scriptable.java

来自「提供ESB 应用mule源代码 提供ESB 应用mule源代码」· Java 代码 · 共 314 行

/*
 * $Id: Scriptable.java 11968 2008-06-06 04:06:18Z dfeist $
 * --------------------------------------------------------------------------------------
 * Copyright (c) MuleSource, Inc.  All rights reserved.  http://www.mulesource.com
 *
 * The software in this package is published under the terms of the CPAL v1.0
 * license, a copy of which has been included with this distribution in the
 * LICENSE.txt file.
 */

package org.mule.module.scripting.component;

import org.mule.MuleServer;
import org.mule.DefaultMuleEventContext;
import org.mule.transport.NullPayload;
import org.mule.api.MuleEvent;
import org.mule.api.lifecycle.Initialisable;
import org.mule.api.lifecycle.InitialisationException;
import org.mule.api.transformer.TransformerException;
import org.mule.api.transport.MessageAdapter;
import org.mule.config.i18n.CoreMessages;
import org.mule.config.i18n.MessageFactory;
import org.mule.util.CollectionUtils;
import org.mule.util.IOUtils;
import org.mule.util.StringUtils;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringReader;
import java.util.Iterator;
import java.util.Map;
import java.util.Properties;

import javax.script.Bindings;
import javax.script.Compilable;
import javax.script.CompiledScript;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * A JSR 223 Script service. Allows any JSR 223 compliant script engines such as
 * JavaScript, Groovy or Rhino to be embedded as Mule components.
 */
public class Scriptable implements Initialisable
{
    /** The actual body of the script */
    private String scriptText;
    
    /** A file from which the script will be loaded */
    private String scriptFile;
    
    /** Parameters to be made available to the script as variables */
    private Properties properties;

    /** The name of the JSR 223 scripting engine (e.g., "groovy") */
    private String scriptEngineName;

    /////////////////////////////////////////////////////////////////////////////
    // Internal variables, not exposed as properties
    /////////////////////////////////////////////////////////////////////////////

    /** A compiled version of the script, if the scripting engine supports it */
    private CompiledScript compiledScript;
    
    private ScriptEngine scriptEngine;
    private ScriptEngineManager scriptEngineManager;
    
    protected transient Log logger = LogFactory.getLog(getClass());
    
    public void initialise() throws InitialisationException
    {
        scriptEngineManager = new ScriptEngineManager();

        // Create scripting engine
        if (scriptEngineName != null)
        {
            scriptEngine = createScriptEngineByName(scriptEngineName);
            if (scriptEngine == null)
            {
                throw new InitialisationException(MessageFactory.createStaticMessage("Scripting engine '" + scriptEngineName + "' not found.  Available engines are: " + listAvailableEngines()), this);
            }
        }
        // Determine scripting engine to use by file extension
        else if (scriptFile != null)
        {
            int i = scriptFile.lastIndexOf(".");
            if (i > -1)
            {
                logger.info("Script Engine name not set. Guessing by file extension.");
                String ext = scriptFile.substring(i + 1);
                scriptEngine = createScriptEngineByExtension(ext);
                if (scriptEngine == null)
                {
                    throw new InitialisationException(MessageFactory.createStaticMessage("File extension '" + ext + "' does not map to a scripting engine.  Available engines are: " + listAvailableEngines()), this);
                }
                else
                {
                    setScriptEngineName(scriptEngine.getFactory().getEngineName());
                }
            }
        }

        Reader script;
        // Load script from variable
        if (StringUtils.isNotBlank(scriptText))
        {
            script = new StringReader(scriptText);
        }
        // Load script from file
        else if (scriptFile != null)
        {
            InputStream is;
            try
            {
                is = IOUtils.getResourceAsStream(scriptFile, getClass());
            }
            catch (IOException e)
            {
                throw new InitialisationException(CoreMessages.cannotLoadFromClasspath(scriptFile), e, this);
            }
            if (is == null)
            {
                throw new InitialisationException(CoreMessages.cannotLoadFromClasspath(scriptFile), this);
            }
            script = new InputStreamReader(is);
        }
        else
        {
            throw new InitialisationException(CoreMessages.propertiesNotSet("scriptText, scriptFile"), this);
        }

        // Pre-compile script if scripting engine supports compilation.
        if (scriptEngine instanceof Compilable)
        {
            try
            {
                compiledScript = ((Compilable) scriptEngine).compile(script);
            }
            catch (ScriptException e)
            {
                throw new InitialisationException(e, this);
            }
        }


    }

    public void populateDefaultBindings(Bindings bindings)
    {
        if (properties != null)
        {
            bindings.putAll((Map) properties);
        }
        bindings.put("log", logger);
        //A place holder for a retuen result if the script doesn't return a result.
        //The script can overwrite this binding
        bindings.put("result", NullPayload.getInstance());
        bindings.put("muleContext", MuleServer.getMuleContext());
    }

    public void populateBindings(Bindings bindings, Object payload)
    {
        populateDefaultBindings(bindings);
        bindings.put("payload", payload);
        //For backward compatability. Usually used by the script transformer since
        //src maps with the argument passed into the transformer
        bindings.put("src", payload);
    }
    
    public void populateBindings(Bindings bindings, MessageAdapter message)
    {
        populateDefaultBindings(bindings);
        bindings.put("message", message);
        //This will get overwritten if populateBindings(Bindings bindings, MuleEvent event) is called
        //and not this method directly.
        bindings.put("payload", message.getPayload());
        //For backward compatability
        bindings.put("src", message.getPayload());

        // Set any message properties as variables for the script.
        String propertyName;
        for (Iterator iterator = message.getPropertyNames().iterator(); iterator.hasNext();)
        {
            propertyName = (String)iterator.next();
            bindings.put(propertyName, message.getProperty(propertyName));
        }
    }

    public void populateBindings(Bindings bindings, MuleEvent event)
    {
        populateBindings(bindings, event.getMessage());
        bindings.put("originalPayload", event.getMessage().getPayload());

        try
        {
            bindings.put("payload", event.transformMessage());
        }
        catch (TransformerException e)
        {
            logger.warn(e);
        }
        
        bindings.put("eventContext", new DefaultMuleEventContext(event));
        bindings.put("id", event.getId());
        bindings.put("service", event.getService());
    }
    
    public Object runScript(Bindings bindings) throws ScriptException
    {
        Object result;
        if (compiledScript != null)
        {
            result = compiledScript.eval(bindings);
        }
        else
        {
            result = scriptEngine.eval(scriptText, bindings);
        }
        
        // The result of the script can be returned directly or it can
        // be set as the variable "result".
        if (result == null)
        {
            result = bindings.get("result");
        }
        return result;
    }

    protected ScriptEngine createScriptEngineByName(String name)
    {
        return scriptEngineManager.getEngineByName(name);
    }

    protected ScriptEngine createScriptEngineByExtension(String ext)
    {
        return scriptEngineManager.getEngineByExtension(ext);
    }

    protected String listAvailableEngines()
    {
        return CollectionUtils.toString(scriptEngineManager.getEngineFactories(), false);
    }

    ////////////////////////////////////////////////////////////////////////////////
    // Getters and setters
    ////////////////////////////////////////////////////////////////////////////////

    public String getScriptText()
    {
        return scriptText;
    }

    public void setScriptText(String scriptText)
    {
        this.scriptText = scriptText;
    }

    public String getScriptFile()
    {
        return scriptFile;
    }

    public void setScriptFile(String scriptFile)
    {
        this.scriptFile = scriptFile;
    }

    public void setScriptEngineName(String scriptEngineName)
    {
        this.scriptEngineName = scriptEngineName;
    }

    public String getScriptEngineName()
    {
        return scriptEngineName;
    }
    
    public Properties getProperties()
    {
        return properties;
    }

    public void setProperties(Properties properties)
    {
        this.properties = properties;
    }
    
    public ScriptEngine getScriptEngine()
    {
        return scriptEngine;
    }

    protected void setScriptEngine(ScriptEngine scriptEngine)
    {
        this.scriptEngine = scriptEngine;
    }

    protected CompiledScript getCompiledScript()
    {
        return compiledScript;
    }

    protected void setCompiledScript(CompiledScript compiledScript)
    {
        this.compiledScript = compiledScript;
    }
}