Module java.scripting
Package javax.script

Class AbstractScriptEngine

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 Details

    • context

      protected ScriptContext context
      The default ScriptContext of this AbstractScriptEngine.

  • Constructor Details

    • 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 Details

    • 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