Data update

Task/Fixed-length-records/Java/fixed-length-records-1.java

@@ -0,0 +1,29 @@
+import module java.base;
+
+public final class FixedLengthRecords {
+
+	public static void main() throws IOException {
+		try ( FileChannel reader = FileChannel.open(Path.of("./infile.dat"), StandardOpenOption.READ);
+			FileChannel writer = FileChannel.open(Path.of("./outfile.dat"), StandardOpenOption.CREATE,
+																			StandardOpenOption.WRITE) ) {
+		
+			ByteBuffer buffer = ByteBuffer.allocate(BUFFER_SIZE);
+			
+			while ( reader.read(buffer) != END_OF_FILE ) {
+				for ( int i = 0, j = BUFFER_SIZE - 1; i < j; j--, i++ ) {
+				    final byte temp = buffer.get(i);
+				    buffer.put(i, buffer.get(j));
+				    buffer.put(j, temp);
+				}
+				
+				buffer.flip();
+				writer.write(buffer);
+				buffer.flip();
+			}
+		}
+	}
+	
+	private static final int BUFFER_SIZE = 80;
+	private static final int END_OF_FILE = -1;
+
+}

Task/Fixed-length-records/Java/fixed-length-records-2.java

@@ -0,0 +1,67 @@
+import module java.base;
+
+public final class FixedLengthRecordsBonusRound {
+
+	public static void main() throws IOException {
+		// Create and display the 'forth.txt' file obtained from the 'sample.txt' file used in the standard task
+		textToBlock("./sample.txt", "./forth.blk");
+		blockToText("./forth.blk", "./forth.txt");		
+		Files.lines(Path.of("./forth.txt")).forEach(IO::println);
+		
+		// Check the result of a round trip conversion: text => block => text
+		textToBlock("./forth.txt", "./forth_2.blk");
+		blockToText("./forth_2.blk", "./forth_2.txt");	
+		final boolean mismatch = ( Files.mismatch(Path.of("./forth.txt"), Path.of("./forth_2.txt")) > 0 );
+		IO.println("Files matched? " + ! mismatch);
+	}
+	
+	// Read the lines of a text file and write them as 64 byte records
+	private static void textToBlock(String inputFilePath, String outputFilePath) {		
+		try ( BufferedReader reader = Files.newBufferedReader(Path.of(inputFilePath));
+			BufferedWriter writer = Files.newBufferedWriter(Path.of(outputFilePath)) ) {
+			
+			int lineCount = 0;
+		    String line;
+		    while ( ( line = reader.readLine() ) != null ) {
+		    	if ( line.length() > LINE_SIZE ) {
+				   	line = line.substring(0, LINE_SIZE);
+				} else if ( line.length() < LINE_SIZE ) {
+				   	line += " ".repeat(LINE_SIZE - line.length());
+				}
+				
+		    	writer.write(line);
+		    	lineCount += 1;
+		    }
+		
+		    // Complete the block with empty lines
+		    final int emptyLineCount = ( LINE_COUNT - lineCount % LINE_COUNT ) % LINE_COUNT;
+		    for ( int i = 0; i < emptyLineCount; i++ ) {
+		    	writer.write(EMPTY_LINE);
+		    }	
+		} catch (IOException ioe) {
+		    ioe.printStackTrace();
+		}
+	}
+	
+	// Read 64 bytes records and write them as lines with trailing spaces removed
+	private static void blockToText(String inputFilePath, String outputFilePath) {
+		try ( FileChannel reader = FileChannel.open(Path.of(inputFilePath), StandardOpenOption.READ);
+			BufferedWriter writer = Files.newBufferedWriter(Path.of(outputFilePath)) ) {
+			
+			ByteBuffer buffer = ByteBuffer.allocate(LINE_SIZE);
+			
+			while ( reader.read(buffer) != END_OF_FILE ) {
+		    	writer.write( new String(buffer.array()).stripTrailing() + System.lineSeparator() );
+		    	buffer.flip();
+		    }			
+		} catch (IOException ioe) {
+			ioe.printStackTrace();
+		}
+	}
+	
+	private static final int LINE_SIZE = 64;
+	private static final int LINE_COUNT = 16;	
+	private static final int END_OF_FILE = -1;
+	private static final String EMPTY_LINE = " ".repeat(LINE_SIZE);
+
+}