/*
 * [TestRegexFragments.java]
 *
 * Summary: Demonstrate techique of coding Regex patterns with fragments.
 *
 * Copyright: (c) 2009-2017 Roedy Green, Canadian Mind Products, http://mindprod.com
 *
 * Licence: This software may be copied and used freely for any purpose but military.
 *          http://mindprod.com/contact/nonmil.html
 *
 * Requires: JDK 1.8+
 *
 * Created with: JetBrains IntelliJ IDEA IDE http://www.jetbrains.com/idea/
 *
 * Version History:
 *  1.0 2009-04-28
 */
package com.mindprod.example;

import java.util.regex.Pattern;

import static java.lang.System.*;

/**
 * Demonstrate techique of coding Regex patterns with fragments.
 * <p/>
 * Show some regexes coded with named fragments and alse the traditional way spelled out longhand.
 *
 * @author Roedy Green, Canadian Mind Products
 * @version 1.0 2009-04-28
 * @since 2009-04-28
 */
@SuppressWarnings( { "UnusedAssignment" } )
public class TestRegexFragments
    {
    /*
    *  Regex fragmant to find YYYY-MM-DD
    */
    private static final String A_DASH = "[/\\-]";

    /*
    *  Regex fragmant to find YYYY-MM-DD
    */
    private static final String A_DD = "[0-3]\\d";

    /**
     * Regex to look for Windows EOL sequence
     */
    private static final String A_EOL = "\\r\\n";

    /**
     * regex fragment to match a =
     */
    private static final String A_EQUAL = "=";

    /*
    *  Regex fragmant to find YYYY-MM-DD
    */
    private static final String A_MM = "\\d{2}";

    /**
     * regex to find a  number eg. 10
     */
    private static final String A_NUMBER = "\\d++";

    /**
     * regex fragment to match a "
     */
    private static final String A_QUOTE = "\"";

    /**
     * regex fragment to look for some spaces
     */
    private static final String A_SPACES = "\\s++";

    /**
     * regex fragment to look for <!--
     */
    private static final String A_START_HTML_COMMENT = "<!\\-\\-";

    /**
     * regex to find a version number eg. 1.5 for program or JDK versions
     */
    private static final String A_VERSION = "\\d++\\.\\d";

    /**
     * regex to find a word
     */
    private static final String A_WORD = "\\w++]";

    /*
    *  Regex fragmant to find YYYY-MM-DD
    */
    private static final String A_YYYY = "[12][90]\\d{2}";

    /*
    *  Regex fragmant to find YYYY-MM-DD
    */
    private static final String A_YYYY_MM__DD = A_YYYY + A_DASH + A_MM + A_DASH + A_DD;

    /*
    *  Regex fragmant to find YYYY-MM-DD, YYYY-MM or just plain YYYY
    */
    private static final String A_YYYY_MM__DD_PARTIAL = A_YYYY + "(?:" + A_DASH + A_MM + "(?:" + A_DASH + A_DD + ")?)?";

    /**
     * pattern to look for @version 9.9
     */
    private static final Pattern FIND_AT_VERSION;

    /**
     * pattern to look for @version 9.9,  done without fragments
     */
    private static final Pattern FIND_AT_VERSION_OLD =
            Pattern.compile( "@version\\s++(\\d++\\.\\d)" );

    /**
     * pattern to look for <!-- macro CMPApplet 1.6
     */
    private static final Pattern FIND_JDK_REQUIRED_CMP_APPLET;

    /**
     * pattern to look for <!-- macro CMPApplet 1.6, done without fragments
     */
    private static final Pattern FIND_JDK_REQUIRED_CMP_APPLET_OLD =
            Pattern.compile( "<!\\-\\-\\s++macro\\s++CMPApplet\\s++(\\d++\\.\\d)\\s++" );

    /**
     * pattern to look for RELEASE_DATE = "2007-04-11", does not capture YYYY-MM-DD
     */
    private static final Pattern FIND_RELEASE_DATE;

    /**
     * pattern to look for RELEASE_DATE = "2007-04-11", does not capture YYYY-MM-DD, done without fragments
     */
    private static final Pattern FIND_RELEASE_DATE_OLD =
            Pattern.compile( "RELEASE_DATE\\s++=\\s++\"[12][90]\\d{2}[/\\-]\\d{2}[/\\-][0-3]\\d\"" );

    static
        {
        FIND_AT_VERSION = Pattern.compile( "@version"
                                           + A_SPACES
                                           + "("
                                           + A_VERSION
                                           + ")" );
        FIND_JDK_REQUIRED_CMP_APPLET =
                Pattern.compile( A_START_HTML_COMMENT
                                 + A_SPACES
                                 + "macro"
                                 + A_SPACES
                                 + "CMPApplet"
                                 + A_SPACES
                                 + "("
                                 + A_VERSION
                                 + ")"
                                 + A_SPACES );
        FIND_RELEASE_DATE = Pattern.compile( "RELEASE_DATE"
                                             + A_SPACES
                                             + A_EQUAL
                                             + A_SPACES
                                             + A_QUOTE
                                             + A_YYYY_MM__DD
                                             + A_QUOTE );
        }

    /**
     * main method. Reassure that both forms of Regex are equivalent.
     *
     * @param args not used
     */
    public static void main( String[] args )
        {
        out.println( FIND_AT_VERSION.toString() );
        assert FIND_AT_VERSION.toString().equals( FIND_AT_VERSION_OLD.toString() ) : "oops";
        assert FIND_JDK_REQUIRED_CMP_APPLET.toString().equals( FIND_JDK_REQUIRED_CMP_APPLET_OLD.toString() ) : "oops";
        assert FIND_RELEASE_DATE.toString().equals( FIND_RELEASE_DATE_OLD.toString() ) : "oops";
        }
    }