);
+
+		final FixedWidthParser parser = new FixedWidthParser(settings);
+		parser.parse(new StringReader(input));
+
+		assertEquals(parser.getContext().comments().size(), 4);
+
+	}
+}