Class AbstractScriptEngine

java.lang.Object

javax.script.AbstractScriptEngine

All Implemented Interfaces:: ScriptEngine

public abstract class AbstractScriptEngine extends Object implements ScriptEngine

Provides a standard implementation for several of the variants of the eval method.

eval(Reader)

eval(String)

eval(String, Bindings)

eval(Reader, Bindings)

are implemented using the abstract methods

eval(Reader,ScriptContext) or eval(String, ScriptContext)

with a SimpleScriptContext.

A SimpleScriptContext is used as the default ScriptContext of the AbstractScriptEngine..

Since:: 1.6

Field Summary

Modifier and Type	Field	Description
`protected ScriptContext`	`context`	The default `ScriptContext` of this `AbstractScriptEngine`.

Fields declared in interface ScriptEngine

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

Modifier and Type	Field	Description
`static final String`	`ARGV`	Reserved key for a named value that passes an array of positional arguments to a script.
`static final String`	`ENGINE`	Reserved key for a named value that is the name of the `ScriptEngine` implementation.
`static final String`	`ENGINE_VERSION`	Reserved key for a named value that identifies the version of the `ScriptEngine` implementation.
`static final String`	`FILENAME`	Reserved key for a named value that is the name of the file being executed.
`static final String`	`LANGUAGE`	Reserved key for a named value that is the full name of Scripting Language supported by the implementation.
`static final String`	`LANGUAGE_VERSION`	Reserved key for the named value that identifies the version of the scripting language supported by the implementation.
`static final String`	`NAME`	Reserved key for a named value that identifies the short name of the scripting language.

Constructor Summary

Constructor	Description
`AbstractScriptEngine()`	Creates a new instance of AbstractScriptEngine using a `SimpleScriptContext` as its default `ScriptContext`.
`AbstractScriptEngine(Bindings n)`	Creates a new instance using the specified `Bindings` as the `ENGINE_SCOPE` `Bindings` in the protected `context` field.

Method Summary

Modifier and Type	Method	Description
`Object`	`eval(Reader reader)`	`eval(Reader)` calls the abstract `eval(Reader, ScriptContext)` passing the value of the `context` field.
`Object`	`eval(Reader reader, Bindings bindings)`	`eval(Reader, Bindings)` calls the abstract `eval(Reader, ScriptContext)` method, passing it a `ScriptContext` whose Reader, Writers and Bindings for scopes other that `ENGINE_SCOPE` are identical to those members of the protected `context` field.
`Object`	`eval(String script)`	Same as `eval(Reader)` except that the abstract `eval(String, ScriptContext)` is used.
`Object`	`eval(String script, Bindings bindings)`	Same as `eval(Reader, Bindings)` except that the abstract `eval(String, ScriptContext)` is used.
`Object`	`get(String key)`	Gets the value for the specified key in the `ENGINE_SCOPE` of the protected `context` field.
`Bindings`	`getBindings(int scope)`	Returns the `Bindings` with the specified scope value in the protected `context` field.
`ScriptContext`	`getContext()`	Returns the value of the protected `context` field.
`protected ScriptContext`	`getScriptContext(Bindings nn)`	Returns a `SimpleScriptContext`.
`void`	`put(String key, Object value)`	Sets the specified value with the specified key in the `ENGINE_SCOPE` `Bindings` of the protected `context` field.
`void`	`setBindings(Bindings bindings, int scope)`	Sets the `Bindings` with the corresponding scope value in the `context` field.
`void`	`setContext(ScriptContext ctxt)`	Sets the value of the protected `context` field to the specified `ScriptContext`.

Methods declared in class Object

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

Modifier and Type	Method	Description
`protected Object`	`clone()`	Creates and returns a copy of this object.
`boolean`	`equals(Object obj)`	Indicates whether some other object is "equal to" this one.
`protected void`	`finalize()`	Deprecated, for removal: This API element is subject to removal in a future version. Finalization is deprecated and subject to removal in a future release.
`final Class<?>`	`getClass()`	Returns the runtime class of this `Object`.
`int`	`hashCode()`	Returns a hash code value for this object.
`final void`	`notify()`	Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()`	Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()`	Returns a string representation of the object.
`final void`	`wait()`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
`final void`	`wait(long timeoutMillis)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis, int nanos)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

Methods declared in interface ScriptEngine

createBindings, eval, eval, getFactory

Modifier and Type	Method	Description
`Bindings`	`createBindings()`	Returns an uninitialized `Bindings`.
`Object`	`eval(Reader reader, ScriptContext context)`	Same as `eval(String, ScriptContext)` where the source of the script is read from a `Reader`.
`Object`	`eval(String script, ScriptContext context)`	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.

Field Details

context

protected ScriptContext context

The default ScriptContext of this AbstractScriptEngine.

Constructor Details

AbstractScriptEngine

public AbstractScriptEngine()

Creates a new instance of AbstractScriptEngine using a SimpleScriptContext as its default ScriptContext.

AbstractScriptEngine

public AbstractScriptEngine(Bindings n)

Creates a new instance using the specified Bindings as the ENGINE_SCOPE Bindings in the protected context field.

Parameters:: n - The specified Bindings.
Throws:: NullPointerException - if n is null.

Method Details

setContext

public void setContext(ScriptContext ctxt)

Sets the value of the protected context field to the specified ScriptContext.

Specified by:: setContext in interface ScriptEngine
Parameters:: ctxt - The specified ScriptContext.
Throws:: NullPointerException - if ctxt is null.

getContext

public ScriptContext getContext()

Returns the value of the protected context field.

Specified by:: getContext in interface ScriptEngine
Returns:: The value of the protected context field.

getBindings

public Bindings getBindings(int scope)

Returns the Bindings with the specified scope value in the protected context field.

Specified by:: getBindings in interface ScriptEngine
Parameters:: scope - The specified scope
Returns:: The corresponding Bindings.
Throws:: IllegalArgumentException - if the value of scope is invalid for the type the protected context field.

setBindings

public void setBindings(Bindings bindings, int scope)

Sets the Bindings with the corresponding scope value in the context field.

Specified by:: setBindings in interface ScriptEngine
Parameters:: bindings - The specified Bindings.; scope - The specified scope.
Throws:: IllegalArgumentException - if the value of scope is invalid for the type the context field.; NullPointerException - if the bindings is null and the scope is ScriptContext.ENGINE_SCOPE

put

public void put(String key, Object value)

Sets the specified value with the specified key in the ENGINE_SCOPE Bindings of the protected context field.

Specified by:: put in interface ScriptEngine
Parameters:: key - The specified key.; value - The specified value.
Throws:: NullPointerException - if key is null.; IllegalArgumentException - if key is empty.

get

public Object get(String key)

Gets the value for the specified key in the ENGINE_SCOPE of the protected context field.

Specified by:: get in interface ScriptEngine
Parameters:: key - The key whose value is to be returned
Returns:: The value for the specified key.
Throws:: NullPointerException - if key is null.; IllegalArgumentException - if key is empty.

eval

public Object eval(Reader reader, Bindings bindings) throws ScriptException

eval(Reader, Bindings) calls the abstract eval(Reader, ScriptContext) method, passing it a ScriptContext whose Reader, Writers and Bindings for scopes other that ENGINE_SCOPE are identical to those members of the protected context field. The specified Bindings is used instead of the ENGINE_SCOPE Bindings of the context field.

Specified by:: eval in interface ScriptEngine
Parameters:: reader - A Reader containing the source of the script.; bindings - A Bindings to use for the ENGINE_SCOPE while the script executes.
Returns:: The return value from eval(Reader, ScriptContext)
Throws:: ScriptException - if an error occurs in script.; NullPointerException - if any of the parameters is null.

eval

public Object eval(String script, Bindings bindings) throws ScriptException

Same as eval(Reader, Bindings) except that the abstract eval(String, ScriptContext) is used.

Specified by:: eval in interface ScriptEngine
Parameters:: script - A String containing the source of the script.; bindings - A Bindings to use as the ENGINE_SCOPE while the script executes.
Returns:: The return value from eval(String, ScriptContext)
Throws:: ScriptException - if an error occurs in script.; NullPointerException - if any of the parameters is null.

eval

public Object eval(Reader reader) throws ScriptException

eval(Reader) calls the abstract eval(Reader, ScriptContext) passing the value of the context field.

Specified by:: eval in interface ScriptEngine
Parameters:: reader - A Reader containing the source of the script.
Returns:: The return value from eval(Reader, ScriptContext)
Throws:: ScriptException - if an error occurs in script.; NullPointerException - if any of the parameters is null.

eval

public Object eval(String script) throws ScriptException

Same as eval(Reader) except that the abstract eval(String, ScriptContext) is used.

Specified by:: eval in interface ScriptEngine
Parameters:: script - A String containing the source of the script.
Returns:: The return value from eval(String, ScriptContext)
Throws:: ScriptException - if an error occurs in script.; NullPointerException - if any of the parameters is null.

getScriptContext

protected ScriptContext getScriptContext(Bindings nn)

Returns a SimpleScriptContext. The SimpleScriptContext:

Uses the specified Bindings for its ENGINE_SCOPE
Uses the Bindings returned by the abstract getGlobalScope method as its GLOBAL_SCOPE
Uses the Reader and Writer in the default ScriptContext of this ScriptEngine

A SimpleScriptContext returned by this method is used to implement eval methods using the abstract eval(Reader,Bindings) and eval(String,Bindings) versions.

Parameters:: nn - Bindings to use for the ENGINE_SCOPE
Returns:: The SimpleScriptContext

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