org.mdiutil.io

Class FilteredBufferedReader

java.lang.Object

java.io.Reader

java.io.BufferedReader

org.mdiutil.io.FilteredBufferedReader

All Implemented Interfaces:

Closeable, AutoCloseable, Readable

public abstract class FilteredBufferedReader
extends BufferedReader

This class is a Buffered reader which allows to filter lines read in the stream. It is also possible to use either of the methods in the BufferedReader class, as the result is guaranteed to behave as expected. To use this class, you have to implement the filterLine(String) method. For example:

    BufferedReader reader = new FilteredBufferedReader(new FileReader(in)) {
       public String filterLine(String line) {
          return line.trim().toLowerCase();
       }
    };
 

In this example, each attempts to the readLine() method will get the next line in the input File, after trimming this line and transforming it to lower case.

Field Summary

Fields inherited from class java.io.Reader

lock

Constructor Summary

Constructors

Constructor and Description
FilteredBufferedReader(Reader in) Create a buffering character-input stream that uses a default-sized input buffer.
FilteredBufferedReader(Reader in, int sz) Create a buffering character-input stream that uses an input buffer of the specified size.

Method Summary

Modifier and Type	Method and Description
abstract String	filterLine(String line) This abstract method allows to filter each line which is read by this Reader.
void	mark(int readAheadLimit) Mark the present position in the stream.
int	read() Read a single character.
int	read(char[] cbuf) Read characters into an array.
int	read(char[] cbuf, int off, int len) Read characters into a portion of an array.
String	readLine() Read a line of text.
boolean	ready() Tell whether this stream is ready to be read.
void	reset() Resets the stream to the most recent mark.
long	skip(long n) Skip characters.

Methods inherited from class java.io.BufferedReader

close, lines, markSupported

Methods inherited from class java.io.Reader

read

Methods inherited from class java.lang.Object

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

Constructor Detail

FilteredBufferedReader

public FilteredBufferedReader(Reader in)

Create a buffering character-input stream that uses a default-sized input buffer.

Parameters:

in - the reader

FilteredBufferedReader

public FilteredBufferedReader(Reader in,
                              int sz)

Create a buffering character-input stream that uses an input buffer of the specified size.

Parameters:

in - the reader

sz - the size of the buffer

Method Detail

readLine

public String readLine()
                throws IOException

Read a line of text. A line is considered to be terminated by any one of a line feed ('\n'), a carriage return ('\r'), or a carriage return followed immediately by a linefeed.

Remark :As for all read methods, the lines will be filtered by the filterLine(String) method.

Overrides:

readLine in class BufferedReader

Returns:

the line

Throws:

IOException

See Also:

BufferedReader.readLine(), filterLine(String)

filterLine

public abstract String filterLine(String line)

This abstract method allows to filter each line which is read by this Reader. A straightforward implementation, which returns the input line unaffected, would be:

  public String filterLine(String line) {
     return line;
  }
 

Parameters:

line - the line

Returns:

the filtered line

read

public int read()
         throws IOException

Read a single character. Remarks:

• As for all read methods, the lines will be filtered by the filterLine(String) method.
• The read method will keep the EOL characters unaffected

Overrides:

read in class BufferedReader

Returns:

the character

Throws:

IOException

See Also:

BufferedReader.read(), filterLine(String)

read

public int read(char[] cbuf,
                int off,
                int len)
         throws IOException

Read characters into a portion of an array. Remarks:

• As for all read methods, the lines will be filtered by the filterLine(String) method.
• The read method will keep the EOL characters unaffected

Overrides:

read in class BufferedReader

Returns:

the character

Throws:

IOException

See Also:

BufferedReader.read(char[], int, int), filterLine(String)

read

public int read(char[] cbuf)
         throws IOException

Read characters into an array. This method will block until some input is available, an I/O error occurs, or the end of the stream is reached. Remarks:

• As for all read methods, the lines will be filtered by the filterLine(String) method.
• The read method will keep the EOL characters unaffected

Overrides:

read in class Reader

Returns:

the character

Throws:

IOException

See Also:

Reader.read(char[]), filterLine(String)

ready

public boolean ready()
              throws IOException

Tell whether this stream is ready to be read. A buffered character stream is ready if the buffer is not empty, or if the underlying character stream is ready.

Overrides:

ready in class BufferedReader

Returns:

true if this stream is ready to be read

Throws:

IOException

See Also:

BufferedReader.ready()

skip

public long skip(long n)
          throws IOException

Skip characters. Users of this method should be aware that this implementation is not efficient for wide skipping, because the stream must read the file line by line.

Overrides:

skip in class BufferedReader

Returns:

the number of characters to skip

Throws:

IOException

See Also:

BufferedReader.skip(long)

mark

public void mark(int readAheadLimit)
          throws IOException

Mark the present position in the stream. Subsequent calls to reset() will attempt to reposition the stream to this point. Remark: Due to the particular way this class uses to read streams, the mark will effectively be defined at the end of a line if it is performed after a readLine() method.

Overrides:

mark in class BufferedReader

Throws:

IOException

See Also:

BufferedReader.mark(int)

reset

public void reset()
           throws IOException

Resets the stream to the most recent mark.

Overrides:

reset in class BufferedReader

Throws:

IOException

See Also:

mark(int), BufferedReader.reset()