package bboss.org.apache.velocity.texen;
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*/
import java.io.File;
import java.io.InputStream;
import java.io.FileInputStream;
import java.io.BufferedInputStream;
import java.io.Writer;
import java.io.FileWriter;
import java.io.IOException;
import java.io.StringWriter;
import java.io.OutputStreamWriter;
import java.io.BufferedWriter;
import java.io.FileOutputStream;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.Properties;
import bboss.org.apache.velocity.Template;
import bboss.org.apache.velocity.context.Context;
import bboss.org.apache.velocity.VelocityContext;
import bboss.org.apache.velocity.app.VelocityEngine;
import bboss.org.apache.velocity.util.ClassUtils;
/**
* A text/code generator class
*
* @author <a href="mailto:leon@opticode.co.za">Leon Messerschmidt</a>
* @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
* @version $Id: Generator.java 463298 2006-10-12 16:10:32Z henning $
*/
public class Generator
{
/**
* Where the texen output will placed.
*/
public static final String OUTPUT_PATH = "output.path";
/**
* Where the velocity templates live.
*/
public static final String TEMPLATE_PATH = "template.path";
/**
* Default properties file used for controlling the
* tools placed in the context.
*/
private static final String DEFAULT_TEXEN_PROPERTIES =
"bboss/org/apache/velocity/texen/defaults/texen.properties";
/**
* Default properties used by texen.
*/
private Properties props = new Properties();
/**
* Context used for generating the texen output.
*/
private Context controlContext;
/**
* Keep track of the file writers used for outputting
* to files. If we come across a file writer more
* then once then the additional output will be
* appended to the file instead of overwritting
* the contents.
*/
private Hashtable writers = new Hashtable();
/**
* The generator tools used for creating additional
* output withing the control template. This could
* use some cleaning up.
*/
private static Generator instance = new Generator();
/**
* This is the encoding for the output file(s).
*/
protected String outputEncoding;
/**
* This is the encoding for the input file(s)
* (templates).
*/
protected String inputEncoding;
/**
* Velocity engine.
*/
protected VelocityEngine ve;
/**
* Default constructor.
*/
private Generator()
{
setDefaultProps();
}
/**
* Create a new generator object with default properties.
*
* @return Generator generator used in the control context.
*/
public static Generator getInstance()
{
return instance;
}
/**
* Set the velocity engine.
* @param ve
*/
public void setVelocityEngine(VelocityEngine ve)
{
this.ve = ve;
}
/**
* Create a new generator object with properties loaded from
* a file. If the file does not exist or any other exception
* occurs during the reading operation the default properties
* are used.
*
* @param propFile properties used to help populate the control context.
*/
public Generator (String propFile)
{
try
{
BufferedInputStream bi = null;
try
{
bi = new BufferedInputStream (new FileInputStream (propFile));
props.load (bi);
}
finally
{
if (bi != null)
{
bi.close();
}
}
}
catch (IOException e)
{
System.err.println("Could not load " + propFile
+ ", falling back to defaults. ("
+ e.getMessage() + ")");
/*
* If something goes wrong we use default properties
*/
setDefaultProps();
}
}
/**
* Create a new Generator object with a given property
* set. The property set will be duplicated.
*
* @param props properties object to help populate the control context.
*/
public Generator (Properties props)
{
this.props = (Properties)props.clone();
}
/**
* Set default properties.
*/
protected void setDefaultProps()
{
ClassLoader classLoader = VelocityEngine.class.getClassLoader();
try
{
InputStream inputStream = null;
try
{
inputStream = classLoader.getResourceAsStream(
DEFAULT_TEXEN_PROPERTIES);
props.load( inputStream );
}
finally
{
if (inputStream != null)
{
inputStream.close();
}
}
}
catch (IOException ioe)
{
System.err.println("Cannot get default properties: " + ioe.getMessage());
}
}
/**
* Set the template path, where Texen will look
* for Velocity templates.
*
* @param templatePath template path for velocity templates.
*/
public void setTemplatePath(String templatePath)
{
props.put(TEMPLATE_PATH, templatePath);
}
/**
* Get the template path.
*
* @return String template path for velocity templates.
*/
public String getTemplatePath()
{
return props.getProperty(TEMPLATE_PATH);
}
/**
* Set the output path for the generated
* output.
* @param outputPath
*/
public void setOutputPath(String outputPath)
{
props.put(OUTPUT_PATH, outputPath);
}
/**
* Get the output path for the generated
* output.
*
* @return String output path for texen output.
*/
public String getOutputPath()
{
return props.getProperty(OUTPUT_PATH);
}
/**
* Set the output encoding.
* @param outputEncoding
*/
public void setOutputEncoding(String outputEncoding)
{
this.outputEncoding = outputEncoding;
}
/**
* Set the input (template) encoding.
* @param inputEncoding
*/
public void setInputEncoding(String inputEncoding)
{
this.inputEncoding = inputEncoding;
}
/**
* Returns a writer, based on encoding and path.
*
* @param path path to the output file
* @param encoding output encoding
* @return A Writer for this generator.
* @throws Exception
*/
public Writer getWriter(String path, String encoding) throws Exception {
Writer writer;
if (encoding == null || encoding.length() == 0 || encoding.equals("8859-1") || encoding.equals("8859_1")) {
writer = new FileWriter(path);
}
else
{
writer = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(path), encoding));
}
return writer;
}
/**
* Returns a template, based on encoding and path.
*
* @param templateName name of the template
* @param encoding template encoding
* @return A Template.
* @throws Exception
*/
public Template getTemplate(String templateName, String encoding) throws Exception {
Template template;
if (encoding == null || encoding.length() == 0 || encoding.equals("8859-1") || encoding.equals("8859_1")) {
template = ve.getTemplate(templateName);
}
else {
template = ve.getTemplate(templateName, encoding);
}
return template;
}
/**
* Parse an input and write the output to an output file. If the
* output file parameter is null or an empty string the result is
* returned as a string object. Otherwise an empty string is returned.
*
* @param inputTemplate input template
* @param outputFile output file
* @return The parsed file.
* @throws Exception
*/
public String parse (String inputTemplate, String outputFile)
throws Exception
{
return parse(inputTemplate, outputFile, null, null);
}
/**
* Parse an input and write the output to an output file. If the
* output file parameter is null or an empty string the result is
* returned as a string object. Otherwise an empty string is returned.
* You can add objects to the context with the objs Hashtable.
*
* @param inputTemplate input template
* @param outputFile output file
* @param objectID id for object to be placed in the control context
* @param object object to be placed in the context
* @return String generated output from velocity
* @throws Exception
*/
public String parse (String inputTemplate,
String outputFile,
String objectID,
Object object)
throws Exception
{
return parse(inputTemplate, null, outputFile, null, objectID, object);
}
/**
* Parse an input and write the output to an output file. If the
* output file parameter is null or an empty string the result is
* returned as a string object. Otherwise an empty string is returned.
* You can add objects to the context with the objs Hashtable.
*
* @param inputTemplate input template
* @param inputEncoding template encoding
* @param outputFile output file
* @param outputEncoding outputEncoding encoding of output file
* @param objectID id for object to be placed in the control context
* @param object object to be placed in the context
* @return String generated output from velocity
* @throws Exception
*/
public String parse (String inputTemplate,
String inputEncoding,
String outputFile,
String outputEncoding,
String objectID,
Object object)
throws Exception
{
if (objectID != null && object != null)
{
controlContext.put(objectID, object);
}
Template template = getTemplate(inputTemplate, inputEncoding != null ? inputEncoding : this.inputEncoding);
if (outputFile == null || outputFile.equals(""))
{
StringWriter sw = new StringWriter();
template.merge (controlContext,sw);
return sw.toString();
}
else
{
Writer writer = null;
if (writers.get(outputFile) == null)
{
/*
* We have never seen this file before so create
* a new file writer for it.
*/
writer = getWriter(
getOutputPath() + File.separator + outputFile,
outputEncoding != null ? outputEncoding : this.outputEncoding
);
/*
* Place the file writer in our collection
* of file writers.
*/
writers.put(outputFile, writer);
}
else
{
writer = (Writer) writers.get(outputFile);
}
VelocityContext vc = new VelocityContext( controlContext );
template.merge (vc,writer);
// commented because it is closed in shutdown();
//fw.close();
return "";
}
}
/**
* Parse the control template and merge it with the control
* context. This is the starting point in texen.
*
* @param controlTemplate control template
* @param controlContext control context
* @return String generated output
* @throws Exception
*/
public String parse (String controlTemplate, Context controlContext)
throws Exception
{
this.controlContext = controlContext;
fillContextDefaults(this.controlContext);
fillContextProperties(this.controlContext);
Template template = getTemplate(controlTemplate, inputEncoding);
StringWriter sw = new StringWriter();
template.merge (controlContext,sw);
return sw.toString();
}
/**
* Create a new context and fill it with the elements of the
* objs Hashtable. Default objects and objects that comes from
* the properties of this Generator object is also added.
*
* @param objs objects to place in the control context
* @return Context context filled with objects
*/
protected Context getContext (Hashtable objs)
{
fillContextHash (controlContext,objs);
return controlContext;
}
/**
* Add all the contents of a Hashtable to the context.
*
* @param context context to fill with objects
* @param objs source of objects
*/
protected void fillContextHash (Context context, Hashtable objs)
{
Enumeration enumeration = objs.keys();
while (enumeration.hasMoreElements())
{
String key = enumeration.nextElement().toString();
context.put (key, objs.get(key));
}
}
/**
* Add properties that will aways be in the context by default
*
* @param context control context to fill with default values.
*/
protected void fillContextDefaults (Context context)
{
context.put ("generator", instance);
context.put ("outputDirectory", getOutputPath());
}
/**
* Add objects to the context from the current properties.
*
* @param context control context to fill with objects
* that are specified in the default.properties
* file
*/
protected void fillContextProperties (Context context)
{
Enumeration enumeration = props.propertyNames();
while (enumeration.hasMoreElements())
{
String nm = (String) enumeration.nextElement();
if (nm.startsWith ("context.objects."))
{
String contextObj = props.getProperty (nm);
int colon = nm.lastIndexOf ('.');
String contextName = nm.substring (colon+1);
try
{
Object o = ClassUtils.getNewInstance(contextObj);
context.put (contextName,o);
}
catch (Exception e)
{
e.printStackTrace();
//TO DO: Log Something Here
}
}
}
}
/**
* Properly shut down the generator, right now
* this is simply flushing and closing the file
* writers that we have been holding on to.
*/
public void shutdown()
{
Iterator iterator = writers.values().iterator();
while(iterator.hasNext())
{
Writer writer = (Writer) iterator.next();
try
{
writer.flush();
}
catch (IOException e)
{
/* do nothing */
}
try
{
writer.close();
}
catch (IOException e)
{
/* do nothing */
}
}
// clear the file writers cache
writers.clear();
}
}