Various io stream classes .47
- 1. Various I/O Stream Classes http://improvejava.blogspot.in/ 1
- 2. Objectives On completion of this period, you would be able to learn • Concept of streams • Various input and output stream classes http://improvejava.blogspot.in/ 2
- 3. Recap In the previous classes, you have studied about exception handling mechanism in java • Types of exceptions in java http://improvejava.blogspot.in/ 3
- 4. Concept of Stream • Java performs I/O through streams •A stream is an abstraction that either produces or consumes information •A stream is linked to an I/O device by Java I/O system •All streams behave in the same manner, even if the actual physical device they are linked to differ •Thus, same I/O classes and methods can be applied to any type of device •For example, the same methods that are used to write console can also be used to write to a disk file http://improvejava.blogspot.in/ 4
- 5. Concept of Stream The following figure gives the relationship of java program with I/O devices Key Board Screen Mouse printer Java Memory Memory Program Disk Disk Network Network Fig. 47.1 Relationship of Java programs with I/O devices http://improvejava.blogspot.in/ 5
- 6. Concept of Stream • The Fig. 47.1 shows in Java all I/O devices may be used with stream •For example, the same methods that are used to write console can also be used to write to a disk file • java implements streams within class hierarchies defined in java.io. package http://improvejava.blogspot.in/ 6
- 7. Concept of Streams • Input refers to flow of data into a program • Output refers to flow of data out of a program as shown in Fig. 47.1 http://improvejava.blogspot.in/ 7
- 8. Concept of Streams Contd.. • I/O operations are complex to understand • But more flexible and powerful • Developers have focused their attention for non keyboard oriented data handling • Developers wanted to perform platform independent I/O, hence the complexity http://improvejava.blogspot.in/ 8
- 9. Various I/O Stream Classes • java.io package defines I/O in terms of streams • Two types of Streams 1. Byte streams • 8 bits, binary data-based • Examples: InputStream and OutputStream classes 2. Character streams • 16 bits, text-based • Examples: Reader and Writer classes http://improvejava.blogspot.in/ 9
- 10. Various I/O Stream Classes • The following diagrams show the class hierarchies of the stream classes • InputStream • OutputStream • Reader • Writer http://improvejava.blogspot.in/ 9CM604.47 10
- 11. Hierarchy of InputStream classes Object InputStream FileInputStream SequenceInpuStream PipedInpuStream ObjectInputStream ByteArrayInputStream StringBufferInputStream FilterInpuStream DataInputStream BufferedInpuStream PushBackInputSteam 11 Fig. 47.2 DataInput http://improvejava.blogspot.in/
- 12. Hierarchy of OutputStream Classes Object OutputStream FileOutputStream ObjectOutputStream PipedOutputStream ByteArrayOutputStream FilterOutpuStream DataOutputStream BufferedOutpuStream PushBackOutputSteam Fig. 47.3 DataOutput http://improvejava.blogspot.in/ 12
- 13. Hierarchy of Reader Classes Object Reader BufferedReader StringReader CharArrayReader PipeReader InputStreamReader FilterReader Fig. 47.4 FileReader PushBackReader http://improvejava.blogspot.in/ 13
- 14. Hierarchy of Writer Classes Object Writer BufferedWriter PrintWriter CharArrayWriter StringWriter FilterWriter PipeWriter FileReader OutputStreamWriter Fig No 47.5 14 FileWriter http://improvejava.blogspot.in/
- 15. Simple Input and Output Streams • FileInputStream and FileOutputStream • Used to read data from or write data to a file on the native file system • PipedInputStream and PipedOutputStream • Implements the input and output components of a pipe • Pipes are used to channel the output from one program (or thread or code block) into the input of another • A PipedInputStream must be connected to a PipedOutputStream and vice versa http://improvejava.blogspot.in/ 15
- 16. Simple Input and Output Streams • ByteArrayInputStream and ByteArrayOutputStream • Reads data from or writes data to a byte array in memory • SequenceInputStream • Concatenates multiple input streams into one input stream • StringBufferInputStream • Allows programs to read from a StringBuffer as if it were an input stream http://improvejava.blogspot.in/ 16
- 17. Filtered Streams • FilterInputStream and FilterOutputStream are subclasses of InputStream and OutputStream • Both are abstract classes • These classes defines the interface for filtered streams • Filtered streams process the data as its being read or written • DataInputStream and DataOutputStream • Reads or writes primitive Java data types in a machine independent format http://improvejava.blogspot.in/ 17
- 18. Filtered Streams • BufferedInputStream and BufferedOutputStream • This is an efficient stream that buffers data while reading or writing • LineNumberInputStream • An input stream that keeps track of line numbers while reading • PushbackInputStream • An input stream with a one-byte pushback buffer PrintStream • An output stream with convenient printing methods http://improvejava.blogspot.in/ 18
- 19. Summary • Flow of bits of information either into the program or from the program to and from • Various input and output devices • Stream is a logical entity that either produces or consumes information • Two types of Streams 1. Byte streams 2. Character streams http://improvejava.blogspot.in/ 19
- 20. Quiz 1. Which of the following is not Byte streams A. Input Stream B. Output Stream C. Reader D. None http://improvejava.blogspot.in/ 20
- 21. Quiz 2. Streams is ordered sequences of data that have a source or a destination A. True B. False http://improvejava.blogspot.in/ 21
- 22. Frequently Asked Questions 1. Explain the concept of Streams 2. Explain the various input output stream classes http://improvejava.blogspot.in/ 22