swift2thrift-generator-cli

Swift2Thrift Code Generator

Swift2Thrift generates .thrift files from Swift-annotated Java files. The generated .thrift files can be fed to a Thrift compiler to generate client and/or server code for other languages.

Usage

$ java -jar swift2thrift-generator-cli-0.9.0-SNAPSHOT-standalone.jar
Usage: Swift2ThriftGenerator [options] <Swift-class-name...>
  Options:
    -allow_multiple_packages
       Allow input classes to reside in different packages. The value of this
       flag defines the generated java.swift namespace. Note that Swift classes
       generated from the resultant Thrift file will all reside in one Java package
    -package, -default_package
       Default package for unqualified classes
       Default: <empty string>
    -map
       Map of external type or service to include file
    -namespace
       Namespace for a particular language to include
    -out
       Thrift IDL output file, defaults to stdout
    -v, -verbose
       Show verbose messages
       Default: false

Important notes:

1. You should pass (fully-qualified) class names, not .java (or .class) filenames.
2. Java ignores the classpath (set via -classpath or $CLASSPATH) if run with -jar. Therefore, run Swift2Thrift with -classpath (or -cp or $CLASSPATH) that contains your Swift classes, but not with -jar.

Tips

• Use -out to save the generated file. Omit -out to see the result on stdout while tweaking options.
• Use -package to save typing. Compare java -cp ..... -package my.long.package.name Class1 Class2 Class3 to java -cp ..... my.long.package.name.Class1 my.long.package.name.Class2 my.long.package.name.Class3.
• Use -map to have include lines in the generated .thrift file for types/services you already have .thrift files for. Example: -map other.package.OtherThriftStruct path/to/file.thrift. Can be used multiple times.
• Use -namespace to generate Thrift namespace declarations for other languages. Useful if you use the generated .thrift files to generate code (clients/servers) for other languages. Example: -namespace cpp mynamespace. Can be used multiple times.
• To include nested classes on the command line, use 'MyTopLevelClass$MyNestedClass'. If running from the shell, be sure to use single quotes or the shell will eat the $MyNestedClass.
• Swift2Thrift checks that all input classes are in the same Java package (whether -package is used or not) and errors if not. You can run Swift2Thrift several times to generate multiple .thrift files if your input classes are in different packages.
• JavaDoc and method ordering can be preserved in the generated .thrift files by compiling your classes with javac -cp swift-javadoc-0.9.0-SNAPSHOT.jar <rest-of-the-command-line> before feeding them to Swift2Thrift. Alternatively, you can use @ThriftDocumentation and @ThriftOrder in your Java sources (but this clutters them, thus not recommended).

Example

MY_CLASSES=swift-service/target/test-classes  # just an example
java -cp swift2thrift-generator-cli/target/swift2thrift-generator-cli-0.9.0-SNAPSHOT-standalone.jar:$MY_CLASSES \
    com.facebook.swift.generator.swift2thrift.Main -package com.facebook.swift.service.annotations \
    DerivedServiceOne -map BaseService path/to/base.thrift \
    -namespace py mycompany.thrift -namespace java com.mycompany -namespace cpp mycompany

Input: The file below compiled into swift-service/target/test-classes/com/facebook/swift/service/annotations/DerivedServiceOne.class

package com.facebook.swift.service.annotations;

import com.facebook.swift.service.ThriftMethod;
import com.facebook.swift.service.ThriftService;

@ThriftService("DerivedServiceOne")
public interface DerivedServiceOne extends BaseService
{
    @ThriftMethod
    public void fooOne();
}

Output:

namespace java.swift com.facebook.swift.service.annotations
namespace py mycompany.thrift
namespace java com.mycompany
namespace cpp mycompany

include "path/to/base.thrift"



service DerivedServiceOne extends base.BaseService {
  void fooOne();
}