org.nuiton.plugin.VelocityTemplateGenerator Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of helper-maven-plugin-api Show documentation
Simple maven mojo api for our projects
There is a newer version: 2.4.1
Show newest version
package org.nuiton.plugin;

/*
 * #%L
 * Helper Maven Plugin :: API
 * $Id: VelocityTemplateGenerator.java 876 2012-11-11 08:14:19Z tchemit $
 * $HeadURL: http://svn.nuiton.org/svn/maven-helper-plugin/tags/maven-helper-plugin-2.1/helper-maven-plugin-api/src/main/java/org/nuiton/plugin/VelocityTemplateGenerator.java $
 * %%
 * Copyright (C) 2009 - 2012 Codelutin, Tony Chemit
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as 
 * published by the Free Software Foundation, either version 3 of the 
 * License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Lesser Public License for more details.
 * 
 * You should have received a copy of the GNU General Lesser Public 
 * License along with this program.  If not, see
 * .
 * #L%
 */

import org.apache.maven.project.MavenProject;
import org.apache.velocity.Template;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.VelocityEngine;
import org.apache.velocity.runtime.resource.loader.JarResourceLoader;

import java.io.File;
import java.io.FileWriter;
import java.io.Writer;
import java.net.URISyntaxException;
import java.net.URL;
import java.util.Properties;

/**
 * Generator of template base on velocity.
 * 
 * TODO TC-20091011 should use plexus velocity component
 *
 * @author tchemit 
 * @since 1.3
 */
public class VelocityTemplateGenerator {

    protected VelocityEngine engine;

    protected MavenProject mavenProject;

    protected Template velocityTemplate;

    public VelocityTemplateGenerator(MavenProject mavenProject,
                                     URL template) throws URISyntaxException {

        if (mavenProject == null) {
            throw new IllegalArgumentException("mavenProject must not be null");
        }

        if (template == null) {
            throw new IllegalArgumentException("template must not be null");
        }

        this.mavenProject = mavenProject;

        Properties props = new Properties();

        String templateName;

        if (template.toURI().isOpaque()) {

            // template is in a jar

            props = new Properties();
            props.setProperty("resource.loader", "jar");
            props.setProperty(
                    "jar.resource.loader.description",
                    "Jar resource loader for default webstart templates"
            );
            props.setProperty(
                    "jar.resource.loader.class",
                    JarResourceLoader.class.getName()
                    //"org.apache.velocity.runtime.resource.loader.JarResourceLoader"
            );

            // obtain the jar url

            String url = template.toString();
            int i = url.indexOf("!");
            templateName = url.substring(i + 2);

            props.setProperty("jar.resource.loader.path",
                              url.substring(0, i + 2));

        } else {

            File f = new File(template.getFile());
            templateName = f.getName();

            props.setProperty("file.resource.loader.path", f.getParent());
        }

        try {
            engine = new VelocityEngine();
            engine.init(props);
        } catch (Exception e) {
            IllegalArgumentException iae = new IllegalArgumentException(
                    "Could not initialise Velocity");
            iae.initCause(e);
            throw iae;
        }

        try {
            velocityTemplate = engine.getTemplate(templateName);
        } catch (Exception e) {
            IllegalArgumentException iae =
                    new IllegalArgumentException(
                            "Could not load the template file from '" +
                            template + "'");
            iae.initCause(e);
            throw iae;
        }
    }

    public void generate(Properties context, Writer writer) throws Exception {

        VelocityContext vcontext = new VelocityContext();

        // Note: properties that contain dots will not be properly parsed by
        // Velocity. Should we replace dots with underscores ?
        addPropertiesToContext(System.getProperties(), vcontext);

        addPropertiesToContext(mavenProject.getProperties(), vcontext);
        addPropertiesToContext(context, vcontext);

        vcontext.put("project", mavenProject.getModel());

        try {
            velocityTemplate.merge(vcontext, writer);
            writer.flush();
        } catch (Exception e) {
            throw new Exception(
                    "Could not generate the template " +
                    velocityTemplate.getName() + ": " + e.getMessage(), e);
        } finally {
            writer.close();
        }
    }

    public void generate(Properties context, File outputFile) throws Exception {


        VelocityContext vcontext = new VelocityContext();

        // Note: properties that contain dots will not be properly parsed by
        // Velocity. Should we replace dots with underscores ?
        addPropertiesToContext(System.getProperties(), vcontext);

        addPropertiesToContext(mavenProject.getProperties(), vcontext);
        addPropertiesToContext(context, vcontext);

        vcontext.put("project", mavenProject.getModel());

        vcontext.put("outputFile", outputFile.getName());

        FileWriter writer = new FileWriter(outputFile);

        try {
            velocityTemplate.merge(vcontext, writer);
            writer.flush();
        } catch (Exception e) {
            throw new Exception(
                    "Could not generate the template " +
                    velocityTemplate.getName() + ": " + e.getMessage(), e);
        } finally {
            writer.close();
        }
    }

    protected void addPropertiesToContext(Properties properties,
                                          VelocityContext context) {

        for (Object o : properties.keySet()) {
            String key = (String) o;
            Object value = properties.get(key);
            context.put(key, value);
        }

    }
}