org.trafodion.rest.script.ScriptManager.java Source code

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Here is the source code for org.trafodion.rest.script.ScriptManager.java

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/**
 *(C) Copyright 2015 Hewlett-Packard Development Company, L.P.
 *
 * 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 org.trafodion.rest.script;

import java.util.List;
import java.util.HashMap;
import java.util.Map;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FilenameFilter;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineFactory;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;
import javax.script.CompiledScript;
import javax.script.Compilable;
import javax.script.Bindings;
import org.apache.log4j.Logger;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public final class ScriptManager {
    private static ScriptManager instance = null;
    private static final Log LOG = LogFactory.getLog(ScriptManager.class.getName());
    private ScriptEngineManager manager = new ScriptEngineManager();
    private Map<String, CompiledScript> m = new HashMap<String, CompiledScript>();
    private ScriptManagerWatcher watcherWorker = null;
    private static final String PYTHON_SUFFIX = ".py";
    private static final String DEFAULT_SCRIPT_NAME = "sys_shell" + PYTHON_SUFFIX;
    private static String restHome = null;

    public synchronized static ScriptManager getInstance() {
        if (instance == null) {
            instance = new ScriptManager();
        }
        return instance;
    }

    private ScriptManager() {
        List<ScriptEngineFactory> engines = manager.getEngineFactories();
        if (engines.isEmpty()) {
            LOG.warn("No scripting engines were found");
            return;
        }

        StringBuffer sb = new StringBuffer();
        sb.append("\nThe following " + engines.size() + " scripting engine(s) were found");

        for (ScriptEngineFactory engine : engines) {
            sb.append("\nEngine name: " + engine.getEngineName() + "\nVersion: " + engine.getEngineVersion()
                    + "\nLanguage: " + engine.getLanguageName());
            List<String> extensions = engine.getExtensions();
            if (extensions.size() > 0) {
                sb.append("\n\tEngine supports the following extensions:");
                for (String e : extensions) {
                    sb.append("\n\t\t" + e);
                }
            }
            List<String> shortNames = engine.getNames();
            if (shortNames.size() > 0) {
                sb.append("\n\tEngine has the following short names:");
                for (String n : engine.getNames()) {
                    sb.append("\n\t\t" + n);
                }
            }

            String[] params = { ScriptEngine.ENGINE, ScriptEngine.ENGINE_VERSION, ScriptEngine.LANGUAGE,
                    ScriptEngine.LANGUAGE_VERSION, ScriptEngine.NAME, "THREADING" };

            sb.append("\n\tEngine has the following parameters:");
            for (String param : params) {
                sb.append("\n\t\t" + param + " = " + engine.getParameter(param));
            }
            sb.append("\n=========================");
        }
        LOG.debug(sb.toString());

        //Get -Drest.home.dir
        restHome = System.getProperty("rest.home.dir");

        //Start the scripts directory watcher
        watcherWorker = new ScriptManagerWatcher("ScriptManagerWatcher", restHome + "/bin/scripts");
    }

    public void runScript(ScriptContext ctx) {
        String scriptName;

        if (ctx.getScriptName().length() == 0)
            scriptName = DEFAULT_SCRIPT_NAME;
        else if (!ctx.getScriptName().endsWith(".py"))
            scriptName = ctx.getScriptName() + PYTHON_SUFFIX;
        else
            scriptName = ctx.getScriptName();

        try {
            ScriptEngine engine = manager.getEngineByName("python");
            Bindings bindings = engine.createBindings();
            bindings.put("scriptcontext", ctx);
            if (engine instanceof Compilable) {
                CompiledScript script = m.get(scriptName);
                if (script == null) {
                    LOG.info("Compiling script " + scriptName);
                    Compilable compilingEngine = (Compilable) engine;
                    try {
                        script = compilingEngine.compile(new FileReader(restHome + "/bin/scripts/" + scriptName));
                    } catch (Exception e) {
                        LOG.warn(e.getMessage());
                    }
                    m.put(scriptName, script);
                }
                script.eval(bindings);
            } else {
                try {
                    engine.eval(new FileReader(restHome + "/bin/scripts/" + scriptName), bindings);
                } catch (Exception e) {
                    LOG.warn(e.getMessage());
                }
            }
        } catch (javax.script.ScriptException se) {
            LOG.warn(se.getMessage());
        }
    }

    public synchronized void removeScript(String name) {
        m.remove(name);
    }
}