StringRegex.java

import java.util.regex.*;
/*
 * 文字列定数を受理する正規表現
*/

class StringRegex
{
    String[] testcase = {
        "\"This is a string.\"",
        "\"This is a \"string\".\"",
        "\"This is a \\\"string\\\".\"",
        "\"This is a string.\\\"",
        "\"This is a \\\\ string.\""
    };

    boolean[] isAccept = { true, false, true, false };

    String regex = "\"(([^\\\\\"])|(\\\\.))*\"";

    public StringRegex()
    {
        System.out.printf("pattern: %s\n", regex);
        //print();

        Pattern p = Pattern.compile(regex);
        for(int i=0; i<testcase.length; i++){
            Matcher m = p.matcher(testcase[i]);
            // 全体
            boolean res = m.matches();
            System.out.printf("%s , %s\n", testcase[i], String.valueOf(res));

            // 部分
            m.reset();
            while(m.find()){
                System.out.println(m.group());
            }
        }
    }

    void print()
    {
        // print testcase
        for(int i=0; i<testcase.length; i++){
            System.out.printf("%s , %s\n", testcase[i], String.valueOf(isAccept[i]));
        }
    }

    public static void main(String[] args)
    {
        new StringRegex();
    }
}