mug

isclaimer: This is not an official Google product.

Mug ()

A small Java 8+ string processing and streams library (javadoc), widely used in Google’s internal Java codebase, with 0 deps (Proto, BigQuery, Guava addons are in separate artifacts).

Full Spectrum of String Utilities

• ✅ 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 than and beyond regex

    sequence(word().followedBy("="), digits(), Map::entry)
        .zeroOrMoreDelimitedBy(",")
        .between("{", "}")         // {k1=100, k2=200, k3=300, ...}
        .parse(input);
  

• DateTimeFormats – define datetime formats by examples
  → DateTimeFormatter format = formatOf("2024-03-14 10.20:00.123 America/New_York")

Streams

• ✅ BiStream – streams Map and pair-wise collections
  → BiStream.zip(keys, values).toMap()
• ✅ MoreStreams – extra stream utilities

    Stream<List<Double>> greenDays = MoreStreams.groupConsecutive(
        stockPrices, (p1, p2) -> p1 <= p2, toUnmodifiableList());
  

Others

• ✅ @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`](./mug/wiki/Iteration-Explained) - implement lazy stream with recursive code - [`BinarySearch`](/mug/mug-guava/src/main/java/com/google/guava/labs/collect/) - solve LeetCode binary search problems → `BinarySearch.inSortedArrayWithTolerance(doubleArray, 0.0001).find(target)` - [`StructuredConcurrency`](/mug/mug/src/main/java/com/google/mu/util/concurrent/) - simple structured concurrency on virtual threads → `concurrently(() -> fetchArm(), () -> fetchLeg(), (arm, leg) -> makeRobot(arm, leg))` - [`Optionals`](./mug/apidocs/com/google/mu/util/Optionals.html) → `return optionally(obj.hasFoo(), obj::getFoo);`

Installation

##### Maven Add the following to pom.xml: ``` com.google.mug mug 10.2 ``` Add `mug-errorprone` to your annotationProcessorPaths: ``` maven-compiler-plugin com.google.errorprone error_prone_core 2.23.0 com.google.mug mug-errorprone 10.2 ``` SafeSql ([javadoc](https://google.github.io/mug/apidocs/com/google/mu/safesql/package-summary.html)): ``` com.google.mug mug-safesql 10.2 ``` Dot Parse Combinators ([javadoc](https://google.github.io/mug/apidocs/com/google/common/labs/parse/package-summary.html)): ``` com.google.mug dot-parse 10.2 ``` Protobuf utils ([javadoc](https://google.github.io/mug/apidocs/com/google/mu/protobuf/util/package-summary.html)): ``` com.google.mug mug-protobuf 10.2 ``` ##### Gradle Add to build.gradle: ``` implementation 'com.google.mug:mug:10.2' implementation 'com.google.mug:mug-safesql:10.2' implementation 'com.google.mug:dot-parse:10.2' implementation 'com.google.mug:mug-guava:10.2' implementation 'com.google.mug:mug-protobuf:10.2' ```

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