interactivespaces.service.template.internal.freemarker.FreemarkerTemplater.java Source code

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Here is the source code for interactivespaces.service.template.internal.freemarker.FreemarkerTemplater.java

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/**
 * Copyright (C) 2013 Google Inc.
 *
 * 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 interactivespaces.service.template.internal.freemarker;

import interactivespaces.InteractiveSpacesException;
import interactivespaces.service.template.Templater;

import com.google.common.io.Closeables;

import freemarker.template.Configuration;
import freemarker.template.DefaultObjectWrapper;
import freemarker.template.Template;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.Map;

/**
 * @author Keith M. Hughes
 */
public class FreemarkerTemplater implements Templater {

    /**
     * The directory containing the templates.
     */
    private final File templateDirectory;

    /**
     * The configuration used by Freemarker.
     */
    private Configuration freemarkerConfig;

    /**
     * Construct a new Freemarker templater.
     *
     * @param templateDirectory
     *          the directory containing the templates
     */
    public FreemarkerTemplater(File templateDirectory) {
        this.templateDirectory = templateDirectory;
    }

    @Override
    public void startup() {
        try {
            freemarkerConfig = new Configuration();
            freemarkerConfig.setDirectoryForTemplateLoading(templateDirectory);
            // Specify how templates will see the data-model. This is an
            // advanced topic... but just use this:
            freemarkerConfig.setObjectWrapper(new DefaultObjectWrapper());
        } catch (IOException e) {
            throw new InteractiveSpacesException("Cannot initialize Freemarker templater", e);
        }
    }

    @Override
    public void shutdown() {
        // Nothing to do
    }

    @Override
    public String instantiateTemplate(String templateName, Map<String, Object> data) {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        Writer out = new OutputStreamWriter(baos);
        try {
            Template template = freemarkerConfig.getTemplate(templateName);

            template.process(data, out);
            out.close();
        } catch (Exception e) {
            throw new InteractiveSpacesException(String.format("Could not instantiate template %s", templateName),
                    e);
        } finally {
            Closeables.closeQuietly(out);
        }

        return new String(baos.toString());
    }

    @Override
    public void writeTemplate(String templateName, Map<String, Object> data, File outputFile) {
        Writer out = null;
        try {
            Template template = freemarkerConfig.getTemplate(templateName);
            out = new FileWriter(outputFile);
            template.process(data, out);
            out.close();
        } catch (Exception e) {
            throw new InteractiveSpacesException(String.format("Could not instantiate template %s", templateName),
                    e);
        } finally {
            Closeables.closeQuietly(out);
        }
    }
}