Ballerina File Library

This library provides APIs to create, delete, rename the file/directory, retrieve metadata of the given file, and manipulate the file paths in a way that is compatible with the operating system, and a Directory Listener, which is used to listen to the file changes in a directory in the local file system.

Directory listener

The file:Listener is used to monitor all the files and subdirectories inside the specified directory.

A Listener endpoint can be defined using the mandatory path parameter and the optional recursive parameter as follows.

listener file:Listener inFolder = new ({
    path: "<The directory path>",
    recursive: false
});

If the listener needs to monitor subdirectories of the given directory, recursive needs to be set to true. The default value of this is false.

A Service has the defined remote methods with the file:FileEvent and can be exposed via a Listener endpoint. When there are changes in the listening directory, the file:FileEvent will be triggered with the action of the file such as creating, modifying, or deleting.

The remote methods supported by the Service are as follows.

onCreate: This method is invoked once a new file is created in the listening directory.

onDelete: This method is invoked once an existing file is deleted from the listening directory.

onModify: This method is invoked once an existing file is modified in the listening directory.

The following code sample shows how to create a Service with the onCreate remote method and attach it to the above Listener endpoint:

service "localObserver" on inFolder {

    remote function onCreate(file:FileEvent m) {
        string msg = "Create: " + m.name;
        log:printInfo(msg);
    }
}

For example demonstrations of the usage, go to Ballerina By Examples.

Issues and projects

Issues and Project tabs are disabled for this repository as this is part of the Ballerina Standard Library. To report bugs, request new features, start new discussions, view project boards, etc. please visit Ballerina Standard Library parent repository.

This repository only contains the source code for the package.

Build from the source

Set up the prerequisites

1. Download and install Java SE Development Kit (JDK) version 21 (from one of the following locations).

   • Oracle

   • OpenJDK

     Note: Set the JAVA_HOME environment variable to the path name of the directory into which you installed JDK.

Build the source

Execute the commands below to build from the source.

1. To build the library:

    ./gradlew clean build
   

2. To run the integration tests:

    ./gradlew clean test
   

3. To build the package without the tests:

    ./gradlew clean build -x test
   

4. To debug the tests:

    ./gradlew clean build -Pdebug=<port>
   

5. To debug the package with Ballerina language:

    ./gradlew clean build -PbalJavaDebug=<port>
   

6. Publish ZIP artifact to the local .m2 repository:

    ./gradlew clean build publishToMavenLocal
   

7. Publish the generated artifacts to the local Ballerina central repository:

    ./gradlew clean build -PpublishToLocalCentral=true
   

8. Publish the generated artifacts to the Ballerina central repository:

    ./gradlew clean build -PpublishToCentral=true
   

Contribute to Ballerina

As an open source project, Ballerina welcomes contributions from the community.

For more information, go to the contribution guidelines.

Code of conduct

All contributors are encouraged to read the Ballerina Code of Conduct.

Useful links

• For more information go to the file library.
• For example demonstrations of the usage, go to Ballerina By Examples.
• Chat live with us via our Discord server.
• Post all technical questions on Stack Overflow with the #ballerina tag.