Package javax.script

Class AbstractScriptEngine

  • All Implemented Interfaces:
    ScriptEngine
    Direct Known Subclasses:
    NashornScriptEngine


    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 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