org.apache.tinkerpop.gremlin.jsr223

## Interface GremlinScriptEngineManager

- All Known Implementing Classes:
    CachedGremlinScriptEngineManager, DefaultGremlinScriptEngineManager

      public interface GremlinScriptEngineManager

  The `ScriptEngineManager` implements a discovery, instantiation and configuration mechanism for `GremlinScriptEngine` classes and also maintains a collection of key/value pairs storing state shared by all engines created by it. This class uses the `ServiceProvider` mechanism to enumerate all the implementations of `GremlinScriptEngineFactory`. The `ScriptEngineManager` provides a method to return a list of all these factories as well as utility methods which look up factories on the basis of language name, file extension and mime type.

  The `Bindings` of key/value pairs, referred to as the "Global Scope" maintained by the manager is available to all instances of @code ScriptEngine} created by the `GremlinScriptEngineManager`. The values in the `Bindings` are generally exposed in all scripts.

  This interface is based quite heavily on the workings of the `ScriptEngineManager` supplied in the `javax.script` packages, but adds some additional features that are specific to Gremlin and TinkerPop. Unfortunately, it's not easily possible to extend `ScriptEngineManager` directly as there certain behaviors don't appear to be be straightforward to implement and member variables are all private. It is important to note that this interface is designed to provide support for "Gremlin-enabled" `ScriptEngine` instances (i.e. those that extend from `GremlinScriptEngine`) and is not meant to manage just any `ScriptEngine` instance that may be on the path.
  Author:
    Stephen Mallette (http://stephen.genoprime.com)

- - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `addPlugin(GremlinPlugin plugin)` Add `GremlinPlugin` instances to customize newly created `GremlinScriptEngine` instances.
    `Object` | `get(String key)` Gets the value for the specified key in the global scope.
    `Bindings` | `getBindings()` Gets the bindings of the `Bindings` in global scope.
    `List<Customizer>` | `getCustomizers(String scriptEngineName)` Get the list of `Customizer` instances filtered by the `scriptEngineName`.
    `GremlinScriptEngine` | `getEngineByExtension(String extension)` Look up and create a `GremlinScriptEngine` for a given extension.
    `GremlinScriptEngine` | `getEngineByMimeType(String mimeType)` Look up and create a `GremlinScriptEngine` for a given mime type.
    `GremlinScriptEngine` | `getEngineByName(String shortName)` Looks up and creates a `GremlinScriptEngine` for a given name.
    `List<GremlinScriptEngineFactory>` | `getEngineFactories()` Returns a list whose elements are instances of all the `GremlinScriptEngineFactory` classes found by the discovery mechanism.
    `void` | `put(String key, Object value)` Sets the specified key/value pair in the global scope.
    `void` | `registerEngineExtension(String extension, GremlinScriptEngineFactory factory)` Registers a `GremlinScriptEngineFactory` to handle an extension.
    `void` | `registerEngineMimeType(String type, GremlinScriptEngineFactory factory)` Registers a `GremlinScriptEngineFactory` to handle a mime type.
    `void` | `registerEngineName(String name, GremlinScriptEngineFactory factory)` Registers a `GremlinScriptEngineFactory` to handle a language name.
    `void` | `setBindings(Bindings bindings)` Stores the specified `Bindings` as a global for all `GremlinScriptEngine` objects created by it.

- - ### Method Detail

    - #### setBindings

          void setBindings(Bindings bindings)

      Stores the specified `Bindings` as a global for all `GremlinScriptEngine` objects created by it.
      Throws:
        `IllegalArgumentException` - if bindings is null.

    - #### getBindings

          Bindings getBindings()

      Gets the bindings of the `Bindings` in global scope.

    - #### put

          void put(String key,
                   Object value)

      Sets the specified key/value pair in the global scope. The key may not be null or empty.
      Throws:
        `IllegalArgumentException` - if key is null or empty.

    - #### get

          Object get(String key)

      Gets the value for the specified key in the global scope.

    - #### getEngineByName

          GremlinScriptEngine getEngineByName(String shortName)

      Looks up and creates a `GremlinScriptEngine` for a given name. The algorithm first searches for a `GremlinScriptEngineFactory` that has been registered as a handler for the specified name using the `registerEngineExtension(String, GremlinScriptEngineFactory)` method. If one is not found, it searches the set of `GremlinScriptEngineFactory` instances stored by the constructor for one with the specified name. If a `ScriptEngineFactory` is found by either method, it is used to create instance of `GremlinScriptEngine`.
      Parameters:
        `shortName` - The short name of the `GremlinScriptEngine` implementation returned by the `ScriptEngineFactory.getNames()` method.
      Returns:
        A `GremlinScriptEngine` created by the factory located in the search. Returns `null` if no such factory was found. The global scope of this manager is applied to the newly created `GremlinScriptEngine`
      Throws:
        `NullPointerException` - if shortName is `null`.

    - #### getEngineByExtension

          GremlinScriptEngine getEngineByExtension(String extension)

      Look up and create a `GremlinScriptEngine` for a given extension. The algorithm used by `getEngineByName(String)` is used except that the search starts by looking for a `GremlinScriptEngineFactory` registered to handle the given extension using `registerEngineExtension(String, GremlinScriptEngineFactory)`.
      Returns:
        The engine to handle scripts with this extension. Returns `null` if not found.
      Throws:
        `NullPointerException` - if extension is `null`.

    - #### getEngineByMimeType

          GremlinScriptEngine getEngineByMimeType(String mimeType)

      Look up and create a `GremlinScriptEngine` for a given mime type. The algorithm used by `getEngineByName(String)` is used except that the search starts by looking for a `GremlinScriptEngineFactory` registered to handle the given mime type using `registerEngineMimeType(String, GremlinScriptEngineFactory)`.
      Parameters:
        `mimeType` - The given mime type
      Returns:
        The engine to handle scripts with this mime type. Returns `null` if not found.
      Throws:
        `NullPointerException` - if mime-type is `null`.

    - #### getEngineFactories

          List<GremlinScriptEngineFactory> getEngineFactories()

      Returns a list whose elements are instances of all the `GremlinScriptEngineFactory` classes found by the discovery mechanism.
      Returns:
        List of all discovered `GremlinScriptEngineFactory` objects.

    - #### addPlugin

          void addPlugin(GremlinPlugin plugin)

      Add `GremlinPlugin` instances to customize newly created `GremlinScriptEngine` instances.

    - #### registerEngineName

          void registerEngineName(String name,
                                  GremlinScriptEngineFactory factory)

      Registers a `GremlinScriptEngineFactory` to handle a language name. Overrides any such association found using the discovery mechanism.
      Parameters:
        `name` - The name to be associated with the `GremlinScriptEngineFactory`
        `factory` - The class to associate with the given name.
      Throws:
        `NullPointerException` - if any of the parameters is null.

    - #### registerEngineMimeType

          void registerEngineMimeType(String type,
                                      GremlinScriptEngineFactory factory)

      Registers a `GremlinScriptEngineFactory` to handle a mime type. Overrides any such association found using the discovery mechanism.
      Parameters:
        `type` - The mime type to be associated with the `GremlinScriptEngineFactory`.
        `factory` - The class to associate with the given mime type.
      Throws:
        `NullPointerException` - if any of the parameters is null.

    - #### registerEngineExtension

          void registerEngineExtension(String extension,
                                       GremlinScriptEngineFactory factory)

      Registers a `GremlinScriptEngineFactory` to handle an extension. Overrides any such association found using the discovery mechanism.
      Parameters:
        `extension` - The extension type to be associated with the `GremlinScriptEngineFactory`
        `factory` - The class to associate with the given extension.
      Throws:
        `NullPointerException` - if any of the parameters is null.

    - #### getCustomizers

          List<Customizer> getCustomizers(String scriptEngineName)

      Get the list of `Customizer` instances filtered by the `scriptEngineName`.

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