SE-1021 Software Engineering II 7/29/2018 SE-1021 Software Engineering II Week 9, Day 2 Exceptions (briefly) Files Bits and Bytes Week 9, Day 3 Lab 8 Complete Demo Lab 9: Start writing/reading bmsoe files SE-1021 Dr. Josiah Yoder Slide style: Dr. Hornick Dr. Josiah Yoder

To catch individually, what order? Exception IllegalArgumentException IOException NumberFormatException RuntimeException SE-1021 Dr. Josiah Yoder Slide style: Dr. Hornick

Slide style: Dr. Hornick … } catch ( ) { } catch ( ) { } SE-1021 Dr. Josiah Yoder Slide style: Dr. Hornick

Slide style: Dr. Hornick Review / New Material How many bits are there in a byte? Write all the three-bit binary numbers. How many values can you encode with a single byte? SE-1021 Dr. Josiah Yoder Slide style: Dr. Hornick

Slide style: Dr. Hornick ASCII table First digit LF – Line feed (\n) 0x0A CR – carriage return (\r) 0x0D Second digit SE-1021 Dr. Josiah Yoder Slide style: Dr. Hornick http://ascii-table.com/img/ascii-table.gif

Slide style: Dr. Hornick ASCII How many bytes do you need to store one ASCII character? How many bits do you need to store one ASCII character? SE-1021 Dr. Josiah Yoder Slide style: Dr. Hornick

Slide style: Dr. Hornick Files A file is a container for a sequence of bytes stored on the computer’s hard drive Each byte is made up of 8 bits An ASCII character is one way of storing letters. “Plain text files” often use ANSI ASCII encoding. To encode other languages, we need to use a different encoding. SE-1021 Dr. Josiah Yoder Slide style: Dr. Hornick

Slide style: Dr. Hornick Using files in Java Both files and folders (Directories) are represented with a “Path” object as discussed earlier We can open the file to get the byte stream (Coding example) Path path = Paths.get(…); boolean isDir = Files.isDirectory(path); SE-1021 Dr. Josiah Yoder Slide style: Dr. Hornick

Reading the bytes from a file InputStream is an abstract class to represent reading bytes FileInputStream is a class that reads bytes from a file You can also get input streams to read bytes from the network, a byte array, etc. Use inputStream.read() to read one byte Returns -1 (an integer) if the byte is not read Use inputStream.read(…) to read multiple bytes at a time SE-1021 Dr. Josiah Yoder Slide style: Dr. Hornick