Mobile platform and version discovery

Platform.java

package com.robbdimitrov.utils;

import java.util.regex.Pattern;

public class Platform {
    public static boolean isIOS(String systemName) {
        Pattern pattern = Pattern.compile("^(ios|iphone)", Pattern.CASE_INSENSITIVE);
        return pattern.matcher(systemName).find();
    }

    public static boolean isAndroid(String systemName) {
        Pattern pattern = Pattern.compile("^android", Pattern.CASE_INSENSITIVE);
        return pattern.matcher(systemName).find();
    }
}

PlatformTest.java

package com.robbdimitrov.utils;

import com.robbdimitrov.utils.Platform;
import org.junit.Test;
import static org.junit.Assert.*;

public class PlatformTest {
    @Test
    public void testIsIOS() {
        assertTrue(Platform.isIOS("ios"));
        assertTrue(Platform.isIOS("iPhone 10.0"));
        assertTrue(Platform.isIOS("iphone 10.0"));
        assertTrue(Platform.isIOS("iOS 14"));

        assertFalse(Platform.isIOS("Nintendo 10.0"));
        assertFalse(Platform.isIOS("droid 10.0"));
        assertFalse(Platform.isIOS(""));
    }

    @Test
    public void testIsAndroid() {
        assertTrue(Platform.isAndroid("Android"));
        assertTrue(Platform.isAndroid("Android 10.0"));
        assertTrue(Platform.isAndroid("android 10.0"));

        assertFalse(Platform.isAndroid("Nintendo 10.0"));
        assertFalse(Platform.isAndroid("droid 10.0"));
        assertFalse(Platform.isAndroid(""));
    }
}

Version.java

package com.robbdimitrov.utils;

import static java.lang.Integer.min;

public class Version {
    public static boolean matches(String current, String required) {
        String sign = required.substring(0, 1);

        String[] currentParts = current.split("\\.");
        String[] requiredParts = required.substring(2).split("\\.");

        if (sign.equals(">")) {
            return greaterThan(currentParts, requiredParts);
        } else if (sign.equals("<")) {
            return lessThan(currentParts, requiredParts);
        }

        return equals(currentParts, requiredParts);
    }

    private static boolean equals(String[] leftParts, String[] rightParts) {
        if (leftParts.length != rightParts.length) {
            return false;
        }

        for (int i = 0; i < leftParts.length; i++) {
            int left = Integer.parseInt(leftParts[i]);
            int right = Integer.parseInt(rightParts[i]);

            if (left != right) {
                return false;
            }
        }

        return true;
    }

    private static boolean greaterThan(String[] leftParts, String[] rightParts) {
        int partsCount = min(leftParts.length, rightParts.length);

        for (int i = 0; i < partsCount; i++) {
            int left = Integer.parseInt(leftParts[i]);
            int right = Integer.parseInt(rightParts[i]);

            if (left == right) {
                continue;
            }
            return left > right;
        }

        return false;
    }

    private static boolean lessThan(String[] leftParts, String[] rightParts) {
        int partsCount = min(leftParts.length, rightParts.length);

        for (int i = 0; i < partsCount; i++) {
            int left = Integer.parseInt(leftParts[i]);
            int right = Integer.parseInt(rightParts[i]);

            if (left == right) {
                continue;
            }
            return left < right;
        }

        return false;
    }
}

VersionTest.java

package com.robbdimitrov.utils;

import com.robbdimitrov.utils.Version;
import org.junit.Test;
import static org.junit.Assert.*;

public class VersionTest {
    @Test
    public void testEquals() {
        assertTrue(Version.matches("10.0.0", "= 10.0.0"));
        assertTrue(Version.matches("10.2", "= 10.2"));

        assertFalse(Version.matches("10.0.0", "= 9.0.0"));
        assertFalse(Version.matches("10.2", "= 10.2.2"));
    }

    @Test
    public void testGreaterThan() {
        assertTrue(Version.matches("10.1.0", "> 10.0.0"));
        assertTrue(Version.matches("11.0.0", "> 10.5.2"));
        assertTrue(Version.matches("10.5.3", "> 10.2"));

        assertFalse(Version.matches("9.0.0", "> 9.0.0"));
        assertFalse(Version.matches("8.9.1", "> 9.0.0"));
        assertFalse(Version.matches("1.0", "> 10.2.2"));
    }

    @Test
    public void testLessThan() {
        assertTrue(Version.matches("10.0.0", "< 10.1.0"));
        assertTrue(Version.matches("10.5.2", "< 11.0.0"));
        assertTrue(Version.matches("10.2", "< 10.5.3"));

        assertFalse(Version.matches("9.0.0", "< 9.0.0"));
        assertFalse(Version.matches("9.0.0", "< 8.9.1"));
        assertFalse(Version.matches("10.2.2", "< 1.0"));
    }
}