Input and Output - Java - page 403

IndentContLineReader is = new new IndentContLineReader (

new StringReader ( sampleTxt ));
String aLine ;
// Print Mail/News Header
System . out . println ( "----- Message Header -----" );
while

new

while (( aLine = is . readLine ()) != null null && aLine . length () > 0 ) {

System . out . println ( is . getLineNumber () + ": " + aLine );

}
// Make "is" behave like normal BufferedReader
is . setContinuationMode ( false

false );

System . out . println ();
// Print Message Body
System . out . println ( "----- Message Body -----" );
while

while (( aLine = is . readLine ()) != null null ) {

System . out . println ( is . getLineNumber () + ": " + aLine );

}
is . close ();

Each of the Reader classes is subclassed from LineNumberReader so that you can use
getLineNumber() . This is a very useful feature when reporting errors back to the user who
prepared an input file; it can save him considerable hunting around in the file if you tell him
the line number on which the error occurred. The Reader classes are actually subclassed
from an abstract ContLineReader subclass, which is first presented in Example 10-8 . This
class encapsulates the basic functionality for keeping track of lines that need to be joined to-
gether, and for enabling or disabling the continuation processing.

Example 10-8. ContLineReader.java
/**
* Subclass of LineNumberReader, parent of others, to allow reading of
* continued lines using the readLine() method. The other Reader methods
* (readInt()) etc.) must not be used. Must subclass to provide the actual
* implementation of readLine().
*/
public

public abstract extends LineNumberReader {

/** Line number of first line in current (possibly continued) line */
protected

abstract class class ContLineReader ContLineReader extends

protected int int firstLineNumber = 0 ;

/** True if handling continuations, false if not; false == "PRE" mode */
protected protected boolean boolean doContinue = true true ;

/** Set the continuation mode */
public public void void setContinuationMode ( boolean boolean b ) {

doContinue = b ;

}