JAVA.IO.LINENUMBERINPUTSTREAM КЛАС В JAVA

Класът java.io.LineNumberInputStream е просто разширение на входен поток, предоставящо допълнителна възможност за запазване на записа на текущия номер на ред.

Линия е поредица от байтове, завършващи с: 'r', т.е. символ за връщане на каретка или знак за нов ред: 'n' или знак за нов ред след знака за връщане на каретка.

Декларация:

public class LineNumberInputStream extends Reader

Конструктори:

  LineNumberInputStream(InputStream in) :    Constructs a newline no. stream that reads it's input from the specified Input Stream.

Методи:

Синтаксис:

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

Изпълнение:

Java

    // Java program illustrating the working of read() method   import     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  ();      }      }   }

Забележка:
Следният код на Java няма да се изпълнява тук, тъй като нямаме достъп до нито един файл в онлайн IDE.
Така че копирайте програмата във вашата система и я стартирайте там.

The ABC.txt файлът, използван в програмата, съдържа:

Hello Geeks. Explaining read() method

Изход:

Hello Geeks. Explaining read() method

Синтаксис:

 public int getLineNumber()   Parameters :    -------   Return :    no. of current line

Изпълнение:

Java

    // Java program illustrating the working of getLineNumber() method   import     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  ();      }      }   }

The ABC.txt файлът, използван в програмата, съдържа:

no. of lines

Изход:

 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

Синтаксис:

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

Изпълнение:

Java

    // Java program illustrating the working of available() method   import     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  ();      }      }   }

The ABC.txt файлът, използван в програмата, съдържа:

available

Изход:

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

Синтаксис:

public void setLineNumber(int arg)   Parameters :    arg : line number to assign   Return :    void   Exception:    -----

Изпълнение:

Java

    // Java program illustrating the working of setLineNumber() method   import     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  ();      }      }   }

The ABC.txt файлът, използван в програмата, съдържа:

LineNumber

Изход:

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

Синтаксис:

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

Изпълнение:

Java

    // Java program illustrating the working of setLineNumber() method   import     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  ();      }      }   }

The ABC.txt файлът, използван в програмата, съдържа:

Program Explaining Skip() method

Изход: '

P r E a n k ) t

Синтаксис:

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

Изпълнение:

Java

    // Java program illustrating the working of read() method   import     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  ();      }      }   }

The ABC.txt файлът, използван в програмата, съдържа:

Read() method

това, което прави методът, е offset = r и maxlen = 5... така че --- т.е. 3 отместване, след това 5 байта, т.е. четене (след това отново отместване, така че --
Изход:

The number of char read: 5 ---Read(--

Синтаксис:

public void mark(int arg)   Parameters :   arg : integer specifying the read limit of the input Stream   Return :   void

Синтаксис:

public void reset()   Parameters :   ----   Return :   void   Exception :   ->   IOException :   If I/O error occurs.

Java програма, обясняваща методите на класа LineNumberInputStream: reset() и 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  ();      }      }   }

Забележка:
Този код няма да работи на онлайн IDE, тъй като тук няма такъв файл.
Можете да стартирате този код на вашата система, за да проверите работата.

ABC.txt файлът, използван в кода, има

HelloGeeks

Изход:

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

Създаване на тест