script-utils-java/com.pambrose.common.script/JavaScript

JavaScript

A script engine wrapper for dynamically compiling and evaluating Java source code.

Supports adding named variables with type parameters, import declarations, and configurable isolation levels. The Java engine needs a global scope: resetForReuse always keeps one, while resetContext(true) removes it, after which evalScript fails.

Variable declarations use fully-qualified type names, so they need no imports. A value whose runtime class cannot be named, such as the private list class behind listOf(1, 2), is declared as its nearest public class or interface.

Common literal JVM-termination calls (System.exit, Runtime.getRuntime().exit/halt) are rejected on a best-effort basis via ScriptGuards. This is a convenience against accidental termination, not a security sandbox (see ScriptGuards) — run untrusted scripts in an isolated process or JVM.

close does nothing, because the Java engine holds no resources to release.

Constructors

JavaScript

constructor()

Properties

engine

val ~~engine~~: ScriptEngine

importDecls

@get:Synchronized

val importDecls: String

Generates Java import statements for all registered import classes.

varDecls

@get:Synchronized

val varDecls: String

Generates Java-style public field declarations for all registered variables.

Functions

add

open fun add(name: String, value: Any, vararg types: KType)

addImport

fun <T> addImport(clazz: Class<T>)

Registers a Java class to be imported in generated scripts; the same as import, under a name Java can call.

assignIsolation

@Synchronized

fun assignIsolation(isolation: Isolation)

Sets the isolation level for the underlying JavaScriptEngine.

open override fun close()

eval

@Synchronized

fun eval(expr: String, action: String = "", verbose: Boolean = false): Any?

Evaluates a Java expr (optionally preceded by an action statement block) inside a generated Main.getValue() method, prepending any registered imports and variable declarations.

evalScript

@Synchronized

fun evalScript(script: String, verbose: Boolean = false): Any?

Evaluates a raw Java script string, prepending any registered import declarations.

import

@Synchronized

fun <T> import(clazz: Class<T>)

Registers a Java class to be imported in generated scripts, by its canonical name, so a nested class is imported as Outer.Inner. Java callers use addImport, since import is a Java keyword.

params

open fun params(name: String, types: Array<out KType>): String

resetContext

fun resetContext(nullGlobalContext: Boolean)

resetForReuse

@Synchronized

open override fun resetForReuse(nullGlobalContext: Boolean)

Resets the context and also clears the imports and restores the default isolation, so the next borrower from a pool starts clean.

JavaScript

See also

Constructors

Properties

Functions