/***
 * streamInputExample.java,v 1.4 1997/08/14 05:25:38 dfs Exp
 *
 * This is a test program demonstrating how to search an InputStream
 * with the OROMatcher Perl5 regular expression classes.  It also
 * demonstrates for those not familiar with regular expressions, how
 * to use parenthesized groups and backreferences.
 *
 * Copyright 1997 ORO, Inc.  All rights reserved.
 ***/

import java.io.*;
import com.oroinc.text.regex.*;

public final class streamInputExample {

  /***
   * This program tries to find SSN values  whose birth and death dates
   * have the same month and day.  See the file streamInputExample.txt
   * for more details.  This program uses the streamInputExample.txt file
   * as sample input.
   ***/

  public static final void main(String args[]) {

    // A regular expression that will find data entries with identical
    // birth and death dates (month and day).  Notice how the backreferences
    // \2 and \3 take care of this.  The first parenthesized group is used
    // to preserve the SSN value, while the second and third are used to
    // record the day and month of birth for use by the backreferences.
    // The fourth and fifth groups save the birth and death years.

    String regex =
    "SSN:\\s+(\\d+)\\s+Month:\\s+(\\d+)\\s+Day:\\s+(\\d+)\\s+Year:\\s+(\\d+)" +
    "\\s+Month:\\s+\\2\\s+Day:\\s+\\3\\s+Year:\\s+(\\d+)";                      
    Perl5Matcher matcher;
    Perl5Compiler compiler;
    Perl5Pattern pattern = null;
    Perl5StreamInput input;
    MatchResult result;
    InputStream file = null;

    // Create Perl5Compiler and Perl5Matcher instances.
    compiler = new Perl5Compiler();
    matcher  = new Perl5Matcher();

    // Attempt to compile the pattern.  If the pattern is not valid,
    // report the error and exit.
    try {
      pattern
	= (Perl5Pattern)compiler.compile(regex,
					 Perl5Compiler.CASE_INSENSITIVE_MASK);
    } catch(MalformedPatternException e) {
      System.err.println("Bad pattern.");
      System.err.println(e.getMessage());
      System.exit(1);
    }


    // Open input file.
    try {
      file = new FileInputStream("streamInputExample.txt");
    } catch(IOException e) {
      System.err.println("Error opening streamInputExample.txt.");
      System.err.println(e.getMessage());
      System.exit(1);
    }

    // Create a Perl5StreamInput instance to search the input stream.
    input   = new Perl5StreamInput(file);

    // We need to put the search loop in a try block because when searching
    // a Perl5StreamInput instance, an IOException may occur, and it must be
    // caught.
    try {
      // Loop until there are no more matches left.
      while(matcher.contains(input, pattern)) {
	// Since we're still in the loop, fetch match that was found.
	result = matcher.getMatch();  

	// Print the SSN which was saved in group 1.
	System.out.println("SSN: " + result.group(1));

	// Print the month which was saved in group 2.
	System.out.println("Month: " + result.group(2));

	// Print the day which was saved in group 3.
	System.out.println("Day: " + result.group(3));

	// Print the birth year which was saved in group 4.
	System.out.println("Birth Year: " + result.group(4));

	// Print the death year which was saved in group 5.
	System.out.println("Death Year: " + result.group(5) + "\n");
      }
    } catch(IOException e) {
      System.err.println("Error occurred while reading file.");
      System.err.println(e.getMessage());
      System.exit(1);
    }
  }
}