com.alternatecomputing.jschnizzle.renderer.WebSequenceRenderer.java Source code

Introduction

Here is the source code for com.alternatecomputing.jschnizzle.renderer.WebSequenceRenderer.java

Source

/*
 * Copyright 2012 Alternate Computing Solutions 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 com.alternatecomputing.jschnizzle.renderer;

import java.awt.image.BufferedImage;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;

import org.apache.batik.transcoder.TranscoderException;
import org.apache.batik.transcoder.TranscoderInput;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.alternatecomputing.jschnizzle.model.Diagram;
import com.alternatecomputing.jschnizzle.model.DiagramStyle;
import com.alternatecomputing.jschnizzle.model.DiagramType;
import com.alternatecomputing.jschnizzle.renderer.util.BufferedImageTranscoder;
import com.alternatecomputing.jschnizzle.util.UIUtils;

public class WebSequenceRenderer implements Renderer {
    private static final Logger LOGGER = LoggerFactory.getLogger(UIUtils.class);
    private DiagramStyle[] styles = new DiagramStyle[] { new DiagramStyle("Plain UML", "default"),
            new DiagramStyle("Green Earth", "earth"), new DiagramStyle("Blue Modern", "modern-blue"),
            new DiagramStyle("MSCGen", "mscgen"), new DiagramStyle("Omegapple", "omegapple"),
            new DiagramStyle("QSD", "qsd"), new DiagramStyle("Rose", "rose"),
            new DiagramStyle("Round Green", "roundgreen"), new DiagramStyle("Napkin", "napkin") };

    public BufferedImage render(Diagram diagram) {
        String script = diagram.getScript();
        if (script == null) {
            throw new RendererException("no script defined.");
        }

        String style = diagram.getStyle().getValue();
        String baseURL = getBaseURL();

        try {
            // build parameter string
            String data = "style=" + style + "&format=svg&message=" + URLEncoder.encode(script, "UTF-8");

            // send the request
            URL url = new URL(baseURL);
            URLConnection conn = url.openConnection();
            conn.setDoOutput(true);
            OutputStreamWriter writer = new OutputStreamWriter(conn.getOutputStream());

            // write parameters
            writer.write(data);
            writer.flush();

            // get the response
            StringBuffer answer = new StringBuffer();
            BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            String line;
            while ((line = reader.readLine()) != null) {
                answer.append(line);
            }
            writer.close();
            reader.close();

            JSONObject json = JSONObject.fromString(answer.toString());

            HttpClient client = new HttpClient();
            String proxyHost = System.getProperty("http.proxyHost");
            String proxyPort = System.getProperty("http.proxyPort");
            if (StringUtils.isNotBlank(proxyHost) && StringUtils.isNotBlank(proxyPort)) {
                client.getHostConfiguration().setProxy(proxyHost, Integer.parseInt(proxyPort));
            }
            String getURI = baseURL + json.getString("img");
            GetMethod getMethod = new GetMethod(getURI);
            client.executeMethod(getMethod);
            String svgContents = getMethod.getResponseBodyAsString();
            getMethod.releaseConnection();
            LOGGER.debug(svgContents);

            diagram.setEncodedImage(svgContents);
            TranscoderInput input = new TranscoderInput(new ByteArrayInputStream(svgContents.getBytes()));
            BufferedImageTranscoder imageTranscoder = new BufferedImageTranscoder();
            imageTranscoder.transcode(input, null);

            // log any errors to the UI console
            JSONArray errors = json.getJSONArray("errors");
            for (int eIdx = 0; eIdx < errors.length(); ++eIdx) {
                LOGGER.error("JSON error: " + errors.getString(eIdx));
            }
            return imageTranscoder.getBufferedImage();

        } catch (MalformedURLException e) {
            throw new RendererException(e);
        } catch (IOException e) {
            throw new RendererException(e);
        } catch (TranscoderException e) {
            throw new RendererException(e);
        }
    }

    public boolean canRender(Diagram diagram) {
        return DiagramType.Sequence.equals(diagram.getType());
    }

    public DiagramStyle[] getStylesForType(DiagramType diagramType) {
        return styles;
    }

    private String getBaseURL() {
        String baseURL = System.getProperty("websequence.url");
        if (baseURL == null) {
            baseURL = "http://www.websequencediagrams.com/";
        }
        return baseURL;
    }

}