mitch-seymour / java-thrift-parser

A Thrift file parser and AST builder written in Java

Java Thrift Parser  

This library contains a parser that can translate the contents of a Thrift file into an Abstract Syntax Tree. Each node in the tree represents a Thrift type that is encountered during the parsing process, and is organized hierarchically under a root Document node. Being able to programatically navigate the structure of a Thrift file opens the door for all kinds of opportunties, so if you use this software in any interesting capacity, be sure to let me know and I’ll share it on the README.

More information about this project is available here.

Download

Gradle:

compile 'com.mitchseymour:java-thrift-parser:0.1.0'

Maven:

<dependency>
  <groupId>com.mitchseymour</groupId>
  <artifactId>java-thrift-parser</artifactId>
  <version>0.1.0</version>
</dependency>

Jar downloads are available from Maven Central.

Components

Recognizer

The Thrift recognizer included in this project can be used like so:

String path = getClass().getResource("/myfile.thrift").getFile();
String idl = readFile(path, StandardCharsets.UTF_8);
ParsingResult<?> result = ThriftParser.apply(idl);

if (result.matched()) {
    // Thrift file is valid
}

AST (Abstract Syntax Tree)

Given the following file:

namespace java com.mitchseymour.thrift.testmonkey

include "gorillas.thrift"

const string FOREST_NAME = "The Mystical Forest"
const bool INHABITABLE = true
const i32 POPULATION = 14203
const i64 DAYS_UNTIL_DISCOVERY = 92233
const list<string> FRUITS_AVAILABLE = ["bananas", "mangoes", "kiwi"]
const list<i64> FOREST_SECTIONS = [1,2]
const map<string,i32> FRUIT_IDS = {"banana" : 1,"mango": 2}

typedef string MonkeyType

enum Family { LESSER_API ANCIENT_APE }
enum Activity { SWIMMING, CLIMBING, SWINGING }
enum ForestAnimal { BIRD, MOUSE, TIGER }
enum WaterAnimal { FISH, ALLIGATOR }

struct Monkey {
    1: string name,
    2: i32 age,
    3: Family ancestry,
    4: list<string> offspring,
    5: map<string,bool> food_likes,
    6: set<Activity> favorite_activities,
    7: BestFriend bff,
}

union BestFriend {
    1: ForestAnimal forest_animal,
    2: WaterAnimal water_animal,
}

exception TooTired {
    1: string message;
}

service Chimp {
    void call(),
    bool is_munching(),
    bool do_activity(1:Activity activity) throws (1:TooTired tooTired),
}

We can build an AST like so:

Optional<DocumentNode> parsedDocument = parseThriftFileAst("/testmonkey.thrift");
assert(parsedDocument.isPresent());
DocumentNode document = parsedDocument.get();
System.out.println(document.printTree());

The above example will output:

    Document:
      Header:
        Include: gorillas.thrift
      Header:
        General Namespace: java com.mitchseymour.thrift.gorillas
      Definition:
        Const: string FOREST_NAME
      Definition:
        Const: bool INHABITABLE
      Definition:
        Const: i32 POPULATION
      Definition:
        Const: i64 DAYS_UNTIL_DISCOVERY
      Definition:
        Const: ListTypeNode FRUITS_AVAILABLE
      Definition:
        Const: ListTypeNode FOREST_SECTIONS
      Definition:
        Const: MapTypeNode FRUIT_IDS
      Definition:
        Type Def: string  MonkeyType
      Definition:
        Enum: Family
          Enum Value: LESSER_API
          Enum Value: ANCIENT_APE
      Definition:
        Enum: Activity
          Enum Value: SWIMMING
          Enum Value: CLIMBING
          Enum Value: SWINGING
      Definition:
        Enum: ForestAnimal
          Enum Value: BIRD
          Enum Value: MOUSE
          Enum Value: TIGER
      Definition:
        Enum: WaterAnimal
          Enum Value: FISH
          Enum Value: ALLIGATOR
      Definition:
        Struct: Monkey
          Field: 1: string name
          Field: 2: i32 age
          Field: 3: Family ancestry
          Field: 4: ListTypeNode offspring
          Field: 5: MapTypeNode food_likes
          Field: 6: SetTypeNode favorite_activities
          Field: 7: BestFriend bff
      Definition:
        Union: BestFriend
          Field: 2: WaterAnimal water_animal
          Field: 1: ForestAnimal forest_animal
      Definition:
        Exception: TooTired
      Definition:
        Service: Chimp
          Function: call
            Arguments:
          Function: is_munching
            Arguments:
          Function: do_activity
            Arguments:
              Field: 1: Activity activity
            Throws:
              Field: 1: TooTired tooTired
      Definition:
        Struct: Gorilla
          Field: 1: string name
          Field: 2: i32 age