package org.andromda.templateengines.freemarker;
import java.io.IOException;
import java.io.StringReader;
import java.io.StringWriter;
import java.io.Writer;
import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import freemarker.template.Configuration;
import freemarker.template.ObjectWrapper;
import freemarker.template.Template;
import org.andromda.core.common.AndroMDALogger;
import org.andromda.core.common.ExceptionUtils;
import org.andromda.core.templateengine.TemplateEngine;
import org.andromda.core.templateengine.TemplateEngineException;
import org.apache.log4j.Appender;
import org.apache.log4j.FileAppender;
import org.apache.log4j.Logger;
import org.apache.log4j.PatternLayout;
/**
* The TemplateEngine implementation for the FreeMarker template processor.
*
* @author Chad Brandon
* @author Olaf Muliawan
* @author Matthias Bohlen (usage of context classloader so that it works in Maven environments)
* @see http://www.freemarker.org
*/
public class FreeMarkerTemplateEngine implements TemplateEngine
{
/**
* @see org.andromda.core.templateengine.TemplateEngine#init(java.lang.String)
*/
public void initialize(String namespace) throws Exception
{
this.initLogger(namespace);
}
/**
* The main Configuration object of Freemarker.
*/
protected Configuration configuration = null;
/**
* @see org.andromda.core.templateengine.TemplateEngine#processTemplate(java.lang.String,
* java.util.Map, java.io.Writer)
*/
public void processTemplate(String templateFile, Map templateObjects, Writer output) throws Exception
{
ExceptionUtils.checkEmpty("templateFile", templateFile);
ExceptionUtils.checkNull("output", output);
if (this.configuration == null)
{
this.configuration = new Configuration();
// tell FreeMarker it should use the ContextClassLoader when
// searching for templates
this.configuration.setTemplateLoader(new ContextResourceLoader());
// use Bean Wrapper, in order to get maximal reflection
// capabilities
this.configuration.setObjectWrapper(ObjectWrapper.BEANS_WRAPPER);
}
// create the template
final Template template = this.configuration.getTemplate(templateFile);
if (templateObjects == null)
{
templateObjects = new HashMap();
}
// - merge data model with template
template.process(templateObjects, output);
}
/**
* Template loader which accesses the context classloader because otherwise
* templates will not be found properly in a multi-classloader environment.
*/
private static class ContextResourceLoader extends freemarker.cache.URLTemplateLoader
{
protected URL getURL(String name)
{
return Thread.currentThread().getContextClassLoader().getResource(name);
}
}
/**
* @see org.andromda.core.templateengine.TemplateEngine#shutdown()
*/
public void shutdown()
{
this.shutdownLogger();
this.configuration = null;
}
/**
* Stores the macro libraries the template.
*/
private List macroLibraries = new ArrayList();
/**
* @see org.andromda.core.templateengine.TemplateEngine#getMacroLibraries()
*/
public List getMacroLibraries()
{
return this.macroLibraries;
}
/**
* @see org.andromda.core.templateengine.TemplateEngine#addMacroLibrary(java.lang.String)
*/
public void addMacroLibrary(String macroLibrary)
{
this.macroLibraries.add(macroLibrary);
}
/**
* @see org.andromda.core.templateengine.TemplateEngine#setMergeLocation(java.lang.String)
*/
public void setMergeLocation(String mergeLocation)
{
}
/**
* The name of the temporary string template.
*/
private static final String STRING_TEMPLATE = "stringTemplate";
/**
* @see org.andromda.core.templateengine.TemplateEngine#getEvaluatedExpression(java.lang.String,
* java.util.Map)
*/
public String getEvaluatedExpression(final String expression, Map templateObjects)
{
try
{
// - create the template
final Template template = new Template(STRING_TEMPLATE, new StringReader(expression), new Configuration());
if (templateObjects == null)
{
templateObjects = new HashMap();
}
final StringWriter output = new StringWriter();
// - merge data model with template
template.process(templateObjects, output);
return output.toString();
}
catch (final Throwable throwable)
{
throw new TemplateEngineException(throwable);
}
}
protected static Logger logger = null;
/**
* Opens a log file for this plugin.
*
* @throws IOException
* if the file cannot be opened
*/
private void initLogger(String pluginName) throws IOException
{
logger = AndroMDALogger.getNamespaceLogger(pluginName);
logger.setAdditivity(false);
FileAppender appender = new FileAppender(new PatternLayout("%-5p %d - %m%n"), AndroMDALogger
.getNamespaceLogFileName(pluginName), true);
logger.addAppender(appender);
}
/**
* Shutdown the associated logger.
*/
private void shutdownLogger()
{
Enumeration appenders = logger.getAllAppenders();
while (appenders.hasMoreElements())
{
Appender appender = (Appender) appenders.nextElement();
if (appender.getName() != null)
{
appender.close();
}
}
}
}