com.kise.kairosdb.util.ScriptBuilder.java Source code

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Here is the source code for com.kise.kairosdb.util.ScriptBuilder.java

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/*
* Copyright 2015 Kratos Integral Systems Europe
*
* Licensed 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 com.kise.kairosdb.util;

import java.util.regex.Pattern;
import javax.script.Invocable;
import javax.script.ScriptEngine;
import javax.script.ScriptException;
import jdk.nashorn.api.scripting.NashornScriptEngineFactory;

/**
 *
 * @author Remi Dettai <rdettai at gmail.com>
 */
public class ScriptBuilder {
    public static final String ERROR_IN_SCRIPT_PARSING = "Error during script parsing, please check the syntax";
    private static final Pattern PATTERN = Pattern.compile("^((.*)([^a-zA-Z\\\\d]))?(return)([ (])(.*)",
            Pattern.DOTALL);

    /**
     * Bundles the script into a function f and builds it into an invocable object.
     * @param script
     * @param arguments
     * @return null if the script could not be built
     */
    public static Invocable buildScript(String script, String... arguments) {
        ScriptEngine engine;
        try {
            engine = new NashornScriptEngineFactory().getScriptEngine(new String[] { "--no-java" });
            engine.eval(bundleAsFonctionF(script, arguments));
        } catch (ScriptException e) {
            return null;
        }

        return (Invocable) engine;

    }

    public static String getScriptError(String script, String... arguments) {
        try {
            ScriptEngine engine = new NashornScriptEngineFactory().getScriptEngine(new String[] { "--no-java" });
            engine.eval(bundleAsFonctionF(script, arguments));
        } catch (ScriptException e) {
            return e.getMessage();
        }

        return null;

    }

    private static String bundleAsFonctionF(String script, String... arguments) {
        String argString = "";
        for (int i = 0; i < arguments.length - 1; i++)
            argString += (arguments[i] + ",");
        if (arguments.length > 0)
            argString += arguments[arguments.length - 1];

        String function;
        if (PATTERN.matcher(script).matches())
            function = "function f(" + argString + "){ " + script + " }";
        else
            function = "function f(" + argString + "){ return " + script + " }";
        return function;
    }

}