Package org.apache.tinkerpop.gremlin.jsr223

Class CachedGremlinScriptEngineManager

java.lang.Object

org.apache.tinkerpop.gremlin.jsr223.DefaultGremlinScriptEngineManager

org.apache.tinkerpop.gremlin.jsr223.CachedGremlinScriptEngineManager

All Implemented Interfaces:

GremlinScriptEngineManager

public class CachedGremlinScriptEngineManager
extends DefaultGremlinScriptEngineManager

An implementation of the GremlinScriptEngineManager that caches the instances of the GremlinScriptEngine instances that are created by it. Note that the cache is relevant to the instance of the CachedGremlinScriptEngineManager and is not global to the JVM.

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 class 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 straightforward to implement and member variables are all private. It is important to note that this class 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.

As this is a "Gremlin" ScriptEngine, certain common imports are automatically applied when a GremlinScriptEngine is instantiated via the GremlinScriptEngineFactory.. Initial imports from gremlin-core come from the CoreImports.

Constructor Summary

Constructors

Constructor	Description
CachedGremlinScriptEngineManager()
CachedGremlinScriptEngineManager(ClassLoader loader)
CachedGremlinScriptEngineManager(Set<String> allowedEngines)	Creates a cached manager with an allowlist of engine names.

Method Summary

Modifier and Type	Method	Description
GremlinScriptEngine	getEngineByExtension(String extension)	Gets a GremlinScriptEngine from cache or creates a new one from the GremlinScriptEngineFactory.
GremlinScriptEngine	getEngineByMimeType(String mimeType)	Gets a GremlinScriptEngine from cache or creates a new one from the GremlinScriptEngineFactory.
GremlinScriptEngine	getEngineByName(String shortName)	Gets a GremlinScriptEngine from cache or creates a new one from the GremlinScriptEngineFactory.

Methods inherited from class org.apache.tinkerpop.gremlin.jsr223.DefaultGremlinScriptEngineManager

addPlugin, get, getBindings, getCustomizers, getEngineFactories, put, registerEngineExtension, registerEngineMimeType, registerEngineName, setBindings

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

CachedGremlinScriptEngineManager

public CachedGremlinScriptEngineManager()

See Also:

• DefaultGremlinScriptEngineManager()

CachedGremlinScriptEngineManager

public CachedGremlinScriptEngineManager(ClassLoader loader)

See Also:

• DefaultGremlinScriptEngineManager(ClassLoader loader)

CachedGremlinScriptEngineManager

public CachedGremlinScriptEngineManager(Set<String> allowedEngines)

Creates a cached manager with an allowlist of engine names.

See Also:

• DefaultGremlinScriptEngineManager(Set)

Method Details

getEngineByName

public GremlinScriptEngine getEngineByName(String shortName)

Gets a GremlinScriptEngine from cache or creates a new one from the GremlinScriptEngineFactory.

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 DefaultGremlinScriptEngineManager.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.

Specified by:

getEngineByName in interface GremlinScriptEngineManager

Overrides:

getEngineByName in class DefaultGremlinScriptEngineManager

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

getEngineByExtension

public GremlinScriptEngine getEngineByExtension(String extension)

Gets a GremlinScriptEngine from cache or creates a new one from the GremlinScriptEngineFactory.

Look up and create a GremlinScriptEngine for a given extension. The algorithm used by DefaultGremlinScriptEngineManager.getEngineByName(String) is used except that the search starts by looking for a GremlinScriptEngineFactory registered to handle the given extension using DefaultGremlinScriptEngineManager.registerEngineExtension(String, GremlinScriptEngineFactory).

Specified by:

getEngineByExtension in interface GremlinScriptEngineManager

Overrides:

getEngineByExtension in class DefaultGremlinScriptEngineManager

Returns:

The engine to handle scripts with this extension. Returns null if not found.

getEngineByMimeType

public GremlinScriptEngine getEngineByMimeType(String mimeType)

Gets a GremlinScriptEngine from cache or creates a new one from the GremlinScriptEngineFactory.

Look up and create a GremlinScriptEngine for a given mime type. The algorithm used by DefaultGremlinScriptEngineManager.getEngineByName(String) is used except that the search starts by looking for a GremlinScriptEngineFactory registered to handle the given mime type using DefaultGremlinScriptEngineManager.registerEngineMimeType(String, GremlinScriptEngineFactory).

Specified by:

getEngineByMimeType in interface GremlinScriptEngineManager

Overrides:

getEngineByMimeType in class DefaultGremlinScriptEngineManager

Parameters:

mimeType - The given mime type

Returns:

The engine to handle scripts with this mime type. Returns null if not found.