Package org.fife.io

Class UnicodeReader

  • All Implemented Interfaces:
    java.io.Closeable, java.lang.AutoCloseable, java.lang.Readable
    public class UnicodeReader
extends java.io.Reader
    A reader capable of identifying Unicode streams by their BOMs. This class will recognize the following encodings:
    • UTF-8
    • UTF-16LE
    • UTF-16BE
    • UTF-32LE
    • UTF-32BE
    If the stream is not found to be any of the above, then a default encoding is used for reading. The user can specify this default encoding, or a system default will be used.

    For optimum performance, it is recommended that you wrap all instances of UnicodeReader with a java.io.BufferedReader.

    This class is mostly ripped off from the workaround in the description of Java Bug 4508058.

    Version:
    0.9

    • Field Summary

      Fields 
      Modifier and Type Field Description
      private static int BOM_SIZE
      The size of a BOM.
      private java.lang.String encoding
      The encoding being used.
      private java.io.InputStreamReader internalIn
      The input stream from which we're really reading.

      • Fields inherited from class java.io.Reader

        lock

    • Constructor Summary

      Constructors 
      Constructor Description
      UnicodeReader​(java.io.File file)
      This utility constructor is here because you will usually use a UnicodeReader on files.
      UnicodeReader​(java.io.File file, java.lang.String defaultEncoding)
      This utility constructor is here because you will usually use a UnicodeReader on files.
      UnicodeReader​(java.io.File file, java.nio.charset.Charset defaultCharset)
      This utility constructor is here because you will usually use a UnicodeReader on files.
      UnicodeReader​(java.io.InputStream in)
      Creates a reader using the encoding specified by the BOM in the file; if there is no recognized BOM, then a system default encoding is used.
      UnicodeReader​(java.io.InputStream in, java.lang.String defaultEncoding)
      Creates a reader using the encoding specified by the BOM in the file; if there is no recognized BOM, then defaultEncoding is used.
      UnicodeReader​(java.io.InputStream in, java.nio.charset.Charset defaultCharset)
      Creates a reader using the encoding specified by the BOM in the file; if there is no recognized BOM, then defaultEncoding is used.
      UnicodeReader​(java.lang.String file)
      This utility constructor is here because you will usually use a UnicodeReader on files.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void close()
      Closes this reader.
      java.lang.String getEncoding()
      Returns the encoding being used to read this input stream (i.e., the encoding of the file).
      protected void init​(java.io.InputStream in, java.lang.String defaultEncoding)
      Read-ahead four bytes and check for BOM marks.
      int read​(char[] cbuf, int off, int len)
      Read characters into a portion of an array.

      • Methods inherited from class java.io.Reader

        mark, markSupported, nullReader, read, read, read, ready, reset, skip, transferTo

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • internalIn

        private java.io.InputStreamReader internalIn
        The input stream from which we're really reading.

      • encoding

        private java.lang.String encoding
        The encoding being used. We keep our own instead of using the string returned by java.io.InputStreamReader since that class does not return user-friendly names.

    • Constructor Detail

      • UnicodeReader

        public UnicodeReader​(java.lang.String file)
              throws java.io.IOException
        This utility constructor is here because you will usually use a UnicodeReader on files.

        Creates a reader using the encoding specified by the BOM in the file; if there is no recognized BOM, then a system default encoding is used.

        Parameters:
        file - The file from which you want to read.
        Throws:
        java.io.IOException - If an error occurs when checking for/reading the BOM.
        java.lang.SecurityException - If a security manager exists and its checkRead method denies read access to the file.

      • UnicodeReader

        public UnicodeReader​(java.io.File file)
              throws java.io.IOException
        This utility constructor is here because you will usually use a UnicodeReader on files.

        Creates a reader using the encoding specified by the BOM in the file; if there is no recognized BOM, then a system default encoding is used.

        Parameters:
        file - The file from which you want to read.
        Throws:
        java.io.IOException - If an error occurs when checking for/reading the BOM.
        java.lang.SecurityException - If a security manager exists and its checkRead method denies read access to the file.

      • UnicodeReader

        public UnicodeReader​(java.io.File file,
                     java.lang.String defaultEncoding)
              throws java.io.IOException
        This utility constructor is here because you will usually use a UnicodeReader on files.

        Creates a reader using the encoding specified by the BOM in the file; if there is no recognized BOM, then a specified default encoding is used.

        Parameters:
        file - The file from which you want to read.
        defaultEncoding - The encoding to use if no BOM is found. If this value is null, a system default is used.
        Throws:
        java.io.IOException - If an error occurs when checking for/reading the BOM.
        java.lang.SecurityException - If a security manager exists and its checkRead method denies read access to the file.

      • UnicodeReader

        public UnicodeReader​(java.io.File file,
                     java.nio.charset.Charset defaultCharset)
              throws java.io.IOException
        This utility constructor is here because you will usually use a UnicodeReader on files.

        Creates a reader using the encoding specified by the BOM in the file; if there is no recognized BOM, then a specified default encoding is used.

        Parameters:
        file - The file from which you want to read.
        defaultCharset - The encoding to use if no BOM is found. If this value is null, a system default is used.
        Throws:
        java.io.IOException - If an error occurs when checking for/reading the BOM.
        java.lang.SecurityException - If a security manager exists and its checkRead method denies read access to the file.

      • UnicodeReader

        public UnicodeReader​(java.io.InputStream in)
              throws java.io.IOException
        Creates a reader using the encoding specified by the BOM in the file; if there is no recognized BOM, then a system default encoding is used.
        Parameters:
        in - The input stream from which to read.
        Throws:
        java.io.IOException - If an error occurs when checking for/reading the BOM.

      • UnicodeReader

        public UnicodeReader​(java.io.InputStream in,
                     java.lang.String defaultEncoding)
              throws java.io.IOException
        Creates a reader using the encoding specified by the BOM in the file; if there is no recognized BOM, then defaultEncoding is used.
        Parameters:
        in - The input stream from which to read.
        defaultEncoding - The encoding to use if no recognized BOM is found. If this value is null, a system default is used.
        Throws:
        java.io.IOException - If an error occurs when checking for/reading the BOM.

      • UnicodeReader

        public UnicodeReader​(java.io.InputStream in,
                     java.nio.charset.Charset defaultCharset)
              throws java.io.IOException
        Creates a reader using the encoding specified by the BOM in the file; if there is no recognized BOM, then defaultEncoding is used.
        Parameters:
        in - The input stream from which to read.
        defaultCharset - The encoding to use if no recognized BOM is found. If this value is null, a system default is used.
        Throws:
        java.io.IOException - If an error occurs when checking for/reading the BOM.

    • Method Detail

      • close

        public void close()
           throws java.io.IOException
        Closes this reader.
        Specified by:
        close in interface java.lang.AutoCloseable
        Specified by:
        close in interface java.io.Closeable
        Specified by:
        close in class java.io.Reader
        Throws:
        java.io.IOException

      • getEncoding

        public java.lang.String getEncoding()
        Returns the encoding being used to read this input stream (i.e., the encoding of the file). If a BOM was recognized, then the specific Unicode type is returned; otherwise, either the default encoding passed into the constructor or the system default is returned.
        Returns:
        The encoding of the stream.

      • init

        protected void init​(java.io.InputStream in,
                    java.lang.String defaultEncoding)
             throws java.io.IOException
        Read-ahead four bytes and check for BOM marks. Extra bytes are unread back to the stream, only BOM bytes are skipped.
        Parameters:
        defaultEncoding - The encoding to use if no BOM was recognized. If this value is null, then a system default is used.
        Throws:
        java.io.IOException - If an error occurs when trying to read a BOM.

      • read

        public int read​(char[] cbuf,
                int off,
                int len)
         throws java.io.IOException
        Read characters into a portion of an array. This method will block until some input is available, an I/O error occurs, or the end of the stream is reached.
        Specified by:
        read in class java.io.Reader
        Parameters:
        cbuf - The buffer into which to read.
        off - The offset at which to start storing characters.
        len - The maximum number of characters to read.
        Returns:
        The number of characters read, or -1 if the end of the stream has been reached.
        Throws:
        java.io.IOException