java.io

Class PushbackReader

  • All Implemented Interfaces:
    Closeable, AutoCloseable, Readable

    public class PushbackReader
    extends FilterReader
    A character-stream reader that allows characters to be pushed back into the stream.
    Since:
    JDK1.1
    • Field Summary

      • Fields inherited from class java.io.FilterReader

        in
      • Fields inherited from class java.io.Reader

        lock
    • Constructor Summary

      Constructors 
      Constructor and Description
      PushbackReader(Reader in)
      Creates a new pushback reader with a one-character pushback buffer.
      PushbackReader(Reader in, int size)
      Creates a new pushback reader with a pushback buffer of the given size.

        

    • Method Summary

      Methods 
      Modifier and Type Method and Description
      void close()
      Closes the stream and releases any system resources associated with it.
      void mark(int readAheadLimit)
      Marks the present position in the stream.
      boolean markSupported()
      Tells whether this stream supports the mark() operation, which it does not.
      int read()
      Reads a single character.
      int read(char[] cbuf, int off, int len)
      Reads characters into a portion of an array.
      boolean ready()
      Tells whether this stream is ready to be read.
      void reset()
      Resets the stream.
      long skip(long n)
      Skips characters.
      void unread(char[] cbuf)
      Pushes back an array of characters by copying it to the front of the pushback buffer.
      void unread(char[] cbuf, int off, int len)
      Pushes back a portion of an array of characters by copying it to the front of the pushback buffer.
      void unread(int c)
      Pushes back a single character by copying it to the front of the pushback buffer.

        

      • Methods inherited from class java.io.Reader

        read, read
    • Constructor Detail

      • PushbackReader

        public PushbackReader(Reader in,
                      int size)
        Creates a new pushback reader with a pushback buffer of the given size.
        Parameters:
        in - The reader from which characters will be read
        size - The size of the pushback buffer
        Throws:
        IllegalArgumentException - if size is <= 0
      • PushbackReader

        public PushbackReader(Reader in)
        Creates a new pushback reader with a one-character pushback buffer.
        Parameters:
        in - The reader from which characters will be read
    • Method Detail

      • read

        public int read()
                 throws IOException
        Reads a single character.
        Overrides:
        read in class FilterReader
        Returns:
        The character read, or -1 if the end of the stream has been reached
        Throws:
        IOException - If an I/O error occurs
      • read

        public int read(char[] cbuf,
               int off,
               int len)
                 throws IOException
        Reads characters into a portion of an array.
        Overrides:
        read in class FilterReader
        Parameters:
        cbuf - Destination buffer
        off - Offset at which to start writing characters
        len - Maximum number of characters to read
        Returns:
        The number of characters read, or -1 if the end of the stream has been reached
        Throws:
        IOException - If an I/O error occurs
      • unread

        public void unread(int c)
                    throws IOException
        Pushes back a single character by copying it to the front of the pushback buffer. After this method returns, the next character to be read will have the value (char)c.
        Parameters:
        c - The int value representing a character to be pushed back
        Throws:
        IOException - If the pushback buffer is full, or if some other I/O error occurs
      • unread

        public void unread(char[] cbuf,
                  int off,
                  int len)
                    throws IOException
        Pushes back a portion of an array of characters by copying it to the front of the pushback buffer. After this method returns, the next character to be read will have the value cbuf[off], the character after that will have the value cbuf[off+1], and so forth.
        Parameters:
        cbuf - Character array
        off - Offset of first character to push back
        len - Number of characters to push back
        Throws:
        IOException - If there is insufficient room in the pushback buffer, or if some other I/O error occurs
      • unread

        public void unread(char[] cbuf)
                    throws IOException
        Pushes back an array of characters by copying it to the front of the pushback buffer. After this method returns, the next character to be read will have the value cbuf[0], the character after that will have the value cbuf[1], and so forth.
        Parameters:
        cbuf - Character array to push back
        Throws:
        IOException - If there is insufficient room in the pushback buffer, or if some other I/O error occurs
      • ready

        public boolean ready()
                      throws IOException
        Tells whether this stream is ready to be read.
        Overrides:
        ready in class FilterReader
        Returns:
        True if the next read() is guaranteed not to block for input, false otherwise. Note that returning false does not guarantee that the next read will block.
        Throws:
        IOException - If an I/O error occurs
      • mark

        public void mark(int readAheadLimit)
                  throws IOException
        Marks the present position in the stream. The mark for class PushbackReader always throws an exception.
        Overrides:
        mark in class FilterReader
        Parameters:
        readAheadLimit - Limit on the number of characters that may be read while still preserving the mark. After reading this many characters, attempting to reset the stream may fail.
        Throws:
        IOException - Always, since mark is not supported
      • reset

        public void reset()
                   throws IOException
        Resets the stream. The reset method of PushbackReader always throws an exception.
        Overrides:
        reset in class FilterReader
        Throws:
        IOException - Always, since reset is not supported
      • markSupported

        public boolean markSupported()
        Tells whether this stream supports the mark() operation, which it does not.
        Overrides:
        markSupported in class FilterReader
        Returns:
        true if and only if this stream supports the mark operation.
      • close

        public void close()
                   throws IOException
        Closes the stream and releases any system resources associated with it. Once the stream has been closed, further read(), unread(), ready(), or skip() invocations will throw an IOException. Closing a previously closed stream has no effect.
        Specified by:
        close in interface Closeable
        Specified by:
        close in interface AutoCloseable
        Overrides:
        close in class FilterReader
        Throws:
        IOException - If an I/O error occurs
      • skip

        public long skip(long n)
                  throws IOException
        Skips characters. This method will block until some characters are available, an I/O error occurs, or the end of the stream is reached.
        Overrides:
        skip in class FilterReader
        Parameters:
        n - The number of characters to skip
        Returns:
        The number of characters actually skipped
        Throws:
        IllegalArgumentException - If n is negative.
        IOException - If an I/O error occurs

Traduction non disponible

Les API Java ne sont pas encore traduites en français sur l'infobrol. Seule la version anglaise est disponible pour l'instant.

Document créé le 29/08/2006, dernière modification le 04/03/2020
Source du document imprimé : https://www.gaudry.be/java-api-rf-java/io/pushbackreader.html

L'infobrol est un site personnel dont le contenu n'engage que moi. Le texte est mis à disposition sous licence CreativeCommons(BY-NC-SA). Plus d'info sur les conditions d'utilisation et sur l'auteur.

Références

  1. Consulter le document html Langue du document :fr Manuel PHP : https://docs.oracle.com, PushbackReader

Ces références et liens indiquent des documents consultés lors de la rédaction de cette page, ou qui peuvent apporter un complément d'information, mais les auteurs de ces sources ne peuvent être tenus responsables du contenu de cette page.
L'auteur de ce site est seul responsable de la manière dont sont présentés ici les différents concepts, et des libertés qui sont prises avec les ouvrages de référence. N'oubliez pas que vous devez croiser les informations de sources multiples afin de diminuer les risques d'erreurs.

Table des matières Haut