Module java.base
Package java.io

Class FilterReader

  • All Implemented Interfaces:
    Closeable,AutoCloseable,Readable
    Direct Known Subclasses:
    PushbackReader
    public abstract classFilterReaderextendsReader
    Abstract class for reading filtered character streams. The abstract classFilterReader itself provides default methods that pass all requests to the contained stream. Subclasses ofFilterReader should override some of these methods and may also provide additional methods and fields.
    Since:
    1.1

    • Field Detail

      • in

        protected Reader in
        The underlying character-input stream.

    • Constructor Detail

      • FilterReader

        protected FilterReader​(Reader in)
        Creates a new filtered reader.
        Parameters:
        in - a Reader object providing the underlying stream.
        Throws:
        NullPointerException - ifin isnull

    • Method Detail

      • read

        public int read()         throwsIOException
        Reads a single character.
        Overrides:
        read in class Reader
        Returns:
        The character read, as an integer in the range 0 to 65535 (0x00-0xffff), 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)         throwsIOException
        Reads characters into a portion of an array.
        Specified by:
        read in class Reader
        Parameters:
        cbuf - Destination buffer
        off - Offset at which to start storing 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
        IndexOutOfBoundsException - If an I/O error occurs

      • skip

        public long skip​(long n)          throwsIOException
        Skips characters.
        Overrides:
        skip in class Reader
        Parameters:
        n - The number of characters to skip
        Returns:
        The number of characters actually skipped
        Throws:
        IOException - If an I/O error occurs

      • ready

        public boolean ready()              throwsIOException
        Tells whether this stream is ready to be read.
        Overrides:
        ready in class Reader
        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

      • markSupported

        public boolean markSupported()
        Tells whether this stream supports the mark() operation.
        Overrides:
        markSupported in class Reader
        Returns:
        true if and only if this stream supports the mark operation.

      • mark

        public void mark​(int readAheadLimit)          throwsIOException
        Marks the present position in the stream.
        Overrides:
        mark in class Reader
        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 - If an I/O error occurs