/*
* Copyright 2005 Joe Walker
*
* 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.directwebremoting.create;
import java.io.File;
import java.io.RandomAccessFile;
import javax.servlet.ServletContext;
import org.apache.bsf.BSFException;
import org.apache.bsf.BSFManager;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.directwebremoting.WebContext;
import org.directwebremoting.WebContextFactory;
import org.directwebremoting.extend.AbstractCreator;
import org.directwebremoting.extend.Creator;
import org.directwebremoting.util.LocalUtil;
/**
* A creator that uses BeanShell to evaluate some script to create an object.
* @author Joe Walker [joe at getahead dot ltd dot uk]
* @author Dennis [devel at muhlesteins dot com]
*/
public class ScriptedCreator extends AbstractCreator implements Creator
{
/**
* Set up some defaults
*/
public ScriptedCreator()
{
// The default is <b>true</b>. This parameter is only used if scriptPath is
// used instead of script. When reloadable is true, ScriptedCreator will
// check to see if the script has been modified before returning the
// existing created class.
setCacheable(false);
}
/**
* The language that we are scripting in. Passed to BSF.
* @return Returns the language.
*/
public String getLanguage()
{
return language;
}
/**
* @param language The language to set.
*/
public void setLanguage(String language)
{
// It would be good to be able to check this, but this seems to fail
// almost all the time
// if (BSFManager.isLanguageRegistered(language))
// {
// throw new IllegalArgumentException(Messages.getString("ScriptedCreator.IllegalLanguage", language));
// }
this.language = language;
}
/**
* Are we caching the script (default: false)
* @return Returns the reloadable variable
*/
public boolean isReloadable()
{
return reloadable;
}
/**
* @param reloadable Whether or not to reload the script.
* The default is <b>true</b>. This parameter is only used if scriptPath is
* used instead of script. When reloadable is true, ScriptedCreator will
* check to see if the script has been modified before returning the
* existing created class.
*/
public void setReloadable(boolean reloadable)
{
this.reloadable = reloadable;
if (reloadable)
{
setCacheable(false);
}
}
/**
* Are we using dynamic classes (i.e. classes generated by BeanShell or
* similar) in which case we want to reuse class defs.
* @return Returns the useDynamicClasses flag state.
*/
public boolean isUseDynamicClasses()
{
return useDynamicClasses;
}
/**
* Are we using dynamic classes (i.e. classes generated by BeanShell or
* similar) in which case we want to reuse class definitions.
* @param useDynamicClasses The useDynamicClasses flag state.
*/
public void setUseDynamicClasses(boolean useDynamicClasses)
{
this.useDynamicClasses = useDynamicClasses;
}
/**
* @return Returns the path of the script.
*/
public String getScriptPath()
{
return scriptPath;
}
/**
* @param scriptPath Context relative path to script.
*/
public void setScriptPath(String scriptPath)
{
if (scriptSrc != null)
{
throw new IllegalArgumentException("Please specify either the script or scriptPath property but not both.");
}
this.scriptPath = scriptPath;
}
/**
* @return Whether or not the script (located at scriptPath) has been modified.
*/
private boolean scriptUpdated()
{
if (null == scriptPath)
{
return false;
}
ServletContext sc = WebContextFactory.get().getServletContext();
File scriptFile = new File(sc.getRealPath(scriptPath));
if (scriptModified < scriptFile.lastModified())
{
log.debug("Script has been updated.");
clazz = null; // make sure that this gets re-compiled.
return true;
}
return false;
}
/**
* @return Returns the script.
* @throws InstantiationException If we can't read from the requested script
*/
public String getScript() throws InstantiationException
{
if (scriptSrc != null)
{
return scriptSrc;
}
if (scriptPath == null)
{
throw new InstantiationException("Missing or empty script.");
}
if (cachedScript != null && (!reloadable || !scriptUpdated()))
{
return cachedScript;
}
// load the script from the path
log.debug("Loading Script from Path: " + scriptPath);
RandomAccessFile in = null;
try
{
ServletContext sc = WebContextFactory.get().getServletContext();
File scriptFile = new File(sc.getRealPath(scriptPath));
// This uses the platform default encoding. If there are complaints
// from people wanting to read script files that are not in the
// default platform encoding then we will need a new param that is
// used here.
scriptModified = scriptFile.lastModified();
in = new RandomAccessFile(scriptFile, "r");
byte[] bytes = new byte[(int) in.length()];
in.readFully(bytes);
cachedScript = new String(bytes);
return cachedScript;
}
catch (Exception ex)
{
log.error(ex.getMessage(), ex);
throw new InstantiationException("Missing or empty script.");
}
finally
{
LocalUtil.close(in);
}
}
/**
* @param scriptSrc The script to set.
*/
public void setScript(String scriptSrc)
{
if (scriptPath != null)
{
throw new IllegalArgumentException("Please specify either the script or scriptPath property but not both.");
}
if (scriptSrc == null || scriptSrc.trim().length() == 0)
{
throw new IllegalArgumentException("Please specify either the script or scriptPath property but not both.");
}
this.scriptSrc = scriptSrc;
}
/**
* What sort of class do we create?
* @param classname The name of the class
*/
public void setClass(String classname)
{
try
{
this.clazz = LocalUtil.classForName(classname);
}
catch (ClassNotFoundException ex)
{
throw new IllegalArgumentException("Class not found: " + classname, ex);
}
}
/* (non-Javadoc)
* @see org.directwebremoting.Creator#getType()
*/
public Class<?> getType()
{
if (clazz == null || (reloadable && scriptUpdated()))
{
try
{
clazz = getInstance().getClass();
}
catch (InstantiationException ex)
{
log.error("Failed to instansiate object to detect type.", ex);
return Object.class;
}
}
return clazz;
}
/* (non-Javadoc)
* @see org.directwebremoting.Creator#getInstance()
*/
public Object getInstance() throws InstantiationException
{
try
{
if (useDynamicClasses && clazz != null)
{
return clazz.newInstance();
}
BSFManager bsfman = new BSFManager();
try
{
WebContext context = WebContextFactory.get();
bsfman.declareBean("context", context, context.getClass());
}
catch (BSFException ex)
{
log.warn("Failed to register WebContext with scripting engine: " + ex.getMessage());
}
return bsfman.eval(language, (null == scriptPath ? "dwr.xml" : scriptPath), 0, 0, getScript());
}
catch (Exception ex)
{
throw new IllegalArgumentException("Failed to getInstance", ex);
}
}
/**
* The log stream
*/
private static final Log log = LogFactory.getLog(ScriptedCreator.class);
/**
* The cached type of object that we are creating.
*/
private Class<?> clazz = null;
/**
* The language that we are scripting in. Passed to BSF.
*/
private String language = null;
/**
* The script that we are asking BSF to execute in order to get an object.
*/
private String scriptSrc = null;
/**
* The path of the script we are asking BSF to execute.
*/
private String scriptPath = null;
/**
* Whether or not to reload the script. Only used if scriptPath is used.
* i.e.: An inline script is not reloadable
*/
private boolean reloadable = true;
/**
* By default we assume that our scripts do not create classes dynamically.
* If they do then we need to take some special care of them.
*/
private boolean useDynamicClasses = false;
/**
* Script modified time. Only used when scriptPath is used.
*/
private long scriptModified = -1;
/**
* Contents of script loaded from scriptPath
*/
private String cachedScript;
}