Struts example source code file (SiteGraph.java)

This example Struts source code file (SiteGraph.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Struts tags/keywords

bytearrayoutputstream, bytearrayoutputstream, could, dotrenderer, io, ioexception, ioexception, log, sitegraph, sitegraph, string, string, strutsexception, tgif, writer

The Struts SiteGraph.java source code

/*
 * $Id: SiteGraph.java 651946 2008-04-27 13:41:38Z apetrelli $
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.struts2.sitegraph;

import java.io.ByteArrayOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.Writer;

import org.apache.struts2.StrutsException;
import org.apache.struts2.sitegraph.renderers.DOTRenderer;

import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerFactory;

/**
 * // START SNIPPET: javadocs-intro
 * SiteGraph is a tool that renders out GraphViz-generated images depicting your
 * Struts-powered web application's flow. SiteGraph requires GraphViz be installed
 * and that the "dot" executable be in your command path. You can find GraphViz
 * at http://www.graphviz.org.
 * // END SNIPPET: javadocs-intro
 * <p/>
 * // START SNIPPET: javadocs-api
 * If you wish to use SiteGraph through its API rather than through the command line,
 * you can do that as well. All you need to do is create a new SiteGraph instance,
 * optionally specify a {@link Writer} to output the dot content to, and then call
 * {@link #prepare()}.
 * // END SNIPPET: javadocs-api
 */
public class SiteGraph {

    private static final Logger LOG = LoggerFactory.getLogger(SiteGraph.class);

    private String configDir;
    private String views;
    private String output;
    private String namespace;
    private Writer writer;

    public SiteGraph(String configDir, String views, String output, String namespace) {
        this.configDir = configDir;
        this.views = views;
        this.output = output;
        this.namespace = namespace;
    }

    public static void main(String[] args) throws IOException {
        LOG.info("SiteGraph starting...");

        if (args.length != 8 && args.length != 6) {
            InputStream is = SiteGraph.class.getResourceAsStream("sitegraph-usage.txt");
            byte[] buffer = new byte[2048];
            int length = -1;
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            while ((length = is.read(buffer)) != -1) {
                baos.write(buffer, 0, length);
            }
            is.close();
            baos.close();

            String usage = baos.toString();
            System.out.println(usage.replaceAll("//.*", ""));
            return;
        }

        String configDir = getArg(args, "config");
        String views = getArg(args, "views");
        String output = getArg(args, "output");
        String namespace = getArg(args, "ns");

        // START SNIPPET: example-api
        SiteGraph siteGraph = new SiteGraph(configDir, views, output, namespace);
        siteGraph.prepare();
        siteGraph.render();
        // END SNIPPET: example-api
    }

    private static String getArg(String[] args, String arg) {
        for (int i = 0; i < args.length; i++) {
            if (("-" + arg).equals(args[i]) && ((i + 1) < args.length)) {
                return args[i + 1];
            }
        }

        return "";
    }

    /**
     * Prepares the dot generated content and writes out to the provided writer
     * object. If no writer has been given, that a {@link FileWriter} pointing to "out.dot"
     * in the specified output directly shall be used.
     */
    public void prepare() {
        if (writer == null) {
            try {
                writer = new FileWriter(output + "/out.dot");
            } catch (IOException e) {
                throw new StrutsException(e);
            }
        }

        StrutsConfigRetriever.setConfiguration(configDir, views.split("[, ]+"));
        DOTRenderer renderer = new DOTRenderer(writer);
        renderer.render(namespace);
    }

    /**
     * Invokes the dot command, cause GraphViz to render out.dot in the form of out.gif,
     * located in the specified output directory. If an error occurs during this process,
     * the error is logged and the method completes without throwing an exception.
     */
    public void render() {
        try {
            Runtime.getRuntime().exec("dot -o" + output + "/out.gif -Tgif " + output + "/out.dot");
        } catch (IOException e) {
            LOG.error("Could not invoke dot", e);
        }
    }

    public void setWriter(Writer writer) {
        this.writer = writer;
    }
}