java.io.LineNumberInputStream class is simply an extension of input stream providing a extra facility to keep the record of current line number.
Line is a sequence of bytes ending with : ‘\r’ i.e. a carriage return character or a newline character : ‘\n’, or a linefeed character following the carriage return character.
Declaration :
public class LineNumberInputStream extends Reader
Constructors :
LineNumberInputStream(InputStream in) : Constructs a newline no. stream that reads it's input from the specified Input Stream.
Methods:
- read() : java.io.LineNumberInputStream.read() reads next byte of data from input stream. It returns int value representing the bytes in the range of ‘0 – 255’. It returns ‘-1’ to indicate end of Input Stream.
Syntax :
public int read() Parameters : ------- Return : int value representing the bytes in the range of '0 - 255'. return -1, indicating end of Input Stream. Exception: IOException : in case I/O error occurs
Implementation :
Java
// Java program illustrating the working of read() methodimport java.io.*;public class NewClass{ public static void main(String[] args) throws IOException { // LineNumberInputStream & FileInputStream initially null LineNumberInputStream geekline = null; FileInputStream geekinput = null; try{ char c; int a; // New InputStream : 'ABC' is created geekinput = new FileInputStream("ABC.txt"); geekline = new LineNumberInputStream(geekinput); // read() method returning Bytes of Input Stream as integer // '-1' indicating to read till end Of Input Stream while((a = geekline.read()) != -1) { // Since read() method returns Integer value // So, we convert each integer value to char c = (char)a; System.out.print(c); } } catch(Exception e) { // In case of error e.printStackTrace(); System.out.println("ERROR Occurs "); } finally { // Closing the streams, Once the End of Input Stream is reached if(geekinput != null) geekinput.close(); if(geekline != null) geekline.close(); } }} |
Note :
The following Java Code won’t run here as we can’t access any file on online IDE.
So, copy the program to your system and run it there.
The ABC.txt file used in the program contains :
Hello Geeks. Explaining read() method
Output :
Hello Geeks. Explaining read() method
- getLineNumber() : java.io.LineNumberInputStream.getLineNumber() returns number of current line.
Syntax :
public int getLineNumber() Parameters : ------- Return : no. of current line
Implementation :
Java
// Java program illustrating the working of getLineNumber() methodimport java.io.*;public class NewClass{ public static void main(String[] args) throws IOException { // LineNumberInputStream & FileInputStream initially null LineNumberInputStream geekline = null; FileInputStream geekinput = null; try { char c; int a, b; // New InputStream : 'ABC' is created geekinput = new FileInputStream("ABC.txt"); geekline = new LineNumberInputStream(geekinput); while((a = geekline.read()) != -1) { // So, we convert each integer value to char c = (char)a; // Use of getLineNumber() : to print line no. a = geekline.getLineNumber(); System.out.println(" At line : " + a); System.out.print(c); } a = geekline.getLineNumber(); System.out.println(" at line: " + a); } catch(Exception e) { // In case of error e.printStackTrace(); System.out.println("ERROR Occurs "); } finally { // Closing the streams, Once the End of Input Stream is reached if(geekinput != null) geekinput.close(); if(geekline != null) geekline.close(); } }} |
Note :
The following Java Code won’t run here as we can’t access any file on online IDE.
So, copy the program to your system and run it there.
The ABC.txt file used in the program contains :
no. of lines
Output :
At line : 0 n At line : 0 o At line : 0 . At line : 0 At line : 0 o At line : 0 f At line : 1 At line : 1 l At line : 1 i At line : 1 n At line : 1 e At line : 1 s at line: 1
- available() : java.io.LineNumberInputStream.available() returns the number of bytes that can be read from the Input Stream without blocking.
Syntax :
public int available() Parameters : ------- Return : returns the no. of bytes that can be read from the Input Stream. Exception: IOException : in case I/O error occurs
Implementation :
Java
// Java program illustrating the working of available() methodimport java.io.*;public class NewClass{ public static void main(String[] args) throws IOException { // LineNumberInputStream & FileInputStream initially null LineNumberInputStream geekline = null; FileInputStream geekinput = null; try{ char c; int a, b; // New InputStream : 'ABC' is created geekinput = new FileInputStream("ABC.txt"); geekline = new LineNumberInputStream(geekinput); while((a = geekline.read()) != -1) { // So, we convert each integer value to char c = (char)a; // Use of available method : return no. of bytes that can be read a = geekline.available(); System.out.println(c + " Bytes available : " + a); } } catch(Exception e) { // In case of error e.printStackTrace(); System.out.println("ERROR Occurs "); } finally { // Closing the streams, Once the End of Input Stream is reached if(geekinput != null) geekinput.close(); if(geekline != null) geekline.close(); } }} |
Note :
The following Java Code won’t run here as we can’t access any file on online IDE.
So, copy the program to your system and run it there.
The ABC.txt file used in the program contains :
available
Output :
a Bytes available : 4 v Bytes available : 3 a Bytes available : 3 i Bytes available : 2 l Bytes available : 2 a Bytes available : 1 b Bytes available : 1 l Bytes available : 0 e Bytes available : 0
- setLineNumber() : java.io.LineNumberInputStream.setLineNumber(int arg) assigns line number to the argument we want.
Syntax :
public void setLineNumber(int arg) Parameters : arg : line number to assign Return : void Exception: -----
Implementation :
Java
// Java program illustrating the working of setLineNumber() methodimport java.io.*;public class NewClass{ public static void main(String[] args) throws IOException { // LineNumberInputStream & FileInputStream initially null LineNumberInputStream geekline = null; FileInputStream geekinput = null; try{ char c; int a, b = 0; // New InputStream : 'ABC' is created geekinput = new FileInputStream("ABC.txt"); geekline = new LineNumberInputStream(geekinput); while((a = geekline.read()) != -1) { // So, we convert each integer value to char c = (char)a; // Use of setLineNumber() : to set the line no. geekline.setLineNumber(100 + b); // getLineNumber() : returning the current line no. a = geekline.getLineNumber(); System.out.println(c + " Line No. Set : " + a); b++; } } catch(Exception e) { // In case of error e.printStackTrace(); System.out.println("ERROR Occurs "); } finally { // Closing the streams, Once the End of Input Stream is reached if(geekinput != null) geekinput.close(); if(geekline != null) geekline.close(); } }} |
Note :
The following Java Code won’t run here as we can’t access any file on online IDE.
So, copy the program to your system and run it there.
The ABC.txt file used in the program contains :
LineNumber
Output :
L Line No. Set : 100 i Line No. Set : 101 n Line No. Set : 102 e Line No. Set : 103 N Line No. Set : 104 u Line No. Set : 105 m Line No. Set : 106 b Line No. Set : 107 e Line No. Set : 108 r Line No. Set : 109
- skip() : java.io.LineNumberInputStream.skip(long arg) skips and discards ‘arg’ bytes from Input Stream data. The skip method of LineNumberInputStream creates a byte array and then repeatedly reads into it until n bytes have been read or the end of the stream has been reached.
Syntax :
public long skip(long arg) Parameters : arg : no. of bytes of Input Stream data to skip. Return : no. of bytes to be skipped Exception: IOException : in case I/O error occurs
Implementation :
Java
// Java program illustrating the working of setLineNumber() methodimport java.io.*;public class NewClass{ public static void main(String[] args) throws IOException { // LineNumberInputStream & FileInputStream initially null LineNumberInputStream geekline = null; FileInputStream geekinput = null; try{ char c; int a, b = 0; // New InputStream : 'ABC' is created geekinput = new FileInputStream("ABC.txt"); geekline = new LineNumberInputStream(geekinput); while((a = geekline.read()) != -1) { // So, we convert each integer value to char c = (char)a; // skip() : to skip and discard 'arg' bytes // Here skip() will skip and discard 3 bytes. geekline.skip(3); System.out.println(c); } } catch(Exception e) { // In case of error e.printStackTrace(); System.out.println("ERROR Occurs "); } finally{ // Closing the streams, Once the End of Input Stream is reached if(geekinput != null) geekinput.close(); if(geekline != null) geekline.close(); } }} |
Note :
The following Java Code won’t run here as we can’t access any file on online IDE.
So, copy the program to your system and run it there.
The ABC.txt file used in the program contains :
Program Explaining Skip() method
Output :”
P r E a n k ) t
- read() : java.io.LineNumberInputStream.read(byte[] buffer, int offset, int maxlen) reads up to ‘maxlen’ bytes from Input Stream into bytes.
Syntax :
public int read(byte[] buffer, int offset, int maxlen) Parameters : buffer : buffer whose data to read offset : starting offset of the data maxlen : max. no. of bytes to read Return : total no. of bytes, else return -1 if End of Input Stream is identified Exception: IOException : in case I/O error occurs
Implementation :
Java
// Java program illustrating the working of read() methodimport java.io.*;public class NewClass{ public static void main(String[] args) throws IOException { // LineNumberInputStream & FileInputStream initially null LineNumberInputStream geekline = null; FileInputStream geekinput = null; try{ char c; int a; // New InputStream : 'ABC' is created geekinput = new FileInputStream("ABC.txt"); geekline = new LineNumberInputStream(geekinput); // read() method returning Bytes of Input Stream as integer // '-1' indicating to read till end Of Input Stream while((a=geekline.read())!=-1) { // Since read() method returns Integer value // So, we convert each integer value to char c = (char)a; System.out.print(c); } } catch(Exception e) { // In case of error e.printStackTrace(); System.out.println("ERROR Occurs "); } finally { // Closing the streams, Once the End of Input Stream is reached if(geekinput != null) geekinput.close(); if(geekline != null) geekline.close(); } }} |
Note :
The following Java Code won’t run here as we can’t access any file on online IDE.
So, copy the program to your system and run it there.
The ABC.txt file used in the program contains :
Read() method
what the method does is offset = r and maxlen = 5… so —i.e. 3 offset, then 5 bytes i.e. Read(, then again offset, so —
Output :
The number of char read: 5 ---Read(--
- mark() : Java.io.LineNumberInputStream.mark(int arg) marks the current position of the input stream. It sets readlimit i.e. maximum number of bytes that can be read before mark position becomes invalid.
Syntax :
public void mark(int arg) Parameters : arg : integer specifying the read limit of the input Stream Return : void
- reset() : Java.io.LineNumberInputStream.reset() is invoked by mark() method. It re-positions the input stream to the marked position.
Syntax :
public void reset() Parameters : ---- Return : void Exception : -> IOException : If I/O error occurs.
Java Program explaining LineNumberInputStream Class methods : reset() and mark()
Java
// Java program illustrating the working of LineNumberInputStream method// mark() and reset()import java.io.*;public class NewClass{ public static void main(String[] args) throws Exception { LineNumberInputStream geekline = null; FileInputStream geek = null; try{ geek = new FileInputStream("GEEKS.txt"); geekline = new LineNumberInputStream(geek); // read() method : reading and printing Characters one by one System.out.println("Char : " + (char)geekline.read()); System.out.println("Char : " + (char)geekline.read()); System.out.println("Char : " + (char)geekline.read()); // mark() : read limiting the 'geek' input stream geekline.mark(0); // skip() : it results in reading of 'e' in G'e'eeks geekline.skip(1); System.out.println("skip() method comes to play"); System.out.println("mark() method comes to play"); System.out.println("Char : " + (char)geekline.read()); System.out.println("Char : " + (char)geekline.read()); System.out.println("Char : " + (char)geekline.read()); boolean check = geekline.markSupported(); if(geekline.markSupported()) { // reset() method : repositioning the stream to marked positions. geekline.reset(); System.out.println("reset() invoked"); System.out.println("Char : " + (char)geekline.read()); System.out.println("Char : " + (char)geekline.read()); } else { System.out.println("reset() method not supported."); } System.out.println("geekline.markSupported() supported reset() : " + check); } catch(Exception except) { // in case of I/O error except.printStackTrace(); } finally { // releasing the resources back to the GarbageCollector when closes if(geek != null) geek.close(); if(geekline != null) geekline.close(); } }} |
Note :
This code won’t run on online IDE as no such file is present here.
You can run this code on your System to check the working.
ABC.txt file used in the code has
HelloGeeks
Output :
Char : H Char : e Char : l skip() method comes to play mark() method comes to play Char : o Char : G Char : e reset() method not supported. geekline.markSupported() supported reset() : false
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