Package org.apache.commons.jexl3.scripting

Class JexlScriptEngine

java.lang.Object

javax.script.AbstractScriptEngine

org.apache.commons.jexl3.scripting.JexlScriptEngine

All Implemented Interfaces:

Compilable, ScriptEngine

public class JexlScriptEngine
extends AbstractScriptEngine
implements Compilable

Implements the JEXL ScriptEngine for JSF-223.

This implementation gives access to both ENGINE_SCOPE and GLOBAL_SCOPE bindings. When a JEXL script accesses a variable for read or write, this implementation checks first ENGINE and then GLOBAL scope. The first one found is used. If no variable is found, and the JEXL script is writing to a variable, it will be stored in the ENGINE scope.

The implementation also creates the "JEXL" script object as an instance of the class JexlScriptEngine.JexlScriptObject for access to utility methods and variables.

See Java Scripting API Javadoc.

Since:

2.0

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static final class	JexlScriptEngine.FactorySingletonHolder	Holds singleton JexlScriptEngineFactory (IODH).
private final class	JexlScriptEngine.JexlCompiledScript	Wrapper to help convert a JEXL JexlScript into a JSR-223 CompiledScript.
private final class	JexlScriptEngine.JexlContextWrapper	Wrapper to help convert a JSR-223 ScriptContext into a JexlContext.
class	JexlScriptEngine.JexlScriptObject	Implements engine and engine context properties for use by JEXL scripts.

Field Summary

Fields

Modifier and Type	Field	Description
(package private) static final int	CACHE_SIZE	The shared expression cache size.
static final String	CONTEXT_KEY	Reserved key for context (mandated by JSR-223).
private static Reference<JexlEngine>	ENGINE	The shared engine instance.
static final String	JEXL_OBJECT_KEY	Reserved key for JexlScriptObject.
(package private) final JexlEngine	jexlEngine	The JEXL EL engine.
(package private) final JexlScriptEngine.JexlScriptObject	jexlObject	The JexlScriptObject instance.
(package private) static final org.apache.commons.logging.Log	LOG	The logger.
(package private) final ScriptEngineFactory	parentFactory	The factory which created this instance.
private static JexlPermissions	PERMISSIONS	The permissions used to create the script engine.

Fields inherited from class javax.script.AbstractScriptEngine

context

Fields inherited from interface javax.script.ScriptEngine

ARGV, ENGINE_VERSION, FILENAME, LANGUAGE, LANGUAGE_VERSION, NAME

Constructor Summary

Constructors

Constructor	Description
JexlScriptEngine()	Default constructor.
JexlScriptEngine(ScriptEngineFactory factory)	Create a scripting engine using the supplied factory.

Method Summary

Modifier and Type	Method	Description
CompiledScript	compile(Reader script)
CompiledScript	compile(String script)
Bindings	createBindings()
Object	eval(Reader reader, ScriptContext context)
Object	eval(String script, ScriptContext context)
private static JexlEngine	getEngine()
ScriptEngineFactory	getFactory()
private static String	readerToString(Reader scriptReader)	Read from a reader into a local buffer and return a String with the contents of the reader.
(package private) static ScriptException	scriptException(Exception e)
static void	setInstance(JexlEngine engine)	Sets the shared instance used for the script engine.
static void	setPermissions(JexlPermissions permissions)	Sets the permissions instance used to create the script engine.

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 Details

ENGINE

private static Reference<JexlEngine> ENGINE

The shared engine instance.

A single soft-reference JEXL engine and JexlUberspect is shared by all instances of JexlScriptEngine.

PERMISSIONS

private static JexlPermissions PERMISSIONS

The permissions used to create the script engine.

LOG

static final org.apache.commons.logging.Log LOG

The logger.

CACHE_SIZE

static final int CACHE_SIZE

The shared expression cache size.

See Also:

• Constant Field Values

CONTEXT_KEY

public static final String CONTEXT_KEY

Reserved key for context (mandated by JSR-223).

See Also:

• Constant Field Values

JEXL_OBJECT_KEY

public static final String JEXL_OBJECT_KEY

Reserved key for JexlScriptObject.

See Also:

• Constant Field Values

jexlObject

final JexlScriptEngine.JexlScriptObject jexlObject

The JexlScriptObject instance.

parentFactory

final ScriptEngineFactory parentFactory

The factory which created this instance.

jexlEngine

final JexlEngine jexlEngine

The JEXL EL engine.

Constructor Details

JexlScriptEngine

public JexlScriptEngine()

Default constructor.

Only intended for use when not using a factory. Sets the factory to JexlScriptEngineFactory.

JexlScriptEngine

public JexlScriptEngine(ScriptEngineFactory factory)

Create a scripting engine using the supplied factory.

Parameters:

factory - the factory which created this instance.

Throws:

NullPointerException - if factory is null

Method Details

getEngine

private static JexlEngine getEngine()

Returns:

the shared JexlEngine instance, create it if necessary

readerToString

private static String readerToString(Reader scriptReader)
                              throws ScriptException

Read from a reader into a local buffer and return a String with the contents of the reader.

Parameters:

scriptReader - to be read.

Returns:

the contents of the reader as a String.

Throws:

ScriptException - on any error reading the reader.

scriptException

static ScriptException scriptException(Exception e)

setInstance

public static void setInstance(JexlEngine engine)

Sets the shared instance used for the script engine.

This should be called early enough to have an effect, ie before any ScriptEngineManager features.

To restore 3.2 script behavior:

JexlScriptEngine.setInstance(new JexlBuilder() .cache(512) .logger(LogFactory.getLog(JexlScriptEngine.class)) .permissions(JexlPermissions.UNRESTRICTED) .create());

Parameters:

engine - the JexlEngine instance to use

Since:

3.3

setPermissions

public static void setPermissions(JexlPermissions permissions)

Sets the permissions instance used to create the script engine.

Calling this method will force engine instance re-creation.

To restore 3.2 script behavior:

JexlScriptEngine.setPermissions(JexlPermissions.UNRESTRICTED);

Parameters:

permissions - the permissions instance to use or null to use the JexlBuilder default

Since:

3.3

compile

public CompiledScript compile(Reader script)
                       throws ScriptException

Specified by:

compile in interface Compilable

Throws:

ScriptException

compile

public CompiledScript compile(String script)
                       throws ScriptException

Specified by:

compile in interface Compilable

Throws:

ScriptException

createBindings

public Bindings createBindings()

Specified by:

createBindings in interface ScriptEngine

eval

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

Specified by:

eval in interface ScriptEngine

Throws:

ScriptException

eval

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

Specified by:

eval in interface ScriptEngine

Throws:

ScriptException

getFactory

public ScriptEngineFactory getFactory()

Specified by:

getFactory in interface ScriptEngine