/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.tinkerpop.gremlin.jsr223;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
/**
* A cache of standard {@code ScriptEngine} instances, instantiated by the standard {@code ScriptEngineManager}.
* These instances are NOT "Gremlin-enabled". See {@link SingleGremlinScriptEngineManager} for the analogous class
* that loads {@link GremlinScriptEngine} instances.
*
* @author Daniel Kuppitz (http://gremlin.guru)
* @author Stephen Mallette (http://stephen.genoprime.com)
*/
public final class ScriptEngineCache {
private ScriptEngineCache() {}
public final static String DEFAULT_SCRIPT_ENGINE = "gremlin-groovy";
private final static ScriptEngineManager SCRIPT_ENGINE_MANAGER = new ScriptEngineManager();
private final static Map<String, ScriptEngine> CACHED_ENGINES = new ConcurrentHashMap<>();
public static ScriptEngine get(final String engineName) {
return CACHED_ENGINES.compute(engineName, (key, engine) -> {
if (null == engine) {
engine = SCRIPT_ENGINE_MANAGER.getEngineByName(engineName);
if (null == engine) {
throw new IllegalArgumentException("There is no script engine with provided name: " + engineName);
}
}
return engine;
});
}
}