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Jawk 6.4.00

Using Extensions

Jawk extensions let Java code expose additional AWK-callable functions to a script. Extensions are never enabled automatically. The host application or CLI invocation decides exactly which extension instances are available.

Important

Extensions are opt-in. Sandbox mode blocks dynamic extension loading during script execution, but preloading an extension through the CLI or the Java host remains an explicit host decision.

How Extensions Are Enabled

There are two supported loading paths:

  • CLI: -l <extension> or --load <extension>
  • Java API: pass extension instances to an Awk constructor

If you do neither, no extension functions are available.

List Available Extensions

From the CLI, print the currently registered extension identifiers:

$ java -jar jawk-6.4.00-standalone.jar --list-ext

From Java, inspect the registry directly:

Awk.listAvailableExtensions().forEach((name, extension) ->
        System.out.println(name + " -> " + extension.getClass().getName()));

The registry may expose multiple identifiers for the same implementation, for example a registered name, a simple class name, and a fully qualified class name.

Load Extensions from the CLI

Load an extension with any supported identifier:

$ java -jar jawk-6.4.00-standalone.jar -l stdin -f script.awk

$ java -jar jawk-6.4.00-standalone.jar -l io.jawk.ext.StdinExtension -f script.awk

If the extension class is not already registered, the CLI can still resolve it by fully qualified class name as long as the class is available on the JVM classpath.

Load Extensions from Java

Pass extension instances directly to Awk:

Awk awk = new Awk(StdinExtension.INSTANCE, new MyExtension());

That keeps extension availability explicit and local to the embedding code.

Built-In Extensions

The current built-in registry includes the stdin extension, which is exposed through identifiers such as:

  • stdin
  • StdinExtension
  • io.jawk.ext.StdinExtension

That extension provides advanced helper functions including StdinHasInput(), StdinGetline(), and StdinBlock().

Sandbox Interaction

Sandboxing and extensions are separate concerns:

  • sandboxing restricts dangerous AWK runtime features
  • extension loading is still an explicit host choice
  • scripts do not get to expand their own capabilities automatically

If you need a sandboxed Java embedding, construct SandboxedAwk with the extension instances you want to allow. If you need a sandboxed CLI run, combine -S with the -l options you want to preload.

See Also

extensions plugins functions loading awk
Links:
  • [1] extensions-writing.html
  • [2] java.html
  • [3] cli.html
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