FreemarkerTemplatingServiceImpl.java

/*
 * Copyright 2018 Global Crop Diversity Trust
 *
 * 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.genesys.server.service.impl;

import java.io.StringReader;
import java.io.StringWriter;
import java.util.Map;

import org.genesys.server.service.FreemarkerTemplating;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.stereotype.Service;

import freemarker.ext.beans.BeansWrapper;
import freemarker.template.Configuration;
import freemarker.template.Template;
import freemarker.template.TemplateExceptionHandler;

/**
 * Templating with Freemarker.
 *
 * @author Matija Obreza
 */
@Service
public class FreemarkerTemplatingServiceImpl implements FreemarkerTemplating, InitializingBean {

    private Configuration freeMarkerCfg;

    @Override
    public void afterPropertiesSet() throws Exception {
        // Create your Configuration instance, and specify if up to what FreeMarker
        // version (here 2.3.27) do you want to apply the fixes that are not 100%
        // backward-compatible. See the Configuration JavaDoc for details.
        final Configuration cfg = new Configuration(Configuration.VERSION_2_3_23);

        cfg.setClassForTemplateLoading(this.getClass(), "/freemarker/");

        // Set the preferred charset template files are stored in. UTF-8 is
        // a good choice in most applications:
        cfg.setDefaultEncoding("UTF-8");

        // Sets how errors will appear.
        // During web page *development* TemplateExceptionHandler.HTML_DEBUG_HANDLER is
        // better.
        cfg.setTemplateExceptionHandler(TemplateExceptionHandler.RETHROW_HANDLER);

        // Don't log exceptions inside FreeMarker that it will thrown at you anyway:
        cfg.setLogTemplateExceptions(false);

        BeansWrapper objectWrapper = (BeansWrapper) cfg.getObjectWrapper();
        cfg.setSharedVariable("statics", objectWrapper.getStaticModels());

        this.freeMarkerCfg = cfg;
    }

    /**
     * Process template.
     *
     * @param template the template
     * @param root the root
     * @return the string
     * @throws FreemarkerException the template exception
     */
    @Override
    public String processTemplate(final String template, final Map<?, ?> root) throws FreemarkerException {
        try {
            final Template temp = new Template("template-" + template.hashCode(), new StringReader(template), this.freeMarkerCfg);
            final StringWriter out = new StringWriter(2048);
            temp.process(root, out);
            return out.toString();
        } catch (final Throwable e) {
            throw new FreemarkerException(e);
        }
    }

    /**
     * Process template resource.
     *
     * @param template the template
     * @param root the root
     * @return the string
     * @throws FreemarkerException obviously
     */
    @Override
    public String processTemplateResource(final String template, final Map<?, ?> root) throws FreemarkerException {
        try {
            final Template temp = freeMarkerCfg.getTemplate(template);
            final StringWriter out = new StringWriter(2048);
            temp.process(root, out);
            return out.toString();
        } catch (final Throwable e) {
            throw new FreemarkerException(e);
        }
    }
}