AbstractScriptEngine (Java Platform SE 8 )

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

Fields
Modifier and Type Field Description

protected ScriptContext context
The default ScriptContext of this AbstractScriptEngine.
- Fields inherited from interface javax.script.ScriptEngine
  ARGV, ENGINE, ENGINE_VERSION, FILENAME, LANGUAGE, LANGUAGE_VERSION, NAME

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

Constructor Summary

Constructors
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

All Methods Instance Methods Concrete Methods
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 inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface javax.script.ScriptEngine
createBindings, eval, eval, getFactory

- Field Detail
  - context
```
protected ScriptContext context
```
    The default ScriptContext of this AbstractScriptEngine.
- Constructor Detail
  - 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 Detail
  - 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

Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
Copyright © 1993, 2025, Oracle and/or its affiliates. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.

Class AbstractScriptEngine

Field Summary

Fields inherited from interface javax.script.ScriptEngine

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface javax.script.ScriptEngine

Field Detail

context

Constructor Detail

AbstractScriptEngine

AbstractScriptEngine

Method Detail

setContext

getContext

getBindings

setBindings

put

get

eval

eval

eval

eval

getScriptContext