de.hasait.genesis.scriptgen.ScriptGenProcessor.java Source code

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Here is the source code for de.hasait.genesis.scriptgen.ScriptGenProcessor.java

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/*
 * Copyright (C) 2017 by Sebastian Hasait (sebastian at hasait dot de)
 *
 * 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 de.hasait.genesis.scriptgen;

import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import javax.annotation.processing.ProcessingEnvironment;
import javax.annotation.processing.SupportedOptions;
import javax.script.Invocable;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;

import jdk.nashorn.api.scripting.NashornScriptEngineFactory;
import org.apache.commons.lang3.StringUtils;

import de.hasait.genesis.base.AbstractGenesisProcessor;
import de.hasait.genesis.base.GeneratorEnv;

@SupportedOptions({ ScriptGenProcessor.OPTION___LOCATIONS })
public class ScriptGenProcessor extends AbstractGenesisProcessor {

    public static final String OPTION___LOCATIONS = "genesis.locations";

    public static final String SCRIPT_LOCATIONS_SPLIT = ";";

    private final List<String> _locations = new ArrayList<>();

    @Override
    public synchronized void init(final ProcessingEnvironment pProcessingEnv) {
        super.init(pProcessingEnv);

        _locations.add("genesis");
        final String rawLocations = processingEnv.getOptions().get(OPTION___LOCATIONS);
        if (rawLocations != null) {
            Collections.addAll(_locations, rawLocations.split(SCRIPT_LOCATIONS_SPLIT));
        }

        registerGenerator(ScriptGen.class, this::processScriptGen);
    }

    private ScriptEngine determineScriptEngine(final String pScriptFileExtension, final ClassLoader pClassLoader) {
        final ScriptEngine engine;
        final NashornScriptEngineFactory nashornScriptEngineFactory = new NashornScriptEngineFactory();
        if (nashornScriptEngineFactory.getExtensions().contains(pScriptFileExtension)) {
            engine = nashornScriptEngineFactory.getScriptEngine(pClassLoader);
        } else {
            final ScriptEngineManager factory = new ScriptEngineManager();
            engine = factory.getEngineByExtension(pScriptFileExtension);
        }
        return engine;
    }

    private void processScriptGen(final ScriptGen pScriptGenAnnotation, final GeneratorEnv pGeneratorEnv)
            throws Exception {
        final String scriptResourcePath = pScriptGenAnnotation.script();
        if (StringUtils.isBlank(scriptResourcePath)) {
            pGeneratorEnv.printError("Parameter \"script\" must not be blank");
            return;
        }

        final ClassLoader classLoader = getClass().getClassLoader();

        URL scriptFileURL = classLoader.getResource(scriptResourcePath);
        if (scriptFileURL == null) {
            for (final String scriptLocationString : _locations) {
                scriptFileURL = classLoader.getResource(scriptLocationString + "/" + scriptResourcePath);
                if (scriptFileURL != null) {
                    break;
                }
            }
        }
        if (scriptFileURL == null) {
            pGeneratorEnv.printError("Script \"%s\" not found", scriptResourcePath);
            return;
        }

        final int indexOfDot = scriptResourcePath.indexOf('.');
        if (indexOfDot <= 1) {
            pGeneratorEnv.printError("Script name \"%s\" must have an extension", scriptResourcePath);
            return;
        }

        final String scriptFileExtension = scriptResourcePath.substring(indexOfDot + 1);

        final ScriptEngine engine = determineScriptEngine(scriptFileExtension, classLoader);

        if (engine == null) {
            pGeneratorEnv.printError("Script extension \"%s\" unsupported", scriptFileExtension);
            return;
        }

        try (InputStream scriptFileIn = scriptFileURL.openStream();
                Reader scriptFileR = new InputStreamReader(scriptFileIn)) {
            engine.eval(scriptFileR);
            final ScriptEnv scriptEnv = new ScriptEnv(pGeneratorEnv, scriptFileURL, pScriptGenAnnotation.args());
            ((Invocable) engine).invokeFunction("generate", scriptEnv);
        }
    }

}