Main.java

import org.apache.commons.lang3.tuple.Pair;

import java.util.Arrays;

public class Main {
    public static void main(String[] args) {
        //noinspection unchecked
        Pair<String, Boolean>[] testCases = new Pair[]{
                Pair.of("ex 1", true),
                Pair.of("px 1", true),
                Pair.of("ex 1 ex 2", true),
                Pair.of("ex 1 px 2", true),
                Pair.of("px 1 px 2", true),
                Pair.of("px 1 ex 2", true),
                Pair.of("ex ex 1", false),
                Pair.of("px px 1", false),
                Pair.of("ex 1 ex", false),
                Pair.of("ex 1 ex 2 ex 3", true),
                Pair.of("ex 1 ex 2 px 3", true),
                Pair.of("ex 1 px 2 px 3", true),
                Pair.of("ex y", false),
                Pair.of("px y", false),
                Pair.of("nx nx nx", true),
                Pair.of("nx xx", false),
                Pair.of("xx nx", false),
                Pair.of("ex 1 nx nx", true),
                Pair.of("xx px 1 xx", true),
                Pair.of("ex nx 1", false),
                Pair.of("nx px 1", false),
        };
        for (Pair<String, Boolean> testcase : testCases) {
            boolean expected = testcase.getRight();
            boolean actual = test(testcase.getLeft().split(" "));
            System.out.println(String.format("expect %s, actual %s", expected, actual));
            System.out.println();
        }
    }

    private static boolean test(String[] attributes) {
        System.out.println(Arrays.toString(attributes));
        boolean hasNX = false;
        boolean hasXX = false;
        long expireMilliseconds = -1;
        for (int i = 0, l = attributes.length; i < l; i++) {
            String attribute = attributes[i];
            switch (attribute.toUpperCase()) {
                case "EX":
                    // EX后面必须带数字
                    if (i + 1 < l) {
                        try {
                            expireMilliseconds = Integer.parseInt(attributes[++i]) * 1000;
                        } catch (NumberFormatException e) {
                            return false;
                        }
                    } else {
                        return false;
                    }
                    break;
                case "PX":
                    // PX后面必须带数字
                    if (i + 1 < l) {
                        try {
                            expireMilliseconds = Long.parseLong(attributes[++i]);
                        } catch (NumberFormatException e) {
                            return false;
                        }
                    } else {
                        return false;
                    }
                    break;
                case "NX":
                    hasNX = true;
                    break;
                case "XX":
                    hasXX = true;
                    break;
                default:
                    return false;
            }
        }
        if (hasNX && hasXX) {
            return false;
        }
        System.out.println(String.format(
                "expireMilliseconds = %s, NX = %s, XX = %s", expireMilliseconds, hasNX, hasXX));
        return true;
    }
}