Package org.apache.commons.jexl3.scripting

Class JexlScriptEngine

  • All Implemented Interfaces:
    javax.script.Compilable, javax.script.ScriptEngine
    public class JexlScriptEngine
extends javax.script.AbstractScriptEngine
implements javax.script.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

    • Field Summary

      Fields 
      Modifier and Type Field Description
      (package private) static int CACHE_SIZE
      The shared expression cache size.
      static java.lang.String CONTEXT_KEY
      Reserved key for context (mandated by JSR-223).
      private static java.lang.ref.Reference<JexlEngine> ENGINE
      The shared engine instance.
      static java.lang.String JEXL_OBJECT_KEY
      Reserved key for JexlScriptObject.
      (package private) JexlEngine jexlEngine
      The JEXL EL engine.
      (package private) JexlScriptEngine.JexlScriptObject jexlObject
      The JexlScriptObject instance.
      (package private) static org.apache.commons.logging.Log LOG
      The logger.
      (package private) javax.script.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​(javax.script.ScriptEngineFactory scriptEngineFactory)
      Create a scripting engine using the supplied factory.

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      javax.script.CompiledScript compile​(java.io.Reader script)  
      javax.script.CompiledScript compile​(java.lang.String script)  
      javax.script.Bindings createBindings()  
      java.lang.Object eval​(java.io.Reader reader, javax.script.ScriptContext context)  
      java.lang.Object eval​(java.lang.String script, javax.script.ScriptContext context)  
      private static JexlEngine getEngine()  
      javax.script.ScriptEngineFactory getFactory()  
      private static java.lang.String readerToString​(java.io.Reader scriptReader)
      Reads from a reader into a local buffer and return a String with the contents of the reader.
      (package private) static javax.script.ScriptException scriptException​(java.lang.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 Detail

      • ENGINE

        private static java.lang.ref.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 java.lang.String CONTEXT_KEY
        Reserved key for context (mandated by JSR-223).
        See Also:
        Constant Field Values

      • JEXL_OBJECT_KEY

        public static final java.lang.String JEXL_OBJECT_KEY
        Reserved key for JexlScriptObject.
        See Also:
        Constant Field Values

      • parentFactory

        final javax.script.ScriptEngineFactory parentFactory
        The factory which created this instance.

      • jexlEngine

        final JexlEngine jexlEngine
        The JEXL EL engine.

    • Constructor Detail

      • JexlScriptEngine

        public JexlScriptEngine()
        Default constructor.

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

      • JexlScriptEngine

        public JexlScriptEngine​(javax.script.ScriptEngineFactory scriptEngineFactory)
        Create a scripting engine using the supplied factory.
        Parameters:
        scriptEngineFactory - the factory which created this instance.
        Throws:
        java.lang.NullPointerException - if factory is null

    • Method Detail

      • getEngine

        private static JexlEngine getEngine()
        Returns:
        the shared JexlEngine instance, create it if necessary

      • readerToString

        private static java.lang.String readerToString​(java.io.Reader scriptReader)
                                        throws javax.script.ScriptException
        Reads 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:
        javax.script.ScriptException - on any error reading the reader.

      • scriptException

        static javax.script.ScriptException scriptException​(java.lang.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 javax.script.CompiledScript compile​(java.io.Reader script)
                                    throws javax.script.ScriptException
        Specified by:
        compile in interface javax.script.Compilable
        Throws:
        javax.script.ScriptException

      • compile

        public javax.script.CompiledScript compile​(java.lang.String script)
                                    throws javax.script.ScriptException
        Specified by:
        compile in interface javax.script.Compilable
        Throws:
        javax.script.ScriptException

      • createBindings

        public javax.script.Bindings createBindings()
        Specified by:
        createBindings in interface javax.script.ScriptEngine

      • eval

        public java.lang.Object eval​(java.io.Reader reader,
                             javax.script.ScriptContext context)
                      throws javax.script.ScriptException
        Specified by:
        eval in interface javax.script.ScriptEngine
        Throws:
        javax.script.ScriptException

      • eval

        public java.lang.Object eval​(java.lang.String script,
                             javax.script.ScriptContext context)
                      throws javax.script.ScriptException
        Specified by:
        eval in interface javax.script.ScriptEngine
        Throws:
        javax.script.ScriptException

      • getFactory

        public javax.script.ScriptEngineFactory getFactory()
        Specified by:
        getFactory in interface javax.script.ScriptEngine