io.mandrel.script.ScriptingService.java Source code

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Here is the source code for io.mandrel.script.ScriptingService.java

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/*
 * Licensed to Mandrel under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Mandrel 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 io.mandrel.script;

import io.mandrel.blob.BlobMetadata;

import java.util.concurrent.Callable;

import javax.script.Compilable;
import javax.script.CompiledScript;
import javax.script.ScriptContext;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.SimpleScriptContext;

import lombok.extern.slf4j.Slf4j;

import org.springframework.stereotype.Component;

import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;

@Component
@Slf4j
public class ScriptingService {

    private final Cache<Integer, CompiledScript> scripts;

    private final ScriptEngineManager sem;

    public ScriptingService() {
        ClassLoader classLoader = getClass().getClassLoader();

        sem = new ScriptEngineManager(classLoader);
        scripts = CacheBuilder.newBuilder().build();

        sem.getEngineFactories().stream().forEach(factory -> {
            log.debug("Engine : {}, version: {}, threading: {}", factory.getEngineName(),
                    factory.getEngineVersion(), factory.getParameter("THREADING"));
        });
    }

    public Object execScript(String engineName, final String script, BlobMetadata data, Object input)
            throws Exception {

        final ScriptEngine engine = getEngineByName(engineName);

        if (engine == null) {
            throw new UnknownScriptEngineException();
        }

        ScriptContext bindings = getBindings(data, input);

        return execScript(script, engine, bindings);
    }

    public Object execScript(final String script, final ScriptEngine engine, ScriptContext bindings)
            throws Exception {
        if (engine instanceof Compilable) {
            CompiledScript compiled = scripts.get(script.hashCode(), new Callable<CompiledScript>() {
                public CompiledScript call() throws Exception {
                    return ((Compilable) engine).compile(script);
                }
            });
            return compiled.eval(bindings);
        } else {
            return engine.eval(script, bindings);
        }
    }

    public ScriptContext getBindings(BlobMetadata data, Object input) {
        ScriptContext bindings = new SimpleScriptContext();
        bindings.setAttribute("input", input, ScriptContext.ENGINE_SCOPE);
        bindings.setAttribute("uri", data.getUri(), ScriptContext.ENGINE_SCOPE);
        return bindings;
    }

    public ScriptEngine getEngineByName(String engineName) {
        return sem.getEngineByName(engineName);
    }
}