Disclaimer: This is not an official Google product.
Mug (
)
A small Java 8+ string processing and streams library (javadoc), battle tested in Google's internal codebase, with 0 deps (Proto, BigQuery, Guava addons are in separate artifacts). 
Strings
- ✅
Substring– simple and composable substring extraction & manipulation
→Substring.between("(", ")").from("call(foo)") → "foo" - ✅
StringFormat– compile-time-safe bidirectional parsing/formatting
→new StringFormat("/home/{user}/{date}").parse(filePath, (user, date) -> ...) - ✅
Parser– everyday string parsing easier, faster and beyond regexsequence(word().followedBy("="), digits(), Map::entry) .zeroOrMoreDelimitedBy(",") .between("{", "}") // {k1=100, k2=200, k3=300, ...} .parseSkipping(Character::isWhitespace, input); DateTimeFormats– define datetime formats by examples
→DateTimeFormatter format = formatOf("2024-03-14 10.8.10:00.123 America/New_York")
Streams
- ✅
BiStream– streamsMapand pair-wise collections
→BiStream.zip(keys, values).toMap() - ✅
MoreStreams– extra stream utilitiesStream<List<Double>> greenDays = MoreStreams.groupConsecutive( stockPrices, (p1, p2) -> p1 <= p2, toUnmodifiableList());
Compile-Time Guardrails
- ✅
@ParametersMustMatchByNamerecord Profile(String userId, String userName) {}new Profile(user.id(), user.name())Compiles ✅new Profile(user.name(), user.id())Does Not Compile ❌
- ✅
SafeSql– compile-time-enforced safe, composable SQL template
→SafeSql.of("select id, `{col}` from Users where id = {id}", col, id)
More tools
Iteration- implement lazy stream with recursive codeBinarySearch- solve LeetCode binary search problems
→BinarySearch.inSortedArrayWithTolerance(doubleArray, 0.0001).find(target)StructuredConcurrency- simple structured concurrency on virtual threads
→concurrently(() -> fetchArm(), () -> fetchLeg(), (arm, leg) -> makeRobot(arm, leg))Optionals
→return optionally(obj.hasFoo(), obj::getFoo);
Installation
Maven
Add the following to pom.xml:
<dependency>
<groupId>com.google.mug</groupId>
<artifactId>mug</artifactId>
<version>10.8.1</version>
</dependency>
Add mug-errorprone to your annotationProcessorPaths:
<build>
<pluginManagement>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<annotationProcessorPaths>
<path>
<groupId>com.google.errorprone</groupId>
<artifactId>error_prone_core</artifactId>
<version>2.23.0</version>
</path>
<path>
<groupId>com.google.mug</groupId>
<artifactId>mug-errorprone</artifactId>
<version>10.8.1</version>
</path>
</annotationProcessorPaths>
</configuration>
</plugin>
</plugins>
</pluginManagement>
</build>
SafeSql (javadoc):
<dependency>
<groupId>com.google.mug</groupId>
<artifactId>mug-safesql</artifactId>
<version>10.8.1</version>
</dependency>
Dot Parse Combinators (javadoc):
<dependency>
<groupId>com.google.mug</groupId>
<artifactId>dot-parse</artifactId>
<version>10.8.1</version>
</dependency>
Protobuf utils (javadoc):
<dependency>
<groupId>com.google.mug</groupId>
<artifactId>mug-protobuf</artifactId>
<version>10.8.1</version>
</dependency>
Gradle
Add to build.gradle:
implementation 'com.google.mug:mug:10.8.1'
implementation 'com.google.mug:mug-safesql:10.8.1'
implementation 'com.google.mug:dot-parse:10.8.1'
implementation 'com.google.mug:mug-guava:10.8.1'
implementation 'com.google.mug:mug-protobuf:10.8.1'
