com.anrisoftware.resources.templates.worker.STTemplateWorker Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of resources-st Show documentation
Loads and caches ST4 resources.
There is a newer version: 4.7.0
/*
 * Copyright 2012-2014 Erwin Müller 
 *
 * This file is part of resources-st.
 *
 * resources-st 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.
 *
 * resources-st 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 Public License for more
 * details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with resources-st. If not, see .
 */
package com.anrisoftware.resources.templates.worker;

import static com.anrisoftware.resources.templates.worker.STTemplateWorkerFactory.DELIMITER_START_CHAR_PROPERTY;
import static com.anrisoftware.resources.templates.worker.STTemplateWorkerFactory.DELIMITER_STOP_CHAR_PROPERTY;
import static com.anrisoftware.resources.templates.worker.STTemplateWorkerFactory.ENCODING_PROPERTY;
import static org.apache.commons.lang3.ArrayUtils.remove;

import java.io.ObjectStreamException;
import java.io.Serializable;
import java.net.URL;
import java.util.List;
import java.util.Map;
import java.util.Properties;

import org.stringtemplate.v4.ST;
import org.stringtemplate.v4.STErrorListener;
import org.stringtemplate.v4.STGroupFile;
import org.stringtemplate.v4.compiler.STException;
import org.stringtemplate.v4.misc.STMessage;

import com.anrisoftware.propertiesutils.ContextProperties;
import com.anrisoftware.resources.api.ResourcesException;
import com.anrisoftware.resources.templates.api.AttributeRenderer;
import com.anrisoftware.resources.templates.api.TemplateWorker;
import com.google.inject.Inject;
import com.google.inject.assistedinject.Assisted;

/**
 * Template worker that is using a String
 * Template template engine.
 * 
 * @author Erwin Mueller, [email protected]
 * @since 1.0
 */
@SuppressWarnings("serial")
class STTemplateWorker implements TemplateWorker {

	private final STTemplateWorkerLogger log;

	private final ContextProperties properties;

	private final URL templateUrl;

	private final Map attributes;

	private transient STGroupFile groupFile;

	private transient ResourcesException error;

	/**
	 * @see STTemplateWorkerFactory#create(URL, Properties, Map)
	 */
	@Inject
	STTemplateWorker(STTemplateWorkerLogger logger, @Assisted URL templateUrl,
			@Assisted Properties properties,
			@Assisted Map attributes)
			throws ResourcesException {
		this.log = logger;
		this.templateUrl = templateUrl;
		this.properties = new ContextProperties(this, properties);
		this.attributes = attributes;
		createGroupFile();
	}

	private Object readResolve() throws ObjectStreamException {
		createGroupFile();
		return this;
	}

	private void createGroupFile() {
		this.groupFile = openGroupFile(templateUrl);
		setupRenderers(groupFile);
		groupFile.setListener(new STErrorListener() {

			@Override
			public void runTimeError(STMessage msg) {
				error = log.errorProcessTemplate(msg, templateUrl);
			}

			@Override
			public void internalError(STMessage msg) {
				error = log.errorProcessTemplate(msg, templateUrl);
			}

			@Override
			public void compileTimeError(STMessage msg) {
				error = log.errorProcessTemplate(msg, templateUrl);
			}

			@Override
			public void IOError(STMessage msg) {
				error = log.errorProcessTemplate(msg, templateUrl);
			}
		});
	}

	private void setupRenderers(STGroupFile group) {
		if (!attributes.containsKey(STTemplateWorkerFactory.RENDERERS_KEY)) {
			return;
		}
		@SuppressWarnings({ "unchecked", "rawtypes" })
		List renderers = (List) attributes
				.get(STTemplateWorkerFactory.RENDERERS_KEY);
		for (AttributeRenderer renderer : renderers) {
			group.registerRenderer(renderer.getAttributeType(), renderer);
		}
	}

	private STGroupFile openGroupFile(URL templateUrl)
			throws ResourcesException {
		String encoding;
		char startChar;
		char stopChar;
		encoding = properties.getProperty(ENCODING_PROPERTY);
		startChar = properties.getCharProperty(DELIMITER_START_CHAR_PROPERTY);
		stopChar = properties.getCharProperty(DELIMITER_STOP_CHAR_PROPERTY);
		try {
			return new STGroupFile(templateUrl, encoding, startChar, stopChar);
		} catch (STException e) {
			throw log.errorOpenGroupFile(e);
		}
	}

	@Override
	public Properties getProperties() {
		return properties;
	}

	@Override
	public Map getAttributes() {
		return attributes;
	}

	@Override
	public URL getURL() {
		return templateUrl;
	}

	/**
	 * @param name
	 *            the template group name and the template name if the
	 *            conditions apply: a) the specified data array is empty or b)
	 *            the data array contains only attribute name-value pairs.
	 * 
	 * @param data
	 *            the data array containing attribute-name-value pairs. The
	 *            first element {@code data[0]} can contain the name of the
	 *            template in the template group. If so, then the amount of
	 *            elements in the array must be odd. If the amount of elements
	 *            in the array is not odd then the data array does not contain
	 *            the template name as the first element.
	 */
	@Override
	public String process(String name, Object... data)
			throws ResourcesException {
		ST template = createTemplate(name, data);
		String rendered = renderTemplate(template);
		log.templateProcessed(name);
		return rendered;
	}

	private ST createTemplate(String templateName, Object... data)
			throws ResourcesException {
		templateName = getTemplateName(templateName, data);
		ST template = groupFile.getInstanceOf(templateName);
		log.checkTemplateCreated(template, templateName, templateUrl);
		throwErrors();
		setupTemplateAttributes(template, data);
		return template;
	}

	private void setupTemplateAttributes(ST template, Object[] data) {
		if (data.length % 2 != 0) {
			data = remove(data, 0);
		}
		for (int i = 0; i < data.length; i++) {
			template.add(data[i].toString(), data[++i]);
		}
	}

	private String getTemplateName(String templateName, Object[] data) {
		if (data.length == 0) {
			return templateName;
		} else if (data.length % 2 == 0) {
			return templateName;
		} else {
			return data[0].toString();
		}
	}

	private String renderTemplate(ST template) throws ResourcesException {
		String rendered = template.render();
		throwErrors();
		return rendered;
	}

	private void throwErrors() throws ResourcesException {
		if (error != null) {
			throw error;
		}
	}
}