org.hbird.business.scripting.bean.ScriptExecutor.java Source code

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Here is the source code for org.hbird.business.scripting.bean.ScriptExecutor.java

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/**
 * Licensed to the Hummingbird Foundation (HF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The HF 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.hbird.business.scripting.bean;

import java.io.File;
import java.io.IOException;
import java.util.Set;

import javax.script.*;

import org.apache.commons.io.FileUtils;
import org.apache.log4j.Logger;
import org.hbird.business.scripting.ScriptComponent;
import org.hbird.exchange.core.EntityInstance;

/** 
 * The script executor will evaluate scripts. 
 * 
 * The executor receives the script as a component.
 */
public class ScriptExecutor {

    private static org.apache.log4j.Logger LOG = Logger.getLogger(ScriptExecutor.class);

    /** The configuration request defining the script to be executed. */
    protected ScriptComponent component = null;

    /** The script engine that will execute the script.*/
    protected ScriptEngine engine = null;

    public ScriptExecutor(ScriptComponent component) {
        this.component = component;

        ScriptEngineManager factory = new ScriptEngineManager();
        engine = factory.getEngineByName(component.format);

        engine.put("output", component.output);

        /** */
        if (component.script == null || component.script.equals("") == true) {

            /** Default root is the the resource folder of the current project. */
            String root = "src/main/resources/library/";
            if (System.getProperty("hbird.scriptlibrary") != null) {
                root = System.getProperty("hbird.scriptlibrary");
                if (root.endsWith("/") == false) {
                    root += "/";
                }
            }

            File file = new File(root + component.getScriptName() + ".js");
            if (file.exists() == false) {
                LOG.error("Failed to find script file '" + file.getAbsolutePath() + "'.");
                LOG.error(
                        "Use the runtime system property '-Dhbird.scriptlibrary=[path]' to point to the script library. Script will not be evaluated.");
            } else {
                try {
                    component.script = FileUtils.readFileToString(file);
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    /**
     * Method for receiving an input parameter and evaluating the value of the script. The
     * method will only evaluate the script if all input parameters have been received. 
     * 
     * @param in A parameter required to evaluate the script.
     * @return A parameter holding the return value of the script. May be null if the script could not evaluate.
     */
    public EntityInstance calculate(EntityInstance in) {

        LOG.debug("Script '" + component.getName() + "': received dependent object '" + in.getID()
                + "' with timestamp '.");

        EntityInstance returnValue = null;

        try {
            /** Bind the parameter to the script. */
            if (component.inputBinding.get(in.getID()) == null) {
                LOG.error("Script '" + component.getID()
                        + "': Error in binding of parameters. The runtime parameter '" + in.getID()
                        + "' was received, but has not been bound to any script parameter.");
            } else {
                engine.put(component.inputBinding.get(in.getID()), in);

                /** Check if a binding has been created for all needed parameters. */
                if (ready()) {
                    LOG.info("Script '" + component.getID()
                            + "': All dependent values set. Evaluating script that will create object '"
                            + component.output.getID() + "'");
                    engine.eval(component.script);

                    /** The request output object has been bound to the engine. The script can
                     * thus update it directly. Only the timestamp and uuid should also be set. */
                    returnValue = component.output;
                    returnValue.setTimestamp(System.currentTimeMillis());
                    returnValue.setIssuedBy(this.component.getName());
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        return returnValue;
    }

    /**
     * Method to evaluate whether all required input parameters have been set.
     * 
     * @return True if all input parameters have been bound to the engine. Else false.
     */
    protected boolean ready() {
        for (String parameter : component.inputBinding.values()) {
            if (engine.getBindings(ScriptContext.ENGINE_SCOPE).containsKey(parameter) == false) {
                LOG.debug("Script '" + component.getName() + "' Still missing dependency '" + parameter + "'.");
                return false;
            }
        }

        return true;
    }

    public Set<String> getDependencies() {
        return component.inputBinding.keySet();
    }
}