VelocityTemplateProcessorImpl.java

/*******************************************************************************
 * Copyright 2011 iovation
 * 
 * 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.javadrop;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.util.Map;
import java.util.Properties;

import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.plugin.logging.Log;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.Velocity;
import org.apache.velocity.exception.ResourceNotFoundException;

/**
 * This uses velocity to process scripts.
 * 
 * @author gcooperpdx
 * 
 */
public class VelocityTemplateProcessorImpl implements TemplateProcessor {
    /**
     * Logging for build output
     */
    private Log _mavenLog;

    public VelocityTemplateProcessorImpl(Log log) {
        this._mavenLog = log;
    }

    private Log getLog() {
        return _mavenLog;
    }

    /**
     * Process one of the templates, substituting variables defined in the pom.
     * 
     * @param inputTemplateFile
     *            File to be processed, without the '.vm'
     * @param convertedFile
     *            Filename, including directory, for the final file.
     */
    @Override
    public void applyVTemplate(File inputTemplateFile, File convertedFile,
            Map<String, String> templateParams) throws MojoExecutionException {
        VelocityContext velContext = new VelocityContext();
        for (Map.Entry<String, String> tParam : templateParams.entrySet()) {
            velContext.put(tParam.getKey(), tParam.getValue());
        }
        // Get the .vm templates from the classpath
        Properties props = new Properties();
        props.setProperty("resource.loader", "classpath");
        props.setProperty("classpath.resource.loader.class",
                "org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader");
        try {
            Velocity.init(props);
            File outputDirectory = convertedFile.getParentFile();
            outputDirectory.mkdirs();
            BufferedWriter writer = new BufferedWriter(new FileWriter(
                    convertedFile));

            Velocity.mergeTemplate(inputTemplateFile.getPath(), "UTF-8",
                    velContext, writer);
            writer.flush();
            writer.close();
        } catch (ResourceNotFoundException rex) {
            getLog().warn("Resource not found:" + inputTemplateFile.getAbsolutePath());
        } catch (Exception e) {
            getLog().error("Velocity processing problem", e);
            throw new MojoExecutionException(
                    "Velocity template processing problem within maven plugin");
        }
    }

}