Module jdk.scripting.nashorn

Package jdk.nashorn.api.scripting

Class NashornScriptEngine

java.lang.Object

javax.script.AbstractScriptEngine

jdk.nashorn.api.scripting.NashornScriptEngine

All Implemented Interfaces:

Compilable, Invocable, ScriptEngine

public final class NashornScriptEngine
extends AbstractScriptEngine
implements Compilable, Invocable

JSR-223 compliant script engine for Nashorn. Instances are not created directly, but rather returned through NashornScriptEngineFactory.getScriptEngine(). Note that this engine implements the Compilable and Invocable interfaces, allowing for efficient precompilation and repeated execution of scripts.

Since:

1.8u40

See Also:

NashornScriptEngineFactory

Field Summary

Fields

Modifier and Type	Field	Description
static String	NASHORN_GLOBAL	Key used to associate Nashorn global object mirror with arbitrary Bindings instance.

Fields inherited from class javax.script.AbstractScriptEngine

context

Fields inherited from interface javax.script.ScriptEngine

ARGV, ENGINE, ENGINE_VERSION, FILENAME, LANGUAGE, LANGUAGE_VERSION, NAME

Method Summary

Modifier and Type	Method	Description
CompiledScript	compile(Reader reader)	Compiles the script (source read from Reader) for later execution.
CompiledScript	compile(String str)	Compiles the script (source represented as a String) for later execution.
Bindings	createBindings()	Returns an uninitialized Bindings.
Object	eval(Reader reader, ScriptContext ctxt)	Same as eval(String, ScriptContext) where the source of the script is read from a Reader.
Object	eval(String script, ScriptContext ctxt)	Causes the immediate execution of the script whose source is the String passed as the first argument.
ScriptEngineFactory	getFactory()	Returns a ScriptEngineFactory for the class to which this ScriptEngine belongs.
<T> T	getInterface(Class<T> clazz)	Returns an implementation of an interface using functions compiled in the interpreter.
<T> T	getInterface(Object thiz, Class<T> clazz)	Returns an implementation of an interface using member functions of a scripting object compiled in the interpreter.
Object	invokeFunction(String name, Object... args)	Used to call top-level procedures and functions defined in scripts.
Object	invokeMethod(Object thiz, String name, Object... args)	Calls a method on a script object compiled during a previous script execution, which is retained in the state of the ScriptEngine.

Methods inherited from class javax.script.AbstractScriptEngine

eval, eval, eval, eval, get, getBindings, getContext, getScriptContext, put, setBindings, setContext

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

NASHORN_GLOBAL

public static final String NASHORN_GLOBAL

Key used to associate Nashorn global object mirror with arbitrary Bindings instance.

See Also:

Constant Field Values

Method Detail

eval

public Object eval(Reader reader,
                   ScriptContext ctxt)
            throws ScriptException

Description copied from interface: ScriptEngine

Same as eval(String, ScriptContext) where the source of the script is read from a Reader.

Specified by:

eval in interface ScriptEngine

Parameters:

reader - The source of the script to be executed by the script engine.

ctxt - The ScriptContext passed to the script engine.

Returns:

The value returned from the execution of the script.

Throws:

ScriptException - if an error occurs in script. ScriptEngines should create and throw ScriptException wrappers for checked Exceptions thrown by underlying scripting implementations.

eval

public Object eval(String script,
                   ScriptContext ctxt)
            throws ScriptException

Description copied from interface: ScriptEngine

Causes the immediate execution of the script whose source is the String passed as the first argument. The script may be reparsed or recompiled before execution. State left in the engine from previous executions, including variable values and compiled procedures may be visible during this execution.

Specified by:

eval in interface ScriptEngine

Parameters:

script - The script to be executed by the script engine.

ctxt - A ScriptContext exposing sets of attributes in different scopes. The meanings of the scopes ScriptContext.GLOBAL_SCOPE, and ScriptContext.ENGINE_SCOPE are defined in the specification.

The ENGINE_SCOPE Bindings of the ScriptContext contains the bindings of scripting variables to application objects to be used during this script execution.

Returns:

The value returned from the execution of the script.

Throws:

ScriptException - if an error occurs in script. ScriptEngines should create and throw ScriptException wrappers for checked Exceptions thrown by underlying scripting implementations.

getFactory

public ScriptEngineFactory getFactory()

Description copied from interface: ScriptEngine

Returns a ScriptEngineFactory for the class to which this ScriptEngine belongs.

Specified by:

getFactory in interface ScriptEngine

Returns:

The ScriptEngineFactory

createBindings

public Bindings createBindings()

Description copied from interface: ScriptEngine

Returns an uninitialized Bindings.

Specified by:

createBindings in interface ScriptEngine

Returns:

A Bindings that can be used to replace the state of this ScriptEngine.

compile

public CompiledScript compile(Reader reader)
                       throws ScriptException

Description copied from interface: Compilable

Compiles the script (source read from Reader) for later execution. Functionality is identical to compile(String) other than the way in which the source is passed.

Specified by:

compile in interface Compilable

Parameters:

reader - The reader from which the script source is obtained.

Returns:

An instance of a subclass of CompiledScript to be executed later using one of its eval methods of CompiledScript.

Throws:

ScriptException - if compilation fails.

compile

public CompiledScript compile(String str)
                       throws ScriptException

Description copied from interface: Compilable

Compiles the script (source represented as a String) for later execution.

Specified by:

compile in interface Compilable

Parameters:

str - The source of the script, represented as a String.

Returns:

An instance of a subclass of CompiledScript to be executed later using one of the eval methods of CompiledScript.

Throws:

ScriptException - if compilation fails.

invokeFunction

public Object invokeFunction(String name,
                             Object... args)
                      throws ScriptException,
                             NoSuchMethodException

Description copied from interface: Invocable

Used to call top-level procedures and functions defined in scripts.

Specified by:

invokeFunction in interface Invocable

Parameters:

name - of the procedure or function to call

args - Arguments to pass to the procedure or function

Returns:

The value returned by the procedure or function

Throws:

ScriptException - if an error occurs during invocation of the method.

NoSuchMethodException - if method with given name or matching argument types cannot be found.

invokeMethod

public Object invokeMethod(Object thiz,
                           String name,
                           Object... args)
                    throws ScriptException,
                           NoSuchMethodException

Description copied from interface: Invocable

Calls a method on a script object compiled during a previous script execution, which is retained in the state of the ScriptEngine.

Specified by:

invokeMethod in interface Invocable

Parameters:

thiz - If the procedure is a member of a class defined in the script and thiz is an instance of that class returned by a previous execution or invocation, the named method is called through that instance.

name - The name of the procedure to be called.

args - Arguments to pass to the procedure. The rules for converting the arguments to scripting variables are implementation-specific.

Returns:

The value returned by the procedure. The rules for converting the scripting variable returned by the script method to a Java Object are implementation-specific.

Throws:

ScriptException - if an error occurs during invocation of the method.

NoSuchMethodException - if method with given name or matching argument types cannot be found.

getInterface

public <T> T getInterface(Class<T> clazz)

Description copied from interface: Invocable

Returns an implementation of an interface using functions compiled in the interpreter. The methods of the interface may be implemented using the invokeFunction method.

Specified by:

getInterface in interface Invocable

Type Parameters:

T - the type of the interface to return

Parameters:

clazz - The Class object of the interface to return.

Returns:

An instance of requested interface - null if the requested interface is unavailable, i. e. if compiled functions in the ScriptEngine cannot be found matching the ones in the requested interface.

getInterface

public <T> T getInterface(Object thiz,
                          Class<T> clazz)

Description copied from interface: Invocable

Returns an implementation of an interface using member functions of a scripting object compiled in the interpreter. The methods of the interface may be implemented using the invokeMethod method.

Specified by:

getInterface in interface Invocable

Type Parameters:

T - the type of the interface to return

Parameters:

thiz - The scripting object whose member functions are used to implement the methods of the interface.

clazz - The Class object of the interface to return.

Returns:

An instance of requested interface - null if the requested interface is unavailable, i. e. if compiled methods in the ScriptEngine cannot be found matching the ones in the requested interface.