DotGenerator.java

/**
 * Copyright (C) 2009 Original Authors
 *
 * This file is part of Spring ME.
 *
 * Spring ME is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2, or (at your option) any
 * later version.
 *
 * Spring ME 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 General Public License
 * along with Spring ME; see the file COPYING. If not, write to the Free
 * Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301 USA.
 *
 * Linking this library statically or dynamically with other modules is
 * making a combined work based on this library. Thus, the terms and
 * conditions of the GNU General Public License cover the whole
 * combination.
 *
 * As a special exception, the copyright holders of this library give you
 * permission to link this library with independent modules to produce an
 * executable, regardless of the license terms of these independent
 * modules, and to copy and distribute the resulting executable under
 * terms of your choice, provided that you also meet, for each linked
 * independent module, the terms and conditions of the license of that
 * module. An independent module is a module which is not derived from or
 * based on this library. If you modify this library, you may extend this
 * exception to your version of the library, but you are not obligated to
 * do so. If you do not wish to do so, delete this exception statement
 * from your version.
 */
package me.springframework.di.gen.dot;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.Writer;

import me.springframework.di.Configuration;
import me.springframework.di.antlr.InstanceAttributeRenderer;
import me.springframework.di.gen.factory.BeanFactoryGenerator;
import me.springframework.di.gen.factory.GeneratorException;

import org.antlr.stringtemplate.StringTemplate;
import org.antlr.stringtemplate.StringTemplateGroup;
import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;


/**
 * A class generating a dot file reflecting the DI configuration.
 * 
 * @author Wilfred Springer (wis)
 * 
 */
public class DotGenerator {

    /**
     * The template to use.
     */
    private static final String TEMPLATE = "/dot.stg";

    /**
     * The catalog providing style information for shapes.
     */
    private StyleCatalog catalog;

    /**
     * Constructs a new instance.
     * 
     * @param catalog
     *            The catalog providing shape style information.
     */
    public DotGenerator(StyleCatalog catalog) {
        super();
        this.catalog = catalog;
    }

    /**
     * Constructs a new instance. (Default styles.)
     */
    public DotGenerator() {
        this(new NullStyleCatalog());
    }

    /**
     * Generates a dot file from the {@link Configuration} passed in.
     * 
     * @param config
     *            The configuration.
     * @param targetFile
     *            The target file. (The file, nor the target directory need to
     *            exist yet.)
     * @throws GeneratorException
     *             If - for some reason - it turns out to be impossible to
     *             generate the dot file.
     */
    public final void generate(Configuration config, File targetFile) throws GeneratorException {
        Writer writer = null;
        try {
            FileUtils.forceMkdir(targetFile.getParentFile());
            writer = new FileWriter(targetFile);
            FileUtils.writeStringToFile(targetFile, process(config));
        } catch (IOException ioe) {
            throw new GeneratorException(ioe);
        } finally {
            IOUtils.closeQuietly(writer);
        }
    }

    /**
     * Generates the text to be written.
     * 
     * @param definitions
     *            The {@link Configuration} defining the configuration of wired
     *            objects.
     * @return The text of the output file.
     */
    public String process(Configuration definitions) {
        InputStream in = BeanFactoryGenerator.class.getResourceAsStream(TEMPLATE);
        Reader reader = new InputStreamReader(in);
        StringTemplateGroup group = new StringTemplateGroup(reader);
        StringTemplate template = group.getInstanceOf("template");
        template.registerRenderer(String.class, new InstanceAttributeRenderer(catalog));
        template.setAttribute("definitions", definitions);
        return template.toString();
    }

    /**
     * The interface allowing us to map type names to style information.
     * 
     */
    public interface StyleCatalog {

        /**
         * Returns the fill color for the shape representing the bean of the
         * type passed in.
         * 
         * @param type
         *            The type name of the bean for which we need its fill
         *            color.
         * @return The fill color. (A color name.)
         */
        String getColor(String type);

    }

    /**
     * A null implementation, allowing us to avoid having to pass in catalogs
     * when we don't want to.
     * 
     * @author Wilfred Springer (wis)
     * 
     */
    public static class NullStyleCatalog implements StyleCatalog {

        /*
         * (non-Javadoc)
         * @see me.springframework.di.gen.DotGenerator.StyleCatalog#getColor(java.lang.String)
         */
        public String getColor(String type) {
            return "white";
        }

    }

}