Module java.scripting

Package javax.script

Class SimpleScriptContext

java.lang.Object

javax.script.SimpleScriptContext

All Implemented Interfaces:

ScriptContext

public class SimpleScriptContext
extends Object
implements ScriptContext

Simple implementation of ScriptContext.

Since:

1.6

Field Summary

Fields

Modifier and Type	Field	Description
protected Bindings	engineScope	This is the engine scope bindings.
protected Writer	errorWriter	This is the writer to be used to output errors from scripts.
protected Bindings	globalScope	This is the global scope bindings.
protected Reader	reader	This is the reader to be used for input from scripts.
protected Writer	writer	This is the writer to be used to output from scripts.

Fields declared in interface javax.script.ScriptContext

ENGINE_SCOPE, GLOBAL_SCOPE

Constructor Summary

Constructors

Constructor	Description
SimpleScriptContext()	Create a SimpleScriptContext.

Method Summary

Modifier and Type	Method	Description
Object	getAttribute(String name)	Retrieves the value of the attribute with the given name in the scope occurring earliest in the search order.
Object	getAttribute(String name, int scope)	Gets the value of an attribute in a given scope.
int	getAttributesScope(String name)	Get the lowest scope in which an attribute is defined.
Bindings	getBindings(int scope)	Returns the value of the engineScope field if specified scope is ENGINE_SCOPE.
Writer	getErrorWriter()	Returns the Writer used to display error output.
Reader	getReader()	Returns a Reader to be used by the script to read input.
List<Integer>	getScopes()	Returns immutable List of all the valid values for scope in the ScriptContext.
Writer	getWriter()	Returns the Writer for scripts to use when displaying output.
Object	removeAttribute(String name, int scope)	Remove an attribute in a given scope.
void	setAttribute(String name, Object value, int scope)	Sets the value of an attribute in a given scope.
void	setBindings(Bindings bindings, int scope)	Sets a Bindings of attributes for the given scope.
void	setErrorWriter(Writer writer)	Sets the Writer used to display error output.
void	setReader(Reader reader)	Sets the Reader for scripts to read input .
void	setWriter(Writer writer)	Sets the Writer for scripts to use when displaying output.

Methods declared in class java.lang.Object

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

Field Details

writer

protected Writer writer

This is the writer to be used to output from scripts. By default, a PrintWriter based on System.out is used. Accessor methods getWriter, setWriter are used to manage this field.

See Also:

• System.out
• PrintWriter

errorWriter

protected Writer errorWriter

This is the writer to be used to output errors from scripts. By default, a PrintWriter based on System.err is used. Accessor methods getErrorWriter, setErrorWriter are used to manage this field.

See Also:

• System.err
• PrintWriter

reader

protected Reader reader

This is the reader to be used for input from scripts. By default, a InputStreamReader based on System.in is used and default charset is used by this reader. Accessor methods getReader, setReader are used to manage this field.

See Also:

• System.in
• InputStreamReader

engineScope

protected Bindings engineScope

This is the engine scope bindings. By default, a SimpleBindings is used. Accessor methods setBindings, getBindings are used to manage this field.

See Also:

• SimpleBindings

globalScope

protected Bindings globalScope

This is the global scope bindings. By default, a null value (which means no global scope) is used. Accessor methods setBindings, getBindings are used to manage this field.

Constructor Details

SimpleScriptContext

public SimpleScriptContext()

Create a SimpleScriptContext.

Method Details

setBindings

public void setBindings(Bindings bindings,
 int scope)

Sets a Bindings of attributes for the given scope. If the value of scope is ENGINE_SCOPE the given Bindings replaces the engineScope field. If the value of scope is GLOBAL_SCOPE the given Bindings replaces the globalScope field.

Specified by:

setBindings in interface ScriptContext

Parameters:

bindings - The Bindings of attributes to set.

scope - The value of the scope in which the attributes are set.

Throws:

IllegalArgumentException - if scope is invalid.

NullPointerException - if the value of scope is ENGINE_SCOPE and the specified Bindings is null.

getAttribute

public Object getAttribute(String name)

Retrieves the value of the attribute with the given name in the scope occurring earliest in the search order. The order is determined by the numeric value of the scope parameter (lowest scope values first.)

Specified by:

getAttribute in interface ScriptContext

Parameters:

name - The name of the attribute to retrieve.

Returns:

The value of the attribute in the lowest scope for which an attribute with the given name is defined. Returns null if no attribute with the name exists in any scope.

Throws:

NullPointerException - if the name is null.

IllegalArgumentException - if the name is empty.

getAttribute

public Object getAttribute(String name,
 int scope)

Gets the value of an attribute in a given scope.

Specified by:

getAttribute in interface ScriptContext

Parameters:

name - The name of the attribute to retrieve.

scope - The scope in which to retrieve the attribute.

Returns:

The value of the attribute. Returns null is the name does not exist in the given scope.

Throws:

IllegalArgumentException - if the name is empty or if the value of scope is invalid.

NullPointerException - if the name is null.

removeAttribute

public Object removeAttribute(String name,
 int scope)

Remove an attribute in a given scope.

Specified by:

removeAttribute in interface ScriptContext

Parameters:

name - The name of the attribute to remove

scope - The scope in which to remove the attribute

Returns:

The removed value.

Throws:

IllegalArgumentException - if the name is empty or if the scope is invalid.

NullPointerException - if the name is null.

setAttribute

public void setAttribute(String name,
 Object value,
 int scope)

Sets the value of an attribute in a given scope. If the scope is GLOBAL_SCOPE and no Bindings is set for GLOBAL_SCOPE, then setAttribute call is a no-op.

Specified by:

setAttribute in interface ScriptContext

Parameters:

name - The name of the attribute to set

value - The value of the attribute

scope - The scope in which to set the attribute

Throws:

IllegalArgumentException - if the name is empty or if the scope is invalid.

NullPointerException - if the name is null.

getWriter

public Writer getWriter()

Returns the Writer for scripts to use when displaying output.

Specified by:

getWriter in interface ScriptContext

Returns:

The Writer.

getReader

public Reader getReader()

Returns a Reader to be used by the script to read input.

Specified by:

getReader in interface ScriptContext

Returns:

The Reader.

setReader

public void setReader(Reader reader)

Sets the Reader for scripts to read input .

Specified by:

setReader in interface ScriptContext

Parameters:

reader - The new Reader.

setWriter

public void setWriter(Writer writer)

Sets the Writer for scripts to use when displaying output.

Specified by:

setWriter in interface ScriptContext

Parameters:

writer - The new Writer.

getErrorWriter

public Writer getErrorWriter()

Returns the Writer used to display error output.

Specified by:

getErrorWriter in interface ScriptContext

Returns:

The Writer

setErrorWriter

public void setErrorWriter(Writer writer)

Sets the Writer used to display error output.

Specified by:

setErrorWriter in interface ScriptContext

Parameters:

writer - The Writer.

getAttributesScope

public int getAttributesScope(String name)

Get the lowest scope in which an attribute is defined.

Specified by:

getAttributesScope in interface ScriptContext

Parameters:

name - Name of the attribute .

Returns:

The lowest scope. Returns -1 if no attribute with the given name is defined in any scope.

Throws:

NullPointerException - if name is null.

IllegalArgumentException - if name is empty.

getBindings

public Bindings getBindings(int scope)

Returns the value of the engineScope field if specified scope is ENGINE_SCOPE. Returns the value of the globalScope field if the specified scope is GLOBAL_SCOPE.

Specified by:

getBindings in interface ScriptContext

Parameters:

scope - The specified scope

Returns:

The value of either the engineScope or globalScope field.

Throws:

IllegalArgumentException - if the value of scope is invalid.

getScopes

public List<Integer> getScopes()

Returns immutable List of all the valid values for scope in the ScriptContext.

Specified by:

getScopes in interface ScriptContext

Returns:

list of scope values